Theoretical prediction method of subcooled flow boiling CHF
Energy Technology Data Exchange (ETDEWEB)
Kwon, Young Min; Chang, Soon Heung [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)
1999-12-31
A theoretical critical heat flux (CHF ) model, based on lateral bubble coalescence on the heated wall, is proposed to predict the subcooled flow boiling CHF in a uniformly heated vertical tube. The model is based on the concept that a single layer of bubbles contacted to the heated wall prevents a bulk liquid from reaching the wall at near CHF condition. Comparisons between the model predictions and experimental data result in satisfactory agreement within less than 9.73% root-mean-square error by the appropriate choice of the critical void fraction in the bubbly layer. The present model shows comparable performance with the CHF look-up table of Groeneveld et al.. 28 refs., 11 figs., 1 tab. (Author)
Theoretical prediction method of subcooled flow boiling CHF
Energy Technology Data Exchange (ETDEWEB)
Kwon, Young Min; Chang, Soon Heung [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)
1998-12-31
A theoretical critical heat flux (CHF ) model, based on lateral bubble coalescence on the heated wall, is proposed to predict the subcooled flow boiling CHF in a uniformly heated vertical tube. The model is based on the concept that a single layer of bubbles contacted to the heated wall prevents a bulk liquid from reaching the wall at near CHF condition. Comparisons between the model predictions and experimental data result in satisfactory agreement within less than 9.73% root-mean-square error by the appropriate choice of the critical void fraction in the bubbly layer. The present model shows comparable performance with the CHF look-up table of Groeneveld et al.. 28 refs., 11 figs., 1 tab. (Author)
Theoretical bases analysis of scientific prediction on marketing principles
A.S. Rosohata
2012-01-01
The article presents an overview categorical apparatus of scientific predictions and theoretical foundations results of scientific forecasting. They are integral part of effective management of economic activities. The approaches to the prediction of scientists in different fields of Social science and the categories modification of scientific prediction, based on principles of marketing are proposed.
Prediction and Theoretical Investigation of the Morphology of ...
African Journals Online (AJOL)
Key Laboratory of Food Nutrition and Safety (Tianjin University of Science and ... Keywords: Erythromycin dihydrate, Morphology prediction, Theoretical ... For atomic charge assignments and .... interactions involved in its attachment energy, in.
Theoretical predictions for vehicular headways and their clusters
Krbálek, Milan
2013-11-01
This paper presents a derivation of analytical predictions for steady-state distributions of netto time gaps among clusters of vehicles moving inside a traffic stream. Using the thermodynamic socio-physical traffic model with short-ranged repulsion between particles (originally introduced in Krbálek and Helbing 2004 Physica A 333 370) we first derive the time-clearance distribution in the model and confront it with relation to the theoretical criteria for the acceptability of analytical clearance distributions. Consecutively, the approximating statistical distributions for the so-called time multi-clearances are calculated by means of the theory of functional convolutions. Moreover, all the theoretical surmises used during the above-mentioned calculations are evaluated by the statistical analysis of traffic data. The mathematical predictions acquired in this paper are thoroughly compared with relevant empirical quantities and discussed in the context of traffic theory.
Theoretical models to predict the mechanical behavior of thick composite tubes
Directory of Open Access Journals (Sweden)
Volnei Tita
2012-02-01
Full Text Available This paper shows theoretical models (analytical formulations to predict the mechanical behavior of thick composite tubes and how some parameters can influence this behavior. Thus, firstly, it was developed the analytical formulations for a pressurized tube made of composite material with a single thick ply and only one lamination angle. For this case, the stress distribution and the displacement fields are investigated as function of different lamination angles and reinforcement volume fractions. The results obtained by the theoretical model are physic consistent and coherent with the literature information. After that, the previous formulations are extended in order to predict the mechanical behavior of a thick laminated tube. Both analytical formulations are implemented as a computational tool via Matlab code. The results obtained by the computational tool are compared to the finite element analyses, and the stress distribution is considered coherent. Moreover, the engineering computational tool is used to perform failure analysis, using different types of failure criteria, which identifies the damaged ply and the mode of failure.
Theoretical prediction of crystallization kinetics of a supercooled Lennard-Jones fluid
Gunawardana, K. G. S. H.; Song, Xueyu
2018-05-01
The first order curvature correction to the crystal-liquid interfacial free energy is calculated using a theoretical model based on the interfacial excess thermodynamic properties. The correction parameter (δ), which is analogous to the Tolman length at a liquid-vapor interface, is found to be 0.48 ± 0.05 for a Lennard-Jones (LJ) fluid. We show that this curvature correction is crucial in predicting the nucleation barrier when the size of the crystal nucleus is small. The thermodynamic driving force (Δμ) corresponding to available simulated nucleation conditions is also calculated by combining the simulated data with a classical density functional theory. In this paper, we show that the classical nucleation theory is capable of predicting the nucleation barrier with excellent agreement to the simulated results when the curvature correction to the interfacial free energy is accounted for.
Darmon, David
2018-03-01
In the absence of mechanistic or phenomenological models of real-world systems, data-driven models become necessary. The discovery of various embedding theorems in the 1980s and 1990s motivated a powerful set of tools for analyzing deterministic dynamical systems via delay-coordinate embeddings of observations of their component states. However, in many branches of science, the condition of operational determinism is not satisfied, and stochastic models must be brought to bear. For such stochastic models, the tool set developed for delay-coordinate embedding is no longer appropriate, and a new toolkit must be developed. We present an information-theoretic criterion, the negative log-predictive likelihood, for selecting the embedding dimension for a predictively optimal data-driven model of a stochastic dynamical system. We develop a nonparametric estimator for the negative log-predictive likelihood and compare its performance to a recently proposed criterion based on active information storage. Finally, we show how the output of the model selection procedure can be used to compare candidate predictors for a stochastic system to an information-theoretic lower bound.
Theoretical model for cavitation erosion prediction in centrifugal pump impeller
International Nuclear Information System (INIS)
Rayan, M.A.; Mahgob, M.M.; Mostafa, N.H.
1990-01-01
Cavitation is known to have great effects on pump hydraulic and mechanical characteristics. These effects are mainly described by deviation in pump performance, increasing vibration and noise level as well as erosion of blade and casing materials. In the present work, only the hydrodynamic aspect of cavitation was considered. The efforts were directed toward the study of cavitation inception, cavity mechanics and material erosion in order to clarify the macrohydrodynamic aspects of cavitation erosive wear in real machines. As a result of this study, it was found that cavitation damage can be predicted from model data. The obtained theoretical results show good agreement with the experimental results obtained in this investigation and with results of some other investigations. The application of the findings of this work will help the design engineer in predicting the erosion rate, according to the different operating conditions. (author)
Comparison between theoretical predictions and tracking
International Nuclear Information System (INIS)
Ruggiero, A.G.
1985-01-01
The beam-beam interaction in a proton-antiproton collider has been an outstanding issue for a long time. Several theoretical predictions have been made in the past which range from the appearance of single beam-beam driven resonances to the onset of stochasticity and Arnold diffusion and the presence of chaotic trajectories. All these effects would cause a limit on the maximum strength of the beam-beam interaction, the so called beam-beam tune-shift, and speculative values have been offered ranging from as low as 0.0005 to as large as a fraction of unit. The lower limit could be caused in a more complicated situation where the external focussing forces which keep the two beams in the same storage ring are also modulated in time. These theoretical predictions have been compared with extensive computer tracking where the motion of the particles is followed turn after turn over very long periods of time. Though it is indeed possible to observe the formation of several resonances, nevertheless the onset of connected stochasticity seems to occur at too large beam-beam tune-shift to be of any practical relevance. Moreover no Arnold diffusion has been observed to have any practical significance. Chaotic trajectories have been found to embed the phase space in disconnected regions of appreciable extension. They increase in numbers considerably when time modulation of external focussing forces is added. 15 refs., 18 figs
Comparison between theoretical predictions and tracking
Energy Technology Data Exchange (ETDEWEB)
Ruggiero, A.G.
1985-01-01
The beam-beam interaction in a proton-antiproton collider has been an outstanding issue for a long time. Several theoretical predictions have been made in the past which range from the appearance of single beam-beam driven resonances to the onset of stochasticity and Arnold diffusion and the presence of chaotic trajectories. All these effects would cause a limit on the maximum strength of the beam-beam interaction, the so called beam-beam tune-shift, and speculative values have been offered ranging from as low as 0.0005 to as large as a fraction of unit. The lower limit could be caused in a more complicated situation where the external focussing forces which keep the two beams in the same storage ring are also modulated in time. These theoretical predictions have been compared with extensive computer tracking where the motion of the particles is followed turn after turn over very long periods of time. Though it is indeed possible to observe the formation of several resonances, nevertheless the onset of connected stochasticity seems to occur at too large beam-beam tune-shift to be of any practical relevance. Moreover no Arnold diffusion has been observed to have any practical significance. Chaotic trajectories have been found to embed the phase space in disconnected regions of appreciable extension. They increase in numbers considerably when time modulation of external focussing forces is added. 15 refs., 18 figs.
Physics of mind: Experimental confirmations of theoretical predictions.
Schoeller, Félix; Perlovsky, Leonid; Arseniev, Dmitry
2018-02-02
What is common among Newtonian mechanics, statistical physics, thermodynamics, quantum physics, the theory of relativity, astrophysics and the theory of superstrings? All these areas of physics have in common a methodology, which is discussed in the first few lines of the review. Is a physics of the mind possible? Is it possible to describe how a mind adapts in real time to changes in the physical world through a theory based on a few basic laws? From perception and elementary cognition to emotions and abstract ideas allowing high-level cognition and executive functioning, at nearly all levels of study, the mind shows variability and uncertainties. Is it possible to turn psychology and neuroscience into so-called "hard" sciences? This review discusses several established first principles for the description of mind and their mathematical formulations. A mathematical model of mind is derived from these principles. This model includes mechanisms of instincts, emotions, behavior, cognition, concepts, language, intuitions, and imagination. We clarify fundamental notions such as the opposition between the conscious and the unconscious, the knowledge instinct and aesthetic emotions, as well as humans' universal abilities for symbols and meaning. In particular, the review discusses in length evolutionary and cognitive functions of aesthetic emotions and musical emotions. Several theoretical predictions are derived from the model, some of which have been experimentally confirmed. These empirical results are summarized and we introduce new theoretical developments. Several unsolved theoretical problems are proposed, as well as new experimental challenges for future research. Copyright © 2017. Published by Elsevier B.V.
Theoretical predictions for side-chain liquid-crystal polymers and comparison to experiment
International Nuclear Information System (INIS)
Dowell, F.
1988-01-01
This paper presents results from a new unique microscopic molecular theory for side-chain liquid-crystalline polymers (LCPs) in the nematic (N) and multiple smectic-A (SA) LC phases and the isotropic (I) liquid phase. There are no ad hoc or arbitrarily adjustable parameters in this theory. The agreement between the theoretical and experimental values for various properties (including transition temperatures and quadratic characteristic radii) is very good (relative deviations between 0% and less than 6.2%). The theoretical results also show--for the first time--that the N and I phases for these LCPs involve the packing of plate-like sections of backbones and side chains and that the local bilayer SA phase involves packing of side-chains within a plate-like section. This type of packing is predicted to be typical for side-chain LCPs. This theory can predict--for the first time--whether the side chains of a molecule pack on the same or alternating opposite sides of the backbone and whether side chains on different molecules interdigitate (overlap) with each other. 13 refs., 1 fig., 4 tabs
International Nuclear Information System (INIS)
Perali, A.; Pieri, P.; Strinati, G.C.
2004-01-01
Theoretical predictions for the Bardeen-Cooper-Schrieffer-Bose-Einstein condensation crossover of trapped Fermi atoms are compared with recent experimental results for the density profiles of L 6 i. The calculations rest on a single theoretical approach that includes pairing fluctuations beyond mean-field. Excellent agreement with experimental results is obtained. Theoretical predictions for the zero-temperature chemical potential and gap at the unitarity limit are also found to compare extremely well with Quantum Monte Carlo simulations and with recent experimental results
Distinguishing prognostic and predictive biomarkers: An information theoretic approach.
Sechidis, Konstantinos; Papangelou, Konstantinos; Metcalfe, Paul D; Svensson, David; Weatherall, James; Brown, Gavin
2018-05-02
The identification of biomarkers to support decision-making is central to personalised medicine, in both clinical and research scenarios. The challenge can be seen in two halves: identifying predictive markers, which guide the development/use of tailored therapies; and identifying prognostic markers, which guide other aspects of care and clinical trial planning, i.e. prognostic markers can be considered as covariates for stratification. Mistakenly assuming a biomarker to be predictive, when it is in fact largely prognostic (and vice-versa) is highly undesirable, and can result in financial, ethical and personal consequences. We present a framework for data-driven ranking of biomarkers on their prognostic/predictive strength, using a novel information theoretic method. This approach provides a natural algebra to discuss and quantify the individual predictive and prognostic strength, in a self-consistent mathematical framework. Our contribution is a novel procedure, INFO+, which naturally distinguishes the prognostic vs predictive role of each biomarker and handles higher order interactions. In a comprehensive empirical evaluation INFO+ outperforms more complex methods, most notably when noise factors dominate, and biomarkers are likely to be falsely identified as predictive, when in fact they are just strongly prognostic. Furthermore, we show that our methods can be 1-3 orders of magnitude faster than competitors, making it useful for biomarker discovery in 'big data' scenarios. Finally, we apply our methods to identify predictive biomarkers on two real clinical trials, and introduce a new graphical representation that provides greater insight into the prognostic and predictive strength of each biomarker. R implementations of the suggested methods are available at https://github.com/sechidis. konstantinos.sechidis@manchester.ac.uk. Supplementary data are available at Bioinformatics online.
Time dependent patient no-show predictive modelling development.
Huang, Yu-Li; Hanauer, David A
2016-05-09
Purpose - The purpose of this paper is to develop evident-based predictive no-show models considering patients' each past appointment status, a time-dependent component, as an independent predictor to improve predictability. Design/methodology/approach - A ten-year retrospective data set was extracted from a pediatric clinic. It consisted of 7,291 distinct patients who had at least two visits along with their appointment characteristics, patient demographics, and insurance information. Logistic regression was adopted to develop no-show models using two-thirds of the data for training and the remaining data for validation. The no-show threshold was then determined based on minimizing the misclassification of show/no-show assignments. There were a total of 26 predictive model developed based on the number of available past appointments. Simulation was employed to test the effective of each model on costs of patient wait time, physician idle time, and overtime. Findings - The results demonstrated the misclassification rate and the area under the curve of the receiver operating characteristic gradually improved as more appointment history was included until around the 20th predictive model. The overbooking method with no-show predictive models suggested incorporating up to the 16th model and outperformed other overbooking methods by as much as 9.4 per cent in the cost per patient while allowing two additional patients in a clinic day. Research limitations/implications - The challenge now is to actually implement the no-show predictive model systematically to further demonstrate its robustness and simplicity in various scheduling systems. Originality/value - This paper provides examples of how to build the no-show predictive models with time-dependent components to improve the overbooking policy. Accurately identifying scheduled patients' show/no-show status allows clinics to proactively schedule patients to reduce the negative impact of patient no-shows.
Weir, Donald S.; Jumper, Stephen J.; Burley, Casey L.; Golub, Robert A.
1995-01-01
This document describes the theoretical methods used in the rotorcraft noise prediction system (ROTONET), which is a part of the NASA Aircraft Noise Prediction Program (ANOPP). The ANOPP code consists of an executive, database manager, and prediction modules for jet engine, propeller, and rotor noise. The ROTONET subsystem contains modules for the prediction of rotor airloads and performance with momentum theory and prescribed wake aerodynamics, rotor tone noise with compact chordwise and full-surface solutions to the Ffowcs-Williams-Hawkings equations, semiempirical airfoil broadband noise, and turbulence ingestion broadband noise. Flight dynamics, atmosphere propagation, and noise metric calculations are covered in NASA TM-83199, Parts 1, 2, and 3.
A Game Theoretic Approach to Cyber Attack Prediction
Energy Technology Data Exchange (ETDEWEB)
Peng Liu
2005-11-28
The area investigated by this project is cyber attack prediction. With a focus on correlation-based prediction, current attack prediction methodologies overlook the strategic nature of cyber attack-defense scenarios. As a result, current cyber attack prediction methodologies are very limited in predicting strategic behaviors of attackers in enforcing nontrivial cyber attacks such as DDoS attacks, and may result in low accuracy in correlation-based predictions. This project develops a game theoretic framework for cyber attack prediction, where an automatic game-theory-based attack prediction method is proposed. Being able to quantitatively predict the likelihood of (sequences of) attack actions, our attack prediction methodology can predict fine-grained strategic behaviors of attackers and may greatly improve the accuracy of correlation-based prediction. To our best knowledge, this project develops the first comprehensive framework for incentive-based modeling and inference of attack intent, objectives, and strategies; and this project develops the first method that can predict fine-grained strategic behaviors of attackers. The significance of this research and the benefit to the public can be demonstrated to certain extent by (a) the severe threat of cyber attacks to the critical infrastructures of the nation, including many infrastructures overseen by the Department of Energy, (b) the importance of cyber security to critical infrastructure protection, and (c) the importance of cyber attack prediction to achieving cyber security.
A Theoretical Model for the Prediction of Siphon Breaking Phenomenon
International Nuclear Information System (INIS)
Bae, Youngmin; Kim, Young-In; Seo, Jae-Kwang; Kim, Keung Koo; Yoon, Juhyeon
2014-01-01
A siphon phenomenon or siphoning often refers to the movement of liquid from a higher elevation to a lower one through a tube in an inverted U shape (whose top is typically located above the liquid surface) under the action of gravity, and has been used in a variety of reallife applications such as a toilet bowl and a Greedy cup. However, liquid drainage due to siphoning sometimes needs to be prevented. For example, a siphon breaker, which is designed to limit the siphon effect by allowing the gas entrainment into a siphon line, is installed in order to maintain the pool water level above the reactor core when a loss of coolant accident (LOCA) occurs in an open-pool type research reactor. In this paper, we develop a theoretical model to predict the siphon breaking phenomenon. In this paper, a theoretical model to predict the siphon breaking phenomenon is developed. It is shown that the present model predicts well the fundamental features of the siphon breaking phenomenon and undershooting height
A Theoretical Model for the Prediction of Siphon Breaking Phenomenon
Energy Technology Data Exchange (ETDEWEB)
Bae, Youngmin; Kim, Young-In; Seo, Jae-Kwang; Kim, Keung Koo; Yoon, Juhyeon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2014-10-15
A siphon phenomenon or siphoning often refers to the movement of liquid from a higher elevation to a lower one through a tube in an inverted U shape (whose top is typically located above the liquid surface) under the action of gravity, and has been used in a variety of reallife applications such as a toilet bowl and a Greedy cup. However, liquid drainage due to siphoning sometimes needs to be prevented. For example, a siphon breaker, which is designed to limit the siphon effect by allowing the gas entrainment into a siphon line, is installed in order to maintain the pool water level above the reactor core when a loss of coolant accident (LOCA) occurs in an open-pool type research reactor. In this paper, we develop a theoretical model to predict the siphon breaking phenomenon. In this paper, a theoretical model to predict the siphon breaking phenomenon is developed. It is shown that the present model predicts well the fundamental features of the siphon breaking phenomenon and undershooting height.
Atahan-Evrenk, Sule; Aspuru-Guzik, Alán
2014-01-01
The theoretical prediction and characterization of the solid-state structure of organic semiconductors has tremendous potential for the discovery of new high performance materials. To date, the theoretical analysis mostly relied on the availability of crystal structures obtained through X-ray diffraction. However, the theoretical prediction of the crystal structures of organic semiconductor molecules remains a challenge. This review highlights some of the recent advances in the determination of structure-property relationships of the known organic semiconductor single-crystals and summarizes a few available studies on the prediction of the crystal structures of p-type organic semiconductors for transistor applications.
Prediction of the theoretical capacity of non-aqueous lithium-air batteries
International Nuclear Information System (INIS)
Tan, Peng; Wei, Zhaohuan; Shyy, W.; Zhao, T.S.
2013-01-01
Highlights: • The theoretical capacity of non-aqueous lithium-air batteries is predicted. • Key battery design parameters are defined and considered. • The theoretical battery capacity is about 10% of the lithium capacity. • The battery mass and volume changes after discharge are also studied. - Abstract: In attempt to realistically assess the high-capacity feature of emerging lithium-air batteries, a model is developed for predicting the theoretical capacity of non-aqueous lithium-air batteries. Unlike previous models that were formulated by assuming that the active materials and electrolyte are perfectly balanced according to the electrochemical reaction, the present model takes account of the fraction of the reaction products (Li 2 O 2 and Li 2 O), the utilization of the onboard lithium metal, the utilization of the void volume of the porous cathode, and the onboard excess electrolyte. Results show that the gravimetric capacity increases from 1033 to 1334 mA h/g when the reaction product varies from pure Li 2 O 2 to pure Li 2 O. It is further demonstrated that the capacity declines drastically from 1080 to 307 mA h/g when the case of full utilization of the onboard lithium is altered to that only 10% of the metal is utilized. Similarly, the capacity declines from 1080 to 144 mA h/g when the case of full occupation of the cathode void volume by the reaction products is varied to that only 10% of the void volume is occupied. In general, the theoretical gravimetric capacity of typical non-aqueous lithium-air batteries falls in the range of 380–450 mA h/g, which is about 10–12% of the gravimetric capacity calculated based on the energy density of the lithium metal. The present model also facilitates the study of the effects of different parameters on the mass and volume change of non-aqueous lithium-air batteries
A theoretical model for predicting the Peak Cutting Force of conical picks
Directory of Open Access Journals (Sweden)
Gao Kuidong
2014-01-01
Full Text Available In order to predict the PCF (Peak Cutting Force of conical pick in rock cutting process, a theoretical model is established based on elastic fracture mechanics theory. The vertical fracture model of rock cutting fragment is also established based on the maximum tensile criterion. The relation between vertical fracture angle and associated parameters (cutting parameter and ratio B of rock compressive strength to tensile strength is obtained by numerical analysis method and polynomial regression method, and the correctness of rock vertical fracture model is verified through experiments. Linear regression coefficient between the PCF of prediction and experiments is 0.81, and significance level less than 0.05 shows that the model for predicting the PCF is correct and reliable. A comparative analysis between the PCF obtained from this model and Evans model reveals that the result of this prediction model is more reliable and accurate. The results of this work could provide some guidance for studying the rock cutting theory of conical pick and designing the cutting mechanism.
Rolling force prediction for strip casting using theoretical model and artificial intelligence
Institute of Scientific and Technical Information of China (English)
CAO Guang-ming; LI Cheng-gang; ZHOU Guo-ping; LIU Zhen-yu; WU Di; WANG Guo-dong; LIU Xiang-hua
2010-01-01
Rolling force for strip casting of 1Cr17 ferritic stainless steel was predicted using theoretical model and artificial intelligence.Solution zone was classified into two parts by kiss point position during casting strip.Navier-Stokes equation in fluid mechanics and stream function were introduced to analyze the rheological property of liquid zone and mushy zone,and deduce the analytic equation of unit compression stress distribution.The traditional hot rolling model was still used in the solid zone.Neural networks based on feedforward training algorithm in Bayesian regularization were introduced to build model for kiss point position.The results show that calculation accuracy for verification data of 94.67% is in the range of+7.0%,which indicates that the predicting accuracy of this model is very high.
International Nuclear Information System (INIS)
Leite Lopes, J.
1984-01-01
A report is given on the theoretical prediction and the experimental discovery of elementary particles from the electron to the weak intermediate vector bosons. The work of Lattes, Occhialini and Powell which put in evidence the pions predicted by Yukawa was the starting point of the modern experimental particle physics
International Nuclear Information System (INIS)
Lopes, J.L.
1984-01-01
A report is given on the theoretical prediction and the experimental discovery of elementary particles from the electron to the weak intermediate vector bosons. The work of Lattes, Occhialini and Powell which put in evidence the pions predicted by Yukawa was the starting point of the modern experimental particle physics. (Author) [pt
A theoretical model for predicting neutron fluxes for cyclic Neutron ...
African Journals Online (AJOL)
A theoretical model has been developed for prediction of thermal neutron fluxes required for cyclic irradiations of a sample to obtain the same activity previously used for the detection of any radionuclide of interest. The model is suitable for radiotracer production or for long-lived neutron activation products where the ...
Experimental tests and theoretical predictions for electroweak processes
International Nuclear Information System (INIS)
Martinelli, G.; Istituto Nazionale di Fisica Nucleare, Frascati
1987-01-01
In sect. 2, I will briefly recall the basic ingredients of the standard model and I will define the relevant parameters. Low-energy processes which enter into the determination of neutral-current couplings to fermions (in particular sin 2 θ W ) are presented in sect. 3. Radiative corrections to these processes are discussed in sect. 4. In sect. 5 the measurements of the W and Z 0 masses at the SPS collider are described and compared with theoretical predictions including one-loop radiative corrections. (orig./BBO)
Theoretical predictions for alpha particle spectroscopic strengths
International Nuclear Information System (INIS)
Draayer, J.P.
1975-01-01
Multinucleon transfers induced in heavy-ion reactions of the type ( 6 Li,d) furnish a selective probe with which to study the interplay between rotational and clustering phenomena so characteristic of the structure of the light sd-shell nuclei. For these nuclei, theoretical predictions for inter-band as well as intra-band transfer strengths can be made using recently tabulated results for angular momentum dependent SU 3 inclusion R 3 relative spectroscopic strengths and angular momentum independent SU 6 inclusion SU 3 coefficients of fractional parentage. The pure SU 3 (oscillator)-SU 4 (supermultiplet) symmetry limit agrees well with results obtained using available eigenfunctions determined in large shell model calculations. In particular, the scalar nature of a transferred ''alpha''-cluster insures that the effect of spatial symmetry admixtures in the initial and final states of the target and residual nuclei are minimized. Sum rule quantities provide a measure of the probable effects of symmetry breaking. Strength variations within a band are expected; transfers to core excited states are often favored. Results extracted from exact finite range DWBA analyses of ( 6 Li,d) data on 16 , 18 O, 20 , 21 , 22 Ne, 24 , 25 Mg show some anomalies in our understanding of the structure and/or reaction mechanisms. (18 figures) (U.S.)
A comparison of SAR ATR performance with information theoretic predictions
Blacknell, David
2003-09-01
Performance assessment of automatic target detection and recognition algorithms for SAR systems (or indeed any other sensors) is essential if the military utility of the system / algorithm mix is to be quantified. This is a relatively straightforward task if extensive trials data from an existing system is used. However, a crucial requirement is to assess the potential performance of novel systems as a guide to procurement decisions. This task is no longer straightforward since a hypothetical system cannot provide experimental trials data. QinetiQ has previously developed a theoretical technique for classification algorithm performance assessment based on information theory. The purpose of the study presented here has been to validate this approach. To this end, experimental SAR imagery of targets has been collected using the QinetiQ Enhanced Surveillance Radar to allow algorithm performance assessments as a number of parameters are varied. In particular, performance comparisons can be made for (i) resolutions up to 0.1m, (ii) single channel versus polarimetric (iii) targets in the open versus targets in scrubland and (iv) use versus non-use of camouflage. The change in performance as these parameters are varied has been quantified from the experimental imagery whilst the information theoretic approach has been used to predict the expected variation of performance with parameter value. A comparison of these measured and predicted assessments has revealed the strengths and weaknesses of the theoretical technique as will be discussed in the paper.
Mesoscopic structure prediction of nanoparticle assembly and coassembly: Theoretical foundation
Hur, Kahyun
2010-01-01
In this work, we present a theoretical framework that unifies polymer field theory and density functional theory in order to efficiently predict ordered nanostructure formation of systems having considerable complexity in terms of molecular structures and interactions. We validate our approach by comparing its predictions with previous simulation results for model systems. We illustrate the flexibility of our approach by applying it to hybrid systems composed of block copolymers and ligand coated nanoparticles. We expect that our approach will enable the treatment of multicomponent self-assembly with a level of molecular complexity that approaches experimental systems. © 2010 American Institute of Physics.
Large Hadron Collider (LHC) phenomenology, operational challenges and theoretical predictions
Gilles, Abelin R
2013-01-01
The Large Hadron Collider (LHC) is the highest-energy particle collider ever constructed and is considered "one of the great engineering milestones of mankind." It was built by the European Organization for Nuclear Research (CERN) from 1998 to 2008, with the aim of allowing physicists to test the predictions of different theories of particle physics and high-energy physics, and particularly prove or disprove the existence of the theorized Higgs boson and of the large family of new particles predicted by supersymmetric theories. In this book, the authors study the phenomenology, operational challenges and theoretical predictions of LHC. Topics discussed include neutral and charged black hole remnants at the LHC; the modified statistics approach for the thermodynamical model of multiparticle production; and astroparticle physics and cosmology in the LHC era.
Search for an interstellar Si2C molecule: A theoretical prediction
Indian Academy of Sciences (India)
63, No. 3. — journal of. September 2004 physics pp. 627–631. Search for an interstellar Si2C molecule: A theoretical prediction. SURESH CHANDRA. School of ... top molecule as its electric dipole moment µ lies along the axis of intermediate moment of inertia. Because of differences between the molecular parameters of.
Predicting Child Abuse Potential: An Empirical Investigation of Two Theoretical Frameworks
Begle, Angela Moreland; Dumas, Jean E.; Hanson, Rochelle F.
2010-01-01
This study investigated two theoretical risk models predicting child maltreatment potential: (a) Belsky's (1993) developmental-ecological model and (b) the cumulative risk model in a sample of 610 caregivers (49% African American, 46% European American; 53% single) with a child between 3 and 6 years old. Results extend the literature by using a…
Theoretical prediction of thermodynamic activities of liquid Au-Sn-X (X=Bi, Sb, Zn) solder systems
Energy Technology Data Exchange (ETDEWEB)
Awe, O.E., E-mail: draweoe2004@yahoo.com [Department of Physics, University of Ibadan, Ibadan (Nigeria); Department of Physics and Engineering Physics, Obafemi Awolowo University, Ile-Ife (Nigeria); Oshakuade, O.M. [Department of Physics, University of Ibadan, Ibadan (Nigeria)
2017-02-15
Molecular interaction volume model has been theoretically used to predict the thermodynamic activities of tin in Au-Sn-Bi and Au-Sn-Sb and the thermodynamic activity of zinc in Au-Sn-Zn at experimental temperatures 800 K, 873 K and 973 K, respectively. On the premise of agreement between the predicted and experimental values, we predicted the activities of the remaining two components in each of the three systems. This prediction was extended from three cross-sections to five cross-sections, and to temperature range 400–600 K, relevant for applications. Iso-activities were plotted. Results show that addition of tin reduces the tendency for chemical short range order in both Au-Sb and Au-Zn systems, while addition of gold and bismuth, respectively, reduce the tendency for chemical short range order in Sn-Sb and Au-Sn systems. Also, we found that, in the desired high-temperature region for applications, while a combination of chemical order and miscibility of components exist in both Au-Sn-Bi and Au-Sn-Zn systems, only chemical order exist in the Au-Sn-Sb system. Results, further show that increase in temperature reduces the phase separation tendency in Au-Sn-Bi system.
International Nuclear Information System (INIS)
Kotschenreuther, M.; Wong, H.V.; Lyster, P.L.; Berk, H.L.; Denton, R.; Miner, W.H.; Valanju, P.
1991-12-01
The theoretical transport from kinetic micro-instabilities driven by ion temperature gradients is a sheared slab is compared to experimentally inferred transport in L-mode tokamaks. Low noise gyrokinetic simulation techniques are used to obtain the ion thermal transport coefficient X. This X is much smaller than in experiments, and so cannot explain L-mode confinement. Previous predictions based on fluid models gave much greater X than experiments. Linear and nonlinear comparisons with the fluid model show that it greatly overestimates transport for experimental parameters. In addition, disagreements among previous analytic and simulation calculations of X in the fluid model are reconciled
International Nuclear Information System (INIS)
Kalinkin, B.N.; Gareev, F.A.
1999-01-01
It is shown that it is just Dubna that possesses the priority both in the recent synthesis of a superheavy nucleus with charge Z=114 (Flerov Laboratory of Nuclear Reactions, JINR) and in its theoretical prediction (Bogolyubov Laboratory of Theoretical Physics, JINR) made 33 years ago. Possible sizes of the 'island of stability' of superheavy nuclei are discussed
Theoretical predictions for pp and panti p elastic scattering in the TeV energy domain
International Nuclear Information System (INIS)
Bourrely, C.; Martin, A.
1984-01-01
We present theoretical predictions on total cross-sections and elastic scattering in the TeV energy domain obtained from the present experimental situation at the ISR and the panti p Collider. (orig.)
Czech Academy of Sciences Publication Activity Database
Bogdanić, Grozdana; Pavlíček, Jan; Wichterle, Ivan
2012-01-01
Roč. 42, SI (2012), s. 1873-1878 E-ISSN 1877-7058. [International Congress of Chemical and Process Engineering CHISA 2012 and 15th Conference PRES 2012 /20./. Prague, 25.08.2012-29.08.2012] Institutional support: RVO:67985858 Keywords : petroleum fluids * prediction * physico-chemical properties Subject RIV: CF - Physical ; Theoretical Chemistry
Theoretical Predictions of Cross-Sections of the Super-Heavy Elements
Bouriquet, B.; Kosenko, G.; Abe, Y.
The evaluation of the residue cross-sections of reactionssynthesising superheavy elements has been achieved by the combination of the two-step model for fusion and the evaporation code (KEWPIE) for survival probability. The theoretical scheme of those calculations is presented, and some encouraging results are given, together with some difficulties. With this approach, the measured excitation functions of the 1n reactions producing elements with Z=108, 110, 111 and 112 are well reproduced. Thus, the model has been used to predict the cross-sections of the reactions leading to the formation of the elements with Z=113 and Z=114.
Theoretical predictions of cross-sections of the super-heavy elements
International Nuclear Information System (INIS)
Bouriquet, B.; Abe, Y.; Kosenko, G.
2004-01-01
The evaluation of the residue cross-sections of reactions synthesising superheavy elements has been achieved by the combination of the two-step model for fusion and the evaporation code (KEWPIE) for survival probability. The theoretical scheme of those calculations is presented, and some encouraging results are given, together with some difficulties. With this approach, the measured excitation functions of the 1n reactions producing elements with Z = 108, 110, 111 and 112 are well reproduced. Thus, the model has been used to predict the cross-sections of the reactions leading to the formation of the elements with Z = 113 and Z = 114. (author)
Ab-initio theoretical predictions of structural properties of semiconductors
International Nuclear Information System (INIS)
Rodriguez, C.O.; Peltzer y Blanca, E.L.; Cappannini, O.M.
1983-01-01
Calculations of the total energies of Si, GaP and C together with related structural properties are presented. The results show good agreement with experimental values (differences of less than 6%). They also agree with other recent theoretical results. Calculations for Si and GaP have already been reported and are given here as a reference. (L.C.) [pt
Dedes, I.; Dudek, J.
2018-03-01
We examine the effects of the parametric correlations on the predictive capacities of the theoretical modelling keeping in mind the nuclear structure applications. The main purpose of this work is to illustrate the method of establishing the presence and determining the form of parametric correlations within a model as well as an algorithm of elimination by substitution (see text) of parametric correlations. We examine the effects of the elimination of the parametric correlations on the stabilisation of the model predictions further and further away from the fitting zone. It follows that the choice of the physics case and the selection of the associated model are of secondary importance in this case. Under these circumstances we give priority to the relative simplicity of the underlying mathematical algorithm, provided the model is realistic. Following such criteria, we focus specifically on an important but relatively simple case of doubly magic spherical nuclei. To profit from the algorithmic simplicity we chose working with the phenomenological spherically symmetric Woods–Saxon mean-field. We employ two variants of the underlying Hamiltonian, the traditional one involving both the central and the spin orbit potential in the Woods–Saxon form and the more advanced version with the self-consistent density-dependent spin–orbit interaction. We compare the effects of eliminating of various types of correlations and discuss the improvement of the quality of predictions (‘predictive power’) under realistic parameter adjustment conditions.
Delayed hydride cracking: theoretical model testing to predict cracking velocity
International Nuclear Information System (INIS)
Mieza, Juan I.; Vigna, Gustavo L.; Domizzi, Gladys
2009-01-01
Pressure tubes from Candu nuclear reactors as any other component manufactured with Zr alloys are prone to delayed hydride cracking. That is why it is important to be able to predict the cracking velocity during the component lifetime from parameters easy to be measured, such as: hydrogen concentration, mechanical and microstructural properties. Two of the theoretical models reported in literature to calculate the DHC velocity were chosen and combined, and using the appropriate variables allowed a comparison with experimental results of samples from Zr-2.5 Nb tubes with different mechanical and structural properties. In addition, velocities measured by other authors in irradiated materials could be reproduced using the model described above. (author)
Minetti, A E; Ardigò, L P; Susta, D; Cotelli, F
1998-12-01
The use of muscles as power dissipators is investigated in this study, both from the modellistic and the experimental points of view. Theoretical predictions of the drop landing manoeuvre for a range of initial conditions have been obtained by accounting for the mechanical characteristics of knee extensor muscles, the limb geometry and assuming maximum neural activation. Resulting dynamics have been represented in the phase plane (vertical displacement versus speed) to better classify the damping performance. Predictions of safe landing in sedentary subjects were associated to dropping from a maximum (feet) height of 1.6-2.0 m (about 11 m on the moon). Athletes can extend up to 2.6-3.0 m, while for obese males (m = 100 kg, standard stature) the limit should reduce to 0.9-1.3 m. These results have been calculated by including in the model the estimated stiffness of the 'global elastic elements' acting below the squat position. Experimental landings from a height of 0.4, 0.7, 1.1 m (sedentary males (SM) and male (AM) and female (AF) athletes from the alpine ski national team) showed dynamics similar to the model predictions. While the peak power (for a drop height of about 0.7 m) was similar in SM and AF (AM shows a +40% increase, about 33 W/kg), AF stopped the downward movement after a time interval (0.219 +/- 0.030 s) from touch-down 20% significantly shorter than SM. Landing strategy and the effect of anatomical constraints are discussed in the paper.
Probing the CuO planes with positrons in high Tc cuprates: theoretical predictions
International Nuclear Information System (INIS)
Barbiellini, B.; Jarlborg, T.; Massidda, S.; Peter, M.
1995-01-01
Positron annihilation spectroscopy is a useful tool to investigate the Fermi surface in high T c superconductors. To study the physics of the copper-oxygen subsystem that forms the Cu-O layers, it is important to provide theoretical predictions, on materials where there is a large overlap between the positron and the interesting Cu-O planes. We have performed first-principle electronic structure calculations obtained using the linear muffin-tin orbital and the full-potential linearized augmented plane wave methods. The positron charge distributions and their sensitivity to different potentials are calculated. Secondly, we have computed the annihilation rates and the electron-positron momentum density in order to give predictions of the Fermi surface signals. (orig.)
Ismail, M.; Adel, A.
2018-04-01
The α -decay half-lives of the recently synthesized superheavy nuclei (SHN) are investigated by employing the density dependent cluster model. A realistic nucleon-nucleon (NN ) interaction with a finite-range exchange part is used to calculate the microscopic α -nucleus potential in the well-established double-folding model. The calculated potential is then implemented to find both the assault frequency and the penetration probability of the α particle by means of the Wentzel-Kramers-Brillouin (WKB) approximation in combination with the Bohr-Sommerfeld quantization condition. The calculated values of α -decay half-lives of the recently synthesized Og isotopes and its decay products are in good agreement with the experimental data. Moreover, the calculated values of α -decay half-lives have been compared with those values evaluated using other theoretical models, and it was found that our theoretical values match well with their counterparts. The competition between α decay and spontaneous fission is investigated and predictions for possible decay modes for the unknown nuclei 118 290 -298Og are presented. We studied the behavior of the α -decay half-lives of Og isotopes and their decay products as a function of the mass number of the parent nuclei. We found that the behavior of the curves is governed by proton and neutron magic numbers found from previous studies. The proton numbers Z =114 , 116, 108, 106 and the neutron numbers N =172 , 164, 162, 158 show some magic character. We hope that the theoretical prediction of α -decay chains provides a new perspective to experimentalists.
Theoretical isochrones with decreasing gravitational constant
International Nuclear Information System (INIS)
Vandenberg, D.A.
1976-01-01
Van Flandern has postulated a variation of the gravitational constant at the rate approximately -8 x 10 -11 /yr. This variation, consistent with Hoyle-Narlikar and Dirac cosmologies, has been assumed in the computation of a 5 x 10 9 yr theoretical isochrone. Present results show that, even for this age, theory predicts a cluster turn-off luminosity approximately 0.5 to 1.0 mag fainter than the observed turn-offs of globular clusters. Unsatisfactory agreement between theoretical and observed luminosity functions is also indicated. (author)
Predicting Freshman Persistence and Voluntary Dropout Decisions from a Theoretical Model.
Pascarella, Ernest T.; Terenzini, Patrick T.
1980-01-01
A five-scale instrument developed from a theoretical model of college attrition correctly identified the persistence/voluntary withdrawal decisions of 78.5 percent of 773 freshmen in a large, residential university. Findings showed that student relationships with faculty were particularly important. (Author/PHR)
Machine-Learning-Based No Show Prediction in Outpatient Visits
Directory of Open Access Journals (Sweden)
Carlos Elvira
2018-03-01
Full Text Available A recurring problem in healthcare is the high percentage of patients who miss their appointment, be it a consultation or a hospital test. The present study seeks patient’s behavioural patterns that allow predicting the probability of no- shows. We explore the convenience of using Big Data Machine Learning models to accomplish this task. To begin with, a predictive model based only on variables associated with the target appointment is built. Then the model is improved by considering the patient’s history of appointments. In both cases, the Gradient Boosting algorithm was the predictor of choice. Our numerical results are considered promising given the small amount of information available. However, there seems to be plenty of room to improve the model if we manage to collect additional data for both patients and appointments.
Theoretical Predictions of Freestanding Honeycomb Sheets of Cadmium Chalcogenides
Energy Technology Data Exchange (ETDEWEB)
Zhou, Jia [ORNL; Huang, Jingsong [ORNL; Sumpter, Bobby G [ORNL; Kent, Paul R [ORNL; Xie, Yu [ORNL; Terrones Maldonado, Humberto [ORNL; Smith, Sean C [ORNL
2014-01-01
Two-dimensional (2D) nanocrystals of CdX (X = S, Se, Te) typically grown by colloidal synthesis are coated with organic ligands. Recent experimental work on ZnSe showed that the organic ligands can be removed at elevated temperature, giving a freestanding 2D sheet of ZnSe. In this theoretical work, freestanding single- to few-layer sheets of CdX, each possessing a pseudo honeycomb lattice, are considered by cutting along all possible lattice planes of the bulk zinc blende (ZB) and wurtzite (WZ) phases. Using density functional theory, we have systematically studied their geometric structures, energetics, and electronic properties. A strong surface distortion is found to occur for all of the layered sheets, and yet all of the pseudo honeycomb lattices are preserved, giving unique types of surface corrugations and different electronic properties. The energetics, in combination with phonon mode calculations and molecular dynamics simulations, indicate that the syntheses of these freestanding 2D sheets could be selective, with the single- to few-layer WZ110, WZ100, and ZB110 sheets being favored. Through the GW approximation, it is found that all single-layer sheets have large band gaps falling into the ultraviolet range, while thicker sheets in general have reduced band gaps in the visible and ultraviolet range. On the basis of the present work and the experimental studies on freestanding double-layer sheets of ZnSe, we envision that the freestanding 2D layered sheets of CdX predicted herein are potential synthesis targets, which may offer tunable band gaps depending on their structural features including surface corrugations, stacking motifs, and number of layers.
Theoretical prediction of the energy stability of graphene nanoblisters
Glukhova, O. E.; Slepchenkov, M. M.; Barkov, P. V.
2018-04-01
The paper presents the results of a theoretical prediction of the energy stability of graphene nanoblisters with various geometrical parameters. As a criterion for the evaluation of the stability of investigated carbon objects we propose to consider the value of local stress of the nanoblister atomic grid. Numerical evaluation of stresses experienced by atoms of the graphene blister framework was carried out by means of an original method for calculation of local stresses that is based on energy approach. Atomistic models of graphene nanoblisters corresponding to the natural experiment data were built for the first time in this work. New physical regularities of the influence of topology on the thermodynamic stability of nanoblisters were established as a result of the analysis of the numerical experiment data. We built the distribution of local stresses for graphene blister structures, whose atomic grid contains a variety of structural defects. We have shown how the concentration and location of defects affect the picture of the distribution of the maximum stresses experienced by the atoms of the nanoblisters.
Theoretical prediction of thermal conductivity for thermal protection systems
International Nuclear Information System (INIS)
Gori, F.; Corasaniti, S.; Worek, W.M.; Minkowycz, W.J.
2012-01-01
The present work is aimed to evaluate the effective thermal conductivity of an ablative composite material in the state of virgin material and in three paths of degradation. The composite material is undergoing ablation with formation of void pores or char and void pores. The one dimensional effective thermal conductivity is evaluated theoretically by the solution of heat conduction under two assumptions, i.e. parallel isotherms and parallel heat fluxes. The paper presents the theoretical model applied to an elementary cubic cell of the composite material which is made of two crossed fibres and a matrix. A numerical simulation is carried out to compare the numerical results with the theoretical ones for different values of the filler volume fraction. - Highlights: ► Theoretical models of the thermal conductivity of an ablative composite. ► Composite material is made of two crossed fibres and a matrix. ► Three mechanisms of degradation are investigated. ► One dimensional thermal conductivity is evaluated by the heat conduction equation. ► Numerical simulations to be compared with the theoretical models.
Theoretical optical spectroscopy of complex systems
Energy Technology Data Exchange (ETDEWEB)
Conte, A. Mosca, E-mail: adriano.mosca.conte@roma2.infn.it [MIFP, NAST, ETSF,CNR INFM-SMC, Universitá di Roma Tor Vergata, Via della Ricerca Scientifica 1, Roma (Italy); Violante, C., E-mail: claudia.violante@roma2.infn.it [MIFP, NAST, ETSF,CNR INFM-SMC, Universitá di Roma Tor Vergata, Via della Ricerca Scientifica 1, Roma (Italy); Missori, M., E-mail: mauro.missori@isc.cnr.it [Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, Via Salaria Km 29.300, 00016 Monterotondo Scalo (Rome) (Italy); Bechstedt, F., E-mail: bech@ifto.physik.uni-jena.de [Institut fur Festkorpertheorie und -optik, Friedrich-Schiller-Universitat, Max-Wien-Platz 1, 07743 Jena (Germany); Teodonio, L. [MIFP, NAST, ETSF,CNR INFM-SMC, Universitá di Roma Tor Vergata, Via della Ricerca Scientifica 1, Roma (Italy); Istituto centrale per il restauro e la conservazione del patrimonio archivistico e librario (IC-RCPAL), Italian Minister for Cultural Heritage, Via Milano 76, 00184 Rome (Italy); Ippoliti, E.; Carloni, P. [German Research School for Simulation Sciences, Julich (Germany); Guidoni, L., E-mail: leonardo.guidoni@univaq.it [Università degli Studi di L’Aquila, Dipartimento di Chimica e Materiali, Via Campo di Pile, 67100 L’Aquila (Italy); Pulci, O., E-mail: olivia.pulci@roma2.infn.it [MIFP, NAST, ETSF,CNR INFM-SMC, Universitá di Roma Tor Vergata, Via della Ricerca Scientifica 1, Roma (Italy)
2013-08-15
Highlights: ► We review some theoretical condensed matter ab initio spectroscopic computational techniques. ► We show several applications ranging from 0 to 3 dimensional systems. ► For each system studied, we show which kind of information it is possible to obtain by performing these calculations. -- Abstract: We review here some of the most reliable and efficient computational theoretical ab initio techniques for the prediction of optical and electronic spectroscopic properties and show some important applications to molecules, surfaces, and solids. We investigate the role of the solvent in the optical absorption spectrum of indole molecule. We study the excited-state properties of a photo-active minimal model molecule for the retinal of rhodopsin, responsible for vision mechanism in animals. We then show a study about spectroscopic properties of Si(1 1 1) surface. Finally we simulate a bulk system: paper, that is mainly made of cellulose, a pseudo-crystalline material representing 40% of annual biomass production in the Earth.
Theoretical optical spectroscopy of complex systems
International Nuclear Information System (INIS)
Conte, A. Mosca; Violante, C.; Missori, M.; Bechstedt, F.; Teodonio, L.; Ippoliti, E.; Carloni, P.; Guidoni, L.; Pulci, O.
2013-01-01
Highlights: ► We review some theoretical condensed matter ab initio spectroscopic computational techniques. ► We show several applications ranging from 0 to 3 dimensional systems. ► For each system studied, we show which kind of information it is possible to obtain by performing these calculations. -- Abstract: We review here some of the most reliable and efficient computational theoretical ab initio techniques for the prediction of optical and electronic spectroscopic properties and show some important applications to molecules, surfaces, and solids. We investigate the role of the solvent in the optical absorption spectrum of indole molecule. We study the excited-state properties of a photo-active minimal model molecule for the retinal of rhodopsin, responsible for vision mechanism in animals. We then show a study about spectroscopic properties of Si(1 1 1) surface. Finally we simulate a bulk system: paper, that is mainly made of cellulose, a pseudo-crystalline material representing 40% of annual biomass production in the Earth
A theoretical prediction of critical heat flux in saturated pool boiling during power transients
International Nuclear Information System (INIS)
Pasamehmetoglu, K.O.; Nelson, R.A.; Gunnerson, F.S.
1987-01-01
Understanding and predicting critical heat flux (CHF) behavior during steady-state and transient conditions is of fundamental interest in the design, operation, and safety of boiling and two-phase flow devices. Presented within this paper are the results of a comprehensive theoretical study specifically conducted to model transient CHF behavior in saturated pool boiling. Thermal energy conduction within a heating element and its influence on the CHF are also discussed. The resultant theory provides new insight into the basic physics of the CHF phenomenon and indicates favorable agreement with the experimental data from cylindrical heaters with small radii. However, the flat-ribbon heater data compared poorly with the present theory, although the general trend was predicted. Finally, various factors that affect the discrepency between the data and the theory are listed
International Nuclear Information System (INIS)
Carroll, David L; Verdeyen, Joseph T
2013-01-01
The exciplex pumped alkali laser (XPAL) system has been demonstrated in mixtures of Cs vapour, Ar, with and without ethane, by pumping Cs-Ar atomic collision pairs and subsequent dissociation of diatomic, electronically excited CsAr molecules (exciplexes or excimers). The blue satellites of the alkali D 2 lines provide an advantageous pathway for optically pumping atomic alkali lasers on the principal series (resonance) transitions with broad linewidth (>2 nm) semiconductor diode lasers. The development of a simple theoretical analysis of continuous-wave XPAL systems is presented along with predictions as a function of temperature and pump intensity. The model predicts that an optical-to-optical efficiency in the range of 40-50% can be achieved for XPAL.
Directory of Open Access Journals (Sweden)
Tammy M K Cheng
Full Text Available Recent analyses of human genome sequences have given rise to impressive advances in identifying non-synonymous single nucleotide polymorphisms (nsSNPs. By contrast, the annotation of nsSNPs and their links to diseases are progressing at a much slower pace. Many of the current approaches to analysing disease-associated nsSNPs use primarily sequence and evolutionary information, while structural information is relatively less exploited. In order to explore the potential of such information, we developed a structure-based approach, Bongo (Bonds ON Graph, to predict structural effects of nsSNPs. Bongo considers protein structures as residue-residue interaction networks and applies graph theoretical measures to identify the residues that are critical for maintaining structural stability by assessing the consequences on the interaction network of single point mutations. Our results show that Bongo is able to identify mutations that cause both local and global structural effects, with a remarkably low false positive rate. Application of the Bongo method to the prediction of 506 disease-associated nsSNPs resulted in a performance (positive predictive value, PPV, 78.5% similar to that of PolyPhen (PPV, 77.2% and PANTHER (PPV, 72.2%. As the Bongo method is solely structure-based, our results indicate that the structural changes resulting from nsSNPs are closely associated to their pathological consequences.
Molecular approach of uranyl/mineral surfaces: theoretical approach
International Nuclear Information System (INIS)
Roques, J.
2009-01-01
As migration of radio-toxic elements through the geosphere is one of the processes which may affect the safety of a radioactive waste storage site, the author shows that numerical modelling is a support to experimental result exploitation, and allows the development of new interpretation and prediction codes. He shows that molecular modelling can be used to study processes of interaction between an actinide ion (notably a uranyl ion) and a mineral surface (a TiO 2 substrate). He also reports the predictive theoretical study of the interaction between an uranyl ion and a gibbsite substrate
A theoretical adaptive model of thermal comfort - Adaptive Predicted Mean Vote (aPMV)
Energy Technology Data Exchange (ETDEWEB)
Yao, Runming [School of Construction Management and Engineering, The University of Reading (United Kingdom); Faculty of Urban Construction and Environmental Engineering, Chongqing University (China); Li, Baizhan [Key Laboratory of the Three Gorges Reservoir Region' s Eco-Environment (Ministry of Education), Chongqing University (China); Faculty of Urban Construction and Environmental Engineering, Chongqing University (China); Liu, Jing [School of Construction Management and Engineering, The University of Reading (United Kingdom)
2009-10-15
This paper presents in detail a theoretical adaptive model of thermal comfort based on the ''Black Box'' theory, taking into account factors such as culture, climate, social, psychological and behavioural adaptations, which have an impact on the senses used to detect thermal comfort. The model is called the Adaptive Predicted Mean Vote (aPMV) model. The aPMV model explains, by applying the cybernetics concept, the phenomena that the Predicted Mean Vote (PMV) is greater than the Actual Mean Vote (AMV) in free-running buildings, which has been revealed by many researchers in field studies. An Adaptive coefficient ({lambda}) representing the adaptive factors that affect the sense of thermal comfort has been proposed. The empirical coefficients in warm and cool conditions for the Chongqing area in China have been derived by applying the least square method to the monitored onsite environmental data and the thermal comfort survey results. (author)
Computational tools for experimental determination and theoretical prediction of protein structure
Energy Technology Data Exchange (ETDEWEB)
O`Donoghue, S.; Rost, B.
1995-12-31
This tutorial was one of eight tutorials selected to be presented at the Third International Conference on Intelligent Systems for Molecular Biology which was held in the United Kingdom from July 16 to 19, 1995. The authors intend to review the state of the art in the experimental determination of protein 3D structure (focus on nuclear magnetic resonance), and in the theoretical prediction of protein function and of protein structure in 1D, 2D and 3D from sequence. All the atomic resolution structures determined so far have been derived from either X-ray crystallography (the majority so far) or Nuclear Magnetic Resonance (NMR) Spectroscopy (becoming increasingly more important). The authors briefly describe the physical methods behind both of these techniques; the major computational methods involved will be covered in some detail. They highlight parallels and differences between the methods, and also the current limitations. Special emphasis will be given to techniques which have application to ab initio structure prediction. Large scale sequencing techniques increase the gap between the number of known proteins sequences and that of known protein structures. They describe the scope and principles of methods that contribute successfully to closing that gap. Emphasis will be given on the specification of adequate testing procedures to validate such methods.
Blatt, John M
1979-01-01
A classic work by two leading physicists and scientific educators endures as an uncommonly clear and cogent investigation and correlation of key aspects of theoretical nuclear physics. It is probably the most widely adopted book on the subject. The authors approach the subject as ""the theoretical concepts, methods, and considerations which have been devised in order to interpret the experimental material and to advance our ability to predict and control nuclear phenomena.""The present volume does not pretend to cover all aspects of theoretical nuclear physics. Its coverage is restricted to
Theoretical spectroscopic study of the conjugate microcystin-LR-europium cryptate
Energy Technology Data Exchange (ETDEWEB)
Santos, Julio G.; Dutra, Jose Diogo L.; Costa Junior, Nivan B. da; Freire, Ricardo O., E-mail: rfreire@ufs.br [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil). Departamento de Quimica; Alves Junior, Severino; Sa, Gilberto F. de [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Quimica Fundamental
2013-02-15
In this work, theoretical tools were used to study spectroscopic properties of the conjugate microcystin-LR-europium cryptate. The Sparkle/AM1 model was applied to predict the geometry of the system and the INDO/S-CIS model was used to calculate the excited state energies. Based on the Judd-Ofelt theory, the intensity parameters were predicted and a theoretical model based on the theory of the 4f-4f transitions was applied to calculate energy transfer and backtransfer rates, radiative and non-radiative decay rates, quantum efficiency and quantum yield. A detailed study of the luminescent properties of the conjugate Microcystin-LR-europium cryptate was carried out. The results show that the theoretical quantum yield of luminescence of 23% is in good agreement with the experimental value published. This fact suggests that this theoretical protocol can be used to design new systems in order to improve their luminescence properties. The results suggest that this luminescent system may be a good conjugate for using in assay ELISA for detection by luminescence of the Microcystin-LR in water. (author)
Directory of Open Access Journals (Sweden)
Chaminda Jayasundara
2009-01-01
Full Text Available University library administrators in Sri Lanka have begun to search for alternative ways to satisfy their clientele on the basis of service quality. This article aims at providing a theoretical model to facilitate the identification of service quality attributes and domains that may be used to predict customer satisfaction from a service quality perspective. The effectiveness of existing service quality models such as LibQUAL, SERVQUAL and SERVPREF have been questioned. In that regard, this study developed a theoretical model for academic libraries in Sri Lanka based on the disconfirmation and performance-only paradigms. These perspectives were considered by researchers to be the core mechanism to develop service quality/customer satisfaction models. The attributes and domain identification of service quality was carried out with a stratified sample of 263 participants selected from postgraduate and undergraduate students and academic staff members from the faculties of Arts in four universities in Sri Lanka. The study established that responsiveness, supportiveness, building environment, collection and access, furniture and facilities, technology, Web services and service delivery were quality domains which can be used to predict customer satisfaction. The theoretical model is unique in its domain structure compared to the existing models. The model needs to be statistically tested to make it valid and parsimonious.
Theoretical pKa prediction of the α-phosphate moiety of uridine 5‧-diphosphate-GlcNAc
Vipperla, Bhavaniprasad; Griffiths, Thomas M.; Wang, Xingyong; Yu, Haibo
2017-01-01
The pKa value of the α-phosphate moiety of uridine 5‧-diphosphate-GlcNAc (UDP-GlcNAc) has been successfully calculated using density functional theory methods in conjunction with the Polarizable Continuum Models. Theoretical methods were benchmarked over a dataset comprising of alkyl phosphates. B3LYP/6-31+G(d,p) calculations using SMD solvation model provide excellent agreement with the experimental data. The predicted pKa for UDP-GlcNAc is consistent with most recent NMR studies but much higher than what it has long been thought to be. The importance of this study is evident that the predicted pKa for UDP-GlcNAc supports its potential role as a catalytic base in the substrate-assisted biocatalysis.
Lamb shift in muonic hydrogen-I. Verification and update of theoretical predictions
International Nuclear Information System (INIS)
Jentschura, U.D.
2011-01-01
Research highlights: → The QED theory of muonic hydrogen energy levels is verified and updated. → Previously obtained results of Pachucki and Borie are confirmed. → The influence of the vacuum polarization potential onto the Bethe logarithm is calculated nonperturbatively. → A model-independent estimate of the Zemach moment correction is given. → Parametrically, the observed discrepancy of theory and experiment is shown to be substantial and large. - Abstract: In view of the recently observed discrepancy of theory and experiment for muonic hydrogen [R. Pohl et al., Nature 466 (2010) 213], we reexamine the theory on which the quantum electrodynamic (QED) predictions are based. In particular, we update the theory of the 2P-2S Lamb shift, by calculating the self-energy of the bound muon in the full Coulomb + vacuum polarization (Uehling) potential. We also investigate the relativistic two-body corrections to the vacuum polarization shift, and we analyze the influence of the shape of the nuclear charge distribution on the proton radius determination. The uncertainty associated with the third Zemach moment 3 > 2 in the determination of the proton radius from the measurement is estimated. An updated theoretical prediction for the 2S-2P transition is given.
Theoretical prediction of a rotating magnon wave packet in ferromagnets.
Matsumoto, Ryo; Murakami, Shuichi
2011-05-13
We theoretically show that the magnon wave packet has a rotational motion in two ways: a self-rotation and a motion along the boundary of the sample (edge current). They are similar to the cyclotron motion of electrons, but unlike electrons the magnons have no charge and the rotation is not due to the Lorentz force. These rotational motions are caused by the Berry phase in momentum space from the magnon band structure. Furthermore, the rotational motion of the magnon gives an additional correction term to the magnon Hall effect. We also discuss the Berry curvature effect in the classical limit of long-wavelength magnetostatic spin waves having macroscopic coherence length.
Directory of Open Access Journals (Sweden)
Guisan Antoine
2009-04-01
Full Text Available Abstract Background Multiple logistic regression is precluded from many practical applications in ecology that aim to predict the geographic distributions of species because it requires absence data, which are rarely available or are unreliable. In order to use multiple logistic regression, many studies have simulated "pseudo-absences" through a number of strategies, but it is unknown how the choice of strategy influences models and their geographic predictions of species. In this paper we evaluate the effect of several prevailing pseudo-absence strategies on the predictions of the geographic distribution of a virtual species whose "true" distribution and relationship to three environmental predictors was predefined. We evaluated the effect of using a real absences b pseudo-absences selected randomly from the background and c two-step approaches: pseudo-absences selected from low suitability areas predicted by either Ecological Niche Factor Analysis: (ENFA or BIOCLIM. We compared how the choice of pseudo-absence strategy affected model fit, predictive power, and information-theoretic model selection results. Results Models built with true absences had the best predictive power, best discriminatory power, and the "true" model (the one that contained the correct predictors was supported by the data according to AIC, as expected. Models based on random pseudo-absences had among the lowest fit, but yielded the second highest AUC value (0.97, and the "true" model was also supported by the data. Models based on two-step approaches had intermediate fit, the lowest predictive power, and the "true" model was not supported by the data. Conclusion If ecologists wish to build parsimonious GLM models that will allow them to make robust predictions, a reasonable approach is to use a large number of randomly selected pseudo-absences, and perform model selection based on an information theoretic approach. However, the resulting models can be expected to have
Exploratory experimental and theoretical studies of cyclone gasification of wood powder
Energy Technology Data Exchange (ETDEWEB)
Fredriksson, Christian
1999-11-01
This thesis describes an exploratory experimental and theoretical study of gasification of wood powder in a cyclone gasifier. The generated gas could be used to operate a gas turbine in a combined cycle power plant. The objective has been to develop the understanding of cyclone gasification by experimental studies of the performance of a cyclone designed in principle as a separation cyclone and by comparisons between the experimental results and theoretical predictions. The experiments were carried out with commercial Swedish wood powder fuels, injected with air or steam/air mixture through two diametrically opposite tangential inlets and gasified at atmospheric pressure in cyclones of two different configurations with a volume of about 0.034 m{sup 3}. The studies show that stable gasification of this fuel can be obtained for a specific fuel feeding rate of about 5 MW/m{sup 3} cyclone volume for equivalence ratios above 0.15 and that the equivalence ratio had to be kept below about 0.4 in order to avoid material temperatures above 950 deg C. A cyclone with a short outlet pipe, designed as a conventional separation cyclone was found to give lower char conversion than a modified cyclone with a long outlet pipe. The heating value of the gas was found to be approximately 4.5 MJ/kg. The dust load in the product gas was measured to between 1000 and 2500 mg/Nm{sup 3}. It was possible to separate at least 40-60% of the potassium and 60-90% of the sodium supplied with the wood. The alkali that left the cyclone with the product gas appear to be in solid or melted phase in the unseparated char particles and consequently not vaporised during gasification. As the K and Na were assumed to remain within the particles during gasification, it was concluded that to reduce the amount of alkali metals in the product gas it would be necessary to improve the particle separation efficiency. The results of the theoretical modelling, using the existing models in the commercial software CFX
Doyle, F; McGee, H M; Conroy, R M; Delaney, M
2011-05-01
Depression is associated with increased cardiovascular risk in acute coronary syndrome (ACS) patients, but some argue that elevated depression is actually a marker of cardiovascular disease severity. Therefore, disease indices should better predict depression than established theoretical causes of depression (interpersonal life events, reinforcing events, cognitive distortions, type D personality). However, little theory-based research has been conducted in this area. In a cross-sectional design, ACS patients (n = 336) completed questionnaires assessing depression and psychosocial vulnerabilities. Nested logistic regression assessed the relative contribution of demographic or vulnerability factors, or disease indices or vulnerabilities to depression. In multivariate analysis, all vulnerabilities were independent significant predictors of depression (scoring above threshold on any scale, 48%). Demographic variables accounted for vulnerabilities accounting for significantly more (pseudo R² = 0.16, χ²(change) = 150.9, df = 4, p vulnerabilities increased the overall variance explained to 22% (pseudo R² = 0.22, χ² = 58.6, df = 4, p vulnerabilities predicted depression status better than did either demographic or disease indices. The presence of these proximal causes of depression suggests that depression in ACS patients is not simply a result of cardiovascular disease severity.
International Nuclear Information System (INIS)
Figueroa, Aldo; Meunier, Patrice; Villermaux, Emmanuel; Cuevas, Sergio; Ramos, Eduardo
2014-01-01
We present a combination of experiment, theory, and modelling on laminar mixing at large Péclet number. The flow is produced by oscillating electromagnetic forces in a thin electrolytic fluid layer, leading to oscillating dipoles, quadrupoles, octopoles, and disordered flows. The numerical simulations are based on the Diffusive Strip Method (DSM) which was recently introduced (P. Meunier and E. Villermaux, “The diffusive strip method for scalar mixing in two-dimensions,” J. Fluid Mech. 662, 134–172 (2010)) to solve the advection-diffusion problem by combining Lagrangian techniques and theoretical modelling of the diffusion. Numerical simulations obtained with the DSM are in reasonable agreement with quantitative dye visualization experiments of the scalar fields. A theoretical model based on log-normal Probability Density Functions (PDFs) of stretching factors, characteristic of homogeneous turbulence in the Batchelor regime, allows to predict the PDFs of scalar in agreement with numerical and experimental results. This model also indicates that the PDFs of scalar are asymptotically close to log-normal at late stages, except for the large concentration levels which correspond to low stretching factors
International Nuclear Information System (INIS)
Lashgari, Mohsen; Malek, Ali M.
2010-01-01
Using quantum electrochemical approaches based on density functional theory and cluster/polarized continuum model, we investigated the corrosion behavior of aluminum in HCl and NaOH media containing phenol inhibitor. In this regard, we determined the geometry and electronic structure of the species at metal/solution interface. The investigations revealed that the interaction energies of hydroxide corrosive agents with aluminum surface should be more negative than those of chloride ones. The inhibitor adsorption in acid is more likely to have a physical nature while it appears as though to be chemical in basic media. To verify these predictions, using Tafel plots, we studied the phenomena from experimental viewpoint. The studies confirmed that the rate of corrosion in alkaline solution is substantially greater than in HCl media. Moreover, phenol is a potential-molecule having mixed-type inhibition mechanism. The relationship between inhibitory action and molecular parameters was discussed and the activity in alkaline media was also theoretically anticipated. This prediction was in accord with experiment.
DEFF Research Database (Denmark)
Nie, Jinzhe; Fang, Lei; Zhang, Ge
2015-01-01
for cooling, dehumidification and indoor air cleaning in normal office, commercial or residential buildings. The desiccant rotor was used for dehumidification and indoor air cleaning; the heat pump provided sensible cooling and regeneration heat for the desiccant rotor. The theoretical model consisted of two...... and predicted. The theoretical model was validated by experimental data. Validating results showed that the model could be used to predict the performance of HP-SDC. The results also showed that the HP-SDC could clean air borne contaminants effectively and could provide an energy efficient choice...
The First Galaxies Theoretical Predictions and Observational Clues
Mobasher, Bahram; Bromm, Volker
2013-01-01
New observations of the period between the cosmic recombination and the end of reionization are posing intriguing questions about where the first generations of stars were formed, how the first galaxies were assembled, whether these galaxies have low redshift counterparts, and what role the early galaxies played in the reionization process. Combining the new observational data with theoretical models can shed new light on open issues regarding the star formation process, its role in the reionization of the Universe, and the metal enrichment in galaxies at those early epochs. This volume brings together leading experts in the field to discuss our current level of understanding and what may come in the near future as our observational as well as theoretical tools improve. The book confronts the theory of how the first stars, black holes, and galaxies formed with current and planned observations. This synthesis is very timely, just ahead of the establishment of major new facilities, such as the James Webb Space ...
International Nuclear Information System (INIS)
Majcen, D.; Itard, L.C.M.; Visscher, H.
2013-01-01
In Europe, the Energy Performance of Buildings Directive (EPBD) provides for compulsory energy performance certification (labelling) for all existing dwellings. In the Netherlands, a labelling scheme was introduced in 2008. Certificates contain the energy label of the dwelling and corresponding theoretical gas and electricity consumption, calculated based on the dwellings physical characteristics, its heating, ventilation and cooling systems and standard use characteristics. This paper reports on a large-scale study of around 200,000 dwellings comparing labels and theoretical energy use with data on actual energy use. The study shows that dwellings with a low energy label actually consume much less energy than predicted by the label, but on the other hand, energy-efficient dwellings consume more than predicted. In practice, policy targets are set according to the theoretical rather than the actual consumptions of the building stock. In line with identified discrepancies, the study shows that whereas most energy reduction targets can be met according to the theoretical energy consumption of the dwelling stock, the future actual energy reduction potential is much lower and fails to meet most of the current energy reduction targets. - Highlights: ► Actual gas consumption in Dutch dwellings is lower than the theoretical. ► In the dwellings with label A–B, theoretical gas consumption is lower than actual gas consumption. ► In less efficient dwellings, theoretical gas consumption is much higher than the actual. ► Most current energy reduction targets are unachievable if modelled with actual instead of theoretical energy consumption
Information-Theoretic Evidence for Predictive Coding in the Face-Processing System.
Brodski-Guerniero, Alla; Paasch, Georg-Friedrich; Wollstadt, Patricia; Özdemir, Ipek; Lizier, Joseph T; Wibral, Michael
2017-08-23
Predictive coding suggests that the brain infers the causes of its sensations by combining sensory evidence with internal predictions based on available prior knowledge. However, the neurophysiological correlates of (pre)activated prior knowledge serving these predictions are still unknown. Based on the idea that such preactivated prior knowledge must be maintained until needed, we measured the amount of maintained information in neural signals via the active information storage (AIS) measure. AIS was calculated on whole-brain beamformer-reconstructed source time courses from MEG recordings of 52 human subjects during the baseline of a Mooney face/house detection task. Preactivation of prior knowledge for faces showed as α-band-related and β-band-related AIS increases in content-specific areas; these AIS increases were behaviorally relevant in the brain's fusiform face area. Further, AIS allowed decoding of the cued category on a trial-by-trial basis. Our results support accounts indicating that activated prior knowledge and the corresponding predictions are signaled in low-frequency activity (information our eyes/retina and other sensory organs receive from the outside world, but strongly depends also on information already present in our brains, such as prior knowledge about specific situations or objects. A currently popular theory in neuroscience, predictive coding theory, suggests that this prior knowledge is used by the brain to form internal predictions about upcoming sensory information. However, neurophysiological evidence for this hypothesis is rare, mostly because this kind of evidence requires strong a priori assumptions about the specific predictions the brain makes and the brain areas involved. Using a novel, assumption-free approach, we find that face-related prior knowledge and the derived predictions are represented in low-frequency brain activity. Copyright © 2017 the authors 0270-6474/17/378273-11$15.00/0.
Experimental and theoretical assessment of flexural properties of hybrid natural fibre composites
DEFF Research Database (Denmark)
Raghavalu Thirumalai, Durai Prabhakaran; Toftegaard, Helmuth Langmaack; Markussen, Christen Malte
2014-01-01
The concept of hybridization of natural fibre composites with synthetic fibres is attracting increasing scientific attention. The present study addresses the flexural properties of hybrid flax/glass/epoxy composites to demonstrate the potential benefits of hybridization. The study covers both...... experimental and theoretical assessments. Composite laminates with different hybrid fibre mixing ratios and different layer configurations were manufactured, and their volumetric composition and flexural properties were measured. The relationship between volume fractions in the composites is shown to be well...... predicted as a function of the hybrid fibre mixing ratio. The flexural modulus of the composites is theoretically assessed by using micromechanical models and laminate theory. The model predictions are compared with the experimentally determined flexural properties. Both approaches show that the flexural...
Energy Technology Data Exchange (ETDEWEB)
Virot, F., E-mail: francois.virot@irsn.fr; Barrachin, M.; Souvi, S.; Cantrel, L.
2014-10-15
Highlights: • Standard enthalpies of formation of BeH, BeH{sub 2}, BeOH, Be(OH){sub 2} have been calculated. • The impact of hydrogen isotopy on thermodynamic properties has been shown. • Speciation in the vacuum vessel shows that the main tritiated species is tritiated steam. • Beryllium hydroxide and hydride could exist during an accidental event. - Abstract: By quantum chemistry calculations, we have evaluated the standard enthalpies of formation of some gaseous species of the Be-O-H chemical system: BeH, BeH{sub 2}, BeOH, Be(OH){sub 2} for which the values in the referenced thermodynamic databases (NIST-JANAF [1] or COACH [2]) were, due to the lack of experimental data, estimated or reported with a large uncertainty. Comparison between post-HF, DFT approaches and available experimental data allows validation of the ability of an accurate exchange-correlation functional, VSXC, to predict the thermo-chemical properties of the beryllium species of interest. Deviation of enthalpy of formation induced by changes in hydrogen isotopy has been also calculated. From these new theoretically determinated data, we have calculated the chemical speciation in conditions simulating an accident of water ingress in the vacuum vessel of ITER.
Energy Technology Data Exchange (ETDEWEB)
Johnson, T.J.; Davis, E.J.
2000-05-01
An experimental and theoretical investigation of the electrophoretic clarification rate of colloidal suspensions was conducted. The suspensions included a coal-washing effluent and a model system of TiO{sub 2} particles. A parametric study of TiO{sub 2} suspensions was performed to validate and analysis of the electrophoretic motion of the clarification front formed between a clear zone and the suspension. To measure the electric field strength needed in the prediction of the location of the front, a moveable probe and salt bridge were connected to a reference electrode. Using the measured electric field strengths, it was found that the numerical solution to the unit cell electrophoresis model agrees with the measured clarification rates. For suspensions with moderately thick electric double layers and high particle volume fractions the deviations from classical Smoluchowski theory are substantial, and the numerical analysis is in somewhat better agreement with the data than a prior solution of the problem. The numerical model reduces to the predictions of previous theories as the thickness of the electric double layer decreases, and it is in good agreement with the clarification rate measured for a coal-washing effluent suspension with thin electric double layers.
Energy Technology Data Exchange (ETDEWEB)
Carriger, John F. [U.S. Environmental Protection Agency, Office of Research and Development, Gulf Ecology Division, Gulf Breeze, FL, 32561 (United States); Martin, Todd M. [U.S. Environmental Protection Agency, Office of Research and Development, Sustainable Technology Division, Cincinnati, OH, 45220 (United States); Barron, Mace G., E-mail: barron.mace@epa.gov [U.S. Environmental Protection Agency, Office of Research and Development, Gulf Ecology Division, Gulf Breeze, FL, 32561 (United States)
2016-11-15
Highlights: • A Bayesian network was developed to classify chemical mode of action (MoA). • The network was based on the aquatic toxicity MoA for over 1000 chemicals. • A Markov blanket algorithm selected a subset of theoretical molecular descriptors. • Sensitivity analyses found influential descriptors for classifying the MoAs. • Overall precision of the Bayesian MoA classification model was 80%. - Abstract: The mode of toxic action (MoA) has been recognized as a key determinant of chemical toxicity, but development of predictive MoA classification models in aquatic toxicology has been limited. We developed a Bayesian network model to classify aquatic toxicity MoA using a recently published dataset containing over one thousand chemicals with MoA assignments for aquatic animal toxicity. Two dimensional theoretical chemical descriptors were generated for each chemical using the Toxicity Estimation Software Tool. The model was developed through augmented Markov blanket discovery from the dataset of 1098 chemicals with the MoA broad classifications as a target node. From cross validation, the overall precision for the model was 80.2%. The best precision was for the AChEI MoA (93.5%) where 257 chemicals out of 275 were correctly classified. Model precision was poorest for the reactivity MoA (48.5%) where 48 out of 99 reactive chemicals were correctly classified. Narcosis represented the largest class within the MoA dataset and had a precision and reliability of 80.0%, reflecting the global precision across all of the MoAs. False negatives for narcosis most often fell into electron transport inhibition, neurotoxicity or reactivity MoAs. False negatives for all other MoAs were most often narcosis. A probabilistic sensitivity analysis was undertaken for each MoA to examine the sensitivity to individual and multiple descriptor findings. The results show that the Markov blanket of a structurally complex dataset can simplify analysis and interpretation by
Actual and theoretical gas consumption in Dutch dwellings: What causes the differences?
International Nuclear Information System (INIS)
Majcen, Daša; Itard, Laure; Visscher, Henk
2013-01-01
Energy labels in buildings are awarded based on theoretical gas and electricity consumption based on dwelling's physical characteristics. Prior to this research, a large-scale study was conducted in The Netherlands comparing theoretical energy use with data on actual energy use revealing substantial discrepancies (Majcen et al., 2013). This study uses identical energy label data, supplemented with additional data sources in order to reveal how different parameters influence theoretical and actual consumptions gas and electricity. Analysis is conducted through descriptive statistics and regression analysis. Regression analysis explained far less of the variation in the actual consumption than in the theoretical and has shown that variables such as floor area, ownership type, salary and the value of the house, which predicted a high degree of change in actual gas consumption, were insignificant (ownership, salary, value) or had a minor impact on theoretical consumption (floor area). Since some possibly fundamental variables were unavailable for regression analysis, we also conducted a sensitivity study of theoretical gas consumption. It showed that average indoor temperature, ventilation rate and accuracy of U-value have a large influence on the theoretical gas consumption; whereas the number of occupants and internal heat load have a rather limited impact. - Highlights: • Floor area, ownership, salary and value predict the change in actual gas use well. • Mentioned variables are insignificant or have small impact on theoretical use. • Energy consumption of less energy efficient systems is overestimated. • Accurate model assumptions and inspections would reduce the discrepancies. • Big discrepancies stem from misassumption of temperature, heated floor area, U values
Theoretical prediction of ion conductivity in solid state HfO2
Zhang, Wei; Chen, Wen-Zhou; Sun, Jiu-Yu; Jiang, Zhen-Yi
2013-01-01
A theoretical prediction of ion conductivity for solid state HfO2 is carried out in analogy to ZrO2 based on the density functional calculation. Geometric and electronic structures of pure bulks exhibit similarity for the two materials. Negative formation enthalpy and negative vacancy formation energy are found for YSH (yttria-stabilized hafnia) and YSZ (yttria-stabilized zirconia), suggesting the stability of both materials. Low activation energies (below 0.7 eV) of diffusion are found in both materials, and YSH's is a little higher than that of YSZ. In addition, for both HfO2 and ZrO2, the supercells with native oxygen vacancies are also studied. The so-called defect states are observed in the supercells with neutral and +1 charge native vacancy but not in the +2 charge one. It can give an explanation to the relatively lower activation energies of yttria-doped oxides and +2 charge vacancy supercells. A brief discussion is presented to explain the different YSH ion conductivities in the experiment and obtained by us, and we attribute this to the different ion vibrations at different temperatures.
Residual Strength Prediction of Debond Damaged Sandwich Panels
DEFF Research Database (Denmark)
Berggreen, Carl Christian
followed by debond growth. The developed theoretical procedure is an extension of the Crack Surface Displacement method, here denoted the Crack Surface Displacement Extrapolation method. The method is first developed in 2D and then extended to 3D by use of a number of realistic assumptions...... for the considered configurations. Comparison of the theoretical predictions to two series of large-scale experiments with loadings (uniform and non-uniform in-plane compression) comparable with real life loading scenarios for sandwich ships shows that the model is indeed able to predict the failure modes...
Energy Technology Data Exchange (ETDEWEB)
Dhavalikar, Rohan [Department of Chemical Engineering, University of Florida, 1030 Center Drive, Gainesville, FL 32611 (United States); Rinaldi, Carlos, E-mail: carlos.rinaldi@bme.ufl.edu [Department of Chemical Engineering, University of Florida, 1030 Center Drive, Gainesville, FL 32611 (United States); J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Drive, Gainesville, FL 32611 (United States)
2016-12-01
Magnetic nanoparticles in alternating magnetic fields (AMFs) transfer some of the field's energy to their surroundings in the form of heat, a property that has attracted significant attention for use in cancer treatment through hyperthermia and in developing magnetic drug carriers that can be actuated to release their cargo externally using magnetic fields. To date, most work in this field has focused on the use of AMFs that actuate heat release by nanoparticles over large regions, without the ability to select specific nanoparticle-loaded regions for heating while leaving other nanoparticle-loaded regions unaffected. In parallel, magnetic particle imaging (MPI) has emerged as a promising approach to image the distribution of magnetic nanoparticle tracers in vivo, with sub-millimeter spatial resolution. The underlying principle in MPI is the application of a selection magnetic field gradient, which defines a small region of low bias field, superimposed with an AMF (of lower frequency and amplitude than those normally used to actuate heating by the nanoparticles) to obtain a signal which is proportional to the concentration of particles in the region of low bias field. Here we extend previous models for estimating the energy dissipation rates of magnetic nanoparticles in uniform AMFs to provide theoretical predictions of how the selection magnetic field gradient used in MPI can be used to selectively actuate heating by magnetic nanoparticles in the low bias field region of the selection magnetic field gradient. Theoretical predictions are given for the spatial decay in energy dissipation rate under magnetic field gradients representative of those that can be achieved with current MPI technology. These results underscore the potential of combining MPI and higher amplitude/frequency actuation AMFs to achieve selective magnetic fluid hyperthermia (MFH) guided by MPI. - Highlights: • SAR predictions based on a field-dependent magnetization relaxation model.
Theoretical predictions for glass flow into an evacuated canister
International Nuclear Information System (INIS)
Routt, K.R.; Crow, K.R.
1983-01-01
Radioactive waste currently stored at the Savannah River Plant in liquid form is to be immobilized by incorporating it into a borosilicate glass. The glass melter for this process will consist of a refractory lined, steel vessel operated at a glass temperature of 1150 0 C. At the end of a two-year projected melter lifetime, the glass inside the melter is to be drained prior to disposition of the melter vessel. One proposed technique for accomplishing this drainage is by sucking the glass into an evacuated canister. The theoretical bases for design of an evacuated canister for draining a glass melter have been developed and tested. The theoretical equations governing transient and steady-state flow were substantiated with both a silicone glass simulant and molten glass
Theoretically predicted soft x-ray emission and absorption spectra of graphitic-structured BC2N
Muramatsu, Yasuji
Theoretical B K, C K and N K x-ray emission/absorption spectra of three possible graphitic-structured BC2N clusters are predicted based on the B2p-, C2p-, and N2p- density-of-states (DOS) calculated by discrete variational (DV)-X[alpha] molecular orbital calculations. Several prominent differences in DOS spectral features among BC2Ns, h-BN, and graphite are confirmed from comparison of calculated B2p-, C2p-, and N2p-DOS spectra. These variations in the spectra allow BC2N structures to be positively identified by high-resolution x-ray emission/absorption spectroscopy in the B K, C K, and N K regions.
A theoretical prediction of critical heat flux in subcooled pool boiling during power transients
International Nuclear Information System (INIS)
Pasamehmetoglu, K.O.; Nelson, R.A.; Gunnerson, F.S.
1988-01-01
Understanding and predicting critical heat flux (CHF) behavior during steady-state and transient conditions are of fundamenatal interest in the design, operation, safety of boiling and two-phase flow devices. This paper discusses the results of a comprehensive theoretical study made specifically to model transient CHF behavior in subcooled pool boiling. This study is based upon a simplified steady-state CHF model in terms of the vapor mass growth period. The results obtained from this theory indicate favorable agreement with the experimental data from cylindrical heaters with small radii. The statistical nature of the vapor mass behavior in transient boiling also is considered and upper and lower limits for the current theory are established. Various factors that affect the discrepancy between the data and the theory are discussed
Piao, Linfeng; Park, Hyungmin; Jo, Chris Hyunchul
2017-01-01
In the present study, we propose a theoretical framework to predict the recovery rates of platelets and white blood cells in the process of centrifugal separation of whole blood contained in a tube for the preparation of platelet-rich plasma. Compared to previous efforts to optimize or standardize the protocols of centrifugation, we try to further the physical background (i.e., based on the multiphase flow phenomena) of analysis to develop a universal approach that can be applied to widely different conditions. That is, one-dimensional quasi-linear partial differential equation to describe the centrifugal sedimentation of dispersed phase (red and white blood cells) in continuous phase (plasma) is derived based on the kinematic-wave theory. With the information of whole blood volume and tube geometry considered, it is possible to determine the positions of interfaces between supernatant/suspension and suspension/sediment, i.e., the particle concentration gradient in a tube, for a wide range of centrifugation parameters (time and acceleration). While establishing a theory to predict the recovery rates of the platelet and white blood cell from the pre-determined interface positions, we also propose a new correlation model between the recovery rates of plasma and platelets, which is found to be a function of the whole blood volume, centrifugal time and acceleration, and tube geometry. The present predictions for optimal condition show good agreements with available human clinical data, obtained from different conditions, indicating the universal applicability of our method. Furthermore, the dependence of recovery rates on centrifugal conditions reveals that there exist a different critical acceleration and time for the maximum recovery rate of platelets and white blood cells, respectively. The other parameters such as hematocrit, whole blood volume and tube geometry are also found to strongly affect the maximum recovery rates of blood cells, and finally, as a strategy
Theoretical predictions of the lateral spreading of implanted ions
International Nuclear Information System (INIS)
Ashworth, D.G.; Oven, R.
1986-01-01
The theoretical model and computer program (AAMPITS-3D) of Ashworth and co-workers for the calculation of three-dimensional distributions of implanted ions in multi-element amorphous targets are extended to show that the lateral rest distribution is gaussian in a form with a lateral standard deviation (lateral-spread function) which is a function of depth beneath the target surface. A method is given whereby this function may be accurately determined from a knowledge of the projected range and chord range rest distribution functions. Examples of the lateral-spread function are given for boron, phosphorus and arsenic ions implanted into silicon and a detailed description is given of how the lateral-spread function may be used in conjunction with the projected range rest distribution function to provide a fully three-dimensional rest distribution of ions implanted into amorphous targets. Examples of normalised single ion isodensity contours computed from AMPITS-3D are compared with those obtained using the previous assumption of a lateral standard deviation which was independent of distance beneath the target surface. (author)
Theoretical basis of the new particles
International Nuclear Information System (INIS)
Rujula, A.
1977-01-01
The four-quark standard gauge field theory of weak, electromagnetic and strong interactions is reviewed and placed into a historical perspective since as early as 1961. Theoretical predictions of the model are compared to experimental observations available as of the Conference date, charm production in e + e - annihilation being in the spotlight. Virtues and shortcomings of the standard model are discussed. The model is concluded to have been an incredibly successful predictive tool. Some theoretical developments around the standard model are also discussed in view of CP violation in SU(2)xU(1) gauge theories, the Higgs' bosons and superunification of weak, strong and electromagnetic interactions
A theoretical model for prediction of deposition efficiency in cold spraying
International Nuclear Information System (INIS)
Li Changjiu; Li Wenya; Wang Yuyue; Yang Guanjun; Fukanuma, H.
2005-01-01
The deposition behavior of a spray particle stream with a particle size distribution was theoretically examined for cold spraying in terms of deposition efficiency as a function of particle parameters and spray angle. The theoretical relation was established between the deposition efficiency and spray angle. The experiments were conducted by measuring deposition efficiency at different driving gas conditions and different spray angles using gas-atomized copper powder. It was found that the theoretically estimated results agreed reasonably well with the experimental ones. Based on the theoretical model and experimental results, it was revealed that the distribution of particle velocity resulting from particle size distribution influences significantly the deposition efficiency in cold spraying. It was necessary for the majority of particles to achieve a velocity higher than the critical velocity in order to improve the deposition efficiency. The normal component of particle velocity contributed to the deposition of the particle under the off-nomal spray condition. The deposition efficiency of sprayed particles decreased owing to the decrease of the normal velocity component as spray was performed at off-normal angle
Energy Technology Data Exchange (ETDEWEB)
Tsoukos, S; Kateris, A; Kalivas, N; Spyrou, G; Panayiotakis, G [Department of Medical Physics, School of Medicine, University of Patras, 265 00 pAtras (Greece); Kandarakis, I; Gavouras, D [Department of Medical Instrumentation Technology, Technological Educational Institution of Athens (Greece)
1999-12-31
A theoretical model predicting the intensity of light emitted by x-ray imaging phosphor screens per unit of area and time over incident x-ray flux (absolute efficiency) was developed. The model takes into account : A) the structure of the screens which consists of luminescent grains embedded in a binding matrix. B) the direct deposition of energy by x-ray absorption effects.. C) the re-absorption of K fluorescence characteristic x-rays produced when the x-ray energy exceeds the energy of the K absorption edge of the phosphor material. To test the model a set of (Gd,La)2O2S:Tb phosphor screens was prepared by sedimentation in the laboratory. Experimental absolute efficiency data were obtained at x-ray tube voltage range from 40 to 160 kVp. The coincidence between experimental and theoretical results were satisfactory. (authors) 7 refs., 4 figs.
Judge, Timothy A; Rodell, Jessica B; Klinger, Ryan L; Simon, Lauren S; Crawford, Eean R
2013-11-01
Integrating 2 theoretical perspectives on predictor-criterion relationships, the present study developed and tested a hierarchical framework in which each five-factor model (FFM) personality trait comprises 2 DeYoung, Quilty, and Peterson (2007) facets, which in turn comprise 6 Costa and McCrae (1992) NEO facets. Both theoretical perspectives-the bandwidth-fidelity dilemma and construct correspondence-suggest that lower order traits would better predict facets of job performance (task performance and contextual performance). They differ, however, as to the relative merits of broad and narrow traits in predicting a broad criterion (overall job performance). We first meta-analyzed the relationship of the 30 NEO facets to overall job performance and its facets. Overall, 1,176 correlations from 410 independent samples (combined N = 406,029) were coded and meta-analyzed. We then formed the 10 DeYoung et al. facets from the NEO facets, and 5 broad traits from those facets. Overall, results provided support for the 6-2-1 framework in general and the importance of the NEO facets in particular. (c) 2013 APA, all rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Johnson, T.J.; Davis, E.J. [University of Washington, Seattle, WA (USA). Dept. of Chemical Engineering
2000-05-01
An experimental and theoretical investigation of the electrophoretic clarification rate of colloidal suspensions was conducted. The suspensions included a coal-washing effluent and a model system of TiO{sub 2} particles. A parametric study of TiO{sub 2} suspensions was performed to validate an analysis of the electrophoretic motion of the clarification front formed between a clear zone and the suspension. To measure the electric field strength needed in the prediction of the location of the front, a moveable probe and salt bridge were connected to a reference electrode. Using the measured electric field strength, it was found that the numerical solution to the unit cell electrophoresis model agrees with the measured clarification rates. For suspensions with moderately thick electric double layers and high particle volume fractions the deviations from classical Smoluchowski theory are substantial, and the numerical analysis is in somewhat better agreement with the data than a prior solution of the problem. The numerical model reduces to the predictions of previous theories as the thickness of the electric double layer decreases, and it is in good agreement with the clarification rate measured for a coal-washing effluent suspension with thin electric double layers. 21 refs., 8 figs., 4 tabs.
Hindumathi, V; Kranthi, T; Rao, S B; Manimaran, P
2014-06-01
With rapidly changing technology, prediction of candidate genes has become an indispensable task in recent years mainly in the field of biological research. The empirical methods for candidate gene prioritization that succors to explore the potential pathway between genetic determinants and complex diseases are highly cumbersome and labor intensive. In such a scenario predicting potential targets for a disease state through in silico approaches are of researcher's interest. The prodigious availability of protein interaction data coupled with gene annotation renders an ease in the accurate determination of disease specific candidate genes. In our work we have prioritized the cervix related cancer candidate genes by employing Csaba Ortutay and his co-workers approach of identifying the candidate genes through graph theoretical centrality measures and gene ontology. With the advantage of the human protein interaction data, cervical cancer gene sets and the ontological terms, we were able to predict 15 novel candidates for cervical carcinogenesis. The disease relevance of the anticipated candidate genes was corroborated through a literature survey. Also the presence of the drugs for these candidates was detected through Therapeutic Target Database (TTD) and DrugMap Central (DMC) which affirms that they may be endowed as potential drug targets for cervical cancer.
Si, Guo-Ning; Chen, Lan; Li, Bao-Guo
2014-04-01
Base on the Kawakita powder compression equation, a general theoretical model for predicting the compression characteristics of multi-components pharmaceutical powders with different mass ratios was developed. The uniaxial flat-face compression tests of powder lactose, starch and microcrystalline cellulose were carried out, separately. Therefore, the Kawakita equation parameters of the powder materials were obtained. The uniaxial flat-face compression tests of the powder mixtures of lactose, starch, microcrystalline cellulose and sodium stearyl fumarate with five mass ratios were conducted, through which, the correlation between mixture density and loading pressure and the Kawakita equation curves were obtained. Finally, the theoretical prediction values were compared with experimental results. The analysis showed that the errors in predicting mixture densities were less than 5.0% and the errors of Kawakita vertical coordinate were within 4.6%, which indicated that the theoretical model could be used to predict the direct compaction characteristics of multi-component pharmaceutical powders.
Accurate predictions for the LHC made easy
CERN. Geneva
2014-01-01
The data recorded by the LHC experiments is of a very high quality. To get the most out of the data, precise theory predictions, including uncertainty estimates, are needed to reduce as much as possible theoretical bias in the experimental analyses. Recently, significant progress has been made in computing Next-to-Leading Order (NLO) computations, including matching to the parton shower, that allow for these accurate, hadron-level predictions. I shall discuss one of these efforts, the MadGraph5_aMC@NLO program, that aims at the complete automation of predictions at the NLO accuracy within the SM as well as New Physics theories. I’ll illustrate some of the theoretical ideas behind this program, show some selected applications to LHC physics, as well as describe the future plans.
Directory of Open Access Journals (Sweden)
2009-11-01
Full Text Available This paper has investigated theoretically the influence of sliding speed and temperature on the hysteretic friction in case of a smooth, reciprocating steel ball sliding on smooth rubber plate by finite element method (FEM. Generalized Maxwell-models combined with Mooney-Rivlin model have been used to describe the material behaviour of the ethylenepropylene-diene-monomer (EPDM rubber studied. Additionally, the effect of the technique applied at the parameter identification of the material model and the number of Maxwell elements on the coefficient of friction (COF was also investigated. Finally, the open parameter of the Greenwood-Tabor analytical model has been determined from a fit to the FE results. By fitting, as usual, the Maxwell-model to the storage modulus master curve the predicted COF, in a broad frequency range, will be underestimated even in case of 40-term Maxwell-model. To obtain more accurate numerical prediction or to provide an upper limit for the hysteretic friction, in the interesting frequency range, the Maxwell parameters should be determined, as proposed, from a fit to the measured loss factor master curve. This conclusion can be generalized for all the FE simulations where the hysteresis plays an important role.
MHD activity in the ISX-B tokamak: experimental results and theoretical interpretation
Energy Technology Data Exchange (ETDEWEB)
Carreras, B.A.; Dunlap, J.L.; Bell, J.D.; Charlton, L.A.; Cooper, W.A.; Dory, R.A.; Hender, T.C.; Hicks, H.R.; Holmes, J.A.; Lynch, V.E.
1982-01-01
The observed spectrum of MHD fluctuations in the ISX-B tokamak is clearly dominated by the n=1 mode when the q=1 surface is in the plasma. This fact agrees well with theoretical predictions based on 3-D resistive MHD calculations. They show that the (m=1; n=1) mode is then the dominant instability. It drives other n=1 modes through toroidal coupling and n>1 modes through nonlinear couplings. These theoretically predicted mode structures have been compared in detail with the experimentally measured wave forms (using arrays of soft x-ray detectors). The agreement is excellent. More detailed comparisons between theory and experiment have required careful reconstructions of the ISX-B equilibria. The equilibria so constructed have permitted a precise evaluation of the ideal MHD stability properties of ISX-B. The present results indicate that the high ..beta.. ISX-B equilibria are marginally stable to finite eta ideal MHD modes. The resistive MHD calculations also show that at finite ..beta.. there are unstable resistive pressure driven modes.
Experimental, computational and theoretical studies of δ′ phase coarsening in Al–Li alloys
International Nuclear Information System (INIS)
Pletcher, B.A.; Wang, K.G.; Glicksman, M.E.
2012-01-01
Experimental characterization of microstructure evolution in three binary Al–Li alloys provides critical tests of both diffusion screening theory and multiparticle diffusion simulations, which predict late-stage phase-coarsening kinetics. Particle size distributions, growth kinetics and maximum particle sizes obtained using quantitative, centered dark-field transmission electron microscopy are compared quantitatively with theoretical and computational predictions. We also demonstrate the dependence on δ′ precipitate volume fraction of the rate constant for coarsening and the microstructure’s maximum particle size, both of which remained undetermined for this alloy system for nearly a half century. Our experiments show quantitatively that the diffusion-screening theoretical description of phase coarsening yields reasonable kinetic predictions, and that useful simulations of microstructure evolution are obtained via multiparticle diffusion. The tested theory and simulation method will provide useful tools for future design of two-phase alloys for elevated temperature applications.
Energy Technology Data Exchange (ETDEWEB)
Prilutski, Yu.I.; Durov, S.S.; Yashchuk, V.N.; Ogul' chansky, T.Yu.; Pogorelov, V.E.; Astashkin, Yu.A. [Kievskij Gosudarstvennyj Univ. (Ukraine). Radiofizicheskij Fakul' tet; Buzaneva, E.V.; Kirghisov, Yu.D. [Department of Radiophysics, Kiev Shevchenko University, Vladimirskaya Str., 64, 252033 Kiev (Ukraine); Andrievsky, G.V. [Institute for Therapy of the Academy of Medical Sciences of Ukraine, Postysheva Str. 2a, 310116 Kharkov (Ukraine); Scharff, P. [Institut fuer Anorganische und Analytische Chemie, TU Clausthal, Paul-Ernst-Strasse 4, D-38670 Clausthal-Zellerfeld (Germany)
1999-12-01
The formation in water of highly stable hydrated clusters (I{sub h} symmetry group) and microcrystals (T{sub h} symmetry group) from C{sub 60} fullerenes is theoretically predicted using a molecular dynamics calculation. The proposed models are confirmed by the experiments on the Raman and absorption spectra of the fullerene aqueous solution. The additional study of the structure of C{sub 60} fullerene aggregates in the dry layer on the support (dielectric/semiconductor) is also performed. (orig.)
Communication: Theoretical prediction of free-energy landscapes for complex self-assembly
Energy Technology Data Exchange (ETDEWEB)
Jacobs, William M.; Reinhardt, Aleks; Frenkel, Daan [Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW (United Kingdom)
2015-01-14
We present a technique for calculating free-energy profiles for the nucleation of multicomponent structures that contain as many species as building blocks. We find that a key factor is the topology of the graph describing the connectivity of the target assembly. By considering the designed interactions separately from weaker, incidental interactions, our approach yields predictions for the equilibrium yield and nucleation barriers. These predictions are in good agreement with corresponding Monte Carlo simulations. We show that a few fundamental properties of the connectivity graph determine the most prominent features of the assembly thermodynamics. Surprisingly, we find that polydispersity in the strengths of the designed interactions stabilizes intermediate structures and can be used to sculpt the free-energy landscape for self-assembly. Finally, we demonstrate that weak incidental interactions can preclude assembly at equilibrium due to the combinatorial possibilities for incorrect association.
Energy Technology Data Exchange (ETDEWEB)
Loux, P C [Environmental Research Corporation, Alexandria, VA (United States)
1969-07-01
Nuclear generated ground motion is defined and then related to the physical parameters that cause it. Techniques employed for prediction of ground motion peak amplitude, frequency spectra and response spectra are explored, with initial emphasis on the analysis of data collected at the Nevada Test Site (NTS). NTS postshot measurements are compared with pre-shot predictions. Applicability of these techniques to new areas, for example, Plowshare sites, must be questioned. Fortunately, the Atomic Energy Commission is sponsoring complementary studies to improve prediction capabilities primarily in new locations outside the NTS region. Some of these are discussed in the light of anomalous seismic behavior, and comparisons are given showing theoretical versus experimental results. In conclusion, current ground motion prediction techniques are applied to events off the NTS. Predictions are compared with measurements for the event Faultless and for the Plowshare events, Gasbuggy, Cabriolet, and Buggy I. (author)
International Nuclear Information System (INIS)
Loux, P.C.
1969-01-01
Nuclear generated ground motion is defined and then related to the physical parameters that cause it. Techniques employed for prediction of ground motion peak amplitude, frequency spectra and response spectra are explored, with initial emphasis on the analysis of data collected at the Nevada Test Site (NTS). NTS postshot measurements are compared with pre-shot predictions. Applicability of these techniques to new areas, for example, Plowshare sites, must be questioned. Fortunately, the Atomic Energy Commission is sponsoring complementary studies to improve prediction capabilities primarily in new locations outside the NTS region. Some of these are discussed in the light of anomalous seismic behavior, and comparisons are given showing theoretical versus experimental results. In conclusion, current ground motion prediction techniques are applied to events off the NTS. Predictions are compared with measurements for the event Faultless and for the Plowshare events, Gasbuggy, Cabriolet, and Buggy I. (author)
Tau decays: A theoretical perspective
International Nuclear Information System (INIS)
Marciano, W.J.
1992-11-01
Theoretical predictions for various tau decay rates are reviewed. Effects of electroweak radiative corrections are described. Implications for precision tests of the standard model and ''new physics'' searches are discussed. A perspective on the tau decay puzzle and 1-prong problem is given
Theoretical study of a melting curve for tin
International Nuclear Information System (INIS)
Feng, Xi; Ling-Cang, Cai
2009-01-01
The melting curve of Sn has been calculated using the dislocation-mediated melting model with the 'zone-linking method'. The results are in good agreement with the experimental data. According to our calculation, the melting temperature of γ-Sn at zero pressure is about 436 K obtained by the extrapolation of the method from the triple point of Sn. The results show that this calculation method is better than other theoretical methods for predicting the melting curve of polymorphic material Sn. (condensed matter: structure, thermal and mechanical properties)
Van Oyen, Tomas; Blondeaux, Paolo; Van den Eynde, Dries
2013-07-01
A site-by-site comparison between field observations and theoretical predictions of sediment sorting patterns along tidal sand waves is performed for ten locations in the North Sea. At each site, the observed grain size distribution along the bottom topography and the geometry of the bed forms is described in detail and the procedure used to obtain the model parameters is summarized. The model appears to accurately describe the wavelength of the observed sand waves for the majority of the locations; still providing a reliable estimate for the other sites. In addition, it is found that for seven out of the ten locations, the qualitative sorting process provided by the model agrees with the observed grain size distribution. A discussion of the site-by-site comparison is provided which, taking into account uncertainties in the field data, indicates that the model grasps the major part of the key processes controlling the phenomenon.
Comparisons Between Experimental and Semi-theoretical Cutting Forces of CCS Disc Cutters
Xia, Yimin; Guo, Ben; Tan, Qing; Zhang, Xuhui; Lan, Hao; Ji, Zhiyong
2018-05-01
This paper focuses on comparisons between the experimental and semi-theoretical forces of CCS disc cutters acting on different rocks. The experimental forces obtained from LCM tests were used to evaluate the prediction accuracy of a semi-theoretical CSM model. The results show that the CSM model reliably predicts the normal forces acting on red sandstone and granite, but underestimates the normal forces acting on marble. Some additional LCM test data from the literature were collected to further explore the ability of the CSM model to predict the normal forces acting on rocks of different strengths. The CSM model underestimates the normal forces acting on soft rocks, semi-hard rocks and hard rocks by approximately 38, 38 and 10%, respectively, but very accurately predicts those acting on very hard and extremely hard rocks. A calibration factor is introduced to modify the normal forces estimated by the CSM model. The overall trend of the calibration factor is characterized by an exponential decrease with increasing rock uniaxial compressive strength. The mean fitting ratios between the normal forces estimated by the modified CSM model and the experimental normal forces acting on soft rocks, semi-hard rocks and hard rocks are 1.076, 0.879 and 1.013, respectively. The results indicate that the prediction accuracy and the reliability of the CSM model have been improved.
Goffman, Rachel M; Harris, Shannon L; May, Jerrold H; Milicevic, Aleksandra S; Monte, Robert J; Myaskovsky, Larissa; Rodriguez, Keri L; Tjader, Youxu C; Vargas, Dominic L
2017-05-01
Missed appointments reduce the efficiency of the health care system and negatively impact access to care for all patients. Identifying patients at risk for missing an appointment could help health care systems and providers better target interventions to reduce patient no-shows. Our aim was to develop and test a predictive model that identifies patients that have a high probability of missing their outpatient appointments. Demographic information, appointment characteristics, and attendance history were drawn from the existing data sets from four Veterans Affairs health care facilities within six separate service areas. Past attendance behavior was modeled using an empirical Markov model based on up to 10 previous appointments. Using logistic regression, we developed 24 unique predictive models. We implemented the models and tested an intervention strategy using live reminder calls placed 24, 48, and 72 hours ahead of time. The pilot study targeted 1,754 high-risk patients, whose probability of missing an appointment was predicted to be at least 0.2. Our results indicate that three variables were consistently related to a patient's no-show probability in all 24 models: past attendance behavior, the age of the appointment, and having multiple appointments scheduled on that day. After the intervention was implemented, the no-show rate in the pilot group was reduced from the expected value of 35% to 12.16% (p value < 0.0001). The predictive model accurately identified patients who were more likely to miss their appointments. Applying the model in practice enables clinics to apply more intensive intervention measures to high-risk patients. Reprint & Copyright © 2017 Association of Military Surgeons of the U.S.
Theoretical-experimental comparison of vitrified glass container behavior using the Castem system
International Nuclear Information System (INIS)
Moncouyoux, J.P.; Jamet, P.; Combescure, A.; Millard, A.
1989-01-01
This paper compares theoretical predictions of vitrified nuclear waste glass package collapse with experimental values in order to qualify the mathematical models describing canister deformation under external pressure loads. After briefly outlining the program and describing the experiments performed, the paper discusses the theoretical predictions based on the INCA code from the CEA's CASTEM system
Predicting Athletes’ Pre-Exercise Fluid Intake: A Theoretical Integration Approach
Directory of Open Access Journals (Sweden)
Chunxiao Li
2018-05-01
Full Text Available Pre-exercise fluid intake is an important healthy behavior for maintaining athletes’ sports performances and health. However, athletes’ behavioral adherence to fluid intake and its underlying psychological mechanisms have not been investigated. This prospective study aimed to use a health psychology model that integrates the self-determination theory and the theory of planned behavior for understanding pre-exercise fluid intake among athletes. Participants (n = 179 were athletes from college sport teams who completed surveys at two time points. Baseline (Time 1 assessment comprised psychological variables of the integrated model (i.e., autonomous and controlled motivation, attitude, subjective norm, perceived behavioral control, and intention and fluid intake (i.e., behavior was measured prospectively at one month (Time 2. Path analysis showed that the positive association between autonomous motivation and intention was mediated by subjective norm and perceived behavioral control. Controlled motivation positively predicted the subjective norm. Intentions positively predicted pre-exercise fluid intake behavior. Overall, the pattern of results was generally consistent with the integrated model, and it was suggested that athletes’ pre-exercise fluid intake behaviors were associated with the motivational and social cognitive factors of the model. The research findings could be informative for coaches and sport scientists to promote athletes’ pre-exercise fluid intake behaviors.
Evans, R; Ferguson, E
2014-02-01
While blood donation is traditionally described as a behaviour motivated by pure altruism, the assessment of altruism in the blood donation literature has not been theoretically informed. Drawing on theories of altruism from psychology, economics and evolutionary biology, it is argued that a theoretically derived psychometric assessment of altruism is needed. Such a measure is developed in this study that can be used to help inform both our understanding of the altruistic motives of blood donors and recruitment intervention strategies. A cross-sectional survey (N = 414), with a 1-month behavioural follow-up (time 2, N = 77), was designed to assess theoretically derived constructs from psychological, economic and evolutionary biological theories of altruism. Theory of planned behaviour (TPB) variables and co-operation were also assessed at time 1 and a measure of behavioural co-operation at time 2. Five theoretical dimensions (impure altruism, kinship, self-regarding motives, reluctant altruism and egalitarian warm glow) of altruism were identified through factor analyses. These five altruistic motives differentiated blood donors from non-donors (donors scored higher on impure altruism and reluctant altruism), showed incremental validity over TPB constructs to predict donor intention and predicted future co-operative behaviour. These findings show that altruism in the context of blood donation is multifaceted and complex and, does not reflect pure altruism. This has implication for recruitment campaigns that focus solely on pure altruism. © 2013 The Authors. Vox Sanguinis published by John Wiley & Sons Ltd. on behalf of International Society of Blood Transfusion.
Finite-Size Effects in Single Chain Magnets: An Experimental and Theoretical Study
Bogani, L.; Caneschi, A.; Fedi, M.; Gatteschi, D.; Massi, M.; Novak, M. A.; Pini, M. G.; Rettori, A.; Sessoli, R.; Vindigni, A.
2004-05-01
The problem of finite-size effects in s=1/2 Ising systems showing slow dynamics of the magnetization is investigated introducing diamagnetic impurities in a Co2+-radical chain. The static magnetic properties have been measured and analyzed considering the peculiarities induced by the ferrimagnetic character of the compound. The dynamic susceptibility shows that an Arrhenius law is observed with the same energy barrier for the pure and the doped compounds while the prefactor decreases, as theoretically predicted. Multiple spin reversal has also been investigated.
Theoretical prediction and impact of fundamental electric dipole moments
International Nuclear Information System (INIS)
Ellis, Sebastian A.R.; Kane, Gordon L.
2016-01-01
The predicted Standard Model (SM) electric dipole moments (EDMs) of electrons and quarks are tiny, providing an important window to observe new physics. Theories beyond the SM typically allow relatively large EDMs. The EDMs depend on the relative phases of terms in the effective Lagrangian of the extended theory, which are generally unknown. Underlying theories, such as string/M-theories compactified to four dimensions, could predict the phases and thus EDMs in the resulting supersymmetric (SUSY) theory. Earlier one of us, with collaborators, made such a prediction and found, unexpectedly, that the phases were predicted to be zero at tree level in the theory at the unification or string scale ∼O(10 16 GeV). Electroweak (EW) scale EDMs still arise via running from the high scale, and depend only on the SM Yukawa couplings that also give the CKM phase. Here we extend the earlier work by studying the dependence of the low scale EDMs on the constrained but not fully known fundamental Yukawa couplings. The dominant contribution is from two loop diagrams and is not sensitive to the choice of Yukawa texture. The electron EDM should not be found to be larger than about 5×10 −30 e cm, and the neutron EDM should not be larger than about 5×10 −29 e cm. These values are quite a bit smaller than the reported predictions from Split SUSY and typical effective theories, but much larger than the Standard Model prediction. Also, since models with random phases typically give much larger EDMs, it is a significant testable prediction of compactified M-theory that the EDMs should not be above these upper limits. The actual EDMs can be below the limits, so once they are measured they could provide new insight into the fundamental Yukawa couplings of leptons and quarks. We comment also on the role of strong CP violation. EDMs probe fundamental physics near the Planck scale.
Theoretical prediction and impact of fundamental electric dipole moments
Energy Technology Data Exchange (ETDEWEB)
Ellis, Sebastian A.R.; Kane, Gordon L. [Michigan Center for Theoretical Physics (MCTP),Department of Physics, University of Michigan,Ann Arbor, MI 48109 (United States)
2016-01-13
The predicted Standard Model (SM) electric dipole moments (EDMs) of electrons and quarks are tiny, providing an important window to observe new physics. Theories beyond the SM typically allow relatively large EDMs. The EDMs depend on the relative phases of terms in the effective Lagrangian of the extended theory, which are generally unknown. Underlying theories, such as string/M-theories compactified to four dimensions, could predict the phases and thus EDMs in the resulting supersymmetric (SUSY) theory. Earlier one of us, with collaborators, made such a prediction and found, unexpectedly, that the phases were predicted to be zero at tree level in the theory at the unification or string scale ∼O(10{sup 16} GeV). Electroweak (EW) scale EDMs still arise via running from the high scale, and depend only on the SM Yukawa couplings that also give the CKM phase. Here we extend the earlier work by studying the dependence of the low scale EDMs on the constrained but not fully known fundamental Yukawa couplings. The dominant contribution is from two loop diagrams and is not sensitive to the choice of Yukawa texture. The electron EDM should not be found to be larger than about 5×10{sup −30}e cm, and the neutron EDM should not be larger than about 5×10{sup −29}e cm. These values are quite a bit smaller than the reported predictions from Split SUSY and typical effective theories, but much larger than the Standard Model prediction. Also, since models with random phases typically give much larger EDMs, it is a significant testable prediction of compactified M-theory that the EDMs should not be above these upper limits. The actual EDMs can be below the limits, so once they are measured they could provide new insight into the fundamental Yukawa couplings of leptons and quarks. We comment also on the role of strong CP violation. EDMs probe fundamental physics near the Planck scale.
An AP endonuclease 1-DNA polymerase beta complex: theoretical prediction of interacting surfaces.
Directory of Open Access Journals (Sweden)
Alexej Abyzov
2008-04-01
Full Text Available Abasic (AP sites in DNA arise through both endogenous and exogenous mechanisms. Since AP sites can prevent replication and transcription, the cell contains systems for their identification and repair. AP endonuclease (APEX1 cleaves the phosphodiester backbone 5' to the AP site. The cleavage, a key step in the base excision repair pathway, is followed by nucleotide insertion and removal of the downstream deoxyribose moiety, performed most often by DNA polymerase beta (pol-beta. While yeast two-hybrid studies and electrophoretic mobility shift assays provide evidence for interaction of APEX1 and pol-beta, the specifics remain obscure. We describe a theoretical study designed to predict detailed interacting surfaces between APEX1 and pol-beta based on published co-crystal structures of each enzyme bound to DNA. Several potentially interacting complexes were identified by sliding the protein molecules along DNA: two with pol-beta located downstream of APEX1 (3' to the damaged site and three with pol-beta located upstream of APEX1 (5' to the damaged site. Molecular dynamics (MD simulations, ensuring geometrical complementarity of interfaces, enabled us to predict interacting residues and calculate binding energies, which in two cases were sufficient (approximately -10.0 kcal/mol to form a stable complex and in one case a weakly interacting complex. Analysis of interface behavior during MD simulation and visual inspection of interfaces allowed us to conclude that complexes with pol-beta at the 3'-side of APEX1 are those most likely to occur in vivo. Additional multiple sequence analyses of APEX1 and pol-beta in related organisms identified a set of correlated mutations of specific residues at the predicted interfaces. Based on these results, we propose that pol-beta in the open or closed conformation interacts and makes a stable interface with APEX1 bound to a cleaved abasic site on the 3' side. The method described here can be used for analysis in
Corporate prediction models, ratios or regression analysis?
Bijnen, E.J.; Wijn, M.F.C.M.
1994-01-01
The models developed in the literature with respect to the prediction of a company s failure are based on ratios. It has been shown before that these models should be rejected on theoretical grounds. Our study of industrial companies in the Netherlands shows that the ratios which are used in
Theoretical analysis of sound transmission loss through graphene sheets
International Nuclear Information System (INIS)
Natsuki, Toshiaki; Ni, Qing-Qing
2014-01-01
We examine the potential of using graphene sheets (GSs) as sound insulating materials that can be used for nano-devices because of their small size, super electronic, and mechanical properties. In this study, a theoretical analysis is proposed to predict the sound transmission loss through multi-layered GSs, which are formed by stacks of GS and bound together by van der Waals (vdW) forces between individual layers. The result shows that the resonant frequencies of the sound transmission loss occur in the multi-layered GSs and the values are very high. Based on the present analytical solution, we predict the acoustic insulation property for various layers of sheets under both normal incident wave and acoustic field of random incidence source. The scheme could be useful in vibration absorption application of nano devices and materials
Theoretical analysis of sound transmission loss through graphene sheets
Energy Technology Data Exchange (ETDEWEB)
Natsuki, Toshiaki, E-mail: natsuki@shinshu-u.ac.jp [Faculty of Textile Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda 386-8567 (Japan); Institute of Carbon Science and Technology, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553 (Japan); Ni, Qing-Qing [Faculty of Textile Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda 386-8567 (Japan)
2014-11-17
We examine the potential of using graphene sheets (GSs) as sound insulating materials that can be used for nano-devices because of their small size, super electronic, and mechanical properties. In this study, a theoretical analysis is proposed to predict the sound transmission loss through multi-layered GSs, which are formed by stacks of GS and bound together by van der Waals (vdW) forces between individual layers. The result shows that the resonant frequencies of the sound transmission loss occur in the multi-layered GSs and the values are very high. Based on the present analytical solution, we predict the acoustic insulation property for various layers of sheets under both normal incident wave and acoustic field of random incidence source. The scheme could be useful in vibration absorption application of nano devices and materials.
Choi, Garam; Lee, Won Bo
Metal alloys, especially Al-based, are commonly-used materials for various industrial applications. In this paper, the Al-Cu alloys with varying the Al-Cu ratio were investigated based on the first-principle calculation using density functional theory. And the electronic transport properties of the Al-Cu alloys were carried out using Boltzmann transport theory. From the results, the transport properties decrease with Cu-containing ratio at the temperature from moderate to high, but with non-linearity. It is inferred by various scattering effects from the calculation results with relaxation time approximation. For the Al-Cu alloy system, where it is hard to find the reliable experimental data for various alloys, it supports understanding and expectation for the thermal electrical properties from the theoretical prediction. Theoretical and computational soft matters laboratory.
Fong, Aaron; Meyer, Matthew P; O'Leary, Daniel J
2013-02-18
Previous theoretical studies of Mislow's doubly-bridged biphenyl ketone 1 and dihydrodimethylphenanthrene 2 have determined significant entropic contributions to their normal (1) and inverse (2) conformational kinetic isotope effects (CKIEs). To broaden our investigation, we have used density functional methods to characterize the potential energy surfaces and vibrational frequencies for ground and transition structures of additional systems with measured CKIEs, including [2.2]-metaparacyclophane-d (3), 1,1'-binaphthyl (4), 2,2'-dibromo-[1,1'-biphenyl]-4,4'-dicarboxylic acid (5), and the 2-(N,N,N-trimethyl)-2'-(N,N-dimethyl)-diaminobiphenyl cation (6). We have also computed CKIEs in a number of systems whose experimental CKIEs are unknown. These include analogs of 1 in which the C=O groups have been replaced with CH₂ (7), O (8), and S (9) atoms and ring-expanded variants of 2 containing CH₂ (10), O (11), S (12), or C=O (13) groups. Vibrational entropy contributes to the CKIEs in all of these systems with the exception of cyclophane 3, whose isotope effect is predicted to be purely enthalpic in origin and whose Bigeleisen-Mayer ZPE term is equivalent to DDH‡. There is variable correspondence between these terms in the other molecules studied, thus identifying additional examples of systems in which the Bigeleisen-Mayer formalism does not correlate with DH/DS dissections.
Directory of Open Access Journals (Sweden)
Aaron Fong
2013-02-01
Full Text Available Previous theoretical studies of Mislow’s doubly-bridged biphenyl ketone 1 and dihydrodimethylphenanthrene 2 have determined significant entropic contributions to their normal (1 and inverse (2 conformational kinetic isotope effects (CKIEs. To broaden our investigation, we have used density functional methods to characterize the potential energy surfaces and vibrational frequencies for ground and transition structures of additional systems with measured CKIEs, including [2.2]-metaparacyclophane-d (3, 1,1'-binaphthyl (4, 2,2'-dibromo-[1,1'-biphenyl]-4,4'-dicarboxylic acid (5, and the 2-(N,N,N-trimethyl-2'-(N,N-dimethyl-diaminobiphenyl cation (6. We have also computed CKIEs in a number of systems whose experimental CKIEs are unknown. These include analogs of 1 in which the C=O groups have been replaced with CH2 (7, O (8, and S (9 atoms and ring-expanded variants of 2 containing CH2 (10, O (11, S (12, or C=O (13 groups. Vibrational entropy contributes to the CKIEs in all of these systems with the exception of cyclophane 3, whose isotope effect is predicted to be purely enthalpic in origin and whose Bigeleisen-Mayer ZPE term is equivalent to ΔΔ H‡. There is variable correspondence between these terms in the other molecules studied, thus identifying additional examples of systems in which the Bigeleisen-Mayer formalism does not correlate with ΔH/ΔS dissections.
A theoretical perspective on road safety communication campaigns.
Elvik, Rune
2016-12-01
This paper proposes a theoretical perspective on road safety communication campaigns, which may help in identifying the conditions under which such campaigns can be effective. The paper proposes that, from a theoretical point of view, it is reasonable to assume that road user behaviour is, by and large, subjectively rational. This means that road users are assumed to behave the way they think is best. If this assumption is accepted, the best theoretical prediction is that road safety campaigns consisting of persuasive messages only will have no effect on road user behaviour and accordingly no effect on accidents. This theoretical prediction is not supported by meta-analyses of studies that have evaluated the effects of road safety communication campaigns. These analyses conclude that, on the average, such campaigns are associated with an accident reduction. The paper discusses whether this finding can be explained theoretically. The discussion relies on the distinction made by many modern theorists between bounded and perfect rationality. Road user behaviour is characterised by bounded rationality. Hence, if road users can gain insight into the bounds of their rationality, so that they see advantages to themselves of changing behaviour, they are likely to do so. It is, however, largely unknown whether such a mechanism explains why some road safety communication campaigns have been found to be more effective than others. Copyright © 2015 Elsevier Ltd. All rights reserved.
Optimal information transfer in enzymatic networks: A field theoretic formulation
Samanta, Himadri S.; Hinczewski, Michael; Thirumalai, D.
2017-07-01
Signaling in enzymatic networks is typically triggered by environmental fluctuations, resulting in a series of stochastic chemical reactions, leading to corruption of the signal by noise. For example, information flow is initiated by binding of extracellular ligands to receptors, which is transmitted through a cascade involving kinase-phosphatase stochastic chemical reactions. For a class of such networks, we develop a general field-theoretic approach to calculate the error in signal transmission as a function of an appropriate control variable. Application of the theory to a simple push-pull network, a module in the kinase-phosphatase cascade, recovers the exact results for error in signal transmission previously obtained using umbral calculus [Hinczewski and Thirumalai, Phys. Rev. X 4, 041017 (2014), 10.1103/PhysRevX.4.041017]. We illustrate the generality of the theory by studying the minimal errors in noise reduction in a reaction cascade with two connected push-pull modules. Such a cascade behaves as an effective three-species network with a pseudointermediate. In this case, optimal information transfer, resulting in the smallest square of the error between the input and output, occurs with a time delay, which is given by the inverse of the decay rate of the pseudointermediate. Surprisingly, in these examples the minimum error computed using simulations that take nonlinearities and discrete nature of molecules into account coincides with the predictions of a linear theory. In contrast, there are substantial deviations between simulations and predictions of the linear theory in error in signal propagation in an enzymatic push-pull network for a certain range of parameters. Inclusion of second-order perturbative corrections shows that differences between simulations and theoretical predictions are minimized. Our study establishes that a field theoretic formulation of stochastic biological signaling offers a systematic way to understand error propagation in
pDeep: Predicting MS/MS Spectra of Peptides with Deep Learning.
Zhou, Xie-Xuan; Zeng, Wen-Feng; Chi, Hao; Luo, Chunjie; Liu, Chao; Zhan, Jianfeng; He, Si-Min; Zhang, Zhifei
2017-12-05
In tandem mass spectrometry (MS/MS)-based proteomics, search engines rely on comparison between an experimental MS/MS spectrum and the theoretical spectra of the candidate peptides. Hence, accurate prediction of the theoretical spectra of peptides appears to be particularly important. Here, we present pDeep, a deep neural network-based model for the spectrum prediction of peptides. Using the bidirectional long short-term memory (BiLSTM), pDeep can predict higher-energy collisional dissociation, electron-transfer dissociation, and electron-transfer and higher-energy collision dissociation MS/MS spectra of peptides with >0.9 median Pearson correlation coefficients. Further, we showed that intermediate layer of the neural network could reveal physicochemical properties of amino acids, for example the similarities of fragmentation behaviors between amino acids. We also showed the potential of pDeep to distinguish extremely similar peptides (peptides that contain isobaric amino acids, for example, GG = N, AG = Q, or even I = L), which were very difficult to distinguish using traditional search engines.
Theoretical perspective for baryon number violation
International Nuclear Information System (INIS)
Langacker, P.
1982-01-01
In this talk I describe the theoretical predictions for proton decay and other baryon number violating processes, emphasizing that there are many models and theories involving baryon number violation and that it is an experimental problem to distinguish between them. I first review the the theoretical predictions for the unification mass M/sub X/ and for the weak angle sin 2 theta/sub W/. It will be seen that the class of models involving an Su 3 x SU 2 x U 1 invariant desert between M/sub W/ and M/sub X/ are strongly favored. I then turn to baryon number violation. The proton lifetime and branching ratio predictions for the SU 5 and other 3-2-1 desert models are reviewed, with emphasis on distinguishing between models and on the implications of the small value of the QCD parameter lambda/sub anti MS/ that seems to be favored by the data. I then discuss the consequences of low energy supersymmetry for proton decay, nuclear effects, and models with low mass scales. Finally, I mention possible implications of the anomalously large flux of cosmic ray antiprotons that has recently been reported
VAN method of short-term earthquake prediction shows promise
Uyeda, Seiya
Although optimism prevailed in the 1970s, the present consensus on earthquake prediction appears to be quite pessimistic. However, short-term prediction based on geoelectric potential monitoring has stood the test of time in Greece for more than a decade [VarotsosandKulhanek, 1993] Lighthill, 1996]. The method used is called the VAN method.The geoelectric potential changes constantly due to causes such as magnetotelluric effects, lightning, rainfall, leakage from manmade sources, and electrochemical instabilities of electrodes. All of this noise must be eliminated before preseismic signals are identified, if they exist at all. The VAN group apparently accomplished this task for the first time. They installed multiple short (100-200m) dipoles with different lengths in both north-south and east-west directions and long (1-10 km) dipoles in appropriate orientations at their stations (one of their mega-stations, Ioannina, for example, now has 137 dipoles in operation) and found that practically all of the noise could be eliminated by applying a set of criteria to the data.
Finnerty, Niall J; O'Riordan, Saidhbhe L; Lowry, John P; Cloutier, Mathieu; Wellstead, Peter
2013-01-01
Mathematical models of the interactions between alphasynuclein (αS) and reactive oxygen species (ROS) predict a systematic and irreversible switching to damagingly high levels of ROS after sufficient exposure to risk factors associated with Parkinson's disease (PD). We tested this prediction by continuously monitoring real-time changes in neurochemical levels over periods of several days in animals exposed to a toxin known to cause Parkinsonian symptoms. Nitric oxide (NO) sensors were implanted in the brains of freely moving rats and the NO levels continuously recorded while the animals were exposed to paraquat (PQ) injections of various amounts and frequencies. Long-term, real-time measurement of NO in a cohort of animals showed systematic switching in levels when PQ injections of sufficient size and frequency were administered. The experimental observations of changes in NO imply a corresponding switching in endogenous ROS levels and support theoretical predictions of an irreversible change to damagingly high levels of endogenous ROS when PD risks are sufficiently large. Our current results only consider one form of PD risk, however, we are sufficiently confident in them to conclude that: (i) continuous long-term measurement of neurochemical dynamics provide a novel way to measure the temporal change and system dynamics which determine Parkinsonian damage, and (ii) the bistable feedback switching predicted by mathematical modelling seems to exist and that a deeper analysis of its characteristics would provide a way of understanding the pathogenic mechanisms that initiate Parkinsonian cell damage.
Neuhauser, Daniel; Gao, Yi; Arntsen, Christopher; Karshenas, Cyrus; Rabani, Eran; Baer, Roi
2014-08-15
We develop a formalism to calculate the quasiparticle energy within the GW many-body perturbation correction to the density functional theory. The occupied and virtual orbitals of the Kohn-Sham Hamiltonian are replaced by stochastic orbitals used to evaluate the Green function G, the polarization potential W, and, thereby, the GW self-energy. The stochastic GW (sGW) formalism relies on novel theoretical concepts such as stochastic time-dependent Hartree propagation, stochastic matrix compression, and spatial or temporal stochastic decoupling techniques. Beyond the theoretical interest, the formalism enables linear scaling GW calculations breaking the theoretical scaling limit for GW as well as circumventing the need for energy cutoff approximations. We illustrate the method for silicon nanocrystals of varying sizes with N_{e}>3000 electrons.
International Nuclear Information System (INIS)
Jin Kyu Kim; Petin, V.G.; Mishra, K.P.
2007-01-01
Complete text of publication follows. Background: Organisms in their living environment are not exposed to merely a single stress agent. Several factors such as radiation and heat may simultaneously exert their stressful effect to the organisms. The combined exposure to two stressors can result in an enhanced effect that would be expected from the addition of the separate exposures to individual agents. Objective: This study has been undertaken to develop a theoretical model for assessment of combined effects of low dose radiation and mild heat for predictive cellular response assay. Rationale: Present study was motivated from the belief that synergism may occur in terms of lethal lesions arising from the interaction of non-lethal sub-lesions induced by individual agents. The sub-lesions induced by each agent may be negligible or undetectable. But, there exists a possibility of some cross talk between sublesions produced by radiation and heat. These processes may reflect the real mechanisms for inflicting the lethal damage by otherwise ignorable or undetectable insults to exposed organisms. Results: A theoretically developed mathematical model of the synergy was formulated which was tested for validation on the experimental data. The model predictions fairly closely corresponded with several experimental results. .The significance of synergistic effects for radiation biology has been demonstrated. A number of common peculiarities of synergistic interactions were found to play their roles. A unified biophysical concept for synergistic interaction has been suggested. Conclusions: For a constant dose rate, synergistic interaction between radiation and hyperthermia especially at low intensity is realized only within a certain range of temperature, independently of the target object analyzed. For temperatures below the range, the synergistic effect was not observed and cell killing was mainly determined by the damage induced by ionizing radiation. On the contrary, the
Theoretical Prediction of the Forming Limit Band
International Nuclear Information System (INIS)
Banabic, D.; Paraianu, L.; Vos, M.; Jurco, P.
2007-01-01
Forming Limit Band (FLB) is a very useful tool to improve the sheet metal forming simulation robustness. Until now, the study of the FLB was only experimental. This paper presents the first attempt to model the FLB. The authors have established an original method for predicting the two margins of the limit band. The method was illustrated on the AA6111-T43 aluminum alloy. A good agreement with the experiments has been obtained
Theoretical Prediction of the Forming Limit Band
Banabic, D.; Vos, M.; Paraianu, L.; Jurco, P.
2007-04-01
Forming Limit Band (FLB) is a very useful tool to improve the sheet metal forming simulation robustness. Until now, the study of the FLB was only experimental. This paper presents the first attempt to model the FLB. The authors have established an original method for predicting the two margins of the limit band. The method was illustrated on the AA6111-T43 aluminum alloy. A good agreement with the experiments has been obtained.
Lansey, Eli
Optical or photonic metamaterials that operate in the infrared and visible frequency regimes show tremendous promise for solving problems in renewable energy, infrared imaging, and telecommunications. However, many of the theoretical and simulation techniques used at lower frequencies are not applicable to this higher-frequency regime. Furthermore, technological and financial limitations of photonic metamaterial fabrication increases the importance of reliable theoretical models and computational techniques for predicting the optical response of photonic metamaterials. This thesis focuses on aperture array metamaterials. That is, a rectangular, circular, or other shaped cavity or hole embedded in, or penetrating through a metal film. The research in the first portion of this dissertation reflects our interest in developing a fundamental, theoretical understanding of the behavior of light's interaction with these aperture arrays, specifically regarding enhanced optical transmission. We develop an approximate boundary condition for metals at optical frequencies, and a comprehensive, analytical explanation of the physics underlying this effect. These theoretical analyses are augmented by computational techniques in the second portion of this thesis, used both for verification of the theoretical work, and solving more complicated structures. Finally, the last portion of this thesis discusses the results from designing, fabricating and characterizing a light-splitting metamaterial.
Barlett, Christopher; Chamberlin, Kristina; Witkower, Zachary
2017-04-01
The Barlett and Gentile Cyberbullying Model (BGCM) is a learning-based theory that posits the importance of positive cyberbullying attitudes predicting subsequent cyberbullying perpetration. Furthermore, the tenants of the BGCM state that cyberbullying attitude are likely to form when the online aggressor believes that the online environment allows individuals of all physical sizes to harm others and they are perceived as anonymous. Past work has tested parts of the BGCM; no study has used longitudinal methods to examine this model fully. The current study (N = 161) employed a three-wave longitudinal design to test the BGCM. Participants (age range: 18-24) completed measures of the belief that physical strength is irrelevant online and anonymity perceptions at Wave 1, cyberbullying attitudes at Wave 2, and cyberbullying perpetration at Wave 3. Results showed strong support for the BGCM: anonymity perceptions and the belief that physical attributes are irrelevant online at Wave 1 predicted Wave 2 cyberbullying attitudes, which predicted subsequent Wave 3 cyberbullying perpetration. These results support the BGCM and are the first to show empirical support for this model. Aggr. Behav. 43:147-154, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
Information-Theoretic Properties of Auditory Sequences Dynamically Influence Expectation and Memory.
Agres, Kat; Abdallah, Samer; Pearce, Marcus
2018-01-01
A basic function of cognition is to detect regularities in sensory input to facilitate the prediction and recognition of future events. It has been proposed that these implicit expectations arise from an internal predictive coding model, based on knowledge acquired through processes such as statistical learning, but it is unclear how different types of statistical information affect listeners' memory for auditory stimuli. We used a combination of behavioral and computational methods to investigate memory for non-linguistic auditory sequences. Participants repeatedly heard tone sequences varying systematically in their information-theoretic properties. Expectedness ratings of tones were collected during three listening sessions, and a recognition memory test was given after each session. Information-theoretic measures of sequential predictability significantly influenced listeners' expectedness ratings, and variations in these properties had a significant impact on memory performance. Predictable sequences yielded increasingly better memory performance with increasing exposure. Computational simulations using a probabilistic model of auditory expectation suggest that listeners dynamically formed a new, and increasingly accurate, implicit cognitive model of the information-theoretic structure of the sequences throughout the experimental session. Copyright © 2017 Cognitive Science Society, Inc.
Sung, Jaeyoung
2007-07-01
We present an exact theoretical test of Jarzynski's equality (JE) for reversible volume-switching processes of an ideal gas system. The exact analysis shows that the prediction of JE for the free energy difference is the same as the work done on the gas system during the reversible process that is dependent on the shape of path of the reversible volume-switching process.
Theoretical integration and the psychology of sport injury prevention.
Chan, Derwin King-Chung; Hagger, Martin S
2012-09-01
Integrating different theories of motivation to facilitate or predict behaviour change has received an increasing amount of attention within the health, sport and exercise science literature. A recent review article in Sports Medicine, by Keats, Emery and Finch presented an integrated model using two prominent theories in social psychology, self-determination theory (SDT) and the theory of planned behaviour (TPB), aimed at explaining and enhancing athletes' adherence to sport injury prevention. While echoing their optimistic views about the utility of these two theories to explain adherence in this area and the virtues of theoretical integration, we would like to seize this opportunity to clarify several conceptual principles arising from the authors' integration of the theories. Clarifying the theoretical assumptions and explaining precisely how theoretical integration works is crucial not only for improving the comprehensiveness of the integrated framework for predicting injury prevention behaviour, but also to aid the design of effective intervention strategies targeting behavioural adherence. In this article, we use the integration of SDT and TPB as an example to demonstrate how theoretical integration can advance the understanding of injury prevention behaviour in sport.
Prediction of flare activity of stellar aggregates. I. Theoretical part
International Nuclear Information System (INIS)
Mnatsakanyan, M.A.; Mirzoyan, A.L.
1989-01-01
The problem is posed of predicting the number n k (t) of flare stars that have exhibited precisely k flares by the time t on the basis of data on these quantities known during the total time T of observations of the aggregate. The problem posed by Ambartsumyan of determining the distribution function f(ν) of the true frequency of stellar flares from known chronology of these data is equivalent to the limiting form of their formulation - prediction in the future over an infinitely long time. An exact analytic solution of the problem obtained without any assumption about the function f(ν) is given. It permits prediction of the steady flare activity of the aggregate into both the future and the (known) past. It follows from this solution that prediction into the future is in principle impossible to times that exceed the doubled time 2T of the available observations (this means that the problem of determining of the function f(ν) cannot be solved). Moreover, because of the unavoidable fluctuations in the observational data n k (T), such prediction is limited to even shorter times, and these are shorter the larger the value of k. Prediction into the past and into the future on the basis of the data n k (T) at the present time and its possible errors due to small fluctuations in these data are illustrated for the examples of the Pleiades and the Orion aggregate
Models of alien species richness show moderate predictive accuracy and poor transferability
Directory of Open Access Journals (Sweden)
César Capinha
2018-06-01
Full Text Available Robust predictions of alien species richness are useful to assess global biodiversity change. Nevertheless, the capacity to predict spatial patterns of alien species richness remains largely unassessed. Using 22 data sets of alien species richness from diverse taxonomic groups and covering various parts of the world, we evaluated whether different statistical models were able to provide useful predictions of absolute and relative alien species richness, as a function of explanatory variables representing geographical, environmental and socio-economic factors. Five state-of-the-art count data modelling techniques were used and compared: Poisson and negative binomial generalised linear models (GLMs, multivariate adaptive regression splines (MARS, random forests (RF and boosted regression trees (BRT. We found that predictions of absolute alien species richness had a low to moderate accuracy in the region where the models were developed and a consistently poor accuracy in new regions. Predictions of relative richness performed in a superior manner in both geographical settings, but still were not good. Flexible tree ensembles-type techniques (RF and BRT were shown to be significantly better in modelling alien species richness than parametric linear models (such as GLM, despite the latter being more commonly applied for this purpose. Importantly, the poor spatial transferability of models also warrants caution in assuming the generality of the relationships they identify, e.g. by applying projections under future scenario conditions. Ultimately, our results strongly suggest that predictability of spatial variation in richness of alien species richness is limited. The somewhat more robust ability to rank regions according to the number of aliens they have (i.e. relative richness, suggests that models of aliens species richness may be useful for prioritising and comparing regions, but not for predicting exact species numbers.
Wireless Networks under a Backoff Attack: A Game Theoretical Perspective.
Parras, Juan; Zazo, Santiago
2018-01-30
We study a wireless sensor network using CSMA/CA in the MAC layer under a backoff attack: some of the sensors of the network are malicious and deviate from the defined contention mechanism. We use Bianchi's network model to study the impact of the malicious sensors on the total network throughput, showing that it causes the throughput to be unfairly distributed among sensors. We model this conflict using game theory tools, where each sensor is a player. We obtain analytical solutions and propose an algorithm, based on Regret Matching, to learn the equilibrium of the game with an arbitrary number of players. Our approach is validated via simulations, showing that our theoretical predictions adjust to reality.
Predicting the dynamics of bacterial growth inhibition by ribosome-targeting antibiotics
Greulich, Philip; Doležal, Jakub; Scott, Matthew; Evans, Martin R.; Allen, Rosalind J.
2017-12-01
Understanding how antibiotics inhibit bacteria can help to reduce antibiotic use and hence avoid antimicrobial resistance—yet few theoretical models exist for bacterial growth inhibition by a clinically relevant antibiotic treatment regimen. In particular, in the clinic, antibiotic treatment is time-dependent. Here, we use a theoretical model, previously applied to steady-state bacterial growth, to predict the dynamical response of a bacterial cell to a time-dependent dose of ribosome-targeting antibiotic. Our results depend strongly on whether the antibiotic shows reversible transport and/or low-affinity ribosome binding (‘low-affinity antibiotic’) or, in contrast, irreversible transport and/or high affinity ribosome binding (‘high-affinity antibiotic’). For low-affinity antibiotics, our model predicts that growth inhibition depends on the duration of the antibiotic pulse, and can show a transient period of very fast growth following removal of the antibiotic. For high-affinity antibiotics, growth inhibition depends on peak dosage rather than dose duration, and the model predicts a pronounced post-antibiotic effect, due to hysteresis, in which growth can be suppressed for long times after the antibiotic dose has ended. These predictions are experimentally testable and may be of clinical significance.
An Experimental and Theoretical Study on Cavitating Propellers.
1982-10-01
34 And Identfyp eV &to" nMeeJ cascade flow theoretical supercavitating flow performance prediction method partially cavitating flow supercavitating ...the present work was to develop an analytical tool for predicting the off-design performance of supercavitating propellers over a wide range of...operating conditions. Due to the complex nature of the flow phenomena, a lifting line theory sirply combined with the two-dimensional supercavitating
Comparison of experimental and theoretical binding and transition energies in the actinide region
Energy Technology Data Exchange (ETDEWEB)
Krause, M. O.; NESTOR, JR., C. W. [OAK RIDGE NATIONAL LAB., TENN. (USA)
1977-11-15
The present status of experimental and theoretical binding and transition energy determinations is reviewed. Experimental data and the most recent theoretical predictions are compared for the energies of K..cap alpha../sub 1/ X-rays, M series X-rays, K-LL Auger electrons, K, L/sub 3/, M and N levels, and the 4f spin-orbit splitting. In addition, the K..cap alpha../sub 1/ and L/sub 3/ data are fitted by Moseley-type diagrams, and data on the shallow levels and the valence bands of actinide oxides are discussed. Comparison shows that the single-particle Dirac-Fock theory and the inclusion of quantum-electrodynamic contributions predicts energies of the innermost levels generally within the accuracy of data, that is in the order of magnitude of 1 eV. However, in the N, O... shells large deviations do occur presumably due to strong many-electron interactions. The inclusion of many-electron effects in the relativistic theory remains a challenge, as do experimental investigations affording an accuracy of better than 1 eV for the various electronic levels.
Silicene: Recent theoretical advances
Lew Yan Voon, L. C.
2016-04-14
Silicene is a two-dimensional allotrope of silicon with a puckered hexagonal structure closely related to the structure of graphene and that has been predicted to be stable. To date, it has been successfully grown in solution (functionalized) and on substrates. The goal of this review is to provide a summary of recent theoretical advances in the properties of both free-standing silicene as well as in interaction with molecules and substrates, and of proposed device applications.
Silicene: Recent theoretical advances
Lew Yan Voon, L. C.; Zhu, Jiajie; Schwingenschlö gl, Udo
2016-01-01
Silicene is a two-dimensional allotrope of silicon with a puckered hexagonal structure closely related to the structure of graphene and that has been predicted to be stable. To date, it has been successfully grown in solution (functionalized) and on substrates. The goal of this review is to provide a summary of recent theoretical advances in the properties of both free-standing silicene as well as in interaction with molecules and substrates, and of proposed device applications.
Theoretical prediction of experimental jump and pull-in dynamics in a MEMS sensor
Ruzziconi, Laura; Lenci, Stefano; Ramini, Abdallah; Younis, Mohammad I.
2014-01-01
The present research study deals with an electrically actuated MEMS device. An experimental investigation is performed, via frequency sweeps in a neighbourhood of the first natural frequency. Resonant behavior is explored, with special attention devoted to jump and pull-in dynamics. A theoretical single degree-of-freedom spring-mass model is derived. Classical numerical simulations are observed to properly predict the main nonlinear features. Nevertheless, some discrepancies arise, which are particularly visible in the resonant branch. They mainly concern the practical range of existence of each attractor and the final outcome after its disappearance. These differences are likely due to disturbances, which are unavoidable in practice, but have not been included in the model. To take disturbances into account, in addition to the classical local investigations, we consider the global dynamics and explore the robustness of the obtained results by performing a dynamical integrity analysis. Our aim is that of developing an applicable confident estimate of the system response. Integrity profiles and integrity charts are built to detect the parameter range where reliability is practically strong and where it becomes weak. Integrity curves exactly follow the experimental data. They inform about the practical range of actuality. We discuss the combined use of integrity charts in the engineering design. Although we refer to a particular case-study, the approach is very general.
Theoretical prediction of experimental jump and pull-in dynamics in a MEMS sensor
Ruzziconi, Laura
2014-09-15
The present research study deals with an electrically actuated MEMS device. An experimental investigation is performed, via frequency sweeps in a neighbourhood of the first natural frequency. Resonant behavior is explored, with special attention devoted to jump and pull-in dynamics. A theoretical single degree-of-freedom spring-mass model is derived. Classical numerical simulations are observed to properly predict the main nonlinear features. Nevertheless, some discrepancies arise, which are particularly visible in the resonant branch. They mainly concern the practical range of existence of each attractor and the final outcome after its disappearance. These differences are likely due to disturbances, which are unavoidable in practice, but have not been included in the model. To take disturbances into account, in addition to the classical local investigations, we consider the global dynamics and explore the robustness of the obtained results by performing a dynamical integrity analysis. Our aim is that of developing an applicable confident estimate of the system response. Integrity profiles and integrity charts are built to detect the parameter range where reliability is practically strong and where it becomes weak. Integrity curves exactly follow the experimental data. They inform about the practical range of actuality. We discuss the combined use of integrity charts in the engineering design. Although we refer to a particular case-study, the approach is very general.
On the increase of predictive performance with high-level data fusion
International Nuclear Information System (INIS)
Doeswijk, T.G.; Smilde, A.K.; Hageman, J.A.; Westerhuis, J.A.; Eeuwijk, F.A. van
2011-01-01
The combination of the different data sources for classification purposes, also called data fusion, can be done at different levels: low-level, i.e. concatenating data matrices, medium-level, i.e. concatenating data matrices after feature selection and high-level, i.e. combining model outputs. In this paper the predictive performance of high-level data fusion is investigated. Partial least squares is used on each of the data sets and dummy variables representing the classes are used as response variables. Based on the estimated responses y-hat j for data set j and class k, a Gaussian distribution p(g k |y-hat j ) is fitted. A simulation study is performed that shows the theoretical performance of high-level data fusion for two classes and two data sets. Within group correlations of the predicted responses of the two models and differences between the predictive ability of each of the separate models and the fused models are studied. Results show that the error rate is always less than or equal to the best performing subset and can theoretically approach zero. Negative within group correlations always improve the predictive performance. However, if the data sets have a joint basis, as with metabolomics data, this is not likely to happen. For equally performing individual classifiers the best results are expected for small within group correlations. Fusion of a non-predictive classifier with a classifier that exhibits discriminative ability lead to increased predictive performance if the within group correlations are strong. An example with real life data shows the applicability of the simulation results.
Directory of Open Access Journals (Sweden)
Jauhar Fajrin
2017-03-01
Full Text Available This paper presents a comparison of theoretical and experimental deflection of a hybrid sandwich panel under four-point bending load. The paper initially presents few basic equations developed under three-point load, followed by development of model under four-point bending load and a comparative analysis between theoretical and experimental results. It was found that the proposed model for predicting the deflection of hybrid sandwich panels provided fair agreement with the experimental values. Most of the sandwich panels showed theoretical deflection values higher than the experimental values, which is desirable in the design. It was also noticed that the introduction of intermediate layer does not contribute much to reduce the deflection of sandwich panel as the main contributor for the total deflection was the shear deformation of the core that mostly determined by the geometric of the samples and the thickness of the core.
Theoretical studies on aerosol agglomeration processes
Energy Technology Data Exchange (ETDEWEB)
Lehtinen, K.E.J. [VTT Energy, Espoo (Finland). Energy Use
1997-12-31
In this thesis, theoretical modeling of certain aerosol systems has been presented. At first, the aerosol general dynamic equation is introduced, along with a discretization routine for its numerical solution. Of the various possible phenomena affecting aerosol behaviour, this work is mostly focused on aerosol agglomeration. The fundamentals of aerosol agglomeration theory are thus briefly reviewed. The two practical applications of agglomeration studied in this thesis are flue gas cleaning using an electrical agglomerator and nanomaterial synthesis with a free jet reactor. In an electrical agglomerator the aerosol particles are charged and brought into an alternating electric field. The aim is to remove submicron particles from flue gases by collisions with larger particles before conventional gas cleaning devices that have a clear penetration window in the problematic 0.1-1{mu}m size range. A mathematical model was constructed to find out the effects of the different system parameters on the agglomerator`s performance. A crucial part of this task was finding out the collision efficiencies of particles of varying size and charge. The original idea was to use unipolar charging of the particles, and a laboratory scale apparatus was constructed for this purpose. Both theory and experiments clearly show that significant removal of submicron particles can not be achieved by such an arrangement. The theoretical analysis further shows that if the submicron particles and the large collector particles were charged with opposite polarity, significant removal of the submicron particles could be obtained. The second application of agglomeration considered in this thesis is predicting/controlling nanoparticle size in the gas-to-particle aerosol route to material synthesis. In a typical material reactor, a precursor vapor reacts to form molecules of the desired material. In a cooling environment, a particulate phase forms, the dynamics of which are determined by the rates of
Theoretical studies on aerosol agglomeration processes
Energy Technology Data Exchange (ETDEWEB)
Lehtinen, K E.J. [VTT Energy, Espoo (Finland). Energy Use
1998-12-31
In this thesis, theoretical modeling of certain aerosol systems has been presented. At first, the aerosol general dynamic equation is introduced, along with a discretization routine for its numerical solution. Of the various possible phenomena affecting aerosol behaviour, this work is mostly focused on aerosol agglomeration. The fundamentals of aerosol agglomeration theory are thus briefly reviewed. The two practical applications of agglomeration studied in this thesis are flue gas cleaning using an electrical agglomerator and nanomaterial synthesis with a free jet reactor. In an electrical agglomerator the aerosol particles are charged and brought into an alternating electric field. The aim is to remove submicron particles from flue gases by collisions with larger particles before conventional gas cleaning devices that have a clear penetration window in the problematic 0.1-1{mu}m size range. A mathematical model was constructed to find out the effects of the different system parameters on the agglomerator`s performance. A crucial part of this task was finding out the collision efficiencies of particles of varying size and charge. The original idea was to use unipolar charging of the particles, and a laboratory scale apparatus was constructed for this purpose. Both theory and experiments clearly show that significant removal of submicron particles can not be achieved by such an arrangement. The theoretical analysis further shows that if the submicron particles and the large collector particles were charged with opposite polarity, significant removal of the submicron particles could be obtained. The second application of agglomeration considered in this thesis is predicting/controlling nanoparticle size in the gas-to-particle aerosol route to material synthesis. In a typical material reactor, a precursor vapor reacts to form molecules of the desired material. In a cooling environment, a particulate phase forms, the dynamics of which are determined by the rates of
Balbi, V.; Kuhl, E.; Ciarletta, P.
2015-05-01
With nine meters in length, the gastrointestinal tract is not only our longest, but also our structurally most diverse organ. During embryonic development, it evolves as a bilayered tube with an inner endodermal lining and an outer mesodermal layer. Its inner surface displays a wide variety of morphological patterns, which are closely correlated to digestive function. However, the evolution of these intestinal patterns remains poorly understood. Here we show that geometric and mechanical factors can explain intestinal pattern formation. Using the nonlinear field theories of mechanics, we model surface morphogenesis as the instability problem of constrained differential growth. To allow for internal and external expansion, we model the gastrointestinal tract with homogeneous Neumann boundary conditions. To establish estimates for the folding pattern at the onset of folding, we perform a linear stability analysis supplemented by the perturbation theory. To predict pattern evolution in the post-buckling regime, we perform a series of nonlinear finite element simulations. Our model explains why longitudinal folds emerge in the esophagus with a thick and stiff outer layer, whereas circumferential folds emerge in the jejunum with a thinner and softer outer layer. In intermediate regions like the feline esophagus, longitudinal and circumferential folds emerge simultaneously. Our model could serve as a valuable tool to explain and predict alterations in esophageal morphology as a result of developmental disorders or certain digestive pathologies including food allergies.
Sundarraj, Pradeepkumar; Taylor, Robert A.; Banerjee, Debosmita; Maity, Dipak; Sinha Roy, Susanta
2017-01-01
Hybrid solar thermoelectric generators (HSTEGs) have garnered significant research attention recently due to their potential ability to cogenerate heat and electricity. In this paper, theoretical and experimental investigations of the electrical and thermal performance of a HSTEG system are reported. In order to validate the theoretical model, a laboratory scale HSTEG system (based on forced convection cooling) is developed. The HSTEG consists of six thermoelectric generator modules, an electrical heater, and a stainless steel cooling block. Our experimental analysis shows that the HSTEG is capable of producing a maximum electrical power output of 4.7 W, an electrical efficiency of 1.2% and thermal efficiency of 61% for an average temperature difference of 92 °C across the TEG modules with a heater power input of 382 W. These experimental results of the HSTEG system are found to be in good agreement with the theoretical prediction. This experimental/theoretical analysis can also serve as a guide for evaluating the performance of the HSTEG system with forced convection cooling.
Theoretical expectations for σtot at the large hadron collider
Indian Academy of Sciences (India)
particular QCD based model of the energy dependence of the total cross-section, including the effect of soft ... Hence, a critical evaluation of the range of theoretical predictions, is absolutely ... fitted to explain the observed low energy data and the model predictions are then .... Note here that the experimentally measured.
Theoretical investigation of aspects of radioactive contamination
International Nuclear Information System (INIS)
Smith, A.H.; Chandratillake, M.R.; Taylor, J.B.
1998-01-01
The BNFL programme of work has investigated theoretical aspects of the mechanisms responsible for the deposition and adherence of contamination to metallic surfaces and the energetics of physical decontamination processes. The work has been conducted in two phases: The theoretical and laboratory study of deposition of species from aqueous media on to stainless steel; Theoretical assessment of the forces causing the attraction of PuO 2 and UO 2 particles to stainless steel in an air environment and comparison of these forces with the energies delivered by physical jetting processes. The first phase produced a model which was found to give good agreement with plant operational experience of the deposition of simple aqueous ions such as Cobalt. Due to the complexities, however, of surface / colloid and surface / particle interactions the model was found not to be successful at predicting deposition for more complex compounds, such as Ruthenium Nitrosyls. At this stage the model had fulfilled its original requirement of underpinning design work on pipework shielding systems and it was decided not to pursue the library of chemical speciation data that would be necessary to model the behaviour of a full spectrum of possible contaminants. The second phase predicts by theoretical analysis that the relation of the energy delivered by jetting techniques to the physical forces causing the adherence of PuO 2 and UO 2 particles will vary considerably with particle size. This is particularly notably for larger PuO 2 particles which are firmly held as a result of high levels of electrostatic charge due to their intense alpha activity. Small particles tend to be difficult to remove due to the low profile that they present to the jetting medium. Large and small PuO 2 particles and small UO 2 particle are thus predicted to be difficult to remove and will present an energy threshold which may not be crossed by all decontamination techniques. (author)
Wireless Networks under a Backoff Attack: A Game Theoretical Perspective
Directory of Open Access Journals (Sweden)
Juan Parras
2018-01-01
Full Text Available We study a wireless sensor network using CSMA/CA in the MAC layer under a backoff attack: some of the sensors of the network are malicious and deviate from the defined contention mechanism. We use Bianchi’s network model to study the impact of the malicious sensors on the total network throughput, showing that it causes the throughput to be unfairly distributed among sensors. We model this conflict using game theory tools, where each sensor is a player. We obtain analytical solutions and propose an algorithm, based on Regret Matching, to learn the equilibrium of the game with an arbitrary number of players. Our approach is validated via simulations, showing that our theoretical predictions adjust to reality.
Theoretical prediction the removal of mercury from flue gas by MOFs
Liu, Yang; Li, Hailong; Liu, Jing
2016-01-01
Removal of mercury from flue gas has been considered as one of the hot topics in both the scientific and industrial world. Adsorption of elemental mercury (Hg) and oxidized mercury species (HgCl, HgO, and HgS) on a novel metal organic framework (MOF) material, named Mg/DOBDC, with unsaturated metal centers was investigated using density functional theory (DFT) calculations. The results show that Hg stably physi-sorbed on the unsaturated metal center (magnesium ion) of Mg/DOBDC with a binding energy (BE) of −27.5 kJ/mol. A direct interaction between Hg and magnesium ion was revealed by the partial density of state (PDOS) analysis. HgCl multi-interacts with two neighboring magnesium ions simultaneously by its Cl endings and thus resulted in strong adsorption strength (−89.0 kJ/mol). The adsorption energies of HgO and HgS on the Mg/DOBDC were as high as −117.0 kJ/mol and −169.7 kJ/mol, respectively, indicating a strong chemisorption. Theoretical calculations in this study reveal that Mg/DOBDC has the potential to serve as an efficient material for removal of mercury from flue gas.
Theoretical prediction the removal of mercury from flue gas by MOFs
Liu, Yang
2016-07-19
Removal of mercury from flue gas has been considered as one of the hot topics in both the scientific and industrial world. Adsorption of elemental mercury (Hg) and oxidized mercury species (HgCl, HgO, and HgS) on a novel metal organic framework (MOF) material, named Mg/DOBDC, with unsaturated metal centers was investigated using density functional theory (DFT) calculations. The results show that Hg stably physi-sorbed on the unsaturated metal center (magnesium ion) of Mg/DOBDC with a binding energy (BE) of −27.5 kJ/mol. A direct interaction between Hg and magnesium ion was revealed by the partial density of state (PDOS) analysis. HgCl multi-interacts with two neighboring magnesium ions simultaneously by its Cl endings and thus resulted in strong adsorption strength (−89.0 kJ/mol). The adsorption energies of HgO and HgS on the Mg/DOBDC were as high as −117.0 kJ/mol and −169.7 kJ/mol, respectively, indicating a strong chemisorption. Theoretical calculations in this study reveal that Mg/DOBDC has the potential to serve as an efficient material for removal of mercury from flue gas.
DEFF Research Database (Denmark)
Coutinho, João A.P.; Kontogeorgis, Georgios M.; Stenby, Erling H.
1994-01-01
This work shows that, when suitable theoretically based combining rules are used for the cross energy and cross co-volume parameters, cubic equations of state (EoS) with the van der Waals one-fluid mixing rules can adequately represent phase equilibria for the asymmetric CO2/hydrocarbon mixtures...... for the prediction of phase behavior of petroleum fluids. A brief theoretical analysis on the temperature dependency of the Kij interaction parameter is also presented....
Directory of Open Access Journals (Sweden)
Giovanni Rapacciuolo
Full Text Available Conservation planners often wish to predict how species distributions will change in response to environmental changes. Species distribution models (SDMs are the primary tool for making such predictions. Many methods are widely used; however, they all make simplifying assumptions, and predictions can therefore be subject to high uncertainty. With global change well underway, field records of observed range shifts are increasingly being used for testing SDM transferability. We used an unprecedented distribution dataset documenting recent range changes of British vascular plants, birds, and butterflies to test whether correlative SDMs based on climate change provide useful approximations of potential distribution shifts. We modelled past species distributions from climate using nine single techniques and a consensus approach, and projected the geographical extent of these models to a more recent time period based on climate change; we then compared model predictions with recent observed distributions in order to estimate the temporal transferability and prediction accuracy of our models. We also evaluated the relative effect of methodological and taxonomic variation on the performance of SDMs. Models showed good transferability in time when assessed using widespread metrics of accuracy. However, models had low accuracy to predict where occupancy status changed between time periods, especially for declining species. Model performance varied greatly among species within major taxa, but there was also considerable variation among modelling frameworks. Past climatic associations of British species distributions retain a high explanatory power when transferred to recent time--due to their accuracy to predict large areas retained by species--but fail to capture relevant predictors of change. We strongly emphasize the need for caution when using SDMs to predict shifts in species distributions: high explanatory power on temporally-independent records
MERGERS IN ΛCDM: UNCERTAINTIES IN THEORETICAL PREDICTIONS AND INTERPRETATIONS OF THE MERGER RATE
International Nuclear Information System (INIS)
Hopkins, Philip F.; Bundy, Kevin; Wetzel, Andrew; Ma, Chung-Pei; Croton, Darren; Khochfar, Sadegh; Hernquist, Lars; Genel, Shy; Van den Bosch, Frank; Somerville, Rachel S.; Keres, Dusan; Stewart, Kyle; Younger, Joshua D.
2010-01-01
Different theoretical methodologies lead to order-of-magnitude variations in predicted galaxy-galaxy merger rates. We examine how this arises and quantify the dominant uncertainties. Modeling of dark matter and galaxy inspiral/merger times contribute factor of ∼2 uncertainties. Different estimates of the halo-halo merger rate, the subhalo 'destruction' rate, and the halo merger rate with some dynamical friction time delay for galaxy-galaxy mergers, agree to within this factor of ∼2, provided proper care is taken to define mergers consistently. There are some caveats: if halo/subhalo masses are not appropriately defined the major-merger rate can be dramatically suppressed, and in models with 'orphan' galaxies and under-resolved subhalos the merger timescale can be severely over-estimated. The dominant differences in galaxy-galaxy merger rates between models owe to the treatment of the baryonic physics. Cosmological hydrodynamic simulations without strong feedback and some older semi-analytic models (SAMs), with known discrepancies in mass functions, can be biased by large factors (∼5) in predicted merger rates. However, provided that models yield a reasonable match to the total galaxy mass function, the differences in properties of central galaxies are sufficiently small to alone contribute small (factor of ∼1.5) additional systematics to merger rate predictions. But variations in the baryonic physics of satellite galaxies in models can also have a dramatic effect on merger rates. The well-known problem of satellite 'over-quenching' in most current SAMs-whereby SAM satellite populations are too efficiently stripped of their gas-could lead to order-of-magnitude under-estimates of merger rates for low-mass, gas-rich galaxies. Models in which the masses of satellites are fixed by observations (or SAMs adjusted to resolve this 'over-quenching') tend to predict higher merger rates, but with factor of ∼2 uncertainties stemming from the uncertainty in those
Energy Technology Data Exchange (ETDEWEB)
Ranke, P. J. von, E-mail: von.ranke@uol.com.br; Ribeiro, P. O.; Alho, B. P.; Alvarenga, T. S. T.; Nobrega, E. P.; Caldas, A.; Sousa, V. S. R.; Lopes, P. H. O.; Oliveira, N. A. de [Instituto de Física, Universidade do Estado do Rio de Janeiro–UERJ, Rua São Francisco Xavier, 524, 20550-013 Rio de Janeiro (RJ) (Brazil); Carvalho, A. Magnus G. [Laboratório Nacional de Luz Síncrotron, CNPEM, 13083-970 Campinas, São Paulo (Brazil)
2016-05-14
We report the strong correlations between the magnetoresistivity and the magnetic entropy change in the cubic antiferromagnetic TbSb compound. The theoretical investigation was performed through a microscopic model which takes into account the crystalline electrical field anisotropy, exchange coupling interactions between the up and down magnetic sublattices, and the Zeeman interaction. The easy magnetization directions changes from 〈001〉 to 〈110〉 and then to 〈111〉 observed experimentally was successfully theoretically described. Also, the calculation of the temperature dependence of electric resistivity showed good agreement with the experimental data. Theoretical predictions were calculated for the temperature dependence of the magnetic entropy and resistivity changes upon magnetic field variation. Besides, the difference in the spin up and down sublattices resistivity was investigated.
Predicting chaos in memristive oscillator via harmonic balance method.
Wang, Xin; Li, Chuandong; Huang, Tingwen; Duan, Shukai
2012-12-01
This paper studies the possible chaotic behaviors in a memristive oscillator with cubic nonlinearities via harmonic balance method which is also called the method of describing function. This method was proposed to detect chaos in classical Chua's circuit. We first transform the considered memristive oscillator system into Lur'e model and present the prediction of the existence of chaotic behaviors. To ensure the prediction result is correct, the distortion index is also measured. Numerical simulations are presented to show the effectiveness of theoretical results.
Accuracy Analysis of a Box-wing Theoretical SRP Model
Wang, Xiaoya; Hu, Xiaogong; Zhao, Qunhe; Guo, Rui
2016-07-01
For Beidou satellite navigation system (BDS) a high accuracy SRP model is necessary for high precise applications especially with Global BDS establishment in future. The BDS accuracy for broadcast ephemeris need be improved. So, a box-wing theoretical SRP model with fine structure and adding conical shadow factor of earth and moon were established. We verified this SRP model by the GPS Block IIF satellites. The calculation was done with the data of PRN 1, 24, 25, 27 satellites. The results show that the physical SRP model for POD and forecast for GPS IIF satellite has higher accuracy with respect to Bern empirical model. The 3D-RMS of orbit is about 20 centimeters. The POD accuracy for both models is similar but the prediction accuracy with the physical SRP model is more than doubled. We tested 1-day 3-day and 7-day orbit prediction. The longer is the prediction arc length, the more significant is the improvement. The orbit prediction accuracy with the physical SRP model for 1-day, 3-day and 7-day arc length are 0.4m, 2.0m, 10.0m respectively. But they are 0.9m, 5.5m and 30m with Bern empirical model respectively. We apply this means to the BDS and give out a SRP model for Beidou satellites. Then we test and verify the model with Beidou data of one month only for test. Initial results show the model is good but needs more data for verification and improvement. The orbit residual RMS is similar to that with our empirical force model which only estimate the force for along track, across track direction and y-bias. But the orbit overlap and SLR observation evaluation show some improvement. The remaining empirical force is reduced significantly for present Beidou constellation.
Theoretical study of the binding nature of glassy carbon with nickel(II) phthalocyanine complexes
International Nuclear Information System (INIS)
Cortez, Luis; Berrios, Cristhian; Yanez, Mauricio; Cardenas-Jiron, Gloria I.
2009-01-01
A theoretical study at the semiempirical RHF/PM3(tm) level (tm: transition metal) of the binding nature between a glassy carbon (GC) cluster and a nickel(II) complex (nickel(II) phthalocyanine NiPc, nickel(II) tetrasulphophthalocyanine NiTSPc) was performed. Three types of interactions for GC...NiPc (NiTSPc) were studied: (a) through an oxo (O) bridge, (b) through an hydroxo (OH) bridge, and (c) non-bridge. One layer (NiPc, NiTSPc) and two layers (NiPc...NiPc) of complex were considered. The binding energy calculated showed that in both cases NiPc and NiTSPc, the oxo structures are more stable than the hydroxo ones, and than the non-bridge systems. Charge analysis (NAO) predicted that GC gained more electrons in an oxo structure than in the analogues hydroxo. The theoretical results showed an agreement with the experimental data available, an oxo binding between GC and a nickel complex (NiPc, NiTSPc) in aqueous alkaline solutions is formed.
Theoretical study of the binding nature of glassy carbon with nickel(II) phthalocyanine complexes
Energy Technology Data Exchange (ETDEWEB)
Cortez, Luis [Laboratorio de Quimica Teorica, Facultad de Quimica y Biologia, Universidad de Santiago de Chile (USACH), Casilla 40, Correo 33, Santiago (Chile); Berrios, Cristhian [Laboratorio de Electrocatalisis, Facultad de Quimica y Biologia, Universidad de Santiago de Chile (USACH), Casilla 40, Correo 33, Santiago (Chile); Yanez, Mauricio [Laboratorio de Recursos Renovables, Centro de Biotecnologia, Universidad de Concepcion, Casilla-160 C, Concepcion (Chile); Cardenas-Jiron, Gloria I., E-mail: gloria.cardenas@usach.cl [Laboratorio de Quimica Teorica, Facultad de Quimica y Biologia, Universidad de Santiago de Chile (USACH), Casilla 40, Correo 33, Santiago (Chile)
2009-11-26
A theoretical study at the semiempirical RHF/PM3(tm) level (tm: transition metal) of the binding nature between a glassy carbon (GC) cluster and a nickel(II) complex (nickel(II) phthalocyanine NiPc, nickel(II) tetrasulphophthalocyanine NiTSPc) was performed. Three types of interactions for GC...NiPc (NiTSPc) were studied: (a) through an oxo (O) bridge, (b) through an hydroxo (OH) bridge, and (c) non-bridge. One layer (NiPc, NiTSPc) and two layers (NiPc...NiPc) of complex were considered. The binding energy calculated showed that in both cases NiPc and NiTSPc, the oxo structures are more stable than the hydroxo ones, and than the non-bridge systems. Charge analysis (NAO) predicted that GC gained more electrons in an oxo structure than in the analogues hydroxo. The theoretical results showed an agreement with the experimental data available, an oxo binding between GC and a nickel complex (NiPc, NiTSPc) in aqueous alkaline solutions is formed.
Linguistic and Psycho-Linguistic Principles of Linguadidactics (theoretical interpretation
Directory of Open Access Journals (Sweden)
Liudmila Mauzienė
2011-04-01
Full Text Available This article considers linguadidactics being closely related to linguistics, psychology, psycholinguistics and didactics and applies their theoretical statements and regularities in its scientific studies. Methodology refers to linguistics which investigates the language as a teaching subject. Methodology is linked to psychology in two ways. First of all, it is based on psychology as the teaching process is an intellectual psychical act and its regularities are necessary to know. On the other hand, methodology applies rules of pedagogy that predicts ways of learning and development of language skills. The article emphasizes that sustainable work experience and analysis of scientific research show that teaching process is more effective if consistent patterns of linguistics and psychology are appropriately applied.
International Nuclear Information System (INIS)
Kugo, Teruhiko; Mori, Takamasa; Takeda, Toshikazu
2007-01-01
Extended bias factor methods are proposed with two new concepts, the LC method and the PE method, in order to effectively use critical experiments and to enhance the applicability of the bias factor method for the improvement of the prediction accuracy of neutronic characteristics of a target core. Both methods utilize a number of critical experimental results and produce a semifictitious experimental value with them. The LC and PE methods define the semifictitious experimental values by a linear combination of experimental values and the product of exponentiated experimental values, respectively, and the corresponding semifictitious calculation values by those of calculation values. A bias factor is defined by the ratio of the semifictitious experimental value to the semifictitious calculation value in both methods. We formulate how to determine weights for the LC method and exponents for the PE method in order to minimize the variance of the design prediction value obtained by multiplying the design calculation value by the bias factor. From a theoretical comparison of these new methods with the conventional method which utilizes a single experimental result and the generalized bias factor method which was previously proposed to utilize a number of experimental results, it is concluded that the PE method is the most useful method for improving the prediction accuracy. The main advantages of the PE method are summarized as follows. The prediction accuracy is necessarily improved compared with the design calculation value even when experimental results include large experimental errors. This is a special feature that the other methods do not have. The prediction accuracy is most effectively improved by utilizing all the experimental results. From these facts, it can be said that the PE method effectively utilizes all the experimental results and has a possibility to make a full-scale-mockup experiment unnecessary with the use of existing and future benchmark
Group-regularized individual prediction: theory and application to pain.
Lindquist, Martin A; Krishnan, Anjali; López-Solà, Marina; Jepma, Marieke; Woo, Choong-Wan; Koban, Leonie; Roy, Mathieu; Atlas, Lauren Y; Schmidt, Liane; Chang, Luke J; Reynolds Losin, Elizabeth A; Eisenbarth, Hedwig; Ashar, Yoni K; Delk, Elizabeth; Wager, Tor D
2017-01-15
Multivariate pattern analysis (MVPA) has become an important tool for identifying brain representations of psychological processes and clinical outcomes using fMRI and related methods. Such methods can be used to predict or 'decode' psychological states in individual subjects. Single-subject MVPA approaches, however, are limited by the amount and quality of individual-subject data. In spite of higher spatial resolution, predictive accuracy from single-subject data often does not exceed what can be accomplished using coarser, group-level maps, because single-subject patterns are trained on limited amounts of often-noisy data. Here, we present a method that combines population-level priors, in the form of biomarker patterns developed on prior samples, with single-subject MVPA maps to improve single-subject prediction. Theoretical results and simulations motivate a weighting based on the relative variances of biomarker-based prediction-based on population-level predictive maps from prior groups-and individual-subject, cross-validated prediction. Empirical results predicting pain using brain activity on a trial-by-trial basis (single-trial prediction) across 6 studies (N=180 participants) confirm the theoretical predictions. Regularization based on a population-level biomarker-in this case, the Neurologic Pain Signature (NPS)-improved single-subject prediction accuracy compared with idiographic maps based on the individuals' data alone. The regularization scheme that we propose, which we term group-regularized individual prediction (GRIP), can be applied broadly to within-person MVPA-based prediction. We also show how GRIP can be used to evaluate data quality and provide benchmarks for the appropriateness of population-level maps like the NPS for a given individual or study. Copyright © 2015 Elsevier Inc. All rights reserved.
Review of Nearshore Morphologic Prediction
Plant, N. G.; Dalyander, S.; Long, J.
2014-12-01
The evolution of the world's erodible coastlines will determine the balance between the benefits and costs associated with human and ecological utilization of shores, beaches, dunes, barrier islands, wetlands, and estuaries. So, we would like to predict coastal evolution to guide management and planning of human and ecological response to coastal changes. After decades of research investment in data collection, theoretical and statistical analysis, and model development we have a number of empirical, statistical, and deterministic models that can predict the evolution of the shoreline, beaches, dunes, and wetlands over time scales of hours to decades, and even predict the evolution of geologic strata over the course of millennia. Comparisons of predictions to data have demonstrated that these models can have meaningful predictive skill. But these comparisons also highlight the deficiencies in fundamental understanding, formulations, or data that are responsible for prediction errors and uncertainty. Here, we review a subset of predictive models of the nearshore to illustrate tradeoffs in complexity, predictive skill, and sensitivity to input data and parameterization errors. We identify where future improvement in prediction skill will result from improved theoretical understanding, and data collection, and model-data assimilation.
Intellect: a theoretical framework for personality traits related to intellectual achievements.
Mussel, Patrick
2013-05-01
The present article develops a theoretical framework for the structure of personality traits related to intellectual achievements. We postulate a 2-dimensional model, differentiating between 2 processes (Seek and Conquer) and 3 operations (Think, Learn, and Create). The framework was operationalized by a newly developed measure, which was validated based on 2 samples. Subsequently, in 3 studies (overall N = 1,478), the 2-dimensional structure of the Intellect framework was generally supported. Additionally, subdimensions of the Intellect framework specifically predicted conceptually related criteria, including scholastic performance, vocational interest, and leisure activities. Furthermore, results from multidimensional scaling and higher order confirmatory factor analyses show that the framework allows for the incorporation of several constructs that have been proposed on different theoretical backgrounds, such as need for cognition, typical intellectual engagement, curiosity, intrinsic motivation, goal orientation, and openness to ideas. It is concluded that based on the Intellect framework, these constructs, which have been researched separately in the literature, can be meaningfully integrated.
Energy Technology Data Exchange (ETDEWEB)
Gopinath, A.; Puhan, Sukumar; Nagarajan, G. [Internal Combustion Engineering Division, Department of Mechanical Engineering, Anna University, Chennai 600 025, Tamil Nadu (India)
2009-07-15
Biodiesel is an alternative fuel consisting of alkyl esters of fatty acids from vegetable oils or animal fats. The properties of biodiesel depend on the type of vegetable oil used for the transesterification process. The objective of the present work is to theoretically predict the iodine value and the saponification value of different biodiesels from their fatty acid methyl ester composition. The fatty acid ester compositions and the above values of different biodiesels were taken from the available published data. A multiple linear regression model was developed to predict the iodine value and saponification value of different biodiesels. The predicted results showed that the prediction errors were less than 3.4% compared to the available published data. The predicted values were also verified by substituting in the available published model which was developed to predict the higher heating values of biodiesel fuels from their iodine value and the saponification value. The resulting heating values of biodiesels were then compared with the published heating values and reported. (author)
Single-phase and two phase bubbly flow in a T connection: theoretical and experimental study
International Nuclear Information System (INIS)
Hervieu, Eric
1988-01-01
The objective of this research thesis is to highlight the driving factors of the separation of phases of a bubbly flow in a T junction, and to develop a prediction model. In a first part, the author reports the rigorous formulation of equations averaged on the T volume. He shows that it's not possible to solve globally the problem with these equations. Then, he reports a bibliographical study on the modelling of a bubbly flow, and, based upon this study, highlights intrinsic characteristics of the flow, and explains its dynamic mechanisms. He reports the development of the theoretical model, and describes the experimental installation used to validate it. In the third part, he reports the study of the liquid-gas interaction, and presents the adopted approach: study of the behaviour of an isolated bubble within a single-phase flow. Experimentation is used to check theoretical predictions. Results are used to compute phase separation. The obtained results are again compared with experimental results to validate the global relevance of the model [fr
Theoretical Predictions of Springing and Their Comparison with Full Scale Measurements
DEFF Research Database (Denmark)
Gu, X.; Storhaug, G.; Vidic-Perunovic, Jelena
2003-01-01
The present paper considers a large ocean going ship with significant springing responses, which have made a large contribution to the fatigue cracking for certain structural details. Four different theories for predicting ship responses and associated computer programs for predictions of springing...
Theoretical description and predictions of the properties of superheavy nuclei
Energy Technology Data Exchange (ETDEWEB)
Sobiczewski, A [Department of Theoretical Physics, Andrzej Soltan Institute for Nuclear Studies (Poland)
2009-12-31
Theoretical descriptions of superheavy atomic nuclei are shortly reviewed and illustrated by their results. Such properties of these nuclei as their shapes, masses, fission barriers, decay modes, decay energies, half-lives, are discussed. Special attention is given to the shell structure of the nuclei, due to which they exist. The role of the physical studies of the superheavy nuclei for the chemical research on the superheavy elements and, more generally, the relationship between these two kinds of investigation is underlined. This stresses the importance of close cooperation between physicists and chemists, experimentalists and theoreticians, in these studies.
Monahan, Carlyn J.; Muchinsky, Paul M.
1985-01-01
The degree of convergent validity among four methods of identifying vocational preferences is assessed via the decision theoretic paradigm. Vocational preferences identified by Holland's Vocational Preference Inventory (VPI), a rating procedure, and ranking were compared with preferences identified from a policy-capturing model developed from an…
International Nuclear Information System (INIS)
Harrop, L.P.
1982-02-01
Failure rates for non-nuclear pressure vessel populations are often regarded as showing a decrease with time. Empirical evidence can be cited which supports this view. On the other hand theoretical predictions of PWR type reactor pressure vessel failure rates have shown an increasing failure rate with time. It is shown that these two situations are not necessarily incompatible. If adjustments are made to the input data of the theoretical model to treat a non-nuclear pressure vessel population, the model can produce a failure rate which decreases with time. These adjustments are explained and the results obtained are shown. (author)
International Nuclear Information System (INIS)
Green, W.J.
1987-04-01
Simple theoretical models have been developed which are suitable for predicting the thermal responses of irradiated research fuel elements of markedly different geometries when they are subjected to loss-of-coolant accident conditions. These models have been used to calculate temperature responses corresponding to various non-forced convective conditions. Comparisons between experimentally observed temperatures and calculated values have shown that a suitable value for surface thermal emissivity is 0.35; modelling of the fuel element beyond the region of the fuel plate needs to be included since these areas account for approximately 25 per cent of the thermal power dissipated; general agreement between calculated and experimental temperatures for both transient and steady-state conditions is good - the maximum discrepancy between calculated and experimental temperatures for a HIFAR Mark IV/V fuel element is ∼ 70 deg C, and for an Oak Ridge Reactor (ORR) box-type fuel element ∼ 30 deg C; and axial power distribution does not significantly affect thermal responses for the conditions investigated. Overall, the comparisons have shown that the models evolved can reproduce experimental data to a level of accuracy that provides confidence in the modelling technique and the postulated heat dissipation mechanisms, and that these models can be used to predict thermal responses of fuel elements in accident conditions that are not easily investigated experimentally
Ahmed, Arif; Lim, Dongwon; Choi, Cheol Ho; Kim, Sunghwan
2017-06-30
The theoretical enthalpy calculated from the overall protonation reaction (electron transfer plus hydrogen transfer) in positive-mode (+) atmospheric-pressure photoionization (APPI) was compared with experimental results for 49 aromatic compounds. A linear relationship was observed between the calculated ΔH and the relative abundance of the protonated peak. The parameter gives reasonable predictions for all the aromatic hydrocarbon compounds used in this study. A parameter is devised by combining experimental MS data and high-level theoretical calculations. A (+) APPI Q Exactive Orbitrap mass spectrometer was used to obtain MS data for each solution. B3LYP exchange-correlation functions with the standard 6-311+G(df,2p) basis set was used to perform density functional theory (DFT) calculations. All the molecules with ΔH toluene clusters produced protonated ions, regardless of the desolvation temperature. For molecules with ΔH >0, molecular ions were more abundant at typical APPI desolvation temperatures (300°C), while the protonated ions became comparable or dominant at higher temperatures (400°C). The toluene cluster size was an important factor when predicting the ionization behavior of aromatic hydrocarbon ions in (+) APPI. The data used in this study clearly show that the theoretically calculated reaction enthalpy (ΔH) of protonation with toluene dimers can be used to predict the protonation behavior of aromatic compounds. When compounds have a negative ΔH value, the types of ions generated for aromatic compounds could be very well predicted based on the ΔH value. The ΔH can explain overall protonation behavior of compounds with ΔH values >0. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.
Theoretical model for the mechanical behavior of prestressed beams under torsion
Directory of Open Access Journals (Sweden)
Sérgio M.R. Lopes
2014-12-01
Full Text Available In this article, a global theoretical model previously developed and validated by the authors for reinforced concrete beams under torsion is reviewed and corrected in order to predict the global behavior of beams under torsion with uniform longitudinal prestress. These corrections are based on the introduction of prestress factors and on the modification of the equilibrium equations in order to incorporate the contribution of the prestressing reinforcement. The theoretical results obtained with the new model are compared with some available results of prestressed concrete (PC beams under torsion found in the literature. The results obtained in this study validate the proposed computing procedure to predict the overall behavior of PC beams under torsion.
Theoretical pulsation of metallic-line stars
International Nuclear Information System (INIS)
Cox, A.N.; King, D.S.; Hodson, S.W.
1979-01-01
The linear-theory radial-pulsation stability of low-helium delta Scuti variable models (1.0--2.5 Msun) has been investigated to see if metallicism and pulsation can occur simultaneously. Metallicism, which occurs in slowly rotating stars after the gravitational settling of He and the loss of the He II convection zone and its deep mixing for Y< or approx. =0.1, can then be established rapidly compared with the evolution time scale. Pulsation can still occur with driving due to the residual helium and the enhanced hydrogen. With the reduced helium giving no connection zone, the pulsation instability strip, whose blue and edges are estimated in this paoer, is about half as wide as with a normal helium abundance. Zero helium in the surface driving regions, however, produces blue edges so red that probably no instability strip exists at all. The red edge, predicted theoretically on the basis of the importance of convection in the outer zone, agrees well with the observational one. Cool, low-helium and metallic-line stars are then predicted to pulsate in a 200--500 K wide strip that is widest between the main-sequence luminosity of 5 Lsun and 15 Lsun. This strip reasonably includes the observed pulsating delta Del and mild Am stars, but there may be conflicts. Since blue edges for varying ionization-zone helium content occur across the entire instability strip, bluer first and higher overtone pulsations are also predicted everywhere from less than 7000 K to over 8000 K, the redder ones probably showing metallicism
Droplet size in flow: Theoretical model and application to polymer blends
Fortelný, Ivan; JÅ¯za, Josef
2017-05-01
The paper is focused on prediction of the average droplet radius, R, in flowing polymer blends where the droplet size is determined by dynamic equilibrium between the droplet breakup and coalescence. Expressions for the droplet breakup frequency in systems with low and high contents of the dispersed phase are derived using available theoretical and experimental results for model blends. Dependences of the coalescence probability, Pc, on system parameters, following from recent theories, is considered and approximate equation for Pc in a system with a low polydispersity in the droplet size is proposed. Equations for R in systems with low and high contents of the dispersed phase are derived. Combination of these equations predicts realistic dependence of R on the volume fraction of dispersed droplets, φ. Theoretical prediction of the ratio of R to the critical droplet radius at breakup agrees fairly well with experimental values for steadily mixed polymer blends.
Improving protein function prediction methods with integrated literature data
Directory of Open Access Journals (Sweden)
Gabow Aaron P
2008-04-01
Full Text Available Abstract Background Determining the function of uncharacterized proteins is a major challenge in the post-genomic era due to the problem's complexity and scale. Identifying a protein's function contributes to an understanding of its role in the involved pathways, its suitability as a drug target, and its potential for protein modifications. Several graph-theoretic approaches predict unidentified functions of proteins by using the functional annotations of better-characterized proteins in protein-protein interaction networks. We systematically consider the use of literature co-occurrence data, introduce a new method for quantifying the reliability of co-occurrence and test how performance differs across species. We also quantify changes in performance as the prediction algorithms annotate with increased specificity. Results We find that including information on the co-occurrence of proteins within an abstract greatly boosts performance in the Functional Flow graph-theoretic function prediction algorithm in yeast, fly and worm. This increase in performance is not simply due to the presence of additional edges since supplementing protein-protein interactions with co-occurrence data outperforms supplementing with a comparably-sized genetic interaction dataset. Through the combination of protein-protein interactions and co-occurrence data, the neighborhood around unknown proteins is quickly connected to well-characterized nodes which global prediction algorithms can exploit. Our method for quantifying co-occurrence reliability shows superior performance to the other methods, particularly at threshold values around 10% which yield the best trade off between coverage and accuracy. In contrast, the traditional way of asserting co-occurrence when at least one abstract mentions both proteins proves to be the worst method for generating co-occurrence data, introducing too many false positives. Annotating the functions with greater specificity is harder
Empirical and theoretical challenges in aboveground-belowground ecology
DEFF Research Database (Denmark)
W.H. van der Putten,; R.D. Bardgett; P.C. de Ruiter
2009-01-01
of the current conceptual succession models into more predictive models can help targeting empirical studies and generalising their results. Then, we discuss how understanding succession may help to enhance managing arable crops, grasslands and invasive plants, as well as provide insights into the effects...... and environmental settings, we explore where and how they can be supported by theoretical approaches to develop testable predictions and to generalise empirical results. We review four key areas where a combined aboveground-belowground approach offers perspectives for enhancing ecological understanding, namely...
Theoretical predictions of lactate and hydrogen ion distributions in tumours.
Directory of Open Access Journals (Sweden)
Maymona Al-Husari
Full Text Available High levels of lactate and H(+-ions play an important role in the invasive and metastatic cascade of some tumours. We develop a mathematical model of cellular pH regulation focusing on the activity of the Na(+/H(+ exchanger (NHE and the lactate/H(+ symporter (MCT to investigate the spatial correlations of extracellular lactate and H(+-ions. We highlight a crucial role for blood vessel perfusion rates in determining the spatial correlation between these two cations. We also predict critical roles for blood lactate, the activity of the MCTs and NHEs on the direction of the cellular pH gradient in the tumour. We also incorporate experimentally determined heterogeneous distributions of the NHE and MCT transporters. We show that this can give rise to a higher intracellular pH and a lower intracellular lactate but does not affect the direction of the reversed cellular pH gradient or redistribution of protons away from the glycolytic source. On the other hand, including intercellular gap junction communication in our model can give rise to a reversed cellular pH gradient and can influence the levels of pH.
Theoretical Study of Penalized-Likelihood Image Reconstruction for Region of Interest Quantification
International Nuclear Information System (INIS)
Qi, Jinyi; Huesman, Ronald H.
2006-01-01
Region of interest (ROI) quantification is an important task in emission tomography (e.g., positron emission tomography and single photon emission computed tomography). It is essential for exploring clinical factors such as tumor activity, growth rate, and the efficacy of therapeutic interventions. Statistical image reconstruction methods based on the penalized maximum-likelihood (PML) or maximum a posteriori principle have been developed for emission tomography to deal with the low signal-to-noise ratio of the emission data. Similar to the filter cut-off frequency in the filtered backprojection method, the regularization parameter in PML reconstruction controls the resolution and noise tradeoff and, hence, affects ROI quantification. In this paper, we theoretically analyze the performance of ROI quantification in PML reconstructions. Building on previous work, we derive simplified theoretical expressions for the bias, variance, and ensemble mean-squared-error (EMSE) of the estimated total activity in an ROI that is surrounded by a uniform background. When the mean and covariance matrix of the activity inside the ROI are known, the theoretical expressions are readily computable and allow for fast evaluation of image quality for ROI quantification with different regularization parameters. The optimum regularization parameter can then be selected to minimize the EMSE. Computer simulations are conducted for small ROIs with variable uniform uptake. The results show that the theoretical predictions match the Monte Carlo results reasonably well
Molecular adsorption of alkanes on platinum surfaces: A predictive theoretical model
International Nuclear Information System (INIS)
Stinnett, J.A.; Madix, R.J.
1996-01-01
The adsorption probabilities of methane and propane on Pt(111), and propane on Pt(110)-(1x2) have been successfully predicted for a wide range of incident energies and angles with classical stochastic trajectory simulations, using a pairwise additive Morse methyl endash platinum potential previously developed from the measured trapping probabilities of ethane on Pt(111). These predictions, along with those for ethane adsorption on Pt(110)endash(1x2), comprise a unified model for the molecular adsorption of alkanes on platinum surfaces. The simulations show the initial trapping probabilities of methane and propane on Pt(111) are determined to within approximately 10% by the fate of the first bounce. They also indicate that at normal incidence on Pt(111) energy conversions from perpendicular translational motion to both cartwheeling rotation and lattice phonons play increasingly important roles in increasing the trapping probability as the alkane increases in size and molecular weight. For methane itself excitation of parallel translational momentum after the first bounce serves as the most effective energy storage mechanism which facilitates trapping, whereas for propane cartwheel rotational motion plays the dominant role. Excessive excitation of these modes of motion, however, can cause scattering on subsequent bounces by reconversion of the energy into perpendicular translational energy. Collisions of methane with the hollow and bridge sites on the Pt(111) surface appear less effective in trapping than do atop sites. The simulations also suggest excitation of the C endash C endash C bending mode of propane has little effect on the trapping of propane on platinum surfaces for beam energies below 55 kJ/mol. copyright 1996 American Institute of Physics
Production of electroweak bosons at hadron colliders: theoretical aspects
Mangano, Michelangelo L.
2016-01-01
Since the W and Z discovery, hadron colliders have provided a fertile ground, in which continuously improving measurements and theoretical predictions allow to precisely determine the gauge boson properties, and to probe the dynamics of electroweak and strong interactions. This article will review, from a theoretical perspective, the role played by the study, at hadron colliders, of electroweak boson production properties, from the better understanding of the proton structure, to the discovery and studies of the top quark and of the Higgs, to the searches for new phenomena beyond the Standard Model.
Slow dynamics at critical points: the field-theoretical perspective
International Nuclear Information System (INIS)
Gambassi, Andrea
2006-01-01
The dynamics at a critical point provides a simple instance of slow collective evolution, characterised by aging phenomena and by a violation of the fluctuation-dissipation relation even for long times. By virtue of the universality in critical phenomena it is possible to provide quantitative predictions for some aspects of these behaviours by field-theoretical methods. We review some of the theoretical results that have been obtained in recent years for the relevant (universal) quantities, such as the fluctuation-dissipation ratio, associated with the non-equilibrium critical dynamics
Mechanical stretching of proteins-a theoretical survey of the Protein Data Bank
International Nuclear Information System (INIS)
Sulkowska, Joanna I; Cieplak, Marek
2007-01-01
The mechanical stretching of single proteins has been studied experimentally for about 50 proteins, yielding a variety of force patterns and peak forces. Here we perform a theoretical survey of proteins of known native structure and map out the landscape of possible dynamical behaviours under stretching at constant speed. We consider 7510 proteins comprising not more than 150 amino acids and 239 longer proteins. The model used is constructed based on the native geometry. It is solved by methods of molecular dynamics and validated by comparing the theoretical predictions to experimental results. We characterize the distribution of peak forces and investigate correlations with the system size and with the structure classification as characterized by the CATH scheme. Despite the presence of such correlations, proteins with the same CATH index may belong to different classes of dynamical behaviour. We identify proteins with the biggest forces and show that they belong to few topology classes. We determine which protein segments act as mechanical clamps and show that, in most cases, they correspond to long stretches of parallel β-strands, but other mechanisms are also possible. (topical review)
Deng, Jian; Zhou, Guangming; Ji, Le; Wang, Xiaopei
2017-12-01
Mechanical properties and failure mechanisms of a newly designed 3D multi-layer braided composites are evaluated by experimental, numerical and theoretical studies. The microstructure of the composites is introduced. The unit cell technique is employed to address the periodic arrangement of the structure. The volume averaging method is used in theoretical solutions while FEM with reasonable periodic boundary conditions and meshing technique in numerical simulations. Experimental studies are also conducted to verify the feasibility of the proposed models. Predicted elastic properties agree well with the experimental data, indicating the feasibility of the proposed models. Numerical evaluation is more accurate than theoretical assessment. Deformations and stress distributions of the unit cell under tension shows displacement and traction continuity, guaranteeing the rationality of the applied periodic boundary conditions. Although compression and tension modulus are close, the compressive strength only reaches 70% of the tension strength. This indicates that the composites can be weakened in compressive loading. Additionally, by analysing the micrograph of fracture faces and strain-stress curves, a brittle failure mechanism is observed both in composites under tension and compression.
Davies, Christine; Harrison, Judd; Lepage, G. Peter; Monahan, Christopher; Shigemitsu, Junko; Wingate, Matthew
2018-03-01
We present lattice QCD results for the matrix elements of R2 and other dimension-7, ΔB = 2 operators relevant for calculations of Δs, the Bs - B̅s width difference. We have computed correlation functions using 5 ensembles of the MILC Collaboration's 2+1 + 1-flavour gauge field configurations, spanning 3 lattice spacings and light sea quarks masses down to the physical point. The HISQ action is used for the valence strange quarks, and the NRQCD action is used for the bottom quarks. Once our analysis is complete, the theoretical uncertainty in the Standard Model prediction for ΔΓs will be substantially reduced.
Theoretical estimation of Z´ boson mass
International Nuclear Information System (INIS)
Maji, Priya; Banerjee, Debika; Sahoo, Sukadev
2016-01-01
The discovery of Higgs boson at the LHC brings a renewed perspective in particle physics. With the help of Higgs mechanism, standard model (SM) allows the generation of particle mass. The ATLAS and CMS experiments at the LHC have predicted the mass of Higgs boson as m_H=125-126 GeV. Recently, it is claimed that the Higgs boson might interact with dark matter and there exists relation between the Higgs boson and dark matter (DM). Hertzberg has predicted a correlation between the Higgs mass and the abundance of dark matter. His theoretical result is in good agreement with current data. He has predicted the mass of Higgs boson as GeV. The Higgs boson could be coupled to the particle that constitutes all or part of the dark matter in the universe. Light Z´ boson could have important implications in dark matter phenomenology
A course in theoretical physics
Shepherd, P J
2013-01-01
This book is a comprehensive account of five extended modules covering the key branches of twentieth-century theoretical physics, taught by the author over a period of three decades to students on bachelor and master university degree courses in both physics and theoretical physics. The modules cover nonrelativistic quantum mechanics, thermal and statistical physics, many-body theory, classical field theory (including special relativity and electromagnetism), and, finally, relativistic quantum mechanics and gauge theories of quark and lepton interactions, all presented in a single, self-contained volume. In a number of universities, much of the material covered (for example, on Einstein’s general theory of relativity, on the BCS theory of superconductivity, and on the Standard Model, including the theory underlying the prediction of the Higgs boson) is taught in postgraduate courses to beginning PhD students. A distinctive feature of the book is that full, step-by-step mathematical proofs of all essentia...
Accelerator simulation and theoretical modelling of radiation effects (SMoRE)
2018-01-01
This publication summarizes the findings and conclusions of the IAEA coordinated research project (CRP) on accelerator simulation and theoretical modelling of radiation effects, aimed at supporting Member States in the development of advanced radiation-resistant structural materials for implementation in innovative nuclear systems. This aim can be achieved through enhancement of both experimental neutron-emulation capabilities of ion accelerators and improvement of the predictive efficiency of theoretical models and computer codes. This dual approach is challenging but necessary, because outputs of accelerator simulation experiments need adequate theoretical interpretation, and theoretical models and codes need high dose experimental data for their verification. Both ion irradiation investigations and computer modelling have been the specific subjects of the CRP, and the results of these studies are presented in this publication which also includes state-ofthe- art reviews of four major aspects of the project...
Energy Technology Data Exchange (ETDEWEB)
Ko, Han Gyul; Kim, Hong Seok [Seoul Nat' l Univ., Seoul (Korea, Republic of)
2013-01-15
A cyclone separator has been widely used in various industrial processes for removing fine particulate matter because it is easy to fabricate, cost effective, and adaptable to extremely harsh conditions. However, owing to the complex flow field in cyclones, a complete understanding of the detailed mechanisms of particulate removal has not yet been gained. In this study, a theoretical analysis was performed for calculating the collection efficiency and cut off size in cyclones by taking into account the effects of geometrical and flow parameters. The collection efficiency and cut off size values predicted by the theoretical model showed good agreement with experimental measurements for particles with a diameter of 0.5-30{mu}m. It was also revealed that the surface friction, along with the flow and geometrical parameters, has a significant effect on the cyclone performance.
Hake, Anna; Pfeifer, Nico
2017-10-01
Treatment with broadly neutralizing antibodies (bNAbs) has proven effective against HIV-1 infections in humanized mice, non-human primates, and humans. Due to the high mutation rate of HIV-1, resistance testing of the patient's viral strains to the bNAbs is still inevitable. So far, bNAb resistance can only be tested in expensive and time-consuming neutralization experiments. Here, we introduce well-performing computational models that predict the neutralization response of HIV-1 to bNAbs given only the envelope sequence of the virus. Using non-linear support vector machines based on a string kernel, the models learnt even the important binding sites of bNAbs with more complex epitopes, i.e., the CD4 binding site targeting bNAbs, proving thereby the biological relevance of the models. To increase the interpretability of the models, we additionally provide a new kind of motif logo for each query sequence, visualizing those residues of the test sequence that influenced the prediction outcome the most. Moreover, we predicted the neutralization sensitivity of around 34,000 HIV-1 samples from different time points to a broad range of bNAbs, enabling the first analysis of HIV resistance to bNAbs on a global scale. The analysis showed for many of the bNAbs a trend towards antibody resistance over time, which had previously only been discovered for a small non-representative subset of the global HIV-1 population.
Yang, Li; Wang, Guobao; Qi, Jinyi
2016-04-01
Detecting cancerous lesions is a major clinical application of emission tomography. In a previous work, we studied penalized maximum-likelihood (PML) image reconstruction for lesion detection in static PET. Here we extend our theoretical analysis of static PET reconstruction to dynamic PET. We study both the conventional indirect reconstruction and direct reconstruction for Patlak parametric image estimation. In indirect reconstruction, Patlak parametric images are generated by first reconstructing a sequence of dynamic PET images, and then performing Patlak analysis on the time activity curves (TACs) pixel-by-pixel. In direct reconstruction, Patlak parametric images are estimated directly from raw sinogram data by incorporating the Patlak model into the image reconstruction procedure. PML reconstruction is used in both the indirect and direct reconstruction methods. We use a channelized Hotelling observer (CHO) to assess lesion detectability in Patlak parametric images. Simplified expressions for evaluating the lesion detectability have been derived and applied to the selection of the regularization parameter value to maximize detection performance. The proposed method is validated using computer-based Monte Carlo simulations. Good agreements between the theoretical predictions and the Monte Carlo results are observed. Both theoretical predictions and Monte Carlo simulation results show the benefit of the indirect and direct methods under optimized regularization parameters in dynamic PET reconstruction for lesion detection, when compared with the conventional static PET reconstruction.
THEORETICAL EVOLUTION OF OPTICAL STRONG LINES ACROSS COSMIC TIME
Energy Technology Data Exchange (ETDEWEB)
Kewley, Lisa J.; Dopita, Michael A.; Sutherland, Ralph [Research School for Astronomy and Astrophysics, Mount Stromlo Observatory, Cotter Road, Weston, ACT 2611 (Australia); Leitherer, Claus [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Dave, Romeel [Department of Astronomy/Steward Observatory, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States); Yuan, Tiantian [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Allen, Mark [Observatoire de Strasbourg, UMR 7550, Strasbourg 67000 (France); Groves, Brent, E-mail: kewley@mso.anu.edu.au [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany)
2013-09-10
We use the chemical evolution predictions of cosmological hydrodynamic simulations with our latest theoretical stellar population synthesis, photoionization, and shock models to predict the strong line evolution of ensembles of galaxies from z = 3 to the present day. In this paper, we focus on the brightest optical emission-line ratios, [N II]/H{alpha} and [O III]/H{beta}. We use the optical diagnostic Baldwin-Phillips-Terlevich (BPT) diagram as a tool for investigating the spectral properties of ensembles of active galaxies. We use four redshift windows chosen to exploit new near-infrared multi-object spectrographs. We predict how the BPT diagram will appear in these four redshift windows given different sets of assumptions. We show that the position of star-forming galaxies on the BPT diagram traces the interstellar medium conditions and radiation field in galaxies at a given redshift. Galaxies containing active galactic nucleus (AGN) form a mixing sequence with purely star-forming galaxies. This mixing sequence may change dramatically with cosmic time, due to the metallicity sensitivity of the optical emission-lines. Furthermore, the position of the mixing sequence may probe metallicity gradients in galaxies as a function of redshift, depending on the size of the AGN narrow-line region. We apply our latest slow shock models for gas shocked by galactic-scale winds. We show that at high redshift, galactic wind shocks are clearly separated from AGN in line ratio space. Instead, shocks from galactic winds mimic high metallicity starburst galaxies. We discuss our models in the context of future large near-infrared spectroscopic surveys.
Set-Theoretic Approach to Maturity Models
DEFF Research Database (Denmark)
Lasrado, Lester Allan
Despite being widely accepted and applied, maturity models in Information Systems (IS) have been criticized for the lack of theoretical grounding, methodological rigor, empirical validations, and ignorance of multiple and non-linear paths to maturity. This PhD thesis focuses on addressing...... these criticisms by incorporating recent developments in configuration theory, in particular application of set-theoretic approaches. The aim is to show the potential of employing a set-theoretic approach for maturity model research and empirically demonstrating equifinal paths to maturity. Specifically...... methodological guidelines consisting of detailed procedures to systematically apply set theoretic approaches for maturity model research and provides demonstrations of it application on three datasets. The thesis is a collection of six research papers that are written in a sequential manner. The first paper...
Morshedi, Hosein; Naseri, Mosayeb; Hantehzadeh, Mohammad Reza; Elahi, Seyed Mohammad
2018-04-01
In this paper, using a first principles calculation, a two-dimensional structure of silicon-antimony named penta-Sb2Si is predicted. The structural, kinetic, and thermal stabilities of the predicted monolayer are confirmed by the cohesive energy calculation, phonon dispersion analysis, and first principles molecular dynamic simulation, respectively. The electronic properties investigation shows that the pentagonal Sb2Si monolayer is a semiconductor with an indirect band gap of about 1.53 eV (2.1 eV) from GGA-PBE (PBE0 hybrid functional) calculations which can be effectively engineered by employing external biaxial compressive and tensile strain. Furthermore, the optical characteristics calculation indicates that the predicted monolayer has considerable optical absorption and reflectivity in the ultraviolet region. The results suggest that a Sb2Si monolayer has very good potential applications in new nano-optoelectronic devices.
Brian K. Via; chi L. So; Leslie H. Groom; Todd F. Shupe; michael Stine; Jan. Wikaira
2007-01-01
A theoretical model was built predicting the relationship between microfibril angle and lignin content at the Angstrom (A) level. Both theoretical and statistical examination of experimental data supports a square root transformation of lignin to predict microfibril angle. The experimental material used came from 10 longleaf pine (Pinus palustris)...
An Electrically Actuated Microbeam-Based MEMS Device: Experimental and Theoretical Investigation
Ruzziconi, Laura
2017-11-03
The present paper deals with the dynamic behavior of a microelectromechanical systems (MEMS). The device consists of a clamped-clamped microbeam electrostatically and electrodynamically actuated. Our objective is to develop a theoretical analysis, which is able to describe and predict all the main relevant aspects of the experimental response. In the first part of the paper an extensive experimental investigation is conducted. The microbeam is perfectly straight. The first three experimental natural frequencies are identified and the nonlinear dynamics are explored at increasing values of electrodynamic excitation. Several backward and forward frequency sweeps are acquired. The nonlinear behavior is highlighted. The experimental data show the coexistence of the nonresonant and the resonant branch, which perform a bending toward higher frequencies values before undergoing jump or pull-in dynamics. This kind of bending is not particularly common in MEMS. In the second part of the paper, a theoretical single degree-of-freedom model is derived. The unknown parameters are extracted and settled via parametric identification. A single mode reduced-order model is considered, which is obtained via the Galerkin technique. To enhance the computational efficiency, the contribution of the electric force term is computed in advance and stored in a table. Extensive numerical simulations are performed at increasing values of electrodynamic excitation. They are observed to properly predict all the main nonlinear features arising in the device response. This occurs not only at low values of electrodynamic excitation, but also at higher ones
Theoretical study of liquid droplet dispersion in a venturi scrubber.
Fathikalajahi, J; Talaie, M R; Taheri, M
1995-03-01
The droplet concentration distribution in an atomizing scrubber was calculated based on droplet eddy diffusion by a three-dimensional dispersion model. This model is also capable of predicting the liquid flowing on the wall. The theoretical distribution of droplet concentration agrees well with experimental data given by Viswanathan et al. for droplet concentration distribution in a venturi-type scrubber. The results obtained by the model show a non-uniform distribution of drops over the cross section of the scrubber, as noted by the experimental data. While the maximum of droplet concentration distribution may depend on many operating parameters of the scrubber, the results of this study show that the highest uniformity of drop distribution will be reached when penetration length is approximately equal to one-fourth of the depth of the scrubber. The results of this study can be applied to evaluate the removal efficiency of a venturi scrubber.
International Nuclear Information System (INIS)
Lee, Kwon-Yeong; Kim, Moo Hwan; Kim, Moo Hwan
2008-01-01
A theoretical model was developed to investigate a steam condensation with a noncondensable gas in a horizontal tube. The heat transfer through the vapor/noncondensable gas mixture boundary layer consists of the sensible heat transfer and the latent heat transfer given up by the condensing vapor, and it must equal that from the condensate film to the tube wall. Therefore, the total heat transfer coefficient is given by the film, condensation and sensible heat transfer coefficients. The film heat transfer coefficients of the upper and lower portions of the tube were calculated separately from Rosson and Meyers (1965) correlation. The heat and mass transfer analogy was used to analyze the steam/noncondensable gas mixture boundary layer. Here, the Nusselt and Sherwood numbers in the gas phase were modified to incorporate the effects of condensate film roughness, suction, and developing flow. The predictions of the theoretical model for the experimental heat transfer coefficients at the top and bottom of the tube were reasonable. The calculated heat transfer coefficients at the top of the tube were higher than those at the bottom of it, as experimental results. As the temperature potential at the top of tube was lower than that at the bottom of it, the heat fluxes at the upper and lower portions of the tube were similar to each other. Generally speaking, however, the model predictions showed a good agreement with experimental data. The new empirical correlation proposed by Lee and Kim (2008) for the vertical tube was applied to the condensation of steam/noncondensable mixture in a horizontal tube. Nusselt theory and Chato correlation were used to calculate the heat transfer coefficients at top and bottom of the horizontal tube, respectively. The predictions of the new empirical correlation were good and very similar with the theoretical model. (author)
Theoretical model and simulations for a cw exciplex pumped alkali laser.
Huang, Wei; Tan, Rongqing; Li, Zhiyong; Lu, Xiaochuan
2015-12-14
The Exciplex Pumped Alkali Laser (XPAL) system, which is similar to DPAL (Diode Pumped Alkali vapor Laser), has been demonstrated in mixtures of Cs vapor, Ar, with and without ethane. Unlike DPAL, it uses the broadband absorption blue satellite of the alkali D2 line, created by naturally occuring collision pairs. For example, Cs-Ar collision pairs have an absorption width which is as wide as the one of commercial semiconductor diode lasers. A continuous wave XPAL four-level theoretical model is presented in this paper. More factors are considered, such as the spectral dependence of pumped laser absorption for broadband pumping and the longitudinal population variation. Some intra-cavity details, such as longitudinal distributions of pumped laser and alkali laser, can also be solved well. The predictions of optical-to-optical efficiency as a function of temperature and pumped laser intensity are presented. The model predicts that there is an optimum value of temperature or pumped laser intensity. The analysis of the influence of cell length on optical-to-optical efficiency shows that a better performance can be achieved when using longer cell. The prediction of influence of Ar concentration and reflectivity of output coupler shows that higher optical-to-optical efficiency could be achieved if lower reflectivity of output coupler and higher Ar concentration are used. The optical-to-optical efficiency as high as 84% achieved by optimizing configuration with the pumped intensity of 5 × 10⁷ W/cm² presented shows that broadband pumped four-level XPAL system has a potential of high optical-to-optical efficiency.
Theoretical models of neutron emission in fission
International Nuclear Information System (INIS)
Madland, D.G.
1992-01-01
A brief survey of theoretical representations of two of the observables in neutron emission in fission is given, namely, the prompt fission neutron spectrum N(E) and the average prompt neutron multiplicity bar v p . Early representations of the two observables are presented and their deficiencies are discussed. This is followed by summaries and examples of recent theoretical models for the calculation of these quantities. Emphasis is placed upon the predictability and accuracy of the new models. In particular, the dependencies of N(E) and bar v p upon the fissioning nucleus and its excitation energy are treated. Recent work in the calculation of the prompt fission neutron spectrum matrix N(E,E n ), where E n is the energy of the neutron inducing fission, is then discussed. Concluding remarks address the current status of our ability to calculate these observables with confidence, the direction of future theoretical efforts, and limititations to current and future calculations. Finally, recommendations are presented as to which model should be used currently and which model should be pursued in future efforts
Physical violence and psychological abuse among siblings :a theoretical and empirical analysis
Hoffman, Kristi L.
1996-01-01
This study develops and evaluates a theoretical model based on social learning, conflict, and feminist perspectives to explain teenage sibling physical violence and psychological abuse. Using regression analysis and data from 796 young adults, considerable support is found for all three theoretical approaches and suggests an integrated model best predicts acts of violence and abuse among siblings. For physical violence, males and brothers had significantly higher rates. Spousal...
Unbalanced Regressions and the Predictive Equation
DEFF Research Database (Denmark)
Osterrieder, Daniela; Ventosa-Santaulària, Daniel; Vera-Valdés, J. Eduardo
Predictive return regressions with persistent regressors are typically plagued by (asymptotically) biased/inconsistent estimates of the slope, non-standard or potentially even spurious statistical inference, and regression unbalancedness. We alleviate the problem of unbalancedness in the theoreti......Predictive return regressions with persistent regressors are typically plagued by (asymptotically) biased/inconsistent estimates of the slope, non-standard or potentially even spurious statistical inference, and regression unbalancedness. We alleviate the problem of unbalancedness...... in the theoretical predictive equation by suggesting a data generating process, where returns are generated as linear functions of a lagged latent I(0) risk process. The observed predictor is a function of this latent I(0) process, but it is corrupted by a fractionally integrated noise. Such a process may arise due...... to aggregation or unexpected level shifts. In this setup, the practitioner estimates a misspecified, unbalanced, and endogenous predictive regression. We show that the OLS estimate of this regression is inconsistent, but standard inference is possible. To obtain a consistent slope estimate, we then suggest...
Theoretical Simulations of Materials for Nuclear Energy Applications
International Nuclear Information System (INIS)
Abrikosov, A.; Ponomareva, A.V.; Nikonov, A.Y.; Barannikova, S.A.; Dmitriev, A.I.
2014-01-01
We have demonstrated that state-of-the art theoretical calculations have a capability to predict thermodynamic and mechanical properties of materials with very high accuracy, comparable to the experimental accuracy. Considering Fe-Cr alloys, we have investigated the effect of multicomponent alloying on their phase stability, and we have shown that alloying elements Ni, Mn, and Mo, present in RPV steels, reduce the stability of low-Cr steels against binodal, as well as spinodal decomposition. Considering Zr-Nb alloys, we have demonstrated a possibility of obtaining their elastic moduli from ab initio electronic structure calculations. We argue that theoretical simulations represent valuable tool for a design of new materials for nuclear energy applications
Experimental and theoretical study of magnetohydrodynamic ship models.
Cébron, David; Viroulet, Sylvain; Vidal, Jérémie; Masson, Jean-Paul; Viroulet, Philippe
2017-01-01
Magnetohydrodynamic (MHD) ships represent a clear demonstration of the Lorentz force in fluids, which explains the number of students practicals or exercises described on the web. However, the related literature is rather specific and no complete comparison between theory and typical small scale experiments is currently available. This work provides, in a self-consistent framework, a detailed presentation of the relevant theoretical equations for small MHD ships and experimental measurements for future benchmarks. Theoretical results of the literature are adapted to these simple battery/magnets powered ships moving on salt water. Comparison between theory and experiments are performed to validate each theoretical step such as the Tafel and the Kohlrausch laws, or the predicted ship speed. A successful agreement is obtained without any adjustable parameter. Finally, based on these results, an optimal design is then deduced from the theory. Therefore this work provides a solid theoretical and experimental ground for small scale MHD ships, by presenting in detail several approximations and how they affect the boat efficiency. Moreover, the theory is general enough to be adapted to other contexts, such as large scale ships or industrial flow measurement techniques.
Experimental and theoretical study of magnetohydrodynamic ship models.
Directory of Open Access Journals (Sweden)
David Cébron
Full Text Available Magnetohydrodynamic (MHD ships represent a clear demonstration of the Lorentz force in fluids, which explains the number of students practicals or exercises described on the web. However, the related literature is rather specific and no complete comparison between theory and typical small scale experiments is currently available. This work provides, in a self-consistent framework, a detailed presentation of the relevant theoretical equations for small MHD ships and experimental measurements for future benchmarks. Theoretical results of the literature are adapted to these simple battery/magnets powered ships moving on salt water. Comparison between theory and experiments are performed to validate each theoretical step such as the Tafel and the Kohlrausch laws, or the predicted ship speed. A successful agreement is obtained without any adjustable parameter. Finally, based on these results, an optimal design is then deduced from the theory. Therefore this work provides a solid theoretical and experimental ground for small scale MHD ships, by presenting in detail several approximations and how they affect the boat efficiency. Moreover, the theory is general enough to be adapted to other contexts, such as large scale ships or industrial flow measurement techniques.
Mesoscopic structure prediction of nanoparticle assembly and coassembly: Theoretical foundation
Hur, Kahyun; Hennig, Richard G.; Escobedo, Fernando A.; Wiesner, Ulrich
2010-01-01
structures and interactions. We validate our approach by comparing its predictions with previous simulation results for model systems. We illustrate the flexibility of our approach by applying it to hybrid systems composed of block copolymers and ligand
Directory of Open Access Journals (Sweden)
Maria Célia Dantas Pollig
2016-12-01
Full Text Available This paper presents the theoretical basis I have used to better understand the dimension of the task I intend to accomplish. As Educational Advisor at the Federal Institute of Education, Science and Technology of Rio de Janeiro (IFRJ, campus Realengo, my plan is to develop and expand the so called Talent Show Project, by complementing technical training, and providing opportunities for artistic and cultural expression. The study also presents several reflections for achieving the expansion of the scope of the Project intervention, which can become an institutional program developed at IFRJ.
A Symbiotic Framework for coupling Machine Learning and Geosciences in Prediction and Predictability
Ravela, S.
2017-12-01
In this presentation we review the two directions of a symbiotic relationship between machine learning and the geosciences in relation to prediction and predictability. In the first direction, we develop ensemble, information theoretic and manifold learning framework to adaptively improve state and parameter estimates in nonlinear high-dimensional non-Gaussian problems, showing in particular that tractable variational approaches can be produced. We demonstrate these applications in the context of autonomous mapping of environmental coherent structures and other idealized problems. In the reverse direction, we show that data assimilation, particularly probabilistic approaches for filtering and smoothing offer a novel and useful way to train neural networks, and serve as a better basis than gradient based approaches when we must quantify uncertainty in association with nonlinear, chaotic processes. In many inference problems in geosciences we seek to build reduced models to characterize local sensitivies, adjoints or other mechanisms that propagate innovations and errors. Here, the particular use of neural approaches for such propagation trained using ensemble data assimilation provides a novel framework. Through these two examples of inference problems in the earth sciences, we show that not only is learning useful to broaden existing methodology, but in reverse, geophysical methodology can be used to influence paradigms in learning.
Combine experimental and theoretical investigation on an alkaloid-Dimethylisoborreverine
Singh, Swapnil; Singh, Harshita; Karthick, T.; Agarwal, Parag; Erande, Rohan D.; Dethe, Dattatraya H.; Tandon, Poonam
2016-01-01
A combined experimental (FT-IR, 1H and 13C NMR) and theoretical approach is used to study the structure and properties of antimalarial drug dimethylisoborreverine (DMIB). Conformational analysis, has been performed by plotting one dimensional potential energy curve that was computed using density functional theory (DFT) with B3LYP/6-31G method and predicted conformer A1 as the most stable conformer. After full geometry optimization, harmonic wavenumbers were computed for conformer A1 at the DFT/B3LYP/6-311++G(d,P) level. A complete vibrational assignment of all the vibrational modes have been performed on the bases of the potential energy distribution (PED) and theoretical results were found to be in good agreement with the observed data. To predict the solvent effect, the UV-Vis spectra were calculated in different solvents by polarizable continuum model using TD-DFT method. Molecular docking studies were performed to test the biological activity of the sample using SWISSDOCK web server and Hex 8.0.0 software. The molecular electrostatic potential (MESP) was plotted to identify the reactive sites of the molecule. Natural bond orbital (NBO) analysis was performed to get a deep insight of intramolecular charge transfer. Thermodynamical parameters were calculated to predict the direction of chemical reaction.
Directory of Open Access Journals (Sweden)
Parham Eslami-Nejad
2018-02-01
Full Text Available A new avenue in modern heat pump technology is related to the use of natural refrigerants such as carbon dioxide (CO2. The use of CO2 in direct expansion ground source heat pumps (DX-GSHP has also gained significant interest as it offers opportunities for cost reduction of the ground loop, albeit some challenges remain in their development, design and use. To address these challenges and to characterize CO2-DX-GSHP performance for water heating applications, a detailed theoretical model and a fully-instrumented test apparatus was developed and built at CanmetENERGY Research Laboratory. The theoretical model was validated against a set of experimental results and adopted to investigate the performance of the system over a wide operating range. Validation results showed that the model predicts the experimental results within the measurement uncertainty. A detailed system performance analysis was also performed using the theoretical model to understand the system behavior and explore the actions required for performance improvement in future installations. The results of the analysis showed that improper design and control of some components, such as the gas cooler and ground heat exchanger can degrade the system performance by up to 25%, and the heat pump heating capacity by 7.5%.
Satyapal, Shobita; Abel, Nicholas P.; Secrest, Nathan J.
2018-05-01
We conduct for the first time a theoretical investigation of the mid-infrared spectral energy distribution (SED) produced by dust heated by an active galactic nucleus (AGN) and an extreme starburst. These models employ an integrated modeling approach using photoionization and stellar population synthesis models in which both the line and emergent continuum is predicted from gas exposed to the ionizing radiation from a young starburst and an AGN. In this work, we focus on the infrared colors from the Wide-field Infrared Survey Explorer, predicting the dependence of the colors on the input radiation field, the interstellar medium conditions, the obscuring column, and the metallicity. We find that an extreme starburst can mimic an AGN in two band mid-infrared color cuts employed in the literature. However, the three-band color cuts employed in the literature require starbursts with extremely high ionization parameters or gas densities. We show that the extreme mid-infrared colors seen in some blue compact dwarf galaxies are not due to metallicity but rather a combination of high ionization parameters and high column densities. Based on our theoretical calculations, we present a theoretical mid-infrared color cut that will exclude even the most extreme starburst that we have modeled in this work. The theoretical AGN demarcation region presented here can be used to identify elusive AGN candidates for future follow-up studies with the James Webb Space Telescope. The full suite of simulated SEDs are available online.
Experimental and Theoretical Investigations of a Mechanical Lever System Driven by a DC Motor
Nana, B.; Fautso Kuiate, G.; Yamgoué, S. B.
This paper presents theoretical and experimental results on the investigation of the dynamics of a nonlinear electromechanical system made of a lever arm actuated by a DC motor and controlled through a repulsive magnetic force. We use the method of harmonic balance to derive oscillatory solutions. Theoretical tools such as, bifurcation diagrams, Lyapunov exponents, phase portraits, are used to unveil the rich nonlinear behavior of the system including chaos and hysteresis. The experimental results are in close accordance with the theoretical predictions.
DEFF Research Database (Denmark)
Vanko, Gyoergy; Bordage, Amelie; Pápai, Mátyás Imre
2015-01-01
Theoretical predictions show that depending on the populations of the Fe 3d(xy), 3d(xz), and 3d(yz) orbitals two possible quintet states can exist for the high-spin state of the photoswitchable model system [Fe(terpy)(2)](2+). The differences in the structure and molecular properties of these B-5...
Graph-theoretic measures of multivariate association and prediction
International Nuclear Information System (INIS)
Friedman, J.H.; Rafsky, L.C.
1983-01-01
Interpoint-distance-based graphs can be used to define measures of association that extend Kendall's notion of a generalized correlation coefficient. The authors present particular statistics that provide distribution-free tests of independence sensitive to alternatives involving non-monotonic relationships. Moreover, since ordering plays no essential role, the ideas that fully applicable in a multivariate setting. The authors also define an asymmetric coefficient measuring the extent to which (a vector) X can be used to make single-valued predictions of (a vector) Y. The authors discuss various techniques for proving that such statistics are asymptotically normal. As an example of the effectiveness of their approach, the authors present an application to the examination of residuals from multiple regression. 18 references, 2 figures, 1 table
DEFF Research Database (Denmark)
Poel, Mike van der; Gehrig, Edeltraud; Hess, Ortwin
2005-01-01
Ultrafast gain dynamics in an optical amplifier with an active layer of self-organized quantum dots (QDs) emitting near 1.3$muhbox m$is characterized experimentally in a pump-probe experiment and modeled theoretically on the basis of QD Maxwell–Bloch equations. Experiment and theory are in good......$factor) is theoretically predicted and demonstrated in the experiments. The fundamental analysis reveals the underlying physical processes and indicates limitations to QD-based devices....
Theoretical prediction of low-density hexagonal ZnO hollow structures
Energy Technology Data Exchange (ETDEWEB)
Tuoc, Vu Ngoc, E-mail: tuoc.vungoc@hust.edu.vn [Institute of Engineering Physics, Hanoi University of Science and Technology, 1 Dai Co Viet Road, Hanoi (Viet Nam); Huan, Tran Doan [Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269-3136 (United States); Thao, Nguyen Thi [Institute of Engineering Physics, Hanoi University of Science and Technology, 1 Dai Co Viet Road, Hanoi (Viet Nam); Hong Duc University, 307 Le Lai, Thanh Hoa City (Viet Nam); Tuan, Le Manh [Hong Duc University, 307 Le Lai, Thanh Hoa City (Viet Nam)
2016-10-14
Along with wurtzite and zinc blende, zinc oxide (ZnO) has been found in a large number of polymorphs with substantially different properties and, hence, applications. Therefore, predicting and synthesizing new classes of ZnO polymorphs are of great significance and have been gaining considerable interest. Herein, we perform a density functional theory based tight-binding study, predicting several new series of ZnO hollow structures using the bottom-up approach. The geometry of the building blocks allows for obtaining a variety of hexagonal, low-density nanoporous, and flexible ZnO hollow structures. Their stability is discussed by means of the free energy computed within the lattice-dynamics approach. Our calculations also indicate that all the reported hollow structures are wide band gap semiconductors in the same fashion with bulk ZnO. The electronic band structures of the ZnO hollow structures are finally examined in detail.
Predictability and Prediction for an Experimental Cultural Market
Colbaugh, Richard; Glass, Kristin; Ormerod, Paul
Individuals are often influenced by the behavior of others, for instance because they wish to obtain the benefits of coordinated actions or infer otherwise inaccessible information. In such situations this social influence decreases the ex ante predictability of the ensuing social dynamics. We claim that, interestingly, these same social forces can increase the extent to which the outcome of a social process can be predicted very early in the process. This paper explores this claim through a theoretical and empirical analysis of the experimental music market described and analyzed in [1]. We propose a very simple model for this music market, assess the predictability of market outcomes through formal analysis of the model, and use insights derived through this analysis to develop algorithms for predicting market share winners, and their ultimate market shares, in the very early stages of the market. The utility of these predictive algorithms is illustrated through analysis of the experimental music market data sets [2].
Theoretical models for the muon spectrum at sea level
International Nuclear Information System (INIS)
Abdel-Monem, M.S.; Benbrook, J.R.; Osborne, A.R.; Sheldon, W.R.
1975-01-01
The absolute vertical cosmic ray muon spectrum is investigated theoretically. Models of high energy interactions (namely, Maeda-Cantrell (MC), Constant Energy (CE), Cocconi-Koester-Perkins (CKP) and Scaling Models) are used to calculate the spectrum of cosmic ray muons at sea level. A comparison is made between the measured spectrum and that predicted from each of the four theoretical models. It is concluded that the recently available measured muon differential intensities agree with the scaling model for energies less than 100 GeV and with the CKP model for energies greater than 200 GeV. The measured differential intensities (Abdel-Monem et al.) agree with scaling. (orig.) [de
Comparison of pause predictions of two sequence-dependent transcription models
International Nuclear Information System (INIS)
Bai, Lu; Wang, Michelle D
2010-01-01
Two recent theoretical models, Bai et al (2004, 2007) and Tadigotla et al (2006), formulated thermodynamic explanations of sequence-dependent transcription pausing by RNA polymerase (RNAP). The two models differ in some basic assumptions and therefore make different yet overlapping predictions for pause locations, and different predictions on pause kinetics and mechanisms. Here we present a comprehensive comparison of the two models. We show that while they have comparable predictive power of pause locations at low NTP concentrations, the Bai et al model is more accurate than Tadigotla et al at higher NTP concentrations. The pausing kinetics predicted by Bai et al is also consistent with time-course transcription reactions, while Tadigotla et al is unsuited for this type of kinetic prediction. More importantly, the two models in general predict different pausing mechanisms even for the same pausing sites, and the Bai et al model provides an explanation more consistent with recent single molecule observations
Stöltzner, Michael
Answering to the double-faced influence of string theory on mathematical practice and rigour, the mathematical physicists Arthur Jaffe and Frank Quinn have contemplated the idea that there exists a `theoretical' mathematics (alongside `theoretical' physics) whose basic structures and results still require independent corroboration by mathematical proof. In this paper, I shall take the Jaffe-Quinn debate mainly as a problem of mathematical ontology and analyse it against the backdrop of two philosophical views that are appreciative towards informal mathematical development and conjectural results: Lakatos's methodology of proofs and refutations and John von Neumann's opportunistic reading of Hilbert's axiomatic method. The comparison of both approaches shows that mitigating Lakatos's falsificationism makes his insights about mathematical quasi-ontology more relevant to 20th century mathematics in which new structures are introduced by axiomatisation and not necessarily motivated by informal ancestors. The final section discusses the consequences of string theorists' claim to finality for the theory's mathematical make-up. I argue that ontological reductionism as advocated by particle physicists and the quest for mathematically deeper axioms do not necessarily lead to identical results.
A System Theoretical Inspired Approach to Knowledge Construction
DEFF Research Database (Denmark)
Mathiasen, Helle
2008-01-01
student's knowledge construction, in the light of operative constructivism, inspired by the German sociologist N. Luhmann's system theoretical approach to epistemology. Taking observations as operations based on distinction and indication (selection) contingency becomes a fundamental condition in learning...... Abstract The aim of this paper is to discuss the relation between teaching and learning. The point of departure is that teaching environments (communication forums) is a potential facilitator for learning processes and knowledge construction. The paper present a theoretical frame work, to discuss...... processes, and a condition which teaching must address as far as teaching strives to stimulate non-random learning outcomes. Thus learning outcomes understood as the individual learner's knowledge construction cannot be directly predicted from events and characteristics in the environment. This has...
Sodium fires: French strategy - theoretical and experimental developments
International Nuclear Information System (INIS)
Descombes; Thomann; Malet, J.C.; Rzekiecki, R.
1985-01-01
After a description of the needs relating to LMFBR safety analysis and design in terms of prevention, detection and protection, the French strategy concerning sodium fires it presented. It includes theoretical developments supported with relevant experimental program, to allow reliable calculations and predictions for safety and design. The following physical phenomena are detailed: (1) sodium fire (mechanical and thermal effects); (2) sodium-structures interactions; (3) aerosols behavior
Frequency, probability, and prediction: easy solutions to cognitive illusions?
Griffin, D; Buehler, R
1999-02-01
Many errors in probabilistic judgment have been attributed to people's inability to think in statistical terms when faced with information about a single case. Prior theoretical analyses and empirical results imply that the errors associated with case-specific reasoning may be reduced when people make frequentistic predictions about a set of cases. In studies of three previously identified cognitive biases, we find that frequency-based predictions are different from-but no better than-case-specific judgments of probability. First, in studies of the "planning fallacy, " we compare the accuracy of aggregate frequency and case-specific probability judgments in predictions of students' real-life projects. When aggregate and single-case predictions are collected from different respondents, there is little difference between the two: Both are overly optimistic and show little predictive validity. However, in within-subject comparisons, the aggregate judgments are significantly more conservative than the single-case predictions, though still optimistically biased. Results from studies of overconfidence in general knowledge and base rate neglect in categorical prediction underline a general conclusion. Frequentistic predictions made for sets of events are no more statistically sophisticated, nor more accurate, than predictions made for individual events using subjective probability. Copyright 1999 Academic Press.
Shih, Kao-Shang; Hou, Sheng-Mou; Lin, Shang-Chih
2017-12-01
The pullout strength of a screw is an indicator of how secure bone fragments are being held in place. Such bone-purchasing ability is sensitive to bone quality, thread design, and the pilot hole, and is often evaluated by experimental and numerical methods. Historically, there are some mathematical formulae to simulate the screw withdrawal from the synthetic bone. There are great variations in screw specifications. However, extensive investigation of the correlation between experimental and analytical results has not been reported in literature. Referring to the literature formulae, this study aims to evaluate the differences in the calculated pullout strengths. The pullout tests of the surgical screws are measured and the sawbone is used as the testing block. The absolute errors and correlation coefficients of the experimental and analytical results are calculated as the comparison baselines of the formulae. The absolute error of the dental, traumatic, and spinal groups are 21.7%, 95.5%, and 37.0%, respectively. For the screws with a conical profile and/or tiny threads, the calculated and measured results are not well correlated. The formulae are not accurate indicators of the pullout strengths of the screws where the design parameters are slightly varied. However, the experimental and numerical results are highly correlated for the cylindrical screws. The pullout strength of a conical screw is higher than that of its counterpart, but all formulae consistently predict the opposite results. In general, the bony purchase of the buttress threads is securer than that of the symmetric thread. An absolute error of up to 51.4% indicates the theoretical results cannot predict the actual value of the pullout strength. Only thread diameter, pitch, and depth are considered in the investigated formulae. The thread profile and shape should be formulated to modify the slippage mechanism at the bone-screw interfaces and simulate the strength change in the squeezed bones
Basic Modelling principles and Validation of Software for Prediction of Collision Damage
DEFF Research Database (Denmark)
Simonsen, Bo Cerup
2000-01-01
This report describes basic modelling principles, the theoretical background and validation examples for the collision damage prediction module in the ISESO stand-alone software.......This report describes basic modelling principles, the theoretical background and validation examples for the collision damage prediction module in the ISESO stand-alone software....
Prediction of RNA secondary structure using generalized centroid estimators.
Hamada, Michiaki; Kiryu, Hisanori; Sato, Kengo; Mituyama, Toutai; Asai, Kiyoshi
2009-02-15
Recent studies have shown that the methods for predicting secondary structures of RNAs on the basis of posterior decoding of the base-pairing probabilities has an advantage with respect to prediction accuracy over the conventionally utilized minimum free energy methods. However, there is room for improvement in the objective functions presented in previous studies, which are maximized in the posterior decoding with respect to the accuracy measures for secondary structures. We propose novel estimators which improve the accuracy of secondary structure prediction of RNAs. The proposed estimators maximize an objective function which is the weighted sum of the expected number of the true positives and that of the true negatives of the base pairs. The proposed estimators are also improved versions of the ones used in previous works, namely CONTRAfold for secondary structure prediction from a single RNA sequence and McCaskill-MEA for common secondary structure prediction from multiple alignments of RNA sequences. We clarify the relations between the proposed estimators and the estimators presented in previous works, and theoretically show that the previous estimators include additional unnecessary terms in the evaluation measures with respect to the accuracy. Furthermore, computational experiments confirm the theoretical analysis by indicating improvement in the empirical accuracy. The proposed estimators represent extensions of the centroid estimators proposed in Ding et al. and Carvalho and Lawrence, and are applicable to a wide variety of problems in bioinformatics. Supporting information and the CentroidFold software are available online at: http://www.ncrna.org/software/centroidfold/.
A new theoretical approach to analyze complex processes in cytoskeleton proteins.
Li, Xin; Kolomeisky, Anatoly B
2014-03-20
Cytoskeleton proteins are filament structures that support a large number of important biological processes. These dynamic biopolymers exist in nonequilibrium conditions stimulated by hydrolysis chemical reactions in their monomers. Current theoretical methods provide a comprehensive picture of biochemical and biophysical processes in cytoskeleton proteins. However, the description is only qualitative under biologically relevant conditions because utilized theoretical mean-field models neglect correlations. We develop a new theoretical method to describe dynamic processes in cytoskeleton proteins that takes into account spatial correlations in the chemical composition of these biopolymers. Our approach is based on analysis of probabilities of different clusters of subunits. It allows us to obtain exact analytical expressions for a variety of dynamic properties of cytoskeleton filaments. By comparing theoretical predictions with Monte Carlo computer simulations, it is shown that our method provides a fully quantitative description of complex dynamic phenomena in cytoskeleton proteins under all conditions.
Prediction of the dollar to the ruble rate. A system-theoretic approach
Borodachev, Sergey M.
2017-07-01
Proposed a simple state-space model of dollar rate formation based on changes in oil prices and some mechanisms of money transfer between monetary and stock markets. Comparison of predictions by means of input-output model and state-space model is made. It concludes that with proper use of statistical data (Kalman filter) the second approach provides more adequate predictions of the dollar rate.
Retif, Paul; Reinhard, Aurélie; Paquot, Héna; Jouan-Hureaux, Valérie; Chateau, Alicia; Sancey, Lucie; Barberi-Heyob, Muriel; Pinel, Sophie; Bastogne, Thierry
This article addresses the in silico-in vitro prediction issue of organometallic nanoparticles (NPs)-based radiosensitization enhancement. The goal was to carry out computational experiments to quickly identify efficient nanostructures and then to preferentially select the most promising ones for the subsequent in vivo studies. To this aim, this interdisciplinary article introduces a new theoretical Monte Carlo computational ranking method and tests it using 3 different organometallic NPs in terms of size and composition. While the ranking predicted in a classical theoretical scenario did not fit the reference results at all, in contrast, we showed for the first time how our accelerated in silico virtual screening method, based on basic in vitro experimental data (which takes into account the NPs cell biodistribution), was able to predict a relevant ranking in accordance with in vitro clonogenic efficiency. This corroborates the pertinence of such a prior ranking method that could speed up the preclinical development of NPs in radiation therapy.
Shin, Hyun; Lee, Sunghun; Kim, Kwon-Hyeon; Moon, Chang-Ki; Yoo, Seung-Jun; Lee, Jeong-Hwan; Kim, Jang-Joo
2014-07-16
A high-efficiency blue-emitting organic light-emitting diode (OLED) approaching theoretical efficiency using an exciplex-forming co-host composed of N,N'-dicarbazolyl-3,5-benzene (mCP) and bis-4,6-(3,5-di-3-pyridylphenyl)- 2-methylpyrimidine (B3PYMPM) is fabricated. Iridium(III)bis[(4,6-difluorophenyl)- pyridinato-N,C2']picolinate (FIrpic) is used as the emitter, which turns out to have a preferred horizontal dipole orientation in the emitting layer. The OLED shows a maximum external quantum efficiency of 29.5% (a maximum current efficiency of 62.2 cd A(-1) ), which is in perfect agreement with the theoretical prediction. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
International Nuclear Information System (INIS)
Yonomoto, Taisuke; Tasaka, Kanji
1988-01-01
A theoretical and experimental study was conducted to understand two-phase flow discharged from a stratified two-phase region through a small break. This problem is important for an analysis of a small break loss-of-coolant accident (LOCA) in a light water reactor (LWR). The present theoretical results show that a break quality is a function of h/h b , where h is the elevation difference between a bulk water level in the upstream region and break and b the suffix for entrainment initiation. This result is consistent with existing eperimental results in literature. An air-water experiment was also conducted changing a break orientation as an experimental parameter to develop and assess the model. Comparisons between the model and the experimental results show that the present model can satisfactorily predict the flow rate and the quality at the break without using any adjusting constant when liquid entrainment occurs in a stratified two-phase region. When gas entrainment occurs, the experimental data are correlated well by using a single empirical constant. (author)
Pseudoracemic amino acid complexes: blind predictions for flexible two-component crystals.
Görbitz, Carl Henrik; Dalhus, Bjørn; Day, Graeme M
2010-08-14
Ab initio prediction of the crystal packing in complexes between two flexible molecules is a particularly challenging computational chemistry problem. In this work we present results of single crystal structure determinations as well as theoretical predictions for three 1 ratio 1 complexes between hydrophobic l- and d-amino acids (pseudoracemates), known from previous crystallographic work to form structures with one of two alternative hydrogen bonding arrangements. These are accurately reproduced in the theoretical predictions together with a series of patterns that have never been observed experimentally. In this bewildering forest of potential polymorphs, hydrogen bonding arrangements and molecular conformations, the theoretical predictions succeeded, for all three complexes, in finding the correct hydrogen bonding pattern. For two of the complexes, the calculations also reproduce the exact space group and side chain orientations in the best ranked predicted structure. This includes one complex for which the observed crystal packing clearly contradicted previous experience based on experimental data for a substantial number of related amino acid complexes. The results highlight the significant recent advances that have been made in computational methods for crystal structure prediction.
Theoretical model of an optothermal microactuator directly driven by laser beams
International Nuclear Information System (INIS)
Han, Xu; Zhang, Haijun; Xu, Rui; Wang, Shuying; Qin, Chun
2015-01-01
This paper proposes a novel method of optothermal microactuation based on single and dual laser beams (spots). The theoretical model of the optothermal temperature distribution of an expansion arm is established and simulated, indicating that the maximum temperature of the arm irradiated by dual laser spots, at the same laser power level, is much lower than that irradiated by one single spot, and thus the risk of burning out and damaging the optothermal microactuator (OTMA) can be effectively avoided. To verify the presented method, a 750 μm long OTMA with a 100 μm wide expansion arm is designed and microfabricated, and single/dual laser beams with a wavelength of 650 nm are adopted to carry out experiments. The experimental results showed that the optothermal deflection of the OTMA under the irradiation of dual laser spots is larger than that under the irradiation of a single spot with the same power, which is in accordance with theoretical prediction. This method of optothermal microactuation may expand the practical applications of microactuators, which serve as critical units in micromechanical devices and micro-opto-electro-mechanical systems (MOEMS). (paper)
Safety climate and injuries: an examination of theoretical and empirical relationships.
Beus, Jeremy M; Payne, Stephanie C; Bergman, Mindy E; Arthur, Winfred
2010-07-01
Our purpose in this study was to meta-analytically address several theoretical and empirical issues regarding the relationships between safety climate and injuries. First, we distinguished between extant safety climate-->injury and injury-->safety climate relationships for both organizational and psychological safety climates. Second, we examined several potential moderators of these relationships. Meta-analyses revealed that injuries were more predictive of organizational safety climate than safety climate was predictive of injuries. Additionally, the injury-->safety climate relationship was stronger for organizational climate than for psychological climate. Moderator analyses revealed that the degree of content contamination in safety climate measures inflated effects, whereas measurement deficiency attenuated effects. Additionally, moderator analyses showed that as the time period over which injuries were assessed lengthened, the safety climate-->injury relationship was attenuated. Supplemental meta-analyses of specific safety climate dimensions also revealed that perceived management commitment to safety is the most robust predictor of occupational injuries. Contrary to expectations, the operationalization of injuries did not meaningfully moderate safety climate-injury relationships. Implications and recommendations for future research and practice are discussed.
How cells engulf: a review of theoretical approaches to phagocytosis
Richards, David M.; Endres, Robert G.
2017-12-01
Phagocytosis is a fascinating process whereby a cell surrounds and engulfs particles such as bacteria and dead cells. This is crucial both for single-cell organisms (as a way of acquiring nutrients) and as part of the immune system (to destroy foreign invaders). This whole process is hugely complex and involves multiple coordinated events such as membrane remodelling, receptor motion, cytoskeleton reorganisation and intracellular signalling. Because of this, phagocytosis is an excellent system for theoretical study, benefiting from biophysical approaches combined with mathematical modelling. Here, we review these theoretical approaches and discuss the recent mathematical and computational models, including models based on receptors, models focusing on the forces involved, and models employing energetic considerations. Along the way, we highlight a beautiful connection to the physics of phase transitions, consider the role of stochasticity, and examine links between phagocytosis and other types of endocytosis. We cover the recently discovered multistage nature of phagocytosis, showing that the size of the phagocytic cup grows in distinct stages, with an initial slow stage followed by a much quicker second stage starting around half engulfment. We also address the issue of target shape dependence, which is relevant to both pathogen infection and drug delivery, covering both one-dimensional and two-dimensional results. Throughout, we pay particular attention to recent experimental techniques that continue to inform the theoretical studies and provide a means to test model predictions. Finally, we discuss population models, connections to other biological processes, and how physics and modelling will continue to play a key role in future work in this area.
Sibutramine characterization and solubility, a theoretical study
Aceves-Hernández, Juan M.; Nicolás Vázquez, Inés; Hinojosa-Torres, Jaime; Penieres Carrillo, Guillermo; Arroyo Razo, Gabriel; Miranda Ruvalcaba, René
2013-04-01
Solubility data from sibutramine (SBA) in a family of alcohols were obtained at different temperatures. Sibutramine was characterized by using thermal analysis and X-ray diffraction technique. Solubility data were obtained by the saturation method. The van't Hoff equation was used to obtain the theoretical solubility values and the ideal solvent activity coefficient. No polymorphic phenomena were found from the X-ray diffraction analysis, even though this compound is a racemic mixture of (+) and (-) enantiomers. Theoretical calculations showed that the polarisable continuum model was able to reproduce the solubility and stability of sibutramine molecule in gas phase, water and a family of alcohols at B3LYP/6-311++G (d,p) level of theory. Dielectric constant, dipolar moment and solubility in water values as physical parameters were used in those theoretical calculations for explaining that behavior. Experimental and theoretical results were compared and good agreement was obtained. Sibutramine solubility increased from methanol to 1-octanol in theoretical and experimental results.
A method for predicting monthly rainfall patterns
International Nuclear Information System (INIS)
Njau, E.C.
1987-11-01
A brief survey is made of previous methods that have been used to predict rainfall trends or drought spells in different parts of the earth. The basic methodologies or theoretical strategies used in these methods are compared with contents of a recent theory of Sun-Weather/Climate links (Njau, 1985a; 1985b; 1986; 1987a; 1987b; 1987c) which point towards the possibility of practical climatic predictions. It is shown that not only is the theoretical basis of each of these methodologies or strategies fully incorporated into the above-named theory, but also this theory may be used to develop a technique by which future monthly rainfall patterns can be predicted in further and finer details. We describe the latter technique and then illustrate its workability by means of predictions made on monthly rainfall patterns in some East African meteorological stations. (author). 43 refs, 11 figs, 2 tabs
An Order-Theoretic Quantification of Contextuality
Directory of Open Access Journals (Sweden)
Ian T. Durham
2014-09-01
Full Text Available In this essay, I develop order-theoretic notions of determinism and contextuality on domains and topoi. In the process, I develop a method for quantifying contextuality and show that the order-theoretic sense of contextuality is analogous to the sense embodied in the topos-theoretic statement of the Kochen–Specker theorem. Additionally, I argue that this leads to a relation between the entropy associated with measurements on quantum systems and the second law of thermodynamics. The idea that the second law has its origin in the ordering of quantum states and processes dates to at least 1958 and possibly earlier. The suggestion that the mechanism behind this relation is contextuality, is made here for the first time.
Yi, Xingwen; Xu, Bo; Zhang, Jing; Lin, Yun; Qiu, Kun
2014-12-15
Digital coherent superposition (DCS) of optical OFDM subcarrier pairs with Hermitian symmetry can reduce the inter-carrier-interference (ICI) noise resulted from phase noise. In this paper, we show two different implementations of DCS-OFDM that have the same performance in the presence of laser phase noise. We complete the theoretical calculation on ICI reduction by using the model of pure Wiener phase noise. By Taylor expansion of the ICI, we show that the ICI power is cancelled to the second order by DCS. The fourth order term is further derived out and only decided by the ratio of laser linewidth to OFDM subcarrier symbol rate, which can greatly simplify the system design. Finally, we verify our theoretical calculations in simulations and use the analytical results to predict the system performance. DCS-OFDM is expected to be beneficial to certain optical fiber transmissions.
Neurocognitive mechanisms of perception-action coordination: a review and theoretical integration.
Ridderinkhof, K Richard
2014-10-01
The present analysis aims at a theoretical integration of, and a systems-neuroscience perspective on, a variety of historical and contemporary views on perception-action coordination (PAC). We set out to determine the common principles or lawful linkages between sensory and motor systems that explain how perception is action-oriented and how action is perceptually guided. To this end, we analyze the key ingredients to such an integrated framework, examine the architecture of dual-system conjectures of PAC, and endeavor in an historical analysis of the key characteristics, mechanisms, and phenomena of PACs. This analysis will reveal that dual-systems views are in need of fundamental re-thinking, and its elements will be amalgamated with current views on action-oriented predictive processing into a novel integrative theoretical framework (IMPPACT: Impetus, Motivation, and Prediction in Perception-Action Coordination theory). From this framework and its neurocognitive architecture we derive a number of non-trivial predictions regarding conative, motive-driven PAC. We end by presenting a brief outlook on how IMPPACT might present novel insights into certain pathologies and into action expertise. Copyright © 2014 Elsevier Ltd. All rights reserved.
Quicksilver: Fast predictive image registration - A deep learning approach.
Yang, Xiao; Kwitt, Roland; Styner, Martin; Niethammer, Marc
2017-09-01
This paper introduces Quicksilver, a fast deformable image registration method. Quicksilver registration for image-pairs works by patch-wise prediction of a deformation model based directly on image appearance. A deep encoder-decoder network is used as the prediction model. While the prediction strategy is general, we focus on predictions for the Large Deformation Diffeomorphic Metric Mapping (LDDMM) model. Specifically, we predict the momentum-parameterization of LDDMM, which facilitates a patch-wise prediction strategy while maintaining the theoretical properties of LDDMM, such as guaranteed diffeomorphic mappings for sufficiently strong regularization. We also provide a probabilistic version of our prediction network which can be sampled during the testing time to calculate uncertainties in the predicted deformations. Finally, we introduce a new correction network which greatly increases the prediction accuracy of an already existing prediction network. We show experimental results for uni-modal atlas-to-image as well as uni-/multi-modal image-to-image registrations. These experiments demonstrate that our method accurately predicts registrations obtained by numerical optimization, is very fast, achieves state-of-the-art registration results on four standard validation datasets, and can jointly learn an image similarity measure. Quicksilver is freely available as an open-source software. Copyright © 2017 Elsevier Inc. All rights reserved.
Blai, Boris, Jr.
Psychological theories about human motivation and accommodation to environment can be used to achieve a better understanding of the human factors that function in the work environment. Maslow's theory of human motivational behavior provided a theoretical framework for an empirically-derived method to predict job satisfaction and explore the…
Show me the money: incorporating financial motives into the gambling motives questionnaire.
Dechant, Kristianne
2014-12-01
Although research has only recently begun to measure what motivates all levels of gambling involvement, motives could offer a theoretically interesting and practical way to subtype gamblers in research and for responsible gambling initiatives. The Gambling Motives Questionnaire (GMQ) is one measure that weaves together much of the gambling motives literature, but it has been criticized for neglecting financial reasons for gambling. This study uses a series of factor analyses to explore the effect of adding nine financial motives to the GMQ in a heterogeneous sample of 1,014 adult past-year gamblers. After trimming trivial financial motives, the penultimate factor analysis of the 15 GMQ items and four financial motives led to a four-factor solution, with factors tapping enhancement, social, coping and financial motives, as predicted. A final factor analysis performed on a modified GMQ-F (i.e., 16 items, including a financial subscale) revealed the same four factors, and hierarchical regression showed that the financial motives improve the GMQ-F's prediction of gambling frequency. This study provides evidence that omitting financial motives is a clear gap in the GMQ, yet suggests that the GMQ is a promising tool that can be conceptually and empirically strengthened with the simple addition of financial items.
A Simple theoretical model for 63Ni betavoltaic battery
International Nuclear Information System (INIS)
ZUO, Guoping; ZHOU, Jianliang; KE, Guotu
2013-01-01
A numerical simulation of the energy deposition distribution in semiconductors is performed for 63 Ni beta particles. Results show that the energy deposition distribution exhibits an approximate exponential decay law. A simple theoretical model is developed for 63 Ni betavoltaic battery based on the distribution characteristics. The correctness of the model is validated by two literature experiments. Results show that the theoretical short-circuit current agrees well with the experimental results, and the open-circuit voltage deviates from the experimental results in terms of the influence of the PN junction defects and the simplification of the source. The theoretical model can be applied to 63 Ni and 147 Pm betavoltaic batteries. - Highlights: • The energy deposition distribution is found following an approximate exponential decay law when beta particles emitted from 63 Ni pass through a semiconductor. • A simple theoretical model for 63 Ni betavoltaic battery is constructed based on the exponential decay law. • Theoretical model can be applied to the betavoltaic batteries which radioactive source has a similar energy spectrum with 63 Ni, such as 147 Pm
PREDICTION OF CORPORATE BANKRUPTCY IN ROMANIA THROUGH THE USE OF LOGISTIC REGRESSION
Directory of Open Access Journals (Sweden)
Brindescu-Olariu Daniel
2013-07-01
As theoretical contributions, the research proves that the companies that filed for bankruptcy during the crisis period showed signs of weaknesses before the beginning of the crisis. Financial ratios that show relevance in the prediction of corporate bankruptcy at local level have been identified and their correlation with the bankruptcy probability has been evaluated. The model is expected to maintain its accuracy with minimal or no additional calibration for companies from the entire Romanian economy that fit the profile of the target population.
Doyle, Frank; McGee, Hannah; Conroy, Ronán; Delaney, Mary
2011-01-01
Depression is associated with increased cardiovascular risk in patients with acute coronary syndrome (ACS), but some argue that elevated depression is actually a marker of cardiovascular disease severity. Therefore, disease indices should be better predictors of depression than established theoretical causes of depression (interpersonal life events, reinforcing events, cognitive distortions, type D personality). However, little theory-based research has been conducted in this area. In a cross...
Theoretical Predictions of the thermodynamic Properties of Solid Sorbents Capture CO2 Applications
Energy Technology Data Exchange (ETDEWEB)
Duan, Yuhua; Sorescu, Dan; Luebke David; Pennline, Henry
2012-05-02
We are establishing a theoretical procedure to identify most potential candidates of CO{sub 2} solid sorbents from a large solid material databank to meet the DOE programmatic goal for energy conversion; and to explore the optimal working conditions for the promising CO{sub 2} solid sorbents, especially from room to warm T ranges with optimal energy usage, used for both pre- and post-combustion capture technologies.
Energy Technology Data Exchange (ETDEWEB)
Vidal, Monica; Ruiz, Diana Milena [Hospital Clinic de Barcelona, Nuclear Medicine Department, Barcelona (Spain); Vidal-Sicart, Sergi; Paredes, Pilar; Pons, Francesca [Hospital Clinic de Barcelona, Nuclear Medicine Department, Barcelona (Spain); Institut d' Investigacions Biomediques Agusti Pi i Sunyer (IDIBAPS), Barcelona (Spain); Torres, Ferran [Hospital Clinic Barcelona, Statistical of Biostatistics and Data Management Core Facility, IDIBAPS, Barcelona (Spain); Universitat Autonoma de Barcelona, Biostatistics Unit, Faculty of Medicine, Barcelona (Spain)
2016-04-15
In the diagnosis of head and neck melanoma, lymphatic drainage is complex and highly variable. As regional lymph node metastasis is one of the most important prognostic factors, lymphoscintigraphy can help map individual drainage patterns. The aim of this study was to compare the results of lymphoscintigraphy and sentinel lymph node (SLN) detection with theoretical anatomical patterns of lymphatic drainage based on the location of the primary tumour lesion in patients with head and neck melanoma. We also determined the percentage of discrepancies between our lymphoscintigraphy and the theoretical location of nodal drainage predicted by a large lymphoscintigraphic database, in order to explain recurrence and false-negative SLN biopsies. In this retrospective study of 152 patients with head and neck melanoma, the locations of the SLNs on lymphoscintigraphy and detected intraoperatively were compared with the lymphatic drainage predicted by on-line software based on a large melanoma database. All patients showed lymphatic drainage and in all patients at least one SLN was identified by lymphoscintigraphy. Of the 152 patients, 4 had a primary lesion in areas that were not described in the Sydney Melanoma Unit database, so agreement could only be evaluated in 148 patients. Agreement between lymphoscintigraphic findings and the theoretical lymphatic drainage predicted by the software was completely concordant in 119 of the 148 patients (80.4 %, 95 % CI 73.3 - 86 %). However, this concordance was partial (some concordant nodes and others not) in 18 patients (12.2 %, 95 % CI 7.8 - 18.4 %). Discordance was complete in 11 patients (7.4 %, 95 % CI 4.2 - 12.8 %). In melanoma of the head and neck there is a high correlation between lymphatic drainage found by lymphoscintigraphy and the predicted drainage pattern and basins provided by a large reference database. Due to unpredictable drainage, preoperative lymphoscintigraphy is essential to accurately detect the SLNs in head and
Thermodynamics of nanoadsorption from solution: Theoretical and experimental research
International Nuclear Information System (INIS)
Wen, Yan-Zhen; Xue, Yong-Qiang; Cui, Zi-Xiang; Wang, Yan
2015-01-01
Highlights: • The thermodynamic theory of nanoadsorption was proposed. • The thermodynamic relations of nanoadsorption were derived. • The results of the experiments are accord with the theory. - Abstract: In this study, the effect of nanoparticle size on adsorption thermodynamics was investigated. The results of theoretical and experimental studies show that particle size significantly affects the equilibrium constant and thermodynamic properties of nanoadsorption. Relationships between the equilibrium constant, thermodynamic properties and particle size were derived using the thermodynamic theory of nanoadsorption. The equilibrium constant and thermodynamic properties were obtained by investigating the adsorption of Cu 2+ onto different sizes of nano-ZnO and the adsorption of Ag + onto different sizes of nano-TiO 2 . Good agreement was achieved between results obtained by experiments and predicted by theoretical analyses. The equilibrium constant and the molar Gibbs free energy of nanoadsorption were found to increase with smaller nanoparticle size. However, the effects of particle size on the molar enthalpy and the molar entropy are uncertain. In addition, the molar Gibbs free energy, the molar enthalpy, the molar entropy and the logarithm of the equilibrium constant are linearly related to the reciprocal of the diameter of the nanoparticle. The thermodynamic properties revealed in this study may provide important guidelines for research and application in the field of nanoadsorption
Theoretical Prediction of Melting Relations in the Deep Mantle: the Phase Diagram Approach
Belmonte, D.; Ottonello, G. A.; Vetuschi Zuccolini, M.; Attene, M.
2016-12-01
Despite the outstanding progress in computer technology and experimental facilities, understanding melting phase relations in the deep mantle is still an open challenge. In this work a novel computational scheme to predict melting relations at HP-HT by a combination of first principles DFT calculations, polymer chemistry and equilibrium thermodynamics is presented and discussed. The adopted theoretical framework is physically-consistent and allows to compute multi-component phase diagrams relevant to Earth's deep interior in a broad range of P-T conditions by a convex-hull algorithm for Gibbs free energy minimisation purposely developed for high-rank simplexes. The calculated phase diagrams are in turn used as a source of information to gain new insights on the P-T-X evolution of magmas in the deep mantle, providing some thermodynamic constraints to both present-day and early Earth melting processes. High-pressure melting curves of mantle silicates are also obtained as by-product of phase diagram calculation. Application of the above method to the MgO-Al2O3-SiO2 (MAS) ternary system highlights as pressure effects are not only able to change the nature of melting of some minerals (like olivine and pyroxene) from eutectic to peritectic (and vice versa), but also simplify melting relations by drastically reducing the number of phases with a primary phase field at HP-HT conditions. It turns out that mineral phases like Majorite-Pyrope garnet and Anhydrous Phase B (Mg14Si5O24), which are often disregarded in modelling melting processes of mantle assemblages, are stable phases at solidus or liquidus conditions in a P-T range compatible with the mantle transition zone (i.e. P = 16 - 23 GPa and T = 2200 - 2700 °C) when their thermodynamic and thermophysical properties are properly assessed. Financial support to the Senior Author (D.B.) during his stay as Invited Scientist at the Institut de Physique du Globe de Paris (IPGP, Paris) is warmly acknowledged.
Analytical predictions of SGEMP response and comparisons with computer calculations
International Nuclear Information System (INIS)
de Plomb, E.P.
1976-01-01
An analytical formulation for the prediction of SGEMP surface current response is presented. Only two independent dimensionless parameters are required to predict the peak magnitude and rise time of SGEMP induced surface currents. The analysis applies to limited (high fluence) emission as well as unlimited (low fluence) emission. Cause-effect relationships for SGEMP response are treated quantitatively, and yield simple power law dependencies between several physical variables. Analytical predictions for a large matrix of SGEMP cases are compared with an array of about thirty-five computer solutions of similar SGEMP problems, which were collected from three independent research groups. The theoretical solutions generally agree with the computer solutions as well as the computer solutions agree with one another. Such comparisons typically show variations less than a ''factor of two.''
Tapping generalized essentialism to predict outgroup prejudices.
Hodson, Gordon; Skorska, Malvina N
2015-06-01
Psychological essentialism, the perception that groups possess inherent properties binding them and differentiating them from others, is theoretically relevant to predicting prejudice. Recent developments isolate two key dimensions: essentialistic entitativity (EE; groups as unitary, whole, entity-like) and essentialistic naturalness (EN; groups as fixed and immutable). We introduce a novel question: does tapping the covariance between EE and EN, rather than pitting them against each other, boost prejudice prediction? In Study 1 (re-analysis of Roets & Van Hiel, 2011b, Samples 1-3, in Belgium) and Study 2 (new Canadian data) their common/shared variance, modelled as generalized essentialism, doubles the predictive power relative to regression-based approaches with regard to racism (but not anti-gay or -schizophrenic prejudices). Theoretical implications are discussed. © 2014 The British Psychological Society.
Assessing two Theoretical Frameworks of Civic Engagement
Directory of Open Access Journals (Sweden)
Benilde García-Cabrero
2016-03-01
Full Text Available The purpose of this study was to empirically test two major theoretical models: a modified version of the social capital model (Pattie, Seyd and Whiteley, 2003, and the Informed Social Engagement Model (Barr and Selman, 2014; Selman and Kwok, 2010, to explain civic participation and civic knowledge of adolescents from Chile, Colombia and Mexico, using data from the International Civic and Citizenship Education Study 2009 (Schulz, et al., 2010. The models were used to identify factors associated with different levels of knowledge and civic participation: expected participation in legal and illegal protests, and electoral participation. Data were analyzed using regression analysis. Results show that the Informed Social Engagement approach (ISEM, explains better the observed differences in civic knowledge and civic participation, than the Social Capital Model (SCM. That is, the expected values associated with the variables included in the ISEM are closer to the observed values, than those predicted by the SCM. This is true for the three outcomes (expected participation in legal protests, illegal protests, and electoral participation and in the three countries analyzed (Chile, Colombia and Mexico.
Theoretical Study on the Flow of Refilling Stage in a Safety Injection Tank
Energy Technology Data Exchange (ETDEWEB)
Park, Jun Sang [Halla Univ. Daejeon (Korea, Republic of)
2017-10-15
In this study, a theoretical analysis was performed to the flow of refilling stage in a safety injection tank, which is the core cooling system of nuclear power plant in an emergency. A theoretical model was proposed with a nonlinear governing equation defining on the flow of the refilling process of the coolant. Utilizing the Taylor-series expansion, the 1st - order approximation flow equation was obtained, along with its analytic solution of closed type, which could predict accurately the variations of free surface height and flow rate of the coolant. The availability of theoretical result was confirmed by comparing with previous experimental results.
A theoretical and spectroscopic study of co-amorphous naproxen and indomethacin
DEFF Research Database (Denmark)
Löbmann, Korbinian; Laitinen, Riikka; Grohganz, Holger
2013-01-01
. In this study, the co-amorphous drug mixture containing naproxen (NAP) and indomethacin (IND) was investigated using infrared spectroscopy (IR) and quantum mechanical calculations. The structures of both drugs were optimized as monomer, homodimer and heterodimer using density functional theory and used...... for the calculation of IR spectra. Conformational analysis confirmed that the optimized structures were suitable for the theoretical prediction of the spectra. Vibrational modes from the calculation could be matched with experimentally observed spectra for crystalline and amorphous NAP and IND, and it could be shown...... that both drugs exist as homodimers in their respective individual amorphous form. With the results from the experimental single amorphous drugs and theoretical homodimers, a detailed analysis of the experimental co-amorphous and theoretical heterodimer spectra was performed and evaluated. It is suggested...
DEFF Research Database (Denmark)
Horn, Christian Franz; Ivens, Bjørn Sven; Ohneberg, Michael
2014-01-01
In recent years, Prediction Markets gained growing interest as a forecasting tool among researchers as well as practitioners, which resulted in an increasing number of publications. In order to track the latest development of research, comprising the extent and focus of research, this article...... provides a comprehensive review and classification of the literature related to the topic of Prediction Markets. Overall, 316 relevant articles, published in the timeframe from 2007 through 2013, were identified and assigned to a herein presented classification scheme, differentiating between descriptive...... works, articles of theoretical nature, application-oriented studies and articles dealing with the topic of law and policy. The analysis of the research results reveals that more than half of the literature pool deals with the application and actual function tests of Prediction Markets. The results...
Theoretical investigation of field-line quality in a driven spheromak
International Nuclear Information System (INIS)
Cohen, R.H.; Cohen, B.I.; Berk, H.L.
2003-01-01
Theoretical studies aimed at predicting and diagnosing field-line quality in a spheromak are described. These include nonlinear 3-D MHD simulations, stability studies, analyses of confinement in spheromaks dominated by either open (stochastic) field lines or approximate flux surfaces, and a theory of fast electrons as a probe of field-line length. (author)
Theoretical and laboratory investigations of flow through fractures in crystalline rock
International Nuclear Information System (INIS)
Witherspoon, P.A.; Watkins, D.J.; Tsang, Y.W.
1981-01-01
A theoretical model developed for flow through a deformable fracture subject to stresses was successfully tested against laboratory experiments. The model contains no arbitrary parameters and can be used to predict flow rates through a single fracture if the fractional fracture contact area can be estimated and if stress-deformation data are available. These data can be obtained from laboratory or in situ tests. The model has considerable potential for practical application. The permeability of ultralarge samples of fractured crystalline rock as a function of stresses was measured. Results from tests on a pervasively fractured 1-m-diameter specimen of granitic rock showed that drastically simplifying assumptions must be used to apply theoretical models to this type of rock mass. Simple models successfully reproduce the trend of reduced permeability as stress is applied in a direction normal to the fracture plane. The tests also demonstrated how fracture conductivity increases as a result of dilatancy associated with shear displacements. The effect of specimen size on the hydraulic properties of fractured rock was also investigated. Permeability tests were performed on specimens of charcoal black granite containing a single fracture subjected to normal stress. Results are presented for tests performed on a 0.914-m-diameter specimen and on the same specimen after it had been reduced to 0.764 m in diameter. The data show that fracture conductivity is sensitive to stress history and sample disturbance
A new theoretical approach to adsorption desorption behavior of Ga on GaAs surfaces
Kangawa, Y.; Ito, T.; Taguchi, A.; Shiraishi, K.; Ohachi, T.
2001-11-01
We propose a new theoretical approach for studying adsorption-desorption behavior of atoms on semiconductor surfaces. The new theoretical approach based on the ab initio calculations incorporates the free energy of gas phase; therefore we can calculate how adsorption and desorption depends on growth temperature and beam equivalent pressure (BEP). The versatility of the new theoretical approach was confirmed by the calculation of Ga adsorption-desorption transition temperatures and transition BEPs on the GaAs(0 0 1)-(4×2)β2 Ga-rich surface. This new approach is feasible to predict how adsorption and desorption depend on the growth conditions.
Theoretical and experimental morphologies of 4-aminobenzophenone (ABP) crystals
Wang, Qingwu; Sheen, D. B.; Shepherd, E. E. A.; Sherwood, J. N.; Simpson, G. S.; Hammond, R. B.
1997-11-01
The lattice energy (Elatt), slice energies (Eslice) and attachment energies (Eatt) of the different habit faces of ABP crystals have been calculated using the computer program HABIT. On the basis of the attachment energies of different crystal faces, the morphology was defined as {1 0 0}, {0 0 1}, {1 1 0}, {11bar0} and {1 01bar}. To confirm this theoretical prediction, we have grown ABP films and ABP crystals from the vapour phase. In both cases, the morphologically most important face was defined as {1 0 0} face using X-ray diffraction techniques. The remaining faces of the vapour-grown crystals were defined using a projection method, while the crystallites in the films were morphologically analysed by means of atomic force microscopy (AFM). The experimental morphologies are basically in agreement with the computation. Deviations from the equilibrium morphology can be ascribed to departure from equilibrium conditions during growth. For completeness, the results are compared with those for crystals grown from solutions for which deviations in morphology from the theoretical predictions can be ascribed to interaction between the crystal faces and solvent molecules.
Prediction of molecular properties using graph-theoretical invariants
Energy Technology Data Exchange (ETDEWEB)
Helal, N.L.; Steinhaeusler, F.; Winkler-Heil, R. [Inst. of Physics and Biophysics, Univ. of Salzburg, Salzburg (Austria); Eckl, P.M. [Inst. of Genetics and General Biology, Univ. of Salzburg, Salzburg (Austria)
2002-03-01
In man's living and working environments, situations are often encountered in which different ambient factors of a physical, chemical or biological nature could combine with ionizing radiation and give rise to undesirable effects. The list of chemicals, the action of which might combine with that of radiation in the environment is very extensive and many of these chemicals may produce carcinogenic or mutagenic effects or serve as carriers of trace metals, radioactive nuclides or polycyclic aromatic hydrocarbons. High levels of mutagenic chemicals have been reported in many types of food. Broiled meat and fish contain mutagenic compounds arising from the pyrolysis of proteins and amino acids. Mutagens and co-mutagens have also been reported in vegetable derivatives of foods, such as caffeine. As mutagenicity often correlates well with carcinogenicity, the above substances may be considered to be potential carcinogens both alone or in combination with radiation. Progress in the analysis of the interaction of ionizing radiation and toxicants is affected by the lack of scientific data quantitatively relating chemical exposures to a given health risk. The implementation of standard protocols to increase conformity among reported research is urgently needed as a prerequisite for the comparison of data from different laboratories, and the application of this in risk characterization. However, systematic and comprehensive risk management for the multitude of chemical substances which are present on the market and in the environment cannot be based on the availability of experimental data alone. Furthermore, for most existing chemicals these data are not available and will not become available in the near future. Reliable predictions based on quantitative structure-action relationships (QSARs) could represent an effective alternative, provided that, however, differences in the actions of different molecules are linked to differences in their chemical structures. In
Directory of Open Access Journals (Sweden)
Seung Up Kim
Full Text Available Liver stiffness measurement (LSM using transient elastography (FibroScan® can assess liver fibrosis noninvasively. This study investigated whether LSM can predict the development of liver-related events (LREs in chronic hepatitis B (CHB patients showing histologically advanced liver fibrosis.Between March 2006 and April 2010, 128 CHB patients with who underwent LSM and liver biopsy (LB before starting nucleot(side analogues and showed histologically advanced fibrosis (≥F3 with a high viral loads [HBV DNA ≥2,000 IU/mL] were enrolled. All patients were followed regularly to detect LRE development, including hepatic decompensation (variceal bleeding, ascites, hepatic encephalopathy, spontaneous bacterial peritonitis, hepatorenal syndrome and hepatocellular carcinoma (HCC.The mean age of the patient (72 men, 56 women was 52.2 years. During the median follow-up period [median 27.8 (12.6-61.6 months], LREs developed in 19 (14.8% patients (five with hepatic decompensation, 13 with HCC, one with both. Together with age, multivariate analysis identified LSM as an independent predictor of LRE development [P19 kPa were at significantly greater risk than those with LSM≤19 kPa for LRE development (HR, 7.176; 95% CI, 2.257-22.812; P = 0.001.LSM can be a useful predictor of LRE development in CHB patients showing histologically advanced liver fibrosis.
International Nuclear Information System (INIS)
Gray, W.H.; Sun, C.T.
1976-07-01
The mechanical properties of a composite superconducting (NbTi/Cu) wire are characterized in terms of the mechanical properties of each constituent material. For a particular composite superconducting wire, five elastic material constants were experimentally determined and theoretically calculated. Since the Poisson's ratios for the fiber and the matrix material were very close, there was essentially no (less than 1 percent) difference among all the theoretical predictions for any individual mechanical constant. Because of the expense and difficulty of producing elastic constant data of 0.1 percent accuracy, and therefore conclusively determining which theory is best, no further experiments were performed
Hybrid rocket engine, theoretical model and experiment
Chelaru, Teodor-Viorel; Mingireanu, Florin
2011-06-01
The purpose of this paper is to build a theoretical model for the hybrid rocket engine/motor and to validate it using experimental results. The work approaches the main problems of the hybrid motor: the scalability, the stability/controllability of the operating parameters and the increasing of the solid fuel regression rate. At first, we focus on theoretical models for hybrid rocket motor and compare the results with already available experimental data from various research groups. A primary computation model is presented together with results from a numerical algorithm based on a computational model. We present theoretical predictions for several commercial hybrid rocket motors, having different scales and compare them with experimental measurements of those hybrid rocket motors. Next the paper focuses on tribrid rocket motor concept, which by supplementary liquid fuel injection can improve the thrust controllability. A complementary computation model is also presented to estimate regression rate increase of solid fuel doped with oxidizer. Finally, the stability of the hybrid rocket motor is investigated using Liapunov theory. Stability coefficients obtained are dependent on burning parameters while the stability and command matrixes are identified. The paper presents thoroughly the input data of the model, which ensures the reproducibility of the numerical results by independent researchers.
Towards a Game Theoretic View of Secure Computation
DEFF Research Database (Denmark)
Asharov, Gilad; Canetti, Ran; Hazay, Carmit
2011-01-01
We demonstrate how Game Theoretic concepts and formalism can be used to capture cryptographic notions of security. In the restricted but indicative case of two-party protocols in the face of malicious fail-stop faults, we first show how the traditional notions of secrecy and correctness of protoc......We demonstrate how Game Theoretic concepts and formalism can be used to capture cryptographic notions of security. In the restricted but indicative case of two-party protocols in the face of malicious fail-stop faults, we first show how the traditional notions of secrecy and correctness...... of protocols can be captured as properties of Nash equilibria in games for rational players. Next, we concentrate on fairness. Here we demonstrate a Game Theoretic notion and two different cryptographic notions that turn out to all be equivalent. In addition, we provide a simulation based notion that implies...
Dodd, Bucky J.
2013-01-01
Online course design is an emerging practice in higher education, yet few theoretical models currently exist to explain or predict how the diffusion of innovations occurs in this space. This study used a descriptive, quantitative survey research design to examine theoretical relationships between decision-making style and resistance to change…
Theoretical analysis of recirculation zone and buffer zone in the ADS windowless spallation target
International Nuclear Information System (INIS)
Liu, Jie; Pan, Chang-zhao; Tong, Jian-fei; Lu, Wen-qiang
2015-01-01
Highlights: • Height of recirculation zone is very important in windowless target design. • A theoretical formula for the height is derived based on the Bernoulli equation. • Numerical simulation for the LBE is performed and the height of recirculation zone is also obtained. • The theoretically-derived simulation-predicted recirculation zone heights agree with each other very well and the theoretical derivation is proved to be correct. - Abstract: The thermo-hydraulic analysis including reduction of the height of recirculation zone and stability of the free surface is very important in the design and optimization of ADS windowless spallation targets. In the present study, the Bernoulli equation is used to analyze the entire flow process in the target. Formulae for the height of the recirculation zone and the buffer zone are both obtained explicitly. Furthermore, numerical simulation for the heavy metal lead–bismuth eutectic liquid and vapor with cavitation phase change is also performed, and a novel method to calculate the height of the recirculation zone is put forward. By comparison of the theoretical formulae and numerical results, it is clearly shown that they agree with each other very well, and the heights predicted by the two methods are both determined by their own upstream flow parameters
Energy Technology Data Exchange (ETDEWEB)
Rasmussen, Rasmus W.; Winter, Walter
2016-11-15
We discuss the parameter space reach of future experiments searching for heavy neutral leptons (HNLs) at the GeV scale in terms of neutrino mass models with three HNL generations. We focus on two classes of models: Generic assumptions (such as random mass matrices or the Casas-Ibarra parameterization) and flavor symmetry-generated models. We demonstrate that the generic approaches lead to comparable parameter space predictions, which tend to be at least partially within the reach of future experiments. On the other hand, specific flavor symmetry models yield more refined predictions, some of these can be more clearly excluded. We also highlight the importance to measure the flavor-dependent couplings of the HNLs as a model discriminator, and we clarify the impact of assumptions frequently used in the literature to show the parameter space reach for the active-sterile mixings.
International Nuclear Information System (INIS)
Rasmussen, Rasmus W.; Winter, Walter
2016-11-01
We discuss the parameter space reach of future experiments searching for heavy neutral leptons (HNLs) at the GeV scale in terms of neutrino mass models with three HNL generations. We focus on two classes of models: Generic assumptions (such as random mass matrices or the Casas-Ibarra parameterization) and flavor symmetry-generated models. We demonstrate that the generic approaches lead to comparable parameter space predictions, which tend to be at least partially within the reach of future experiments. On the other hand, specific flavor symmetry models yield more refined predictions, some of these can be more clearly excluded. We also highlight the importance to measure the flavor-dependent couplings of the HNLs as a model discriminator, and we clarify the impact of assumptions frequently used in the literature to show the parameter space reach for the active-sterile mixings.
Reliable predictions of waste performance in a geologic repository
International Nuclear Information System (INIS)
Pigford, T.H.; Chambre, P.L.
1985-08-01
Establishing reliable estimates of long-term performance of a waste repository requires emphasis upon valid theories to predict performance. Predicting rates that radionuclides are released from waste packages cannot rest upon empirical extrapolations of laboratory leach data. Reliable predictions can be based on simple bounding theoretical models, such as solubility-limited bulk-flow, if the assumed parameters are reliably known or defensibly conservative. Wherever possible, performance analysis should proceed beyond simple bounding calculations to obtain more realistic - and usually more favorable - estimates of expected performance. Desire for greater realism must be balanced against increasing uncertainties in prediction and loss of reliability. Theoretical predictions of release rate based on mass-transfer analysis are bounding and the theory can be verified. Postulated repository analogues to simulate laboratory leach experiments introduce arbitrary and fictitious repository parameters and are shown not to agree with well-established theory. 34 refs., 3 figs., 2 tabs
International Nuclear Information System (INIS)
Berrichon, J.D.; Louahlia-Gualous, H.; Bandelier, Ph.; Bariteau, N.
2014-01-01
Highlights: • Theoretical model for condensation heat transfer at very low pressure is developed using only one iterative loop. • Experimental results on steam and air steam condensation heat transfer at very low pressure are presented. • The developed model gives the good predictions for local condensation heat transfer at low pressure. • A maximal deterioration of 50% in condensation heat transfer is obtained at low pressure for air fraction of 4%. • A new correlation including effect of a wavy film surface for steam condensation at low pressure is suggested. - Abstract: This paper presents experimental investigation on the influence of very low pressure on local and average condensation heat transfer in a vertical tube. Furthermore, this paper develops an analytical study for film condensation heat transfer coefficient in the presence of non-condensable gas inside a vertical tube. The condensate film thickness is calculated for each location in a tube using mass and heat transfer analogy. The effects of interfacial shear stress and waves on condensate film surface are included in the model. The comparative studies show that the present model well predicts the experimental data of Khun et al. [1]for local condensation of steam air mixture at high pressure. Different correlations defined for condensation heat transfer are evaluated. It is found that the correlations of Cavallini and Zecchin [2] and Shah [3] are the closest to the calculated steam condensation local heat transfer coefficient. The model gives a satisfactory accuracy with the experimental results for condensation heat transfer at very low pressure. The mean deviation between the predictions of the theoretical model with the measurements for pure saturated vapor is 12%. Experimental data show that the increase of air fraction to 4% deteriorates condensation heat transfer at low pressure up to 50%
International Nuclear Information System (INIS)
Ofenheimer, Aldo; Buchmayr, Bruno; Kolleck, Ralf; Merklein, Marion
2005-01-01
The influence of strain paths (loading history) on material formability is well known in sheet forming processes. Sophisticated experimental methods are used to determine the entire shape of strain paths of forming limits for aluminum AA6016-T4 alloy. Forming limits for sheet metal in as-received condition as well as for different pre-deformation are presented. A theoretical approach based on Arrieux's intrinsic Forming Limit Stress Curve (FLSC) concept is employed to numerically predict the influence of loading history on forming severity. The detailed experimental strain paths are used in the theoretical study instead of any linear or bilinear simplified loading histories to demonstrate the predictive quality of forming limits in the state of stress
Predictive information processing in music cognition. A critical review.
Rohrmeier, Martin A; Koelsch, Stefan
2012-02-01
Expectation and prediction constitute central mechanisms in the perception and cognition of music, which have been explored in theoretical and empirical accounts. We review the scope and limits of theoretical accounts of musical prediction with respect to feature-based and temporal prediction. While the concept of prediction is unproblematic for basic single-stream features such as melody, it is not straight-forward for polyphonic structures or higher-order features such as formal predictions. Behavioural results based on explicit and implicit (priming) paradigms provide evidence of priming in various domains that may reflect predictive behaviour. Computational learning models, including symbolic (fragment-based), probabilistic/graphical, or connectionist approaches, provide well-specified predictive models of specific features and feature combinations. While models match some experimental results, full-fledged music prediction cannot yet be modelled. Neuroscientific results regarding the early right-anterior negativity (ERAN) and mismatch negativity (MMN) reflect expectancy violations on different levels of processing complexity, and provide some neural evidence for different predictive mechanisms. At present, the combinations of neural and computational modelling methodologies are at early stages and require further research. Copyright © 2012 Elsevier B.V. All rights reserved.
International Nuclear Information System (INIS)
Karpman, M.G.; Fetisov, G.P.; Bologov, D.V.
1999-01-01
Using the Palatnik criterion a comparative analysis is performed of the theoretical and experimental data on comparative electric erosion and erosion resistance of the electrodes and parts made of different materials upon their treatment using electric pulse technique. A reasonable qualitative agreement of the theoretical and experimental data indicates the possibility of using the Palatnik criterion to predict the serviceability of different pairs of the materials in conditions of electroerosion wear [ru
A state-based probabilistic model for tumor respiratory motion prediction
International Nuclear Information System (INIS)
Kalet, Alan; Sandison, George; Schmitz, Ruth; Wu Huanmei
2010-01-01
This work proposes a new probabilistic mathematical model for predicting tumor motion and position based on a finite state representation using the natural breathing states of exhale, inhale and end of exhale. Tumor motion was broken down into linear breathing states and sequences of states. Breathing state sequences and the observables representing those sequences were analyzed using a hidden Markov model (HMM) to predict the future sequences and new observables. Velocities and other parameters were clustered using a k-means clustering algorithm to associate each state with a set of observables such that a prediction of state also enables a prediction of tumor velocity. A time average model with predictions based on average past state lengths was also computed. State sequences which are known a priori to fit the data were fed into the HMM algorithm to set a theoretical limit of the predictive power of the model. The effectiveness of the presented probabilistic model has been evaluated for gated radiation therapy based on previously tracked tumor motion in four lung cancer patients. Positional prediction accuracy is compared with actual position in terms of the overall RMS errors. Various system delays, ranging from 33 to 1000 ms, were tested. Previous studies have shown duty cycles for latencies of 33 and 200 ms at around 90% and 80%, respectively, for linear, no prediction, Kalman filter and ANN methods as averaged over multiple patients. At 1000 ms, the previously reported duty cycles range from approximately 62% (ANN) down to 34% (no prediction). Average duty cycle for the HMM method was found to be 100% and 91 ± 3% for 33 and 200 ms latency and around 40% for 1000 ms latency in three out of four breathing motion traces. RMS errors were found to be lower than linear and no prediction methods at latencies of 1000 ms. The results show that for system latencies longer than 400 ms, the time average HMM prediction outperforms linear, no prediction, and the more
Modeling and Prediction of Soil Water Vapor Sorption Isotherms
DEFF Research Database (Denmark)
Arthur, Emmanuel; Tuller, Markus; Moldrup, Per
2015-01-01
Soil water vapor sorption isotherms describe the relationship between water activity (aw) and moisture content along adsorption and desorption paths. The isotherms are important for modeling numerous soil processes and are also used to estimate several soil (specific surface area, clay content.......93) for a wide range of soils; and (ii) develop and test regression models for estimating the isotherms from clay content. Preliminary results show reasonable fits of the majority of the investigated empirical and theoretical models to the measured data although some models were not capable to fit both sorption...... directions accurately. Evaluation of the developed prediction equations showed good estimation of the sorption/desorption isotherms for tested soils....
de Jonge, J.; Dormann, C.; van den Tooren, M.; Näswall, K.; Hellgren, J.; Sverke, M.
2008-01-01
This chapter presents a recently developed theoretical model on jobrelated stress and performance, the so-called Demand-Induced Strain Compensation (DISC) model. The DISC model predicts in general that adverse health effects of high job demands can best be compensated for by matching job resources
Theoretical study of the lowest-lying electronic states of Aluminium monoiodide
International Nuclear Information System (INIS)
Taher, F.; Kabbani, A.; Ani-El Houte, W.
2004-01-01
Full text.The spectroscopic study of Aluminium monohalides, especially the Aluminium monoiodide, is important for monitoring such species in high temperature fast-flow reactors. Theoretical calculations of AlI are not available, whereas several studies have been done for the other aluminium monohalides. In this work, CAS-SCF/MRCI calculations are performed for the lowest-lying electronic states of AlI in a range of internuclear distance between 2.30 A and 2.80 A. Ab-initio calculations have been effectuated by using the computational chemistry program Molpro. The basis set used in this study for aluminium atom is that used by Langhoff for aluminium monohalides, of contractions using atomic natural orbitals and a pseudopotential is used for iode. Accurate theoretical spectroscopic constants and potential curves are obtained for the ground state X 1 Σ + and the first excited states a 3 Π and A 1 Π. The calculated values of Te, ωe, ωexe and re of these states are compatible with the experimental results. An ordering of states is represented for the lowest five predicted singlet and lowest five predicted triplet states. These results provide a big support to determine the analogy in the ordering of the electronic states in AlF, AlBr and AlI respectively at lower energies. These theoretical results identify a set of electronic singlet and triplet states unobserved experimentally
Theoretical predictions for charm and bottom production at the LHC
Cacciari, Matteo; Houdeau, Nicolas; Mangano, Michelangelo L; Nason, Paolo; Ridolfi, Giovanni
2012-01-01
We present predictions for a variety of single-inclusive observables that stem from the production of charm and bottom quark pairs at the 7 TeV LHC. They are obtained within the FONLL semi-analytical framework, and with two "Monte Carlo + NLO" approaches, MC@NLO and POWHEG. Results are given for final states and acceptance cuts that are as close as possible to those used by experimental collaborations and, where feasible, are compared to LHC data.
Theoretical predictions of diffusion from Brownian motion in superstrong polymers
International Nuclear Information System (INIS)
Dowell, F.
1991-01-01
This paper presents a summary of unique highly nonlinear static and dynamic theories for chain molecules (actually, for almost any kind of organic molecule), including the first superstrong polymers. These theories have been used to predict and explain (1) the physical self-assembly (self-ordering) of specific kinds of molecules into liquid crystalline (LC) phases (i.e., partially ordered phases) and (2) the diffusion of these molecules in various LC phases and the isotropic (I) liquid phase
Comprehensive update of the atomic mass predictions
International Nuclear Information System (INIS)
Haustein, P.E.
1987-01-01
A project has been completed recently for a comprehensive update of atomic mass predictions. This last occurred in 1976. Over the last 10 years the reliability of these earlier predictions (and others published later) has been analyzed by comparisons of the predictions with new masses from isotopes that were not in the experimental data base when the predictions were prepared. This analysis has highlighted distinct systematic features in various models which frequently result in poor predictions for nuclei that lie far from stability. An overview of the new predictions from models with different theoretical approaches will be presented
Theoretical prediction of the structural properties of uranium chalcogenides under high pressure
Kapoor, Shilpa; Yaduvanshi, Namrata; Singh, Sadhna
2018-05-01
Uranium chalcogenides crystallize in rock salt structure at normal condition and transform to Cesium Chloride structure at high pressure. We have investigated the transition pressure and volume drop of USe and UTe using three body potential model (TBIP). Present model includes long range Columbic, three body interaction forces and short range overlap forces operative up to next nearest neighbors. We have reported the phase transition pressure, relative volume collapses, the thermo physical properties such as molecular force constant (f), infrared absorption frequency (v0), Debye temperature (θD) and Gruneisen parameter (γ) of present chalcogenides and found that our results in general good agreement with experimental and other theoretical data.
Experimental and theoretical studies of 3-benzyloxy-2-nitropyridine
Sun, Wenting; Cui, Yu; Liu, Huimin; Zhao, Haitao; Zhang, Wenqin
2012-10-01
The structure of 3-benzyloxy-2-nitropyridine has been investigated both experimentally and theoretically. The X-ray crystallography results show that the nitro group is tilted out of the pyridine ring plane by 66.4(4)°, which is mainly attributed to the electron-electron repulsions of the lone pairs in O atom of the 3-benzyloxy moiety with O atom in nitro group. An interesting centrosymmetric π-stacking molecular pair has been found in the crystalline state, which results in the approximate coplanarity of the pyridine ring with the benzene ring. The calculated results show that the dihedral angle between the nitro group and pyridine ring from the X3LYP method is much closer to the experimental data than that from the M06-2X one. The existing two conformational isomers of 3-benzyloxy-2-nitropyridine with equal energy explain well the disorder of the nitro group at room temperature. In addition, the vibrational frequencies are also calculated by the X3LYP and M06-2X methods and compared with the experimental results. The prediction from the X3LYP method coincides with the locations of the experimental frequencies well.
Theoretical cytotoxicity models for combined exposure of cells to different radiations
International Nuclear Information System (INIS)
Scott, B.R.
1981-01-01
Theoretical cytotoxicity models for predicting cell survival after sequential or simultaneous exposure of cells to high and low linear energy transfer (LET) radiation are discussed. Major findings are that (1) ordering of sequential exposures can influence the level of cell killing achieved; (2) synergism is unimportant at low doses; (3) effects at very low doses should be additive; (4) use of the conventional relative biological effectiveness approach for predicting combined effects of different radiations is unnecessary at very low doses and can lead to overestimation of risk at moderate and high doses
International Nuclear Information System (INIS)
Lee, Byung Ryung
1997-02-01
This paper presents an experimental and theoretical investigation of interfacial friction factor, wave height and transition criterion from wavy to slug flow in a long horizontal air-water countercurrent stratified flow condition. A series of experiments have been conducted in adiabatic countercurrent stratified flow with the round pipe and rectangular duct test section to develop the interfacial friction factor and the criterion of onset of slugging in horizontal air-water countercurrent stratified flow. An adiabatic semi-empirical correlation for interfacial friction factor has been developed based on the surface roughness concept. A comparison of the measured data in this study and of other investigators with the predictions of the present correlation shows that the agreement is within ±30% error, and that the present correlation is applicable to a broader range of water flow rate than the correlations of previous investigators. The theories which can calculate the wave height and criteria of onset of slug flow in a stratified wavy flow regime have been developed based on the concept of total energy conservation and also wave theory. This theoretical criteria agree better with the measured data than the other criteria available in the literature, but the criteria range about 92∼107% of the measured data. An empirical formula for the criterion has been also developed and compared with the formula in the literatures. Comparison between the measured data and the predictions of the present theory shows that the agreement is within ±8%
Rodrigues, N. S.; Kulkarni, V.; Gao, J.; Chen, J.; Sojka, P. E.
2015-03-01
The current study focuses on experimentally and theoretically improving the characterization of the drop size and drop velocity for like-on-like doublet impinging jets. The experimental measurements were made using phase Doppler anemometry (PDA) at jet Weber numbers We j corresponding to the impact wave regime of impinging jet atomization. A more suitable dynamic range was used for PDA measurements compared to the literature, resulting in more accurate experimental measurements for drop diameters and velocities. There is some disagreement in the literature regarding the ability of linear stability analysis to accurately predict drop diameters in the impact wave regime. This work seeks to provide some clarity. It was discovered that the assumed uniform jet velocity profile was a contributing factor for deviation between diameter predictions based on models in the literature and experimental measurements. Analytical expressions that depend on parameters based on the assumed jet velocity profile are presented in this work. Predictions based on the parabolic and 1/7th power law turbulent profiles were considered and show better agreement with the experimental measurements compared to predictions based on the previous models. Experimental mean drop velocity measurements were compared with predictions from a force balance analysis, and it was observed that the assumed jet velocity profile also influences the predicted velocities, with the turbulent profile agreeing best with the experimental mean velocity. It is concluded that the assumed jet velocity profile has a predominant effect on drop diameter and velocity predictions.
Theoretical and experimental investigations of stochastic boundaries in tokamaks
International Nuclear Information System (INIS)
Ghendrih, Ph.; Grosman, A.; Capes, H.
1996-01-01
The physics of stochastic boundaries are reviewed. The stochastic properties of magnetic field lines are recalled and related to the spectrum of the radial magnetic perturbation. The stochastic region, referred to as the divertor volume, is shown to be bounded to the edge plasma. Theoretical predictions for the transport of energy, current and particles in the divertor volume are analysed for both the laminar and ergodic regimes. (K.A.)
Field-theoretic approach to gravity in the flat space-time
Energy Technology Data Exchange (ETDEWEB)
Cavalleri, G [Centro Informazioni Studi Esperienze, Milan (Italy); Milan Univ. (Italy). Ist. di Fisica); Spinelli, G [Istituto di Matematica del Politecnico di Milano, Milano (Italy)
1980-01-01
In this paper it is discussed how the field-theoretical approach to gravity starting from the flat space-time is wider than the Einstein approach. The flat approach is able to predict the structure of the observable space as a consequence of the behaviour of the particle proper masses. The field equations are formally equal to Einstein's equations without the cosmological term.
Carter, Nathan T; Dalal, Dev K; Boyce, Anthony S; O'Connell, Matthew S; Kung, Mei-Chuan; Delgado, Kristin M
2014-07-01
The personality trait of conscientiousness has seen considerable attention from applied psychologists due to its efficacy for predicting job performance across performance dimensions and occupations. However, recent theoretical and empirical developments have questioned the assumption that more conscientiousness always results in better job performance, suggesting a curvilinear link between the 2. Despite these developments, the results of studies directly testing the idea have been mixed. Here, we propose this link has been obscured by another pervasive assumption known as the dominance model of measurement: that higher scores on traditional personality measures always indicate higher levels of conscientiousness. Recent research suggests dominance models show inferior fit to personality test scores as compared to ideal point models that allow for curvilinear relationships between traits and scores. Using data from 2 different samples of job incumbents, we show the rank-order changes that result from using an ideal point model expose a curvilinear link between conscientiousness and job performance 100% of the time, whereas results using dominance models show mixed results, similar to the current state of the literature. Finally, with an independent cross-validation sample, we show that selection based on predicted performance using ideal point scores results in more favorable objective hiring outcomes. Implications for practice and future research are discussed.
Silicene: a review of recent experimental and theoretical investigations
International Nuclear Information System (INIS)
Houssa, M; Dimoulas, A; Molle, A
2015-01-01
Silicene is the silicon counterpart of graphene, i.e. it consists in a single layer of Si atoms with a hexagonal arrangement. We present a review of recent theoretical and experimental works on this novel two dimensional material. We discuss first the structural, electronic and vibrational properties of free-standing silicene, as predicted from first-principles calculations. We next review theoretical studies on the interaction of silicene with different substrates. The growth and experimental characterization of silicene on Ag(1 1 1) is next discussed, providing insights into the different phases or atomic arrangements of silicene observed on this metallic surface, as well as on its electronic structure. Recent experimental findings about the likely formation of hexagonal Si nanosheets on MoS2 are also highlighted. (topical review)
Theoretical Investigation of CO{sub 2} Adsorption on Graphene
Energy Technology Data Exchange (ETDEWEB)
Lee, Kunjoon; Kim, Seungjoon [Hannam Univ., Daejeon (Korea, Republic of)
2013-10-15
The adsorption of carbon dioxide on graphene sheets was theoretically investigated using density functional theory (DFT) and MP{sub 2} calculations. Geometric parameters and adsorption energies were computed at various levels of theory. The CO{sub 2} chemisorption energies on graphene-C{sub 40} assuming high pressure are predicted to be 71.2-72.1 kcal/mol for the lactone systems depending on various C-O orientations at the UCAM-B3LYP level of theory. Physisorption energies of CO{sub 2} on graphene were predicted to be 2.1 and 3.3 kcal/mol, respectively, at the single-point UMP2/6-31G{sup **} level of theory for perpendicular and parallel orientations.
International Nuclear Information System (INIS)
Meng, Qinglong; Zhang, Bin; Zhong, Sencheng; Zhu, Liguo
2016-01-01
The damage threshold of lithium niobate crystal under single and multiple femtosecond laser pulses has been studied theoretically and experimentally. Firstly, the model for the damage threshold prediction of crystal materials based on the improved rate equation has been proposed. Then, the experimental measure method of the damage threshold of crystal materials has been given in detail. On the basis, the variation of the damage threshold of lithium niobate crystal with the pulse duration has also been analyzed quantitatively. Finally, the damage threshold of lithium niobate crystal under multiple laser pulses has been measured and compared to the theoretical results. The results show that the transmittance of lithium niobate crystal is almost a constant when the laser pulse fluence is relative low, whereas it decreases linearly with the increase in the laser pulse fluence below the damage threshold. The damage threshold of lithium niobate crystal increases with the increase in the duration of the femtosecond laser pulse. And the damage threshold of lithium niobate crystal under multiple laser pulses is obviously lower than that irradiated by a single laser pulse. The theoretical data fall in good agreement with the experimental results. (orig.)
Theoretical Approaches to Nuclear Proliferation
Directory of Open Access Journals (Sweden)
Konstantin S. Tarasov
2015-01-01
Full Text Available This article analyses discussions between representatives of three schools in the theory of international relations - realism, liberalism and constructivism - on the driving factors of nuclear proliferation. The paper examines major theoretical approaches, outlined in the studies of Russian and foreign scientists, to the causes of nuclear weapons development, while unveiling their advantages and limitations. Much of the article has been devoted to alternative approaches, particularly, the role of mathematical modeling in assessing proliferation risks. The analysis also reveals a variety of different approaches to nuclear weapons acquisition, as well as the absence of a comprehensive proliferation theory. Based on the research results the study uncovers major factors both favoring and impeding nuclear proliferation. The author shows that the lack of consensus between realists, liberals and constructivists on the nature of proliferation led a number of scientists to an attempt to explain nuclear rationale by drawing from the insights of more than one school in the theory of IR. Detailed study of the proliferation puzzle contributes to a greater understating of contemporary international realities, helps to identify mechanisms that are most likely to deter states from obtaining nuclear weapons and is of the outmost importance in predicting short- and long-term security environment. Furthermore, analysis of the existing scientific literature on nuclear proliferation helps to determine future research agenda of the subject at hand.
International Nuclear Information System (INIS)
Mitra, S.K.; Hannemann, A.U.
1993-01-01
An experimental and theoretical study has been carried out to investigate the fate of desorption of SO 2 from water drops falling at terminal velocity in air. The experiments were carried out in the Mainz vertical wind tunnel in which water drops of various sizes containing S(IV) in various concentrations were freely suspended in the vertical airstream of the tunnel. The results were compared with the predictions of theoretical models, and with the experiments of Walcek et al. This comparison shows that the predictions of the diffusion model of Kronig and Brink in the formulation given by Walcek and Pruppacher agree well with the experimental results. In contrast, the predictions of the diffusion model which assumes complete internal mixing inside a drop agrees with the experimental results only if the concentration of S(IV) inside the drop is less than that equivalent of an equilibrium SO 2 concentration of 15 ppbv. At larger concentrations, the theoretical predictions of the model for complete internal mixing progressively deviate from the experimental results. It is further shown that Barrie's double film model can be used to interpret the resistance to diffusion inside a drop in terms of a diffusion boundary layer inside the drop which increases in thickness with decreasing concentration of S(IV). Applying our results to the desorption of SO 2 from small and large rain drops falling below an assumed cloud base, shows that for typical contents of S(IV) inside the drops substantial amounts of SO 2 will desorb from these drops unless H 2 O 2 is present in the surrounding air
International Nuclear Information System (INIS)
Holley, W.R.; Chatterjee, A.
1996-01-01
We have developed a general theoretical model for the interaction of ionizing radiation with chromatin. Chromatin is modeled as a 30-nm-diameter solenoidal fiber composed of 20 turns of nucleosomes, 6 nucleosomes per turn. Charged-particle tracks are modeled by partitioning the energy deposition between primary track core, resulting from glancing collisions with 100 eV or less per event, and δ rays due to knock-on collisions involving energy transfers > 100 eV. A Monte Carlo simulation incorporates damages due to the following molecular mechanisms: (1) ionization of water molecules leading to the formation of circ OH, circ H, e aq , etc.; circ OH attack on sugar molecules leading to strand breaks; circ OH attack on bases; direct ionization of the sugar molecules leading to strand breaks; direct ionization of the bases. Our calculations predict significant clustering of damage both locally, over regions up to 40 hp and over regions extending to several kilobase pairs. A characteristic feature of the regional damage predicted by our model is the production of short fragments of DNA associated with multiple nearby strand breaks. Such fragments have subsequently been detected experimentally and are reported in an accompanying paper after exposure to both high- and low-LET radiation. The overall measured yields agree well quantitatively with the theoretical predictions. Our theoretical results predict the existence of a strong peak at about 85 bp, which represents the revolution period about the nucleosome. Other peaks at multiples of about 1,000 bp correspond to the periodicity of the particular solenoid model of chromatin used in these calculations. Theoretical results in combination with experimental data on fragmentation spectra may help determine the consensus or average structure of the chromatin fibers in mammalian DNA. 27 refs., 7 figs
Energy Technology Data Exchange (ETDEWEB)
Honda, H; Wang, H [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study; Nozu, S [Okamaya Prefectural University, Okayama (Japan). Faculty of Computer Science and System Engineering
2000-10-25
A theoretical study has been made of film condensation in helically-grooved, horizontal microfin tubes. The annular flow regime and the stratified flow regime were considered. For the annular flow regime, a previously developed theoretical model was applied. For the stratified flow regime, the height of stratified condensate was estimated by a modified Taitel and Dukler model. For the upper part of the tube exposed to the vapor flow, numerical calculation of Laminar film condensation considering the combined effects of gravity and surface tension forces was conducted. The heat transfer coefficient at the lower part of the tube was estimated by an empirical equation for the internally finned tubes developed by Carnavos. The theoretical predictions of the circumferential average heat transfer coefficient by the two theoretical models were compared with available experimental data for four refrigerants and four tubes. Generally, the annular flow model gave a higher heat transfer coefficient than the stratified flow model in the high quality region, whereas the stratified flow model gave a higher heat transfer coefficient in the low quality region. For tubes with fin heights of 0.16 {approx} 0.24 mm, most of the experimental data agreed within {+-} 20% with the higher of the two theoretical predictions. (author)
Salvatore, Jessica E; Aliev, Fazil; Edwards, Alexis C; Evans, David M; Macleod, John; Hickman, Matthew; Lewis, Glyn; Kendler, Kenneth S; Loukola, Anu; Korhonen, Tellervo; Latvala, Antti; Rose, Richard J; Kaprio, Jaakko; Dick, Danielle M
2014-04-10
Alcohol problems represent a classic example of a complex behavioral outcome that is likely influenced by many genes of small effect. A polygenic approach, which examines aggregate measured genetic effects, can have predictive power in cases where individual genes or genetic variants do not. In the current study, we first tested whether polygenic risk for alcohol problems-derived from genome-wide association estimates of an alcohol problems factor score from the age 18 assessment of the Avon Longitudinal Study of Parents and Children (ALSPAC; n = 4304 individuals of European descent; 57% female)-predicted alcohol problems earlier in development (age 14) in an independent sample (FinnTwin12; n = 1162; 53% female). We then tested whether environmental factors (parental knowledge and peer deviance) moderated polygenic risk to predict alcohol problems in the FinnTwin12 sample. We found evidence for both polygenic association and for additive polygene-environment interaction. Higher polygenic scores predicted a greater number of alcohol problems (range of Pearson partial correlations 0.07-0.08, all p-values ≤ 0.01). Moreover, genetic influences were significantly more pronounced under conditions of low parental knowledge or high peer deviance (unstandardized regression coefficients (b), p-values (p), and percent of variance (R2) accounted for by interaction terms: b = 1.54, p = 0.02, R2 = 0.33%; b = 0.94, p = 0.04, R2 = 0.30%, respectively). Supplementary set-based analyses indicated that the individual top single nucleotide polymorphisms (SNPs) contributing to the polygenic scores were not individually enriched for gene-environment interaction. Although the magnitude of the observed effects are small, this study illustrates the usefulness of polygenic approaches for understanding the pathways by which measured genetic predispositions come together with environmental factors to predict complex behavioral outcomes.
Directory of Open Access Journals (Sweden)
Jessica E. Salvatore
2014-04-01
Full Text Available Alcohol problems represent a classic example of a complex behavioral outcome that is likely influenced by many genes of small effect. A polygenic approach, which examines aggregate measured genetic effects, can have predictive power in cases where individual genes or genetic variants do not. In the current study, we first tested whether polygenic risk for alcohol problems—derived from genome-wide association estimates of an alcohol problems factor score from the age 18 assessment of the Avon Longitudinal Study of Parents and Children (ALSPAC; n = 4304 individuals of European descent; 57% female—predicted alcohol problems earlier in development (age 14 in an independent sample (FinnTwin12; n = 1162; 53% female. We then tested whether environmental factors (parental knowledge and peer deviance moderated polygenic risk to predict alcohol problems in the FinnTwin12 sample. We found evidence for both polygenic association and for additive polygene-environment interaction. Higher polygenic scores predicted a greater number of alcohol problems (range of Pearson partial correlations 0.07–0.08, all p-values ≤ 0.01. Moreover, genetic influences were significantly more pronounced under conditions of low parental knowledge or high peer deviance (unstandardized regression coefficients (b, p-values (p, and percent of variance (R2 accounted for by interaction terms: b = 1.54, p = 0.02, R2 = 0.33%; b = 0.94, p = 0.04, R2 = 0.30%, respectively. Supplementary set-based analyses indicated that the individual top single nucleotide polymorphisms (SNPs contributing to the polygenic scores were not individually enriched for gene-environment interaction. Although the magnitude of the observed effects are small, this study illustrates the usefulness of polygenic approaches for understanding the pathways by which measured genetic predispositions come together with environmental factors to predict complex behavioral outcomes.
Randomized Prediction Games for Adversarial Machine Learning.
Rota Bulo, Samuel; Biggio, Battista; Pillai, Ignazio; Pelillo, Marcello; Roli, Fabio
In spam and malware detection, attackers exploit randomization to obfuscate malicious data and increase their chances of evading detection at test time, e.g., malware code is typically obfuscated using random strings or byte sequences to hide known exploits. Interestingly, randomization has also been proposed to improve security of learning algorithms against evasion attacks, as it results in hiding information about the classifier to the attacker. Recent work has proposed game-theoretical formulations to learn secure classifiers, by simulating different evasion attacks and modifying the classification function accordingly. However, both the classification function and the simulated data manipulations have been modeled in a deterministic manner, without accounting for any form of randomization. In this paper, we overcome this limitation by proposing a randomized prediction game, namely, a noncooperative game-theoretic formulation in which the classifier and the attacker make randomized strategy selections according to some probability distribution defined over the respective strategy set. We show that our approach allows one to improve the tradeoff between attack detection and false alarms with respect to the state-of-the-art secure classifiers, even against attacks that are different from those hypothesized during design, on application examples including handwritten digit recognition, spam, and malware detection.In spam and malware detection, attackers exploit randomization to obfuscate malicious data and increase their chances of evading detection at test time, e.g., malware code is typically obfuscated using random strings or byte sequences to hide known exploits. Interestingly, randomization has also been proposed to improve security of learning algorithms against evasion attacks, as it results in hiding information about the classifier to the attacker. Recent work has proposed game-theoretical formulations to learn secure classifiers, by simulating different
Statistical models for expert judgement and wear prediction
International Nuclear Information System (INIS)
Pulkkinen, U.
1994-01-01
This thesis studies the statistical analysis of expert judgements and prediction of wear. The point of view adopted is the one of information theory and Bayesian statistics. A general Bayesian framework for analyzing both the expert judgements and wear prediction is presented. Information theoretic interpretations are given for some averaging techniques used in the determination of consensus distributions. Further, information theoretic models are compared with a Bayesian model. The general Bayesian framework is then applied in analyzing expert judgements based on ordinal comparisons. In this context, the value of information lost in the ordinal comparison process is analyzed by applying decision theoretic concepts. As a generalization of the Bayesian framework, stochastic filtering models for wear prediction are formulated. These models utilize the information from condition monitoring measurements in updating the residual life distribution of mechanical components. Finally, the application of stochastic control models in optimizing operational strategies for inspected components are studied. Monte-Carlo simulation methods, such as the Gibbs sampler and the stochastic quasi-gradient method, are applied in the determination of posterior distributions and in the solution of stochastic optimization problems. (orig.) (57 refs., 7 figs., 1 tab.)
Sogukpinar, Haci; Bozkurt, Ismail
2018-02-01
Aerodynamic performance of the airfoil plays the most important role to obtain economically maximum efficiency from a wind turbine. Therefore airfoil should have an ideal aerodynamic shape. In this study, aerodynamic simulation of S809 airfoil is conducted and obtained result compared with previously made NASA experimental result and NREL theoretical data. At first, Lift coefficient, lift to drag ratio and pressure coefficient around S809 airfoil are calculated with SST turbulence model, and are compared with experimental and other theoretical data to correlate simulation correctness of the computational approaches. And result indicates good correlation with both experimental and theoretical data. This calculation point out that as the increasing relative velocity, lift to drag ratio increases. Lift to drag ratio attain maximum at the angle around 6 degree and after that starts to decrease again. Comparison shows that CFD code used in this calculation can predict aerodynamic properties of airfoil.
International Nuclear Information System (INIS)
Douglas-Hamilton, D.H.; Feinberg, R.M.; Lowder, R.S.
1975-01-01
A six-temperature kinetic model of the He : He 2 Co 2 : N 2 : CO laser system is developed, in which five temperatures describe the vibrational excitation of the three CO 2 modes, N 2 , and CO, while the sixth refers to the kinetic temperature. Theoretical predictions of gain and laser output are compared with experiments performed on an electron-beam sustained laser used at atmospheric pressure. Gain and laser measurements have been made with initial gas temperature near 200 and 300 degreeK. A stable discharge can be produced in this type of laser in gas mixtures containing no He, and successful electric laser operation has been demonstrated using H 2 as CO 2 ν 2 deactivant. Various gas mixtures have been investigated experimentally and theoretically; specific output J>100 J/liter atm was obtained both in He : N 2 : CO 2 : H 2 3 : 2 : 1 : 0 and 0 : 3 : 1 : 0.08, with efficiencies near 30%. While the gain measured appears to peak later and decay later than predicted, in all laser output measurements there is good agreement between theoretical prediction and experiment
Tokumitsu, S.; Hasegawa, M.
2018-05-01
The coloring phenomena caused by optical rotation of polarized light beams in sugared water can be an appropriate subject for use as an educational tool. In this paper, such coloring phenomena are studied in terms of theory, and the results are compared with experimental results. First, polarized laser beams in red, blue, or green were allowed to travel in sugared water of certain concentrations, and changes in the irradiance of the beams were measured while changing the distance between a pair of polarizing plates arranged in the sugared water. The angle of rotation was then determined for each color. An equation was established for predicting a theoretical value of the angle of rotation for laser beams of specific colors (wavelengths) traveling in sugared water of specific concentrations. The predicted results from the equation exhibited satisfactory agreement with the experimental values obtained from the measurements. In addition, changes in the irradiance of traveling laser beams, as well as the changes in colors observable for white light beams, were also predicted, resulting in good agreement with the observed results.
An experimental and theoretical study of decentralized gas fired liquid heating
Energy Technology Data Exchange (ETDEWEB)
Christensen, Rolf
1996-12-01
The effects on the energy situation in industry when gas fired liquid heaters replace steam have been determined by energy surveys performed in a brewery and a slaughterhouse, measurements of the performance and emissions from liquid heaters installed in these industries, and theoretical analyses of the potential energy. The theoretical study in the first part of the project provides information that allows assessment of the effects on the energy situation, of a part or complete conversion to decentralized heating, under the conditions prevailing in the industries concerned. The second part of the project focused on increasing the liquid heater efficiency and reducing emissions of carbon monoxide and hydrocarbons. Heat transfer and pressure drop for a corrugated tube was investigated experimentally. Empirical correlations for heat transfer and pressure drop for a corrugated tube were developed. These correlations were used in the design model that was developed within this project. The design model was validated against experimental data and data from an industrial application, where a section of the smooth heat exchanger tube was replaced with a corrugated tube. The results show that the design model predicts the outlet flue gas temperature and the heater efficiency quite accurately. The wall temperature at the first corrugation is also predicted with reasonable accuracy. These results make it possible to calculate the location where a corrugated tube can be inserted without causing subcooled boiling or severe fouling. It is shown that emissions of carbon monoxide and hydrocarbons can be held at low levels, even when conventional industrial burners are used. The use of nozzles that produce long soft flames increase the risk for large emissions of hydrocarbons and carbon monoxide. 125 refs, 89 figs, 16 tabs
Energy Technology Data Exchange (ETDEWEB)
Kievsky, A. [Istituto Nazionale di Fisica Nucleare, Pisa (Italy); Rosati, S. [Istituto Nazionale di Fisica Nucleare, Pisa (Italy)]|[Pisa Univ. (Italy). Dipt. di Fisica; Tornow, W. [Duke Univ., Durham, NC (United States). Dept. of Physics; Viviani, M. [Istituto Nazionale di Fisica Nucleare, Pisa (Italy)
1996-09-30
The theoretical approaches for studying N-d processes using realistic, semi-phenomenological NN potentials have matured considerably during the last few years. Accurate calculations of scattering observables are now feasible. Recently, high-quality measurements of N-d scattering at energies below the deuteron breakup threshold became available. Therefore, a detailed comparison between theory and experimental data can now be performed. In this paper the various sets of experimental data for the N-d differential cross section, and the vector and tensor analyzing powers are examined in a critical way in the incident nucleon energy range from 1 to 3 MeV. In order to identify possible inadequacies of the interaction models adopted, phase-shift analyses were performed and compared to the theoretical parameters. (orig.).
Desublimation process: verification and applications of a theoretical model
International Nuclear Information System (INIS)
Eby, R.S.
1979-01-01
A theoretical model simulating the simultaneous heat and mass transfer which takes place during the desublimation of a gas to a solid is presented. Desublimer column loading profiles to experimentally verify the model were obtained using a gamma scintillation technique. The data indicate that, if the physical parameters of the desublimed frost material are known, the model can accurately predict the desublimation phenomenon. The usefulness of the model in different engineering applications is also addressed
Theoretical study of evaporation heat transfer in horizontal microfin tubes: stratified flow model
Energy Technology Data Exchange (ETDEWEB)
Honda, H; Wang, Y S [Kyushu Univ., Inst. for Materials Chemistry and Engineering, Kasuga, Fukuoka (Japan)
2004-08-01
The stratified flow model of evaporation heat transfer in helically grooved, horizontal microfin tubes has been developed. The profile of stratified liquid was determined by a theoretical model previously developed for condensation in horizontal microfin tubes. For the region above the stratified liquid, the meniscus profile in the groove between adjacent fins was determined by a force balance between the gravity and surface tension forces. The thin film evaporation model was applied to predict heat transfer in the thin film region of the meniscus. Heat transfer through the stratified liquid was estimated by using an empirical correlation proposed by Mori et al. The theoretical predictions of the circumferential average heat transfer coefficient were compared with available experimental data for four tubes and three refrigerants. A good agreement was obtained for the region of Fr{sub 0}<2.5 as long as partial dry out of tube surface did not occur. (Author)
Theoretical Work for the Fast Zero-Power Reactor FR-0
Energy Technology Data Exchange (ETDEWEB)
Haeggblom, H
1965-08-15
The theoretical part of the fast reactor physics work in Sweden, has mainly been connected with the FR-0 reactor. The report describes the principal features of this reactor, evaluation of cross sections, calculations of critical masses, reactivity of the air gap and of control rods and calculations of neutron generation time and effective beta values. Carlson codes in spherical and in cylindrical geometry are used to evaluate critical masses and fluxes. In cases when reactivity changes are calculated, complementary methods are perturbation theory and variational calculus. The agreement with experiments is in some cases good, especially the determination of critical mass, but in other cases discrepancies are observed, e.g. the activation of U-238 in the reflector is much larger than the theoretical spectrum predicts.
Theoretical Adiabatic Temperature and Chemical Composition of Sodium Combustion Flame
International Nuclear Information System (INIS)
Okano, Yasushi; Yamaguchi, Akira
2003-01-01
Sodium fire safety analysis requires fundamental combustion properties, e.g., heat of combustion, flame temperature, and composition. We developed the GENESYS code for a theoretical investigation of sodium combustion flame.Our principle conclusions on sodium combustion under atmospheric air conditions are (a) the maximum theoretical flame temperature is 1950 K, and it is not affected by the presence of moisture; the uppermost limiting factor is the chemical instability of the condensed sodium-oxide products under high temperature; (b) the main combustion product is liquid Na 2 O in dry air condition and liquid Na 2 O with gaseous NaOH in moist air; and (c) the chemical equilibrium prediction of the residual gaseous reactants in the flame is indispensable for sodium combustion modeling
Theoretical XANES Study of the Activated Nickel (t-Amylisocyanide) Molecule
International Nuclear Information System (INIS)
Glover, J. L.; Chantler, C. T.; Soldatov, A. V.; Smolentsev, G.; Feiters, M. C.
2007-01-01
XANES is one of the most powerful techniques for investigating the active centres of non-crystalline systems such as synthetic catalysts and enzymes. We have investigated XANES for an active species in the Ni-catalyzed polymerization of isocyanides, the activated Ni (t-amylisocyanide) complex, using two of the most popular theoretical approaches. This is a very large cluster for which it is extremely difficult to derive a converged solution using the Finite Difference Method. The cluster has been linked to important chemical developments for catalysts for isocyanide polymerization. Predicted XANES for the nano-cluster are compared with experimental data, providing an important test for different theoretical approaches. Developments of a finite element method gave excellent agreement with the experimental data, while simpler models were relatively unsuccessful
Theoretical Studies of Nanoclusters (Briefing Charts)
2015-07-23
nanoclusters. However, scanning transmission electron microscopy ( STEM ) measures show cluster inversion occurred to produce MgyCux(!) a) copper atoms b...methane (née CLL -1) as a potential explosive ingredient: a theoretical study”, Propellants, Explosives, Pyrotechnics 38, 9-13 (2013). Jesus Paulo L
A theoretical study of perovskite CsXCl3 (X=Pb, Cd) within first principles calculations
Energy Technology Data Exchange (ETDEWEB)
Ilyas, Bahaa M., E-mail: bahaastring@gmail.com [Department of Physics, University Of Dohuk (Iraq); Elias, Badal H. [Laboratory of Theoretical Physics, Department of Physics, Faculty of Sciences, University of Dohuk (Iraq)
2017-04-01
The structural, elastic, electronic, optical acoustic and thermodynamic properties of the cubic perovskite CsPbCl{sub 3} and CsCdCl{sub 3} unit cell, were studied using an ultra-soft pseudopotential plane wave, the Trouiller-Martins-Functional was utilized to perform these calculations. The study was implemented within both the Local Density Approximation (LDA) and the Generalized Gradient Approximation (GGA). the Generalized Gradient Approximation (GGA) scheme proposed by van Leeuwen-Baerends which is the same as the Perdew-Wang 92 functional have been carried out to preform our calculations. As for the Local Density Approximation (LDA) the Teter-Pade parametrization (4/93) was implemented which is the same as Perdew-Wang that in its turn reproduces the Ceperley-Alder-Functional. The computed GGA/LDA-lattice parameter for both CsCdCl{sub 3} and CsPbCl{sub 3} is in an exquisite agreement with the experimental and theoretical results. The energy band structure shows that CsCdCl{sub 3} is Γ–R indirect band gap insulator, while CsPbCl{sub 3} is an insulator with a direct band gap Γ–Γ separating the valence bands from the conduction bands, which shows metallic nature after pressure 30 GPa. A hybridization exists between Pb-p states and Cl-p states for CsPbCl{sub 3}, and Cd-p states and Cs-p states for the CsCdCl{sub 3} in the valence bonding region. Optimization of both cell shape (geometry) volume were investigated as pressure of 0–20 GPa and 0–40 GPa for the CsCdCl{sub 3} and CsPbCl{sub 3} respectively. The Pressure dependence of cubic perovskite elastic constants, Young modulus, bulk and shear moduli, Lame’s constants, elastic anisotropy factor, elastic wave velocities, phonon dispersion, Debye temperature and the density of states of CsXCl{sub 3} (X=Pb, Cd) were theoretically calculated and compared with the other available theoretical results. The above elastic constants reveal the fact that both compounds are stable and show nature of ductility. For
Kuklja, M M; Kotomin, E A; Merkle, R; Mastrikov, Yu A; Maier, J
2013-04-21
Solid oxide fuel cells (SOFC) are under intensive investigation since the 1980's as these devices open the way for ecologically clean direct conversion of the chemical energy into electricity, avoiding the efficiency limitation by Carnot's cycle for thermochemical conversion. However, the practical development of SOFC faces a number of unresolved fundamental problems, in particular concerning the kinetics of the electrode reactions, especially oxygen reduction reaction. We review recent experimental and theoretical achievements in the current understanding of the cathode performance by exploring and comparing mostly three materials: (La,Sr)MnO3 (LSM), (La,Sr)(Co,Fe)O3 (LSCF) and (Ba,Sr)(Co,Fe)O3 (BSCF). Special attention is paid to a critical evaluation of advantages and disadvantages of BSCF, which shows the best cathode kinetics known so far for oxides. We demonstrate that it is the combined experimental and theoretical analysis of all major elementary steps of the oxygen reduction reaction which allows us to predict the rate determining steps for a given material under specific operational conditions and thus control and improve SOFC performance.
Theoretical and computational analyses of LNG evaporator
Chidambaram, Palani Kumar; Jo, Yang Myung; Kim, Heuy Dong
2017-04-01
Theoretical and numerical analysis on the fluid flow and heat transfer inside a LNG evaporator is conducted in this work. Methane is used instead of LNG as the operating fluid. This is because; methane constitutes over 80% of natural gas. The analytical calculations are performed using simple mass and energy balance equations. The analytical calculations are made to assess the pressure and temperature variations in the steam tube. Multiphase numerical simulations are performed by solving the governing equations (basic flow equations of continuity, momentum and energy equations) in a portion of the evaporator domain consisting of a single steam pipe. The flow equations are solved along with equations of species transport. Multiphase modeling is incorporated using VOF method. Liquid methane is the primary phase. It vaporizes into the secondary phase gaseous methane. Steam is another secondary phase which flows through the heating coils. Turbulence is modeled by a two equation turbulence model. Both the theoretical and numerical predictions are seen to match well with each other. Further parametric studies are planned based on the current research.
The z~4 Lyman Break Galaxies: Colors and Theoretical Predictions
Idzi, Rafal; Somerville, Rachel; Papovich, Casey; Ferguson, Henry C.; Giavalisco, Mauro; Kretchmer, Claudia; Lotz, Jennifer
2004-01-01
We investigate several fundamental properties of z~4 Lyman break galaxies by comparing observations with the predictions of a semianalytic model based on the cold dark matter theory of hierarchical structure formation. We use a sample of B435-dropouts from the Great Observatories Origins Deep Survey and complement the Advanced Camera for Surveys optical B435, V606, i775, and z850 data with the Very Large Telescope Infrared Spectrometer and Array Camera J, H, and Ks observations. We extract B435-dropouts from our semianalytic mock catalog using the same color criteria and magnitude limits that were applied to the observed sample. We find that the i775-Ks colors of the model-derived and observed B435-dropouts are in good agreement. However, we find that the i775-z850 colors differ significantly, indicating perhaps that either too little dust or an incorrect extinction curve has been used. Motivated by the reasonably good agreement between the model and observed data, we present predictions for the stellar masses, star formation rates, and ages for the z~4 Lyman break sample. We find that according to our model, the color selection criteria used to select our z~4 sample surveys 67% of all galaxies at this epoch down to z850Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS5-26555. Based on observations collected at the European Southern Observatory, Chile (ESO programmes 168.A-0485, 64.0-0643, 66.A-0572, and 68.A-0544).
Theoretical aspects of the nucleon-nucleon workshop
International Nuclear Information System (INIS)
Silbar, R.R.
1984-01-01
This report concentrates on the inelastic NN system from 300 to 1500 MeV. Topics covered include the visibility of quark signals, dibaryons, the model dependence of predicted NN inelasticities, and a review of how well present conventional models compare with a rapidly expanding database. The general conclusion is that there is so far no clear evidence in the NN system at intermediate energies for unconventional dibaryon resonances. Short remarks are also made concerning one theoretical contribution on elastic scattering and on new experimental results for deuteron photo-disintegration and pion-nucleon charge exchange. 11 references
International Nuclear Information System (INIS)
Satish Kumar, N.V.; Nayak, A.K.; Vijayan, P.K.; Pal, A.K.; Saha, D.; Sinha, R.K.
2004-01-01
A theoretical and experimental investigation has been carried out to study natural circulation characteristics of an Indian PHWR under reduced inventory conditions. The theoretical model incorporates a quasi-steady state analysis of natural circulation at different system inventories. It predicts the system flow rate under single-phase and two-phase conditions and the inventory at which reflux condensation occurs. The model predictions were compared with test data obtained from FISBE (facility for integral system behaviour experiments), which simulates the thermal hydraulic behaviour of the Indian 220 MWe PHWR. The experimental results were found to be in close agreement with the predictions. It was also found that the natural circulation could be oscillatory under reduced inventory conditions. (orig.)
Holley, W. R.; Chatterjee, A.
1996-01-01
We have developed a general theoretical model for the interaction of ionizing radiation with chromatin. Chromatin is modeled as a 30-nm-diameter solenoidal fiber comprised of 20 turns of nucleosomes, 6 nucleosomes per turn. Charged-particle tracks are modeled by partitioning the energy deposition between primary track core, resulting from glancing collisions with 100 eV or less per event, and delta rays due to knock-on collisions involving energy transfers >100 eV. A Monte Carlo simulation incorporates damages due to the following molecular mechanisms: (1) ionization of water molecules leading to the formation of OH, H, eaq, etc.; (2) OH attack on sugar molecules leading to strand breaks: (3) OH attack on bases; (4) direct ionization of the sugar molecules leading to strand breaks; (5) direct ionization of the bases. Our calculations predict significant clustering of damage both locally, over regions up to 40 bp and over regions extending to several kilobase pairs. A characteristic feature of the regional damage predicted by our model is the production of short fragments of DNA associated with multiple nearby strand breaks. The shapes of the spectra of DNA fragment lengths depend on the symmetries or approximate symmetries of the chromatin structure. Such fragments have subsequently been detected experimentally and are reported in an accompanying paper (B. Rydberg, Radiat, Res. 145, 200-209, 1996) after exposure to both high- and low-LET radiation. The overall measured yields agree well quantitatively with the theoretical predictions. Our theoretical results predict the existence of a strong peak at about 85 bp, which represents the revolution period about the nucleosome. Other peaks at multiples of about 1,000 bp correspond to the periodicity of the particular solenoid model of chromatin used in these calculations. Theoretical results in combination with experimental data on fragmentation spectra may help determine the consensus or average structure of the
Experimental and Theoretical Progress on the GEM Theory
Brandenburg, J. E.
This paper reports experimental and theoretical progress on the GEM unification theory. In theoretical progress, the derivation of the GEM theory using it in a fully covariant form is achieved based on the principle of self-cancellation of the ZPF EM stress-momentum tensor. This derivation reveals that the final Gravity-EM system obeys a Helmholtz-like equation resembling that governing sound propagation. Finally an improved derivation of the formula for the Newton Gravitation constant is shown, qresulting in the formula G = e2/(4πɛ0 me mp) α exp (-2 (α-.86/σ2…) = 6.673443 x10-11 N-m2 kg-2 that agrees with experimental values to 3 parts per 100,000. Experiments have found parity violating weight reductions in gyroscopes driven by rotating EM fields. These experiments appear to confirm gravity modification using electromagnetism predicted by the GEM theory through the Vacuum Bernoulli Equation.
Kochukhov, O.; Ryabchikova, T. A.
2018-02-01
A series of recent theoretical atomic diffusion studies has address the challenging problem of predicting inhomogeneous vertical and horizontal chemical element distributions in the atmospheres of magnetic ApBp stars. Here we critically assess the most sophisticated of such diffusion models - based on a time-dependent treatment of the atomic diffusion in a magnetized stellar atmosphere - by direct comparison with observations as well by testing the widely used surface mapping tools with the spectral line profiles predicted by this theory. We show that the mean abundances of Fe and Cr are grossly underestimated by the time-dependent theoretical diffusion model, with discrepancies reaching a factor of 1000 for Cr. We also demonstrate that Doppler imaging inversion codes, based either on modelling of individual metal lines or line-averaged profiles simulated according to theoretical three-dimensional abundance distribution, are able to reconstruct correct horizontal chemical spot maps despite ignoring the vertical abundance variation. These numerical experiments justify a direct comparison of the empirical two-dimensional Doppler maps with theoretical diffusion calculations. This comparison is generally unfavourable for the current diffusion theory, as very few chemical elements are observed to form overabundance rings in the horizontal field regions as predicted by the theory and there are numerous examples of element accumulations in the vicinity of radial field zones, which cannot be explained by diffusion calculations.
50 years of brown dwarfs from prediction to discovery to forefront of research
2014-01-01
The years 2012/2013 mark the 50th anniversary of the theoretical prediction that Brown Dwarfs, i.e. degenerate objects which are just not massive enough to sustain stable hydrogen fusion, exist. Some 20 years after their discovery, how Brown Dwarfs form is still one of the main open questions in the theory of star formation. In this volume, the pioneers of Brown Dwarf research review the history of the theoretical prediction and the subsequent discovery of Brown Dwarfs. After an introduction, written by Viki Joergens, reviewing Shiv Kumar's theoretical prediction of the existence of brown dwarfs, Takenori Nakano reviews his and Hayashi's calculation of the Hydrogen Burning Minimum Mass. Both predictions happened in the early 1960s. Jill Tarter then writes on the introduction of the term 'Brown Dwarf', before Ben Oppenheimer, Rafael Rebolo and Gibor Basri describe their first discovery of Brown Dwarfs in the 1990s. Lastly, Michael Cushing and Isabelle Baraffe describe the development of the field to the curren...
Theoretical advancements and applications of the low-momentum nucleon-nucleon interaction
Holt, Jason Davidson
One of the most fundamental problems in low-energy nuclear physics is how to calculate nuclear structure observables from the most basic microscopic elements available. The low-momentum nucleon-nucleon interaction Vlow k provides a nearly-unique microscopic starting point for calculations involving finite nuclei. We first discuss the Renormalization Group and Effective Field Theory ideas behind the development of Vlow k and show that Vlow k is expressible as a bare interaction supplemented by a series of counter terms representing a short range interaction. One drawback of Vlow k is that it is necessarily non-Hermitian, and, as such not immediately suited for use in shell model calculations. To remedy this, we present a new method, based on Schmidt orthogonalization, that generates a family of Hermitian low-momentum interactions, and show it is a generalization of several well-known Hermitian transformations. Moreover, this transformation is shown to preserve phase shifts and deuteron properties. To get an effective interaction which takes into account the complicated processes taking place in the nuclear many-body system, Vlow k must be supplemented by the effects of core polarization. Typically calculated to second order, the higher order properties of core polarization have been long-debated. We develop a new method for calculating core polarization diagrams to all order, which, when applied to nuclei in the sd-shell region, is shown to be quite close to the second-order results. In the second part of the Dissertation, we study how the shell model effective interaction derived from Vlow k can predict and explain complex nuclear properties. In particular we will study in depth mixed-symmetry (MS) structures: collective nuclear excitations in which protons and neutrons move out of phase. After a basic theoretical description of these states in terms of the Interacting Boson Model and a discussion of the most important experimental studies, we show that shell model
Directory of Open Access Journals (Sweden)
Hideyuki Usa
2017-01-01
Full Text Available This study attempted to develop a formula for predicting maximum muscle strength value for young, middle-aged, and elderly adults using theoretical Grade 3 muscle strength value (moment fair: Mf—the static muscular moment to support a limb segment against gravity—from the manual muscle test by Daniels et al. A total of 130 healthy Japanese individuals divided by age group performed isometric muscle contractions at maximum effort for various movements of hip joint flexion and extension and knee joint flexion and extension, and the accompanying resisting force was measured and maximum muscle strength value (moment max, Mm was calculated. Body weight and limb segment length (thigh and lower leg length were measured, and Mf was calculated using anthropometric measures and theoretical calculation. There was a linear correlation between Mf and Mm in each of the four movement types in all groups, excepting knee flexion in elderly. However, the formula for predicting maximum muscle strength was not sufficiently compatible in middle-aged and elderly adults, suggesting that the formula obtained in this study is applicable in young adults only.
Impulsivity facets’ predictive relations with DSM-5 PTSD symptom clusters
Roley, Michelle E.; Contractor, Ateka A.; Weiss, Nicole H.; Armour, Cherie; Elhai, Jon D.
2017-01-01
Objective Posttraumatic Stress Disorder (PTSD) has a well-established theoretical and empirical relation with impulsivity. Prior research has not used a multidimensional approach for measuring both PTSD and impulsivity constructs when assessing their relationship. Method The current study assessed the unique relationship of impulsivity facets on PTSD symptom clusters among a non-clinical sample of 412 trauma-exposed adults. Results Linear regression analyses revealed that impulsivity facets best accounted for PTSD’s arousal symptoms. The negative urgency facet of impulsivity was most predictive, as it was associated with all of PTSD’s symptom clusters. Sensation seeking did not predict PTSD’s intrusion symptoms, but did predict the other symptom clusters of PTSD. Lack of perseverance only predicted intrusion symptoms, while lack of premeditation only predicted PTSD’s mood/cognition symptoms. Conclusions Results extend theoretical and empirical research on the impulsivity-PTSD relationship, suggesting that impulsivity facets may serve as both risk and protective factors for PTSD symptoms. PMID:27243571
Theoretical and Experimental Spectroscopic Analysis of Cyano-Substituted Styrylpyridine Compounds
Directory of Open Access Journals (Sweden)
Jorge Lopez-Cruz
2013-02-01
Full Text Available A combined theoretical and experimental study on the structure, infrared, UV-Vis and 1H NMR data of trans-2-(m-cyanostyrylpyridine, trans-2-[3-methyl-(m-cyanostyryl]pyridine and trans-4-(m-cyanostyrylpyridine is presented. The synthesis was carried out with an efficient Knoevenagel condensation using green chemistry conditions. Theoretical geometry optimizations and their IR spectra were carried out using the Density Functional Theory (DFT in both gas and solution phases. For theoretical UV-Vis and 1H NMR spectra, the Time-Dependent DFT (TD-DFT and the Gauge-Including Atomic Orbital (GIAO methods were used, respectively. The theoretical characterization matched the experimental measurements, showing a good correlation. The effect of cyano- and methyl- substituents, as well as of the N-atom position in the pyridine ring on the UV-Vis, IR and NMR spectra, was evaluated. The UV-Vis results showed no significant effect due to electron-withdrawing cyano- and electron-donating methyl-substituents. The N-atom position, however, caused a slight change in the maximum absorption wavelengths. The IR normal modes were assigned for the cyano- and methyl-groups. 1H NMR spectra showed the typical doublet signals due to protons in the trans position of a double bond. The theoretical characterization was visibly useful to assign accurately the signals in IR and 1H NMR spectra, as well as to identify the most probable conformation that could be present in the formation of the styrylpyridine-like compounds.
Lieberman, Amy M; Borovsky, Arielle; Mayberry, Rachel I
2018-01-01
Prediction during sign language comprehension may enable signers to integrate linguistic and non-linguistic information within the visual modality. In two eyetracking experiments, we investigated American Sign language (ASL) semantic prediction in deaf adults and children (aged 4-8 years). Participants viewed ASL sentences in a visual world paradigm in which the sentence-initial verb was either neutral or constrained relative to the sentence-final target noun. Adults and children made anticipatory looks to the target picture before the onset of the target noun in the constrained condition only, showing evidence for semantic prediction. Crucially, signers alternated gaze between the stimulus sign and the target picture only when the sentential object could be predicted from the verb. Signers therefore engage in prediction by optimizing visual attention between divided linguistic and referential signals. These patterns suggest that prediction is a modality-independent process, and theoretical implications are discussed.
Predicting heavy episodic drinking using an extended temporal self-regulation theory.
Black, Nicola; Mullan, Barbara; Sharpe, Louise
2017-10-01
Alcohol consumption contributes significantly to the global burden from disease and injury, and specific patterns of heavy episodic drinking contribute uniquely to this burden. Temporal self-regulation theory and the dual-process model describe similar theoretical constructs that might predict heavy episodic drinking. The aims of this study were to test the utility of temporal self-regulation theory in predicting heavy episodic drinking, and examine whether the theoretical relationships suggested by the dual-process model significantly extend temporal self-regulation theory. This was a predictive study with 149 Australian adults. Measures were questionnaires (self-report habit index, cues to action scale, purpose-made intention questionnaire, timeline follow-back questionnaire) and executive function tasks (Stroop, Tower of London, operation span). Participants completed measures of theoretical constructs at baseline and reported their alcohol consumption two weeks later. Data were analysed using hierarchical multiple linear regression. Temporal self-regulation theory significantly predicted heavy episodic drinking (R 2 =48.0-54.8%, ptheory and the extended temporal self-regulation theory provide good prediction of heavy episodic drinking. Intention, behavioural prepotency, planning ability and inhibitory control may be good targets for interventions designed to decrease heavy episodic drinking. Copyright © 2017 Elsevier Ltd. All rights reserved.
Transionospheric propagation predictions
Klobucher, J. A.; Basu, S.; Basu, S.; Bernhardt, P. A.; Davies, K.; Donatelli, D. E.; Fremouw, E. J.; Goodman, J. M.; Hartmann, G. K.; Leitinger, R.
1979-01-01
The current status and future prospects of the capability to make transionospheric propagation predictions are addressed, highlighting the effects of the ionized media, which dominate for frequencies below 1 to 3 GHz, depending upon the state of the ionosphere and the elevation angle through the Earth-space path. The primary concerns are the predictions of time delay of signal modulation (group path delay) and of radio wave scintillation. Progress in these areas is strongly tied to knowledge of variable structures in the ionosphere ranging from the large scale (thousands of kilometers in horizontal extent) to the fine scale (kilometer size). Ionospheric variability and the relative importance of various mechanisms responsible for the time histories observed in total electron content (TEC), proportional to signal group delay, and in irregularity formation are discussed in terms of capability to make both short and long term predictions. The data base upon which predictions are made is examined for its adequacy, and the prospects for prediction improvements by more theoretical studies as well as by increasing the available statistical data base are examined.
Theoretical aspects of stress corrosion cracking of Alloy 22
Lee, Sang-Kwon; Macdonald, Digby D.
2018-05-01
Theoretical aspects of the stress corrosion cracking of Alloy 22 in contact with saturated NaCl solution are explored in terms of the Coupled Environment Fracture Model (CEFM), which was calibrated upon available experimental crack growth rate data. Crack growth rate (CGR) was then predicted as a function of stress intensity, electrochemical potential, solution conductivity, temperature, and electrochemical crack length (ECL). From the dependence of the CGR on the ECL and the evolution of a semi-elliptical surface crack in a planar surface under constant loading conditions it is predicted that penetration through the 2.5-cm thick Alloy 22 corrosion resistant layer of the waste package (WP) could occur 32,000 years after nucleation. Accordingly, the crack must nucleate within the first 968,000 years of storage. However, we predict that the Alloy 22 corrosion resistant layer will not be penetrated by SCC within the 10,000-year Intermediate Performance Period, even if a crack nucleates immediately upon placement of the WP in the repository.
Theoretical Characterizaiton of Visual Signatures (Muzzle Flash)
Kashinski, D. O.; Scales, A. N.; Vanderley, D. L.; Chase, G. M.; di Nallo, O. E.; Byrd, E. F. C.
2014-05-01
We are investigating the accuracy of theoretical models used to predict the visible, ultraviolet and infrared spectra of product materials ejected from the muzzle of currently fielded systems. Recent advances in solid propellants has made the management of muzzle signature (flash) a principle issue in weapons development across the calibers. A priori prediction of the electromagnetic spectra of formulations will allow researchers to tailor blends that yield desired signatures and determine spectrographic detection ranges. We are currently employing quantum chemistry methods at various levels of sophistication to optimize molecular geometries, compute vibrational frequencies, and determine the optical spectra of specific gas-phase molecules and radicals of interest. Electronic excitations are being computed using Time Dependent Density Functional Theory (TD-DFT). A comparison of computational results to experimental values found in the literature is used to assess the affect of basis set and functional choice on calculation accuracy. The current status of this work will be presented at the conference. Work supported by the ARL, and USMA.
TMX tandem-mirror experiments and thermal-barrier theoretical studies
International Nuclear Information System (INIS)
Simonen, T.C.; Baldwin, D.E.; Allen, S.L.
1982-01-01
This paper describes recent analysis of energy confinement in the Tandem Mirror Experiment (TMX). TMX data also indicates that warm plasma limits the amplitude of the anisotropy driven Alfven ion cyclotron (AIC) mode. Theoretical calculations show strong AIC stabilization with off-normal beam injection as planned in TMX-U and MFTF-B. This paper reports results of theoretical analysis of hot electrons in thermal barriers including electron heating calculations by Monte Carlo and Fokker-Planck codes and analysis of hot electron MHD and microinstability. Initial results from the TMX-U experiment are presented which show the presence of sloshing ions
Theoretical temperature model with experimental validation for CLIC Accelerating Structures
AUTHOR|(CDS)2126138; Vamvakas, Alex; Alme, Johan
Micron level stability of the Compact Linear Collider (CLIC) components is one of the main requirements to meet the luminosity goal for the future $48 \\,km$ long underground linear accelerator. The radio frequency (RF) power used for beam acceleration causes heat generation within the aligned structures, resulting in mechanical movements and structural deformations. A dedicated control of the air- and water- cooling system in the tunnel is therefore crucial to improve alignment accuracy. This thesis investigates the thermo-mechanical behavior of the CLIC Accelerating Structure (AS). In CLIC, the AS must be aligned to a precision of $10\\,\\mu m$. The thesis shows that a relatively simple theoretical model can be used within reasonable accuracy to predict the temperature response of an AS as a function of the applied RF power. During failure scenarios or maintenance interventions, the RF power is turned off resulting in no heat dissipation and decrease in the overall temperature of the components. The theoretica...
Structure of small TiC n clusters: A theoretical study
International Nuclear Information System (INIS)
Largo, Laura; Cimas, Alvaro; Redondo, Pilar; Rayon, Victor M.; Barrientos, Carmen
2006-01-01
A theoretical study of the TiC n (n = 1-8) clusters has been carried out at the B3LYP/6-311+G(d) level. Molecular properties for three different isomers, namely linear, cyclic, and fan species, have been determined. The fan isomers, where the titanium atom is essentially side-bonded to the entire C n unit, are predicted to be more stable than both linear and cyclic isomers. Only for the largest studied species, TiC 8 , the cyclic isomer is located lower in energy. An even-odd parity effect in the incremental binding energies is observed for the three isomers, n-even species being in general more stable for linear and fan isomers, whereas for the cyclic species n-odd clusters are favoured. A topological analysis of the electronic charge density shows that all cyclic isomers correspond to true monocyclic rings, whereas for the fan species a variety of different connectivities has been observed
International Nuclear Information System (INIS)
Riffat, S.B.; Zhao, X.; Doherty, P.S.
2005-01-01
A thin membrane heat-pipe solar collector was designed and constructed to allow heat from solar radiation to be collected at a relatively high efficiency while keeping the capital cost low. A theoretical model incorporating a set of heat balance equations was developed to analyse heat transfer processes occurring in separate regions of the collector, i.e., the top cover, absorber and condenser/manifold areas, and examine their relationship. The thermal performance of the collector was investigated using the theoretical model. The modelling predictions were validated using the experimental data from a referred source. The test efficiency was found to be in the range 40-70%, which is a bitter lower than the values predicted by modelling. The factors influencing these results were investigated
'Impulsar': Experimental and Theoretical Investigations
International Nuclear Information System (INIS)
Apollonov, V. V.
2008-01-01
The Objective of the 'Impulsar' project is to accomplish a circle of experimental, engineering and technological works on creation of a high efficiency laser rocket engine. The project includes many organizations of the rocket industry and Academy of Sciences of Russia. High repetition rate pulse-periodic CO 2 laser system project for launching will be presented. Optical system for 15 MW laser energy delivery and optical matrix of laser engine receiver will by discussed as well. Basic characteristics of the laser-based engine will be compared with theoretical predictions and important stages of further technology implementation (low frequency resonance). Relying on a wide cooperation of different branches of science and industry organizations it is very possible to use the accumulated potential for launching of nano-vehicles during the upcoming 4-5 years
International Nuclear Information System (INIS)
Siemon, R.E.; Armstrong, W.T.; Chrien, R.E.
1985-01-01
Theoretical studies of FRC stability and transport are summarized. Finite Larmor radius theories are shown to be unreliable for explaining the experimentally observed stability to tilting. Control of the n=2 rotational instability has been demonstrated in two-dimensional hybrid code simulations, and the stability appears to be described within MHD if the nearly square equilibria that result from quadrupole fields are taken into account. Simulations of the lower hybrid drift instability in parameter regimes relevant to experiments show good agreement with a non-local theory of the instability. A 1.5-dimensional transport code shows agreement with the energy confinement time but disagreement with the flux loss time observed in FRX-C. The process of FRC translation in which the plasma is formed, translated into a DC solenoid and trapped by magnetic mirrors, has been studied in the FRX-C/T experiment. Efficient transfer of particles, energy and internal magnetic flux are observed with no enhancement of loss processes over in-situ FRC experiments. The axial velocity of the FRC can be estimated reasonably well with a simple model based on conservation of energy. Internal magnetic field probing during translation shows the expected structure of poloidal field and a complex distribution of generally weak toroidal fields. Measurements of radiated power indicate that radiation is a small fraction of the total plasma power loss (typically 8%). Translation has facilitated scaling studies of confinement over a wider range of parameters than were achieved by in-situ FRX-C experiments. For example, the variable xsub(s), the ratio of the separatrix radius to the metal wall radius, has been increased to about 0.7 by allowing the FRC to expand during translation. In all cases, particle confinement times agree within a factor of two with predictions by models that assume a lower hybrid drift resistivity. However, for the conditions studied there are indications that the experimental
Validation of theoretical models through measured pavement response
DEFF Research Database (Denmark)
Ullidtz, Per
1999-01-01
mechanics was quite different from the measured stress, the peak theoretical value being only half of the measured value.On an instrumented pavement structure in the Danish Road Testing Machine, deflections were measured at the surface of the pavement under FWD loading. Different analytical models were...... then used to derive the elastic parameters of the pavement layeres, that would produce deflections matching the measured deflections. Stresses and strains were then calculated at the position of the gauges and compared to the measured values. It was found that all analytical models would predict the tensile...
Theoretical calculation of saturated absorption for multilevel atoms
International Nuclear Information System (INIS)
O'Kane, T.J.; Scholten, R.E.; Farrell, P.M.
1998-01-01
We present the first theoretical saturated absorption spectra for general multi-level atoms, using a model based on extensions of the optical Bloch equations, and using Monte Carlo averaging of the absorption of individual atoms with random trajectories through a standing wave. We are for the first time able to accurately predict the merging of hyperfine and cross-over resonances due to intensity dependent phenomena such as power broadening. Results for 20-level sodium and 24-level rubidium models are presented and compared to experiment, demonstrating excellent agreement
Predictability of weather and climate
National Research Council Canada - National Science Library
Palmer, Tim; Hagedorn, Renate
2006-01-01
... and anthropogenic climate change are among those included. Ensemble systems for forecasting predictability are discussed extensively. Ed Lorenz, father of chaos theory, makes a contribution to theoretical analysis with a previously unpublished paper. This well-balanced volume will be a valuable resource for many years. High-quality chapter autho...
Theoretical study of relative width of photonic band gap for the 3-D ...
Indian Academy of Sciences (India)
... of refractive index and relative radius of the photonic band gap for the fcc closed packed 3-D dielectric microstructure are reported and comparison of experimental observations and theoretical predictions are given. This work is useful for the understanding of photonic crystals and occurrence of the photonic band gap.
Development of Simple Drying Model for Performance Prediction of Solar Dryer: Theoretical Analysis
DEFF Research Database (Denmark)
Singh, Shobhana; Kumar, Subodh
2012-01-01
An analytical moisture diffusion model which considers the influence of external resistance to mass transfer is developed to predict thermal performance of dryer system. The moisture diffusion coefficient, Deff that is necessary to evaluate the prediction model has been determined in terms...... of experimental drying parameters. A laboratory model of mixed-mode solar dryer system is tested with cylindrical potato samples of thickness 5 and 18 mm under simulated indoor conditions. The potato samples were dried at a constant absorbed thermal energy of 750 W/m2 and air mass flow rate of 0.011 kg...
Theoretical predictions of anti-corrosive properties of THAM and its derivatives.
Malinowski, Szymon; Jaroszyńska-Wolińska, Justyna; Herbert, Tony
2017-12-04
We present quantum chemical theoretical estimations of the anti-corrosive properties of THAM (tris(hydroxymethyl)aminomethane) and three derivatives that differ in the number of benzene rings: THAM-1 (2-amino-3-hydroxy-2-(hydroxymethyl) propylobenzoate), THAM-2 (2-amino-2-(hydroxymetyl)prapan-1,3-diyldibenzoate) and THAM-3 (2-amino-propan-1,2,3-triyltribenzoate). Fourteen exchange-correlation functionals based on the density functional theory (DFT) were chosen for quantum chemical study of THAM derivatives. The objective was to examine the effect of benzene rings on potential anti-corrosive properties of THAM compounds. The results indicate that the addition of benzene rings in THAM derivatives is likely to significantly enhance electrostatic bonding of a THAM-based coating to a presented metal surface and, thus, its adhesion and long-term effect in corrosion inhibition. Whereas it is clear that all three derivatives appear to be superior in their bonding characteristics to pure THAM, the potential order of merit between the three is less clear, although THAM-3 presents as possibly superior.
Harmless survey of the theoretical situation in the high temperature superconductivity
International Nuclear Information System (INIS)
Gorkov, L.P.
1989-01-01
The theoretical understanding of the new superconductors progresses slowly despite the large amount of publications. The intention of this paper is to show that partially this is so because a number of key problems remain unresolved experimentally. Meanwhile, some of the recent findings point out in the direction which, if correct, may drastically change theoretical views. Before the authors discuss these new experimental results, a brief overview of the different theoretical approaches is given below
Cao, Xiaofang; Rong, Chunying; Zhong, Aiguo; Lu, Tian; Liu, Shubin
2018-01-15
Molecular acidity is one of the important physiochemical properties of a molecular system, yet its accurate calculation and prediction are still an unresolved problem in the literature. In this work, we propose to make use of the quantities from the information-theoretic (IT) approach in density functional reactivity theory and provide an accurate description of molecular acidity from a completely new perspective. To illustrate our point, five different categories of acidic series, singly and doubly substituted benzoic acids, singly substituted benzenesulfinic acids, benzeneseleninic acids, phenols, and alkyl carboxylic acids, have been thoroughly examined. We show that using IT quantities such as Shannon entropy, Fisher information, Ghosh-Berkowitz-Parr entropy, information gain, Onicescu information energy, and relative Rényi entropy, one is able to simultaneously predict experimental pKa values of these different categories of compounds. Because of the universality of the quantities employed in this work, which are all density dependent, our approach should be general and be applicable to other systems as well. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.
Theoretical and experimental study of electroporation of red blood cells using MEMS technology
Deng, Peigang; Yin, Guangyao; Zhang, Tong Yi; Chang, Donald C.; Lee, Yi Kuen
2010-01-01
A theoretical and experimental study of electroporation (EP) of red blood cells (RBCs) was presented in this paper. With additional strain energy, an energy-based model of an electropore induced on a RBC's membrane at different electric fields was proposed to predict the critical EP electric field strength. In addition, EP experiments with red blood cells at single-cell level was carried out on a micro EP chip. The measured critical EP electric field strengths are in agreement with the numerical predictions. ©2010 IEEE.
Theoretical and experimental study of electroporation of red blood cells using MEMS technology
Deng, Peigang
2010-01-01
A theoretical and experimental study of electroporation (EP) of red blood cells (RBCs) was presented in this paper. With additional strain energy, an energy-based model of an electropore induced on a RBC\\'s membrane at different electric fields was proposed to predict the critical EP electric field strength. In addition, EP experiments with red blood cells at single-cell level was carried out on a micro EP chip. The measured critical EP electric field strengths are in agreement with the numerical predictions. ©2010 IEEE.
Moral, Mónica; García, Gregorio; Peñas, Antonio; Garzón, Andrés; Granadino-Roldán, José M.; Melguizo, Manuel; Fernández-Gómez, Manuel
2012-10-01
This work presents a theoretical and spectroscopic study on the electronic and structural properties of the diphenyl-s-tetrazine molecule (Ph2Tz) and some oligomeric derivatives. Ph2Tz was synthesized through a variation of Pinner-type reaction which uses N-acetylcysteine as catalyst. Insight into the structure and electronic properties of the title compound was obtained through IR, Raman, UV-Vis spectra in different solvents, and theoretical calculations. Theoretical studies have been extended to different n-mers derivatives up to an ideal molecular wire through the oligomeric approximation, predicting this way electronic properties such as LUMO energy levels, electron affinity and reorganization energy in order to assess their possible applications in molecular electronics.
International Nuclear Information System (INIS)
Stacey, Weston M.
2002-01-01
A framework for the predictive calculation of density limits in future tokamaks is proposed. Theoretical models for different density limit phenomena are summarized, and the requirements for additional models are identified. These theoretical density limit models have been incorporated into a relatively simple, but phenomenologically comprehensive, integrated numerical calculation of the core, edge, and divertor plasmas and of the recycling neutrals, in order to obtain plasma parameters needed for the evaluation of the theoretical models. A comparison of these theoretical predictions with observed density limits in current experiments is summarized. A model for the calculation of edge pedestal parameters, which is needed in order to apply the density limit predictions to future tokamaks, is summarized. An application to predict the proximity to density limits and the edge pedestal parameters of the proposed Fusion Ignition Research Experiment is described
Coping and return to work: Measurement and theoretical issues
Directory of Open Access Journals (Sweden)
Magnus Odéen
2010-01-01
Full Text Available Sick leave and early departure from the workforce have serious adverse effects on both individuals and society. Motivation and coping are both important when attempting to return to work. In this article, we wanted to test if either of two coping instruments could predict return to work. Response outcome expectancies as defined in the Cognitive Activation Theory of Stress (CATS (Ursin & Eriksen, 2004 were measured by the CODE scale (Eriksen et al., 1997 and general self-efficacy was measured by the generalized self-efficacy scale (GSE (Schwarzer & Jerusalem, 1995. The instruments were tested in one group of rehabilitation patients (N= 135 and one group of disability pensioners (N=85, who participated in return to work interventions in randomised controlled trials. None of the instruments could predict return to work at any point of measurement. Less than 10% of the theoretical range of the scales was used. The scales appear to measure a concept that is more stable than their underlying theory predicts, and they can not predict an important outcome. Results indicate that caution is advised when making inferences from these instruments to their underlying theories.
Zhao, Dongsheng; Roberts, Gethin Wyn; Lau, Lawrence; Hancock, Craig M; Bai, Ruibin
2016-11-16
Twelve GPS Block IIF satellites, out of the current constellation, can transmit on three-frequency signals (L1, L2, L5). Taking advantages of these signals, Three-Carrier Ambiguity Resolution (TCAR) is expected to bring much benefit for ambiguity resolution. One of the research areas is to find the optimal combined signals for a better ambiguity resolution in geometry-free (GF) and geometry-based (GB) mode. However, the existing researches select the signals through either pure theoretical analysis or testing with simulated data, which might be biased as the real observation condition could be different from theoretical prediction or simulation. In this paper, we propose a theoretical and empirical integrated method, which first selects the possible optimal combined signals in theory and then refines these signals with real triple-frequency GPS data, observed at eleven baselines of different lengths. An interpolation technique is also adopted in order to show changes of the AR performance with the increase in baseline length. The results show that the AR success rate can be improved by 3% in GF mode and 8% in GB mode at certain intervals of the baseline length. Therefore, the TCAR can perform better by adopting the combined signals proposed in this paper when the baseline meets the length condition.
Innovation value chain capability in Malaysian-owned company: A theoretical framework
Abidin, Norkisme Zainal; Suradi, Nur Riza Mohd
2014-09-01
Good quality products or services are no longer adequate to guarantee the sustainability of a company in the present competitive business. Prior research has developed various innovation models with the hope to better understand the innovativeness of the company. Due to countless definitions, indicators, factors, parameter and approaches in the study of innovation, it is difficult to ensure which one will best suit the Malaysian-owned company innovativeness. This paper aims to provide a theoretical background to support the framework of the innovation value chain capability in Malaysian-owned Company. The theoretical framework was based on the literature reviews, expert interviews and focus group study. The framework will be used to predict and assess the innovation value chain capability in Malaysian-owned company.
Béres, Gábor; Weltsch, Zoltán; Lukács, Zsolt; Tisza, Miklós
2018-05-01
Forming limit is a complex concept of limit values related to the onset of local necking in the sheet metal. In cold sheet metal forming, major and minor limit strains are influenced by the sheet thickness, strain path (deformation history) as well as material parameters and microstructure. Forming Limit Curves are plotted in ɛ1 - ɛ2 coordinate system providing the classic strain-based Forming Limit Diagram (FLD). Using the appropriate constitutive model, the limit strains can be changed into the stress-based Forming Limit Diagram (SFLD), irrespective of the strain path. This study is about the effect of the hardening model parameters on defining of limit stress values during Nakazima tests for automotive dual phase (DP) steels. Five limit strain pairs were specified experimentally with the loading of five different sheet geometries, which performed different strain-paths from pure shear (-2ɛ2=ɛ1) up to biaxial stretching (ɛ2=ɛ1). The former works of Hill, Levy-Tyne and Keeler-Brazier made possible some kind of theoretical strain determination, too. This was followed by the stress calculation based on the experimental and theoretical strain data. Since the n exponent in the Nádai expression is varying with the strain at some DP steels, we applied the least-squares method to fit other hardening model parameters (Ludwik, Voce, Hockett-Sherby) to calculate the stress fields belonging to each limit strains. The results showed that each model parameters could produce some discrepancies between the limit stress states in the range of higher equivalent strains than uniaxial stretching. The calculated hardening models were imported to FE code to extend and validate the results by numerical simulations.
Hybrid quantum teleportation: A theoretical model
Energy Technology Data Exchange (ETDEWEB)
Takeda, Shuntaro; Mizuta, Takahiro; Fuwa, Maria; Yoshikawa, Jun-ichi; Yonezawa, Hidehiro; Furusawa, Akira [Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)
2014-12-04
Hybrid quantum teleportation – continuous-variable teleportation of qubits – is a promising approach for deterministically teleporting photonic qubits. We propose how to implement it with current technology. Our theoretical model shows that faithful qubit transfer can be achieved for this teleportation by choosing an optimal gain for the teleporter’s classical channel.
The second physicist on the history of theoretical physics in germany
Jungnickel, Christa
2017-01-01
This book explores the rise of theoretical physics in 19th century Germany. The authors show how the junior second physicist in German universities over time became the theoretical physicist, of equal standing to the experimental physicist. Gustav Kirchhoff, Hermann von Helmholtz, and Max Planck are among the great German theoretical physicists whose work and career are examined in this book. Physics was then the only natural science in which theoretical work developed into a major teaching and research specialty in its own right. Readers will discover how German physicists arrived at a well-defined field of theoretical physics with well understood and generally accepted goals and needs. The authors explain the nature of the work of theoretical physics with many examples, taking care always to locate the research within the workplace. The book is a revised and shortened version of Intellectual Mastery of Nature: Theoretical Physics from Ohm to Einstein, a two-volume work by the same authors. This new edition ...
On determining the prediction limits of mathematical models for time series
International Nuclear Information System (INIS)
Peluso, E.; Gelfusa, M.; Lungaroni, M.; Talebzadeh, S.; Gaudio, P.; Murari, A.; Contributors, JET
2016-01-01
Prediction is one of the main objectives of scientific analysis and it refers to both modelling and forecasting. The determination of the limits of predictability is an important issue of both theoretical and practical relevance. In the case of modelling time series, reached a certain level in performance in either modelling or prediction, it is often important to assess whether all the information available in the data has been exploited or whether there are still margins for improvement of the tools being developed. In this paper, an information theoretic approach is proposed to address this issue and quantify the quality of the models and/or predictions. The excellent properties of the proposed indicator have been proved with the help of a systematic series of numerical tests and a concrete example of extreme relevance for nuclear fusion.
Rocco, Paolo; Cilurzo, Francesco; Minghetti, Paola; Vistoli, Giulio; Pedretti, Alessandro
2017-10-01
The data presented in this article are related to the article titled "Molecular Dynamics as a tool for in silico screening of skin permeability" (Rocco et al., 2017) [1]. Knowledge of the confidence interval and maximum theoretical value of the correlation coefficient r can prove useful to estimate the reliability of developed predictive models, in particular when there is great variability in compiled experimental datasets. In this Data in Brief article, data from purposely designed numerical simulations are presented to show how much the maximum r value is worsened by increasing the data uncertainty. The corresponding confidence interval of r is determined by using the Fisher r → Z transform.
Walsh, Matthew M; Gluck, Kevin A; Gunzelmann, Glenn; Jastrzembski, Tiffany; Krusmark, Michael
2018-03-02
The spacing effect is among the most widely replicated empirical phenomena in the learning sciences, and its relevance to education and training is readily apparent. Yet successful applications of spacing effect research to education and training is rare. Computational modeling can provide the crucial link between a century of accumulated experimental data on the spacing effect and the emerging interest in using that research to enable adaptive instruction. In this paper, we review relevant literature and identify 10 criteria for rigorously evaluating computational models of the spacing effect. Five relate to evaluating the theoretic adequacy of a model, and five relate to evaluating its application potential. We use these criteria to evaluate a novel computational model of the spacing effect called the Predictive Performance Equation (PPE). Predictive Performance Equation combines elements of earlier models of learning and memory including the General Performance Equation, Adaptive Control of Thought-Rational, and the New Theory of Disuse, giving rise to a novel computational account of the spacing effect that performs favorably across the complete sets of theoretic and applied criteria. We implemented two other previously published computational models of the spacing effect and compare them to PPE using the theoretic and applied criteria as guides. © 2018 Cognitive Science Society, Inc.
The Observational and Theoretical Tidal Radii of Globular Clusters in M87
Webb, Jeremy J.; Sills, Alison; Harris, William E.
2012-02-01
Globular clusters have linear sizes (tidal radii) which theory tells us are determined by their masses and by the gravitational potential of their host galaxy. To explore the relationship between observed and expected radii, we utilize the globular cluster population of the Virgo giant M87. Unusually deep, high signal-to-noise images of M87 are used to measure the effective and limiting radii of approximately 2000 globular clusters. To compare with these observations, we simulate a globular cluster population that has the same characteristics as the observed M87 cluster population. Placing these simulated clusters in the well-studied tidal field of M87, the orbit of each cluster is solved and the theoretical tidal radius of each cluster is determined. We compare the predicted relationship between cluster size and projected galactocentric distance to observations. We find that for an isotropic distribution of cluster velocities, theoretical tidal radii are approximately equal to observed limiting radii for R gc < 10 kpc. However, the isotropic simulation predicts a steep increase in cluster size at larger radii, which is not observed in large galaxies beyond the Milky Way. To minimize the discrepancy between theory and observations, we explore the effects of orbital anisotropy on cluster sizes, and suggest a possible orbital anisotropy profile for M87 which yields a better match between theory and observations. Finally, we suggest future studies which will establish a stronger link between theoretical tidal radii and observed radii.
THE OBSERVATIONAL AND THEORETICAL TIDAL RADII OF GLOBULAR CLUSTERS IN M87
International Nuclear Information System (INIS)
Webb, Jeremy J.; Sills, Alison; Harris, William E.
2012-01-01
Globular clusters have linear sizes (tidal radii) which theory tells us are determined by their masses and by the gravitational potential of their host galaxy. To explore the relationship between observed and expected radii, we utilize the globular cluster population of the Virgo giant M87. Unusually deep, high signal-to-noise images of M87 are used to measure the effective and limiting radii of approximately 2000 globular clusters. To compare with these observations, we simulate a globular cluster population that has the same characteristics as the observed M87 cluster population. Placing these simulated clusters in the well-studied tidal field of M87, the orbit of each cluster is solved and the theoretical tidal radius of each cluster is determined. We compare the predicted relationship between cluster size and projected galactocentric distance to observations. We find that for an isotropic distribution of cluster velocities, theoretical tidal radii are approximately equal to observed limiting radii for R gc < 10 kpc. However, the isotropic simulation predicts a steep increase in cluster size at larger radii, which is not observed in large galaxies beyond the Milky Way. To minimize the discrepancy between theory and observations, we explore the effects of orbital anisotropy on cluster sizes, and suggest a possible orbital anisotropy profile for M87 which yields a better match between theory and observations. Finally, we suggest future studies which will establish a stronger link between theoretical tidal radii and observed radii.
Earthquake prediction analysis based on empirical seismic rate: the M8 algorithm
Molchan, G.; Romashkova, L.
2010-12-01
The quality of space-time earthquake prediction is usually characterized by a 2-D error diagram (n, τ), where n is the fraction of failures-to-predict and τ is the local rate of alarm averaged in space. The most reasonable averaging measure for analysis of a prediction strategy is the normalized rate of target events λ(dg) in a subarea dg. In that case the quantity H = 1 - (n + τ) determines the prediction capability of the strategy. The uncertainty of λ(dg) causes difficulties in estimating H and the statistical significance, α, of prediction results. We investigate this problem theoretically and show how the uncertainty of the measure can be taken into account in two situations, viz., the estimation of α and the construction of a confidence zone for the (n, τ)-parameters of the random strategies. We use our approach to analyse the results from prediction of M >= 8.0 events by the M8 method for the period 1985-2009 (the M8.0+ test). The model of λ(dg) based on the events Mw >= 5.5, 1977-2004, and the magnitude range of target events 8.0 <= M < 8.5 are considered as basic to this M8 analysis. We find the point and upper estimates of α and show that they are still unstable because the number of target events in the experiment is small. However, our results argue in favour of non-triviality of the M8 prediction algorithm.
An Experimental and Theoretical Investigation of Micropiiting in Wind Turbine Gears and Bearings
Energy Technology Data Exchange (ETDEWEB)
Kahraman, Ahmet
2012-03-28
In this research study, the micro-pitting related contact failures of wind turbine gearbox components were investigated both experimentally and theoretically. On the experimental side, a twin-disk type test machine was used to simulate wind turbine transmission contacts in terms of their kinematic (rolling and sliding speeds), surface roughnesses, material parameters and lubricant conditions. A test matrix that represents the ranges of contact conditions of the wind turbine gear boxes was defined and executed to bring an empirical understanding to the micro-pitting problem in terms of key contact parameters and operating conditions. On the theoretical side, the first deterministic micro-pitting model based on a mixed elastohydrodynamic lubrication formulations and multi-axial near-surface crack initiation model was developed. This physics-based model includes actual instantaneous asperity contacts associated with real surface roughness profiles for predicting the onset of the micro-pit formation. The predictions from the theoretical model were compared to the experimental data for validation of the models. The close agreement between the model and measurements was demonstrated. With this, the proposed model can be deemed suitable for identifying the mechanisms leading to micro-pitting of gear and bearing surfaces of wind turbine gear boxes, including all key material, lubricant and surface engineering aspects of the problem, and providing solutions to these micro-pitting problems.
Predictive coding in Agency Detection
DEFF Research Database (Denmark)
Andersen, Marc Malmdorf
2017-01-01
Agency detection is a central concept in the cognitive science of religion (CSR). Experimental studies, however, have so far failed to lend support to some of the most common predictions that follow from current theories on agency detection. In this article, I argue that predictive coding, a highly...... promising new framework for understanding perception and action, may solve pending theoretical inconsistencies in agency detection research, account for the puzzling experimental findings mentioned above, and provide hypotheses for future experimental testing. Predictive coding explains how the brain......, unbeknownst to consciousness, engages in sophisticated Bayesian statistics in an effort to constantly predict the hidden causes of sensory input. My fundamental argument is that most false positives in agency detection can be seen as the result of top-down interference in a Bayesian system generating high...
Multi-scale theoretical investigation of hydrogen storage in covalent organic frameworks.
Tylianakis, Emmanuel; Klontzas, Emmanouel; Froudakis, George E
2011-03-01
The quest for efficient hydrogen storage materials has been the limiting step towards the commercialization of hydrogen as an energy carrier and has attracted a lot of attention from the scientific community. Sophisticated multi-scale theoretical techniques have been considered as a valuable tool for the prediction of materials storage properties. Such techniques have also been used for the investigation of hydrogen storage in a novel category of porous materials known as Covalent Organic Frameworks (COFs). These framework materials are consisted of light elements and are characterized by exceptional physicochemical properties such as large surface areas and pore volumes. Combinations of ab initio, Molecular Dynamics (MD) and Grand Canonical Monte-Carlo (GCMC) calculations have been performed to investigate the hydrogen adsorption in these ultra-light materials. The purpose of the present review is to summarize the theoretical hydrogen storage studies that have been published after the discovery of COFs. Experimental and theoretical studies have proven that COFs have comparable or better hydrogen storage abilities than other competitive materials such as MOF. The key factors that can lead to the improvement of the hydrogen storage properties of COFs are highlighted, accompanied with some recently presented theoretical multi-scale studies concerning these factors.
Status of the observed and predicted b anti-b production at the Tevatron
Energy Technology Data Exchange (ETDEWEB)
Happacher, F.; Giromini, P.; /Frascati; Ptohos, F.; /Cyprus U.
2005-09-01
The authors review the experimental status of the b-quark production at the Fermilab Tevatron. They compare all available measurements to perturbative QCD predictions (NLO and FONLL) and also to the parton-level cross section evaluated with parton-shower Monte Carlo generators. They examine both the single b cross section and the so called b{bar b} correlations. The review shows that the experimental situation is quite complicated because the measurements appear to be inconsistent among themselves. In this situation, there is no solid basis to either claim that perturbative QCD is challenged by these measurements or, in contrast, that long-standing discrepancies between data and theory have been resolved by incrementally improving the measurements and the theoretical prediction.
Modelling the cutting edge radius size effect for force prediction in micro milling
DEFF Research Database (Denmark)
Bissacco, Giuliano; Hansen, Hans Nørgaard; Jan, Slunsky
2008-01-01
This paper presents a theoretical model for cutting force prediction in micro milling, taking into account the cutting edge radius size effect, the tool run out and the deviation of the chip flow angle from the inclination angle. A parameterization according to the uncut chip thickness to cutting...... edge radius ratio is used for the parameters involved in the force calculation. The model was verified by means of cutting force measurements in micro milling. The results show good agreement between predicted and measured forces. It is also demonstrated that the use of the Stabler's rule...... is a reasonable approximation and that micro end mill run out is effectively compensated by the deflections induced by the cutting forces....
Wind turbine control and model predictive control for uncertain systems
DEFF Research Database (Denmark)
Thomsen, Sven Creutz
as disturbance models for controller design. The theoretical study deals with Model Predictive Control (MPC). MPC is an optimal control method which is characterized by the use of a receding prediction horizon. MPC has risen in popularity due to its inherent ability to systematically account for time...
International Nuclear Information System (INIS)
Wang, H.-L.; Liu, B.
2014-01-01
This paper investigates what is the largest magnetoelectric (ME) coefficient of ME composites, and how to realize it. From the standpoint of energy conservation, a theoretical analysis is carried out on an imaginary lever structure consisting of a magnetostrictive phase, a piezoelectric phase, and a rigid lever. This structure is a generalization of various composite layouts for optimization on ME effect. The predicted theoretical ultimate ME coefficient plays a similar role as the efficiency of ideal heat engine in thermodynamics, and is used to evaluate the existing typical ME layouts, such as the parallel sandwiched layout and the serial layout. These two typical layouts exhibit ME coefficient much lower than the theoretical largest values, because in the general analysis the stress amplification ratio and the volume ratio can be optimized independently and freely, but in typical layouts they are dependent or fixed. To overcome this shortcoming and achieve the theoretical largest ME coefficient, a new design is presented. In addition, it is found that the most commonly used electric field ME coefficient can be designed to be infinitely large. We doubt the validity of this coefficient as a reasonable ME effect index and consider three more ME coefficients, namely the electric charge ME coefficient, the voltage ME coefficient, and the static electric energy ME coefficient. We note that the theoretical ultimate value of the static electric energy ME coefficient is finite and might be a more proper measure of ME effect
Adulthood Social Class and Union Interest: A First Test of a Theoretical Model.
Mellor, Steven
2016-10-02
A serial mediation model of union interest was tested. Based on theoretical notes provided by Mellor and Golay (in press), adulthood social class was positioned as a predictor of willingness to join a labor union, with success/failure attributions at work and willingness to share work goals positioned as intervening variables. Data from U.S. nonunion employees (N = 560) suggested full mediation after effects were adjusted for childhood social class. In sequence, adulthood social class predicted success/failure attributions at work, success/failure attributions at work predicted willingness to share work goals, and willingness to share work goals predicted willingness to join. Implications for socioeconomic status (SES) research and union expansion are discussed.
The Attribute for Hydrocarbon Prediction Based on Attenuation
International Nuclear Information System (INIS)
Hermana, Maman; Harith, Z Z T; Sum, C W; Ghosh, D P
2014-01-01
Hydrocarbon prediction is a crucial issue in the oil and gas industry. Currently, the prediction of pore fluid and lithology are based on amplitude interpretation which has the potential to produce pitfalls in certain conditions of reservoir. Motivated by this fact, this work is directed to find out other attributes that can be used to reduce the pitfalls in the amplitude interpretation. Some seismic attributes were examined and studies showed that the attenuation attribute is a better attribute for hydrocarbon prediction. Theoretically, the attenuation mechanism of wave propagation is associated with the movement of fluid in the pore; hence the existence of hydrocarbon in the pore will be represented by attenuation attribute directly. In this paper we evaluated the feasibility of the quality factor ratio of P-wave and S-wave (Qp/Qs) as hydrocarbon indicator using well data and also we developed a new attribute based on attenuation for hydrocarbon prediction -- Normalized Energy Reduction Stack (NERS). To achieve these goals, this work was divided into 3 main parts; estimating the Qp/Qs on well log data, testing the new attribute in the synthetic data and applying the new attribute on real data in Malay Basin data. The result show that the Qp/Qs is better than Poisson's ratio and Lamda over Mu as hydrocarbon indicator. The curve, trend analysis and contrast of Qp/Qs is more powerful at distinguishing pore fluid than Poisson ratio and Lamda over Mu. The NERS attribute was successful in distinguishing the hydrocarbon from brine on synthetic data. Applying this attribute on real data on Malay basin, the NERS attribute is qualitatively conformable with the structure and location where the gas is predicted. The quantitative interpretation of this attribute for hydrocarbon prediction needs to be investigated further
International Nuclear Information System (INIS)
Shen Hongbin; Chou Kuochen
2005-01-01
The nucleus is the brain of eukaryotic cells that guides the life processes of the cell by issuing key instructions. For in-depth understanding of the biochemical process of the nucleus, the knowledge of localization of nuclear proteins is very important. With the avalanche of protein sequences generated in the post-genomic era, it is highly desired to develop an automated method for fast annotating the subnuclear locations for numerous newly found nuclear protein sequences so as to be able to timely utilize them for basic research and drug discovery. In view of this, a novel approach is developed for predicting the protein subnuclear location. It is featured by introducing a powerful classifier, the optimized evidence-theoretic K-nearest classifier, and using the pseudo amino acid composition [K.C. Chou, PROTEINS: Structure, Function, and Genetics, 43 (2001) 246], which can incorporate a considerable amount of sequence-order effects, to represent protein samples. As a demonstration, identifications were performed for 370 nuclear proteins among the following 9 subnuclear locations: (1) Cajal body, (2) chromatin, (3) heterochromatin, (4) nuclear diffuse, (5) nuclear pore, (6) nuclear speckle, (7) nucleolus, (8) PcG body, and (9) PML body. The overall success rates thus obtained by both the re-substitution test and jackknife cross-validation test are significantly higher than those by existing classifiers on the same working dataset. It is anticipated that the powerful approach may also become a useful high throughput vehicle to bridge the huge gap occurring in the post-genomic era between the number of gene sequences in databases and the number of gene products that have been functionally characterized. The OET-KNN classifier will be available at www.pami.sjtu.edu.cn/people/hbshen
Genomic Predictability of Interconnected Biparental Maize Populations
Riedelsheimer, Christian; Endelman, Jeffrey B.; Stange, Michael; Sorrells, Mark E.; Jannink, Jean-Luc; Melchinger, Albrecht E.
2013-01-01
Intense structuring of plant breeding populations challenges the design of the training set (TS) in genomic selection (GS). An important open question is how the TS should be constructed from multiple related or unrelated small biparental families to predict progeny from individual crosses. Here, we used a set of five interconnected maize (Zea mays L.) populations of doubled-haploid (DH) lines derived from four parents to systematically investigate how the composition of the TS affects the prediction accuracy for lines from individual crosses. A total of 635 DH lines genotyped with 16,741 polymorphic SNPs were evaluated for five traits including Gibberella ear rot severity and three kernel yield component traits. The populations showed a genomic similarity pattern, which reflects the crossing scheme with a clear separation of full sibs, half sibs, and unrelated groups. Prediction accuracies within full-sib families of DH lines followed closely theoretical expectations, accounting for the influence of sample size and heritability of the trait. Prediction accuracies declined by 42% if full-sib DH lines were replaced by half-sib DH lines, but statistically significantly better results could be achieved if half-sib DH lines were available from both instead of only one parent of the validation population. Once both parents of the validation population were represented in the TS, including more crosses with a constant TS size did not increase accuracies. Unrelated crosses showing opposite linkage phases with the validation population resulted in negative or reduced prediction accuracies, if used alone or in combination with related families, respectively. We suggest identifying and excluding such crosses from the TS. Moreover, the observed variability among populations and traits suggests that these uncertainties must be taken into account in models optimizing the allocation of resources in GS. PMID:23535384
Theoretical Model for the Performance of Liquid Ring Pump Based on the Actual Operating Cycle
Directory of Open Access Journals (Sweden)
Si Huang
2017-01-01
Full Text Available Liquid ring pump is widely applied in many industry fields due to the advantages of isothermal compression process, simple structure, and liquid-sealing. Based on the actual operating cycle of “suction-compression-discharge-expansion,” a universal theoretical model for performance of liquid ring pump was established in this study, to solve the problem that the theoretical models deviated from the actual performance in operating cycle. With the major geometric parameters and operating conditions of a liquid ring pump, the performance parameters such as the actual capacity for suction and discharge, shaft power, and global efficiency can be conveniently predicted by the proposed theoretical model, without the limitation of empiric range, performance data, or the detailed 3D geometry of pumps. The proposed theoretical model was verified by experimental performances of liquid ring pumps and could provide a feasible tool for the application of liquid ring pump.
Theoretical chemistry in Belgium a topical collection from theoretical chemistry accounts
Champagne, Benoît; De Proft, Frank; Leyssens, Tom
2014-01-01
Readers of this volume can take a tour around the research locations in Belgium which are active in theoretical and computational chemistry. Selected researchers from Belgium present research highlights of their work. Originally published in the journal Theoretical Chemistry Accounts, these outstanding contributions are now available in a hardcover print format. This volume will be of benefit in particular to those research groups and libraries that have chosen to have only electronic access to the journal. It also provides valuable content for all researchers in theoretical chemistry.
Modeling of air-gap membrane distillation process: A theoretical and experimental study
Alsaadi, Ahmad Salem
2013-06-03
A one dimensional (1-D) air gap membrane distillation (AGMD) model for flat sheet type modules has been developed. This model is based on mathematical equations that describe the heat and mass transfer mechanisms of a single-stage AGMD process. It can simulate AGMD modules in both co-current and counter-current flow regimes. The theoretical model was validated using AGMD experimental data obtained under different operating conditions and parameters. The predicted water vapor flux was compared to the flux measured at five different feed water temperatures, two different feed water salinities, three different air gap widths and two MD membranes with different average pore sizes. This comparison showed that the model flux predictions are strongly correlated with the experimental data, with model predictions being within +10% of the experimentally determined values. The model was then used to study and analyze the parameters that have significant effect on scaling-up the AGMD process such as the effect of increasing the membrane length, and feed and coolant flow rates. The model was also used to analyze the maximum thermal efficiency of the AGMD process by tracing changes in water production rate and the heat input to the process along the membrane length. This was used to understand the gain in both process production and thermal efficiency for different membrane surface areas and the resultant increases in process capital and water unit cost. © 2013 Elsevier B.V.
A review of theoretical ideas on the EMC effect
International Nuclear Information System (INIS)
Krzywicki, A.
1985-01-01
This paper is a shortened version of a review presented at a nuclear physics conference held in Paris in July 1985. The author concentrates on a sample of representative theoretical ideas. The old dogma, claiming the identity of the structure functions of bound and free nucleons respectively, has been abandoned. Contemplating the plethora of models proposed to explain the EMC effect, the author realizes how unfounded the old dogma has been. However, considerable experimental uncertainties persist (low x region, sea vs. valence, gluon distribution). Also, the predictive power of theoretical models is poor. The author does not see any contradiction between the data and the calculations based on conventional nuclear theory. In this sense, the future theory of the EMC effect will perhaps resemble the rescaling models but, of course, with an improved justification. In any case, it is both important and interesting to achieve a better understanding of the role of QCD degrees of freedom in nuclei
Theoretical studies on the α decay half-lives of hyper and normal ...
Indian Academy of Sciences (India)
The α decay half-lives of hyper and normal isotopes of Po nuclei are studied in the present work. The inclusion of Λ – N interaction changes the half-life for α decay. The theoretical predictions on the α decay half-lives of normal Po isotopes are compared with experimental results and are seen to be matching well with each ...
Validation of predicted exponential concentration profiles of chemicals in soils
International Nuclear Information System (INIS)
Hollander, Anne; Baijens, Iris; Ragas, Ad; Huijbregts, Mark; Meent, Dik van de
2007-01-01
Multimedia mass balance models assume well-mixed homogeneous compartments. Particularly for soils, this does not correspond to reality, which results in potentially large uncertainties in estimates of transport fluxes from soils. A theoretically expected exponential decrease model of chemical concentrations with depth has been proposed, but hardly tested against empirical data. In this paper, we explored the correspondence between theoretically predicted soil concentration profiles and 84 field measured profiles. In most cases, chemical concentrations in soils appear to decline exponentially with depth, and values for the chemical specific soil penetration depth (d p ) are predicted within one order of magnitude. Over all, the reliability of multimedia models will improve when they account for depth-dependent soil concentrations, so we recommend to take into account the described theoretical exponential decrease model of chemical concentrations with depth in chemical fate studies. In this model the d p -values should estimated be either based on local conditions or on a fixed d p -value, which we recommend to be 10 cm for chemicals with a log K ow > 3. - Multimedia mass model predictions will improve when taking into account depth dependent soil concentrations
Detailed comparison of next-to-leading order predictions for jet photoproduction at HERA.
Energy Technology Data Exchange (ETDEWEB)
Harris, B. W.; Klassen, M.; Vossebeld, J.
1999-06-02
The precision of new HERA data on jet photoproduction opens up the possibility to discriminate between different models of the photon structure. This requires equally precise theoretical predictions from perturbative QCD calculations. In the past years, next-to-leading order calculations for the photoproduction of jets at HERA have become available. Using the kinematic cuts of recent ZEUS analyses, we compare the predictions of three calculations for different dijet and three-jet distributions. We find that in general all three calculations agree within the statistical accuracy of the Monte Carlo integration yielding reliable theoretical predictions. In certain restricted regions of phase space, the calculations differ by up to 5%.
Directory of Open Access Journals (Sweden)
F. Kiani
2017-07-01
Full Text Available Analytical measurement of materials requires exact knowledge of their acid dissociation constant (pKa values. In recent years, quantum mechanical calculations have been extensively used to study of acidities in the aqueous solutions and the results were compared with the experimental values. In this study, a theoretical study was carried out on xylenol orange (in water solution by ab initio method. We calculated the pKa values of xylenol orange in water, using high-level ab initio (PM3, DFT (HF, B3LYP/6-31+G(d and SCRF methods. The experimental determination of these values (pKa,s is a challenge because xylenol orange has a low solubility in water. We considered several ionization reactions and equilibriums in water that constitute the indispensable theoretical basis to calculate the pKa values of xylenol orange. The results show that the calculated pKa values have a comparable agreement with the experimentally determined pKa values. Therefore, this method can be used to predict such properties for indicators, drugs and other important molecules.
Theoretical prediction of fast 3D AC electro-osmotic pumps.
Bazant, Martin Z; Ben, Yuxing
2006-11-01
AC electro-osmotic (ACEO) pumps in microfluidics currently involve planar electrode arrays, but recent work on the underlying phenomenon of induced-charge electro-osmosis (ICEO) suggests that three-dimensional (3D) geometries may be exploited to achieve faster flows. In this paper, we present some new design principles for periodic 3D ACEO pumps, such as the "fluid conveyor belt" of ICEO flow over a stepped electrode array. Numerical simulations of these designs (using the standard low-voltage model) predict flow rates almost twenty times faster than existing planar ACEO pumps, for the same applied voltage and minimum feature size. These pumps may enable new portable or implantable lab-on-a-chip devices, since rather fast (mm s(-1)), tuneable flows should be attainable with battery voltages (<10 V).
International Nuclear Information System (INIS)
Barrett, R.C.
1979-01-01
Nowadays the 'experimental' charge densities are produced with convincing error estimates due to new methods and techniques. In addition the accuracy of those experiments means that r.m.s. radii are known within a few hundredths of a fermi. Because of that accuracy the theorists are left far behind. In order to show which theoretical possiblities exist at the moment we will discuss the single particle shell model and the Hartree-Fock or mean field approximation. Corrections to the mean field approximation are described. Finally, some examples and conclusions are presented. (KBE)
Neural Elements for Predictive Coding
Directory of Open Access Journals (Sweden)
Stewart SHIPP
2016-11-01
Full Text Available Predictive coding theories of sensory brain function interpret the hierarchical construction of the cerebral cortex as a Bayesian, generative model capable of predicting the sensory data consistent with any given percept. Predictions are fed backwards in the hierarchy and reciprocated by prediction error in the forward direction, acting to modify the representation of the outside world at increasing levels of abstraction, and so to optimize the nature of perception over a series of iterations. This accounts for many ‘illusory’ instances of perception where what is seen (heard, etc is unduly influenced by what is expected, based on past experience. This simple conception, the hierarchical exchange of prediction and prediction error, confronts a rich cortical microcircuitry that is yet to be fully documented. This article presents the view that, in the current state of theory and practice, it is profitable to begin a two-way exchange: that predictive coding theory can support an understanding of cortical microcircuit function, and prompt particular aspects of future investigation, whilst existing knowledge of microcircuitry can, in return, influence theoretical development. As an example, a neural inference arising from the earliest formulations of predictive coding is that the source populations of forwards and backwards pathways should be completely separate, given their functional distinction; this aspect of circuitry – that neurons with extrinsically bifurcating axons do not project in both directions – has only recently been confirmed. Here, the computational architecture prescribed by a generalized (free-energy formulation of predictive coding is combined with the classic ‘canonical microcircuit’ and the laminar architecture of hierarchical extrinsic connectivity to produce a template schematic, that is further examined in the light of (a updates in the microcircuitry of primate visual cortex, and (b rapid technical advances made
Neural Elements for Predictive Coding.
Shipp, Stewart
2016-01-01
Predictive coding theories of sensory brain function interpret the hierarchical construction of the cerebral cortex as a Bayesian, generative model capable of predicting the sensory data consistent with any given percept. Predictions are fed backward in the hierarchy and reciprocated by prediction error in the forward direction, acting to modify the representation of the outside world at increasing levels of abstraction, and so to optimize the nature of perception over a series of iterations. This accounts for many 'illusory' instances of perception where what is seen (heard, etc.) is unduly influenced by what is expected, based on past experience. This simple conception, the hierarchical exchange of prediction and prediction error, confronts a rich cortical microcircuitry that is yet to be fully documented. This article presents the view that, in the current state of theory and practice, it is profitable to begin a two-way exchange: that predictive coding theory can support an understanding of cortical microcircuit function, and prompt particular aspects of future investigation, whilst existing knowledge of microcircuitry can, in return, influence theoretical development. As an example, a neural inference arising from the earliest formulations of predictive coding is that the source populations of forward and backward pathways should be completely separate, given their functional distinction; this aspect of circuitry - that neurons with extrinsically bifurcating axons do not project in both directions - has only recently been confirmed. Here, the computational architecture prescribed by a generalized (free-energy) formulation of predictive coding is combined with the classic 'canonical microcircuit' and the laminar architecture of hierarchical extrinsic connectivity to produce a template schematic, that is further examined in the light of (a) updates in the microcircuitry of primate visual cortex, and (b) rapid technical advances made possible by transgenic neural
New results for antiproton-proton elastic scattering and various theoretical models
International Nuclear Information System (INIS)
Fazal-e-Aleem; Saleem, M.; Yodh, G.B.
1991-01-01
The most recent measurements of the ratio ρ of the real and imaginary parts of the forward-scattering amplitudes at 0.546 TeV, the total and elastic differential cross sections at 0.546 and 1.8 TeV for proton-antiproton scattering, are compared to the predictions of the generalized Chou-Yang and other theoretical models. For 1.8 TeV, the presence or absence of the break near -t∼0.15 (GeV/c) 2 and of the dip in the vicinity of 0.6 (GeV/c) 2 are also discussed in the light of various predictions. The possibility of a further rise of the ratio ρ at 1.8 TeV is also probed
Theoretical and Empirical Descriptions of Thermospheric Density
Solomon, S. C.; Qian, L.
2004-12-01
The longest-term and most accurate overall description the density of the upper thermosphere is provided by analysis of change in the ephemeris of Earth-orbiting satellites. Empirical models of the thermosphere developed in part from these measurements can do a reasonable job of describing thermospheric properties on a climatological basis, but the promise of first-principles global general circulation models of the coupled thermosphere/ionosphere system is that a true high-resolution, predictive capability may ultimately be developed for thermospheric density. However, several issues are encountered when attempting to tune such models so that they accurately represent absolute densities as a function of altitude, and their changes on solar-rotational and solar-cycle time scales. Among these are the crucial ones of getting the heating rates (from both solar and auroral sources) right, getting the cooling rates right, and establishing the appropriate boundary conditions. However, there are several ancillary issues as well, such as the problem of registering a pressure-coordinate model onto an altitude scale, and dealing with possible departures from hydrostatic equilibrium in empirical models. Thus, tuning a theoretical model to match empirical climatology may be difficult, even in the absence of high temporal or spatial variation of the energy sources. We will discuss some of the challenges involved, and show comparisons of simulations using the NCAR Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM) to empirical model estimates of neutral thermosphere density and temperature. We will also show some recent simulations using measured solar irradiance from the TIMED/SEE instrument as input to the TIE-GCM.
A Game Theoretical Approach to Hacktivism: Is Attack Likelihood a Product of Risks and Payoffs?
Bodford, Jessica E; Kwan, Virginia S Y
2018-02-01
The current study examines hacktivism (i.e., hacking to convey a moral, ethical, or social justice message) through a general game theoretic framework-that is, as a product of costs and benefits. Given the inherent risk of carrying out a hacktivist attack (e.g., legal action, imprisonment), it would be rational for the user to weigh these risks against perceived benefits of carrying out the attack. As such, we examined computer science students' estimations of risks, payoffs, and attack likelihood through a game theoretic design. Furthermore, this study aims at constructing a descriptive profile of potential hacktivists, exploring two predicted covariates of attack decision making, namely, peer prevalence of hacking and sex differences. Contrary to expectations, results suggest that participants' estimations of attack likelihood stemmed solely from expected payoffs, rather than subjective risks. Peer prevalence significantly predicted increased payoffs and attack likelihood, suggesting an underlying descriptive norm in social networks. Notably, we observed no sex differences in the decision to attack, nor in the factors predicting attack likelihood. Implications for policymakers and the understanding and prevention of hacktivism are discussed, as are the possible ramifications of widely communicated payoffs over potential risks in hacking communities.
Experimental studies of caesium iodide aerosol condensation: theoretical interpretation
International Nuclear Information System (INIS)
Beard, A.M.; Benson, C.G.; Horton, K.D.; Buckle, E.R.
1990-07-01
Caesium iodide is predicted to be a significant source of fission product aerosols during the course of a severe accident in a pressurised water reactor (PWR). The nucleation and growth of caesium iodide aerosols have been studied using a plume chamber and the results compared with theoretical values calculated using the approach developed by Buckle for aerosol nucleation. The morphology of the particles was studied using scanning electron microscopy (SEM) and transmission optical microscopy (TOM), whilst the particle size distributions were determined from differential mobility (DMPS) and aerodynamic (APS) measurements. (author)
Energy Technology Data Exchange (ETDEWEB)
Rey, Michael; Tyuterev, Vladimir G. [Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR CNRS 7331, BP 1039, F-51687, Reims Cedex 2 (France); Nikitin, Andrei V., E-mail: michael.rey@univ-reims.fr [Laboratory of Theoretical Spectroscopy, Institute of Atmospheric Optics, SB RAS, 634055 Tomsk (Russian Federation)
2017-10-01
Modeling atmospheres of hot exoplanets and brown dwarfs requires high- T databases that include methane as the major hydrocarbon. We report a complete theoretical line list of {sup 12}CH{sub 4} in the infrared range 0–13,400 cm{sup −1} up to T {sub max} = 3000 K computed via a full quantum-mechanical method from ab initio potential energy and dipole moment surfaces. Over 150 billion transitions were generated with the lower rovibrational energy cutoff 33,000 cm{sup −1} and intensity cutoff down to 10{sup −33} cm/molecule to ensure convergent opacity predictions. Empirical corrections for 3.7 million of the strongest transitions permitted line position accuracies of 0.001–0.01 cm{sup −1}. Full data are partitioned into two sets. “Light lists” contain strong and medium transitions necessary for an accurate description of sharp features in absorption/emission spectra. For a fast and efficient modeling of quasi-continuum cross sections, billions of tiny lines are compressed in “super-line” libraries according to Rey et al. These combined data will be freely accessible via the TheoReTS information system (http://theorets.univ-reims.fr, http://theorets.tsu.ru), which provides a user-friendly interface for simulations of absorption coefficients, cross-sectional transmittance, and radiance. Comparisons with cold, room, and high- T experimental data show that the data reported here represent the first global theoretical methane lists suitable for high-resolution astrophysical applications.
Rey, Michael; Nikitin, Andrei V.; Tyuterev, Vladimir G.
2017-10-01
Modeling atmospheres of hot exoplanets and brown dwarfs requires high-T databases that include methane as the major hydrocarbon. We report a complete theoretical line list of 12CH4 in the infrared range 0-13,400 cm-1 up to T max = 3000 K computed via a full quantum-mechanical method from ab initio potential energy and dipole moment surfaces. Over 150 billion transitions were generated with the lower rovibrational energy cutoff 33,000 cm-1 and intensity cutoff down to 10-33 cm/molecule to ensure convergent opacity predictions. Empirical corrections for 3.7 million of the strongest transitions permitted line position accuracies of 0.001-0.01 cm-1. Full data are partitioned into two sets. “Light lists” contain strong and medium transitions necessary for an accurate description of sharp features in absorption/emission spectra. For a fast and efficient modeling of quasi-continuum cross sections, billions of tiny lines are compressed in “super-line” libraries according to Rey et al. These combined data will be freely accessible via the TheoReTS information system (http://theorets.univ-reims.fr, http://theorets.tsu.ru), which provides a user-friendly interface for simulations of absorption coefficients, cross-sectional transmittance, and radiance. Comparisons with cold, room, and high-T experimental data show that the data reported here represent the first global theoretical methane lists suitable for high-resolution astrophysical applications.
Ku, C.-P. Roger; Heshmat, Hooshang
1994-07-01
Compliant foil bearings operate on either gas or liquid, which makes them very attractive for use in extreme environments such as in high-temperature aircraft turbine engines and cryogenic turbopumps. However, a lack of analytical models to predict the dynamic characteristics of foil bearings forces the bearing designer to rely on prototype testing, which is time-consuming and expensive. In this paper, the authors present a theoretical model to predict the structural stiffness and damping coefficients of the bump foil strip in a journal bearing or damper. Stiffness is calculated based on the perturbation of the journal center with respect to its static equilibrium position. The equivalent viscous damping coefficients are determined based on the area of a closed hysteresis loop of the journal center motion. The authors found, theoretically, that the energy dissipated from this loop was mostly contributed by the frictional motion between contact surfaces. In addition, the source and mechanism of the nonlinear behavior of the bump foil strips were examined. With the introduction of this enhanced model, the analytical tools are now available for the design of compliant foil bearings.
Directory of Open Access Journals (Sweden)
Blanchard Chris M
2007-10-01
Full Text Available Abstract Background Walking is the primary focus of population-based physical activity initiatives but a theoretical understanding of this behaviour is still elusive. The purpose of this study was to integrate personality, the perceived environment, and planning into a theory of planned behaviour (TPB framework to predict leisure-time walking. Methods Participants were a random sample (N = 358 of Canadian adults who completed measures of the TPB, planning, perceived neighbourhood environment, and personality at Time 1 and self-reported walking behaviour two months later. Results Analyses using structural equation modelling provided evidence that leisure-time walking is largely predicted by intention (standardized effect = .42 with an additional independent contribution from proximity to neighbourhood retail shops (standardized effect = .18. Intention, in turn, was predicted by attitudes toward walking and perceived behavioural control. Effects of perceived neighbourhood aesthetics and walking infrastructure on walking were mediated through attitudes and intention. Moderated regression analysis showed that the intention-walking relationship was moderated by conscientiousness and proximity to neighbourhood recreation facilities but not planning. Conclusion Overall, walking behaviour is theoretically complex but may best be addressed at a population level by facilitating strong intentions in a receptive environment even though individual differences may persist.
Prediction of mechanical properties of composites of HDPE/HA/EAA.
Albano, C; Perera, R; Cataño, L; Karam, A; González, G
2011-04-01
In this investigation, the behavior of the mechanical properties of composites of high-density polyethylene/hydroxyapatite (HDPE/HA) with and without ethylene-acrylic acid copolymer (EAA) as possible compatibilizer, was studied. Different mathematical models were used to predict their Young's modulus, tensile strength and elongation at break. A comparison with the experimental results shows that the theoretical models of Guth and Kerner modified can be used to predict the Young's modulus. On the other hand, the values obtained by the Verbeek model do not show a good agreement with the experimental data, since different factors that influence the mechanical properties are considered in this model such as: aspect ratio of the reinforcement, interfacial adhesion, porosity and binder content. TEM analysis confirms the discrepancies obtained between the experimental Young's modulus values and those predicted by the Verbeek model. The values of "P", "a" and "σ(A)" suggest that an interaction among the carboxylic groups of the copolymer and the hydroxyl groups of hydroxyapatite might be present. In composites with 20 and 30 wt% of filler, this interaction does not improve the Young's modulus values, since the deviations of the Verbeek model are significant. Copyright © 2010 Elsevier Ltd. All rights reserved.
Theoretical analysis of balanced truncation for linear switched systems
DEFF Research Database (Denmark)
Petreczky, Mihaly; Wisniewski, Rafal; Leth, John-Josef
2012-01-01
In this paper we present theoretical analysis of model reduction of linear switched systems based on balanced truncation, presented in [1,2]. More precisely, (1) we provide a bound on the estimation error using L2 gain, (2) we provide a system theoretic interpretation of grammians and their singu......In this paper we present theoretical analysis of model reduction of linear switched systems based on balanced truncation, presented in [1,2]. More precisely, (1) we provide a bound on the estimation error using L2 gain, (2) we provide a system theoretic interpretation of grammians...... for showing this independence is realization theory of linear switched systems. [1] H. R. Shaker and R. Wisniewski, "Generalized gramian framework for model/controller order reduction of switched systems", International Journal of Systems Science, Vol. 42, Issue 8, 2011, 1277-1291. [2] H. R. Shaker and R....... Wisniewski, "Switched Systems Reduction Framework Based on Convex Combination of Generalized Gramians", Journal of Control Science and Engineering, 2009....
International Nuclear Information System (INIS)
Moral, Mónica; García, Gregorio; Peñas, Antonio; Garzón, Andrés; Granadino-Roldán, José M.; Melguizo, Manuel; Fernández-Gómez, Manuel
2012-01-01
Highlights: ► We study properties of Ph 2 Tz and (PhTz) n Ph as candidates for organic electronics. ► The synthesis of Ph 2 Tz was performed through a modified Pinner-type reaction. ► IR/Raman spectra allowed to conclude that Ph 2 Tz is nearly planar in liquid phase. ► Electronic structure was studied by UV–Vis/TD-DFT methods in different solvents. ► Bandgap, E LUMO , electron mobility predict some n-type character for limit polymer. -- Abstract: This work presents a theoretical and spectroscopic study on the electronic and structural properties of the diphenyl-s-tetrazine molecule (Ph 2 Tz) and some oligomeric derivatives. Ph 2 Tz was synthesized through a variation of Pinner-type reaction which uses N-acetylcysteine as catalyst. Insight into the structure and electronic properties of the title compound was obtained through IR, Raman, UV–Vis spectra in different solvents, and theoretical calculations. Theoretical studies have been extended to different n-mers derivatives up to an ideal molecular wire through the oligomeric approximation, predicting this way electronic properties such as LUMO energy levels, electron affinity and reorganization energy in order to assess their possible applications in molecular electronics.
The predictive mind and the experience of visual art work.
Kesner, Ladislav
2014-01-01
Among the main challenges of the predictive brain/mind concept is how to link prediction at the neural level to prediction at the cognitive-psychological level and finding conceptually robust and empirically verifiable ways to harness this theoretical framework toward explaining higher-order mental and cognitive phenomena, including the subjective experience of aesthetic and symbolic forms. Building on the tentative prediction error account of visual art, this article extends the application of the predictive coding framework to the visual arts. It does so by linking this theoretical discussion to a subjective, phenomenological account of how a work of art is experienced. In order to engage more deeply with a work of art, viewers must be able to tune or adapt their prediction mechanism to recognize art as a specific class of objects whose ontological nature defies predictability, and they must be able to sustain a productive flow of predictions from low-level sensory, recognitional to abstract semantic, conceptual, and affective inferences. The affective component of the process of predictive error optimization that occurs when a viewer enters into dialog with a painting is constituted both by activating the affective affordances within the image and by the affective consequences of prediction error minimization itself. The predictive coding framework also has implications for the problem of the culturality of vision. A person's mindset, which determines what top-down expectations and predictions are generated, is co-constituted by culture-relative skills and knowledge, which form hyperpriors that operate in the perception of art.
The predictive mind and the experience of visual art work
Kesner, Ladislav
2014-01-01
Among the main challenges of the predictive brain/mind concept is how to link prediction at the neural level to prediction at the cognitive-psychological level and finding conceptually robust and empirically verifiable ways to harness this theoretical framework toward explaining higher-order mental and cognitive phenomena, including the subjective experience of aesthetic and symbolic forms. Building on the tentative prediction error account of visual art, this article extends the application of the predictive coding framework to the visual arts. It does so by linking this theoretical discussion to a subjective, phenomenological account of how a work of art is experienced. In order to engage more deeply with a work of art, viewers must be able to tune or adapt their prediction mechanism to recognize art as a specific class of objects whose ontological nature defies predictability, and they must be able to sustain a productive flow of predictions from low-level sensory, recognitional to abstract semantic, conceptual, and affective inferences. The affective component of the process of predictive error optimization that occurs when a viewer enters into dialog with a painting is constituted both by activating the affective affordances within the image and by the affective consequences of prediction error minimization itself. The predictive coding framework also has implications for the problem of the culturality of vision. A person’s mindset, which determines what top–down expectations and predictions are generated, is co-constituted by culture-relative skills and knowledge, which form hyperpriors that operate in the perception of art. PMID:25566111
Subhapriya, G.; Kalyanaraman, S.; Jeyachandran, M.; Ragavendran, V.; Krishnakumar, V.
2018-04-01
Synthesized 4-nitro-N-(2,4-dinitrophenyl) benzenamine (NDPBA) molecule was confirmed applying the tool of NMR. Theoretical prediction addressed the NMR chemical shifts and correlated well with the experimental data. The molecule subjected to theoretical DFT at 6-311++G** level unraveled the spectroscopic and structural properties of the NDPBA molecule. Moreover the structural features proved the occurrence of intramolecular Nsbnd H· · O hydrogen bonding in the molecule which was further confirmed with the help of Frontier molecular orbital analysis. Vibrational spectroscopic characterization through FT-IR and Raman experimentally and theoretically gave an account for the vibrational properties. An illustration of the topology of the molecule theoretically helped also in finding the hydrogen bonding energy.
Theoretical study of solvent effects on the coil-globule transition
Polson, James M.; Opps, Sheldon B.; Abou Risk, Nicholas
2009-06-01
The coil-globule transition of a polymer in a solvent has been studied using Monte Carlo simulations of a single chain subject to intramolecular interactions as well as a solvent-mediated effective potential. This solvation potential was calculated using several different theoretical approaches for two simple polymer/solvent models, each employing hard-sphere chains and hard-sphere solvent particles as well as attractive square-well potentials between some interaction sites. For each model, collapse is driven by variation in a parameter which changes the energy mismatch between monomers and solvent particles. The solvation potentials were calculated using two fundamentally different methodologies, each designed to predict the conformational behavior of polymers in solution: (1) the polymer reference interaction site model (PRISM) theory and (2) a many-body solvation potential (MBSP) based on scaled particle theory introduced by Grayce [J. Chem. Phys. 106, 5171 (1997)]. For the PRISM calculations, two well-studied solvation monomer-monomer pair potentials were employed, each distinguished by the closure relation used in its derivation: (i) a hypernetted-chain (HNC)-type potential and (ii) a Percus-Yevick (PY)-type potential. The theoretical predictions were each compared to results obtained from explicit-solvent discontinuous molecular dynamics simulations on the same polymer/solvent model systems [J. Chem. Phys. 125, 194904 (2006)]. In each case, the variation in the coil-globule transition properties with solvent density is mostly qualitatively correct, though the quantitative agreement between the theory and prediction is typically poor. The HNC-type potential yields results that are more qualitatively consistent with simulation. The conformational behavior of the polymer upon collapse predicted by the MBSP approach is quantitatively correct for low and moderate solvent densities but is increasingly less accurate for higher densities. At high solvent densities
Information theoretic description of networks
Wilhelm, Thomas; Hollunder, Jens
2007-11-01
We present a new information theoretic approach for network characterizations. It is developed to describe the general type of networks with n nodes and L directed and weighted links, i.e., it also works for the simpler undirected and unweighted networks. The new information theoretic measures for network characterizations are based on a transmitter-receiver analogy of effluxes and influxes. Based on these measures, we classify networks as either complex or non-complex and as either democracy or dictatorship networks. Directed networks, in particular, are furthermore classified as either information spreading and information collecting networks. The complexity classification is based on the information theoretic network complexity measure medium articulation (MA). It is proven that special networks with a medium number of links ( L∼n1.5) show the theoretical maximum complexity MA=(log n)2/2. A network is complex if its MA is larger than the average MA of appropriately randomized networks: MA>MAr. A network is of the democracy type if its redundancy Rdictatorship network. In democracy networks all nodes are, on average, of similar importance, whereas in dictatorship networks some nodes play distinguished roles in network functioning. In other words, democracy networks are characterized by cycling of information (or mass, or energy), while in dictatorship networks there is a straight through-flow from sources to sinks. The classification of directed networks into information spreading and information collecting networks is based on the conditional entropies of the considered networks ( H(A/B)=uncertainty of sender node if receiver node is known, H(B/A)=uncertainty of receiver node if sender node is known): if H(A/B)>H(B/A), it is an information collecting network, otherwise an information spreading network. Finally, different real networks (directed and undirected, weighted and unweighted) are classified according to our general scheme.
Earthquake Prediction Analysis Based on Empirical Seismic Rate: The M8 Algorithm
International Nuclear Information System (INIS)
Molchan, G.; Romashkova, L.
2010-07-01
The quality of space-time earthquake prediction is usually characterized by a two-dimensional error diagram (n,τ), where n is the rate of failures-to-predict and τ is the normalized measure of space-time alarm. The most reasonable space measure for analysis of a prediction strategy is the rate of target events λ(dg) in a sub-area dg. In that case the quantity H = 1-(n +τ) determines the prediction capability of the strategy. The uncertainty of λ(dg) causes difficulties in estimating H and the statistical significance, α, of prediction results. We investigate this problem theoretically and show how the uncertainty of the measure can be taken into account in two situations, viz., the estimation of α and the construction of a confidence zone for the (n,τ)-parameters of the random strategies. We use our approach to analyse the results from prediction of M ≥ 8.0 events by the M8 method for the period 1985-2009 (the M8.0+ test). The model of λ(dg) based on the events Mw ≥ 5.5, 1977-2004, and the magnitude range of target events 8.0 ≤ M < 8.5 are considered as basic to this M8 analysis. We find the point and upper estimates of α and show that they are still unstable because the number of target events in the experiment is small. However, our results argue in favour of non-triviality of the M8 prediction algorithm. (author)
Update on protein structure prediction: results of the 1995 IRBM workshop
DEFF Research Database (Denmark)
Hubbard, Tim; Tramontano, Anna; Hansen, Jan
1996-01-01
Computational tools for protein structure prediction are of great interest to molecular, structural and theoretical biologists due to a rapidly increasing number of protein sequences with no known structure. In October 1995, a workshop was held at IRBM to predict as much as possible about a numbe...
Update on protein structure prediction: results of the 1995 IRBM workshop
DEFF Research Database (Denmark)
Hubbard, Tim; Tramontano, Anna; Hansen, Jan
1996-01-01
Computational tools for protein structure prediction are of great interest to molecular, structural and theoretical biologists due to a rapidly increasing number of protein sequences with no known structure. In October 1995, a workshop was held at IRBM to predict as much as possible about a number...
Predictability in cellular automata.
Agapie, Alexandru; Andreica, Anca; Chira, Camelia; Giuclea, Marius
2014-01-01
Modelled as finite homogeneous Markov chains, probabilistic cellular automata with local transition probabilities in (0, 1) always posses a stationary distribution. This result alone is not very helpful when it comes to predicting the final configuration; one needs also a formula connecting the probabilities in the stationary distribution to some intrinsic feature of the lattice configuration. Previous results on the asynchronous cellular automata have showed that such feature really exists. It is the number of zero-one borders within the automaton's binary configuration. An exponential formula in the number of zero-one borders has been proved for the 1-D, 2-D and 3-D asynchronous automata with neighborhood three, five and seven, respectively. We perform computer experiments on a synchronous cellular automaton to check whether the empirical distribution obeys also that theoretical formula. The numerical results indicate a perfect fit for neighbourhood three and five, which opens the way for a rigorous proof of the formula in this new, synchronous case.
Theoretical Description of the Fission Process
International Nuclear Information System (INIS)
Nazarewicz, Witold
2009-01-01
Advanced theoretical methods and high-performance computers may finally unlock the secrets of nuclear fission, a fundamental nuclear decay that is of great relevance to society. In this work, we studied the phenomenon of spontaneous fission using the symmetry-unrestricted nuclear density functional theory (DFT). Our results show that many observed properties of fissioning nuclei can be explained in terms of pathways in multidimensional collective space corresponding to different geometries of fission products. From the calculated collective potential and collective mass, we estimated spontaneous fission half-lives, and good agreement with experimental data was found. We also predicted a new phenomenon of trimodal spontaneous fission for some transfermium isotopes. Our calculations demonstrate that fission barriers of excited superheavy nuclei vary rapidly with particle number, pointing to the importance of shell effects even at large excitation energies. The results are consistent with recent experiments where superheavy elements were created by bombarding an actinide target with 48-calcium; yet even at high excitation energies, sizable fission barriers remained. Not only does this reveal clues about the conditions for creating new elements, it also provides a wider context for understanding other types of fission. Understanding of the fission process is crucial for many areas of science and technology. Fission governs existence of many transuranium elements, including the predicted long-lived superheavy species. In nuclear astrophysics, fission influences the formation of heavy elements on the final stages of the r-process in a very high neutron density environment. Fission applications are numerous. Improved understanding of the fission process will enable scientists to enhance the safety and reliability of the nation's nuclear stockpile and nuclear reactors. The deployment of a fleet of safe and efficient advanced reactors, which will also minimize radiotoxic
Oumelaz, F.; Nemiri, O.; Boumaza, A.; Ghemid, S.; Meradji, H.; Bin Omran, S.; El Haj Hassan, F.; Rai, D. P.; Khenata, R.
2018-06-01
In this theoretical study, we have investigated the structural, phase transition, electronic, thermodynamic and optical properties of GaPxSb1-x ternary alloys. Our calculations are performed with the WIEN2k code based on density functional theory using the full-potential linearized augmented plane wave method. For the electron exchange-correlation potential, a generalized gradient approximation within Wu-Cohen scheme is considered. The recently developed Tran-Blaha modified Becke-Johnson potential has also been used to improve the underestimated band gap. The structural properties, including the lattice constants, the bulk moduli and their pressure derivatives are in very good agreement with the available experimental data and theoretical results. Several structural phase transitions were studied here to establish the stable structure and to predict the phase transition under hydrostatic pressure. The computed transition pressure (Pt) of the material of our interest from the zinc blende (B3) to the rock salt (B1) phase has been determined and found to agree well with the experimental and theoretical data. The calculated band structure shows that GaSb binary compound and the ternary alloys are direct band gap semiconductors. Optical parameters such as the dielectric constants and the refractive indices are calculated and analyzed. The thermodynamic results are also interpreted and analyzed.
Was the Recent Downturn in US GDP Predictable?
Mehmet Balcilar; Rangan Gupta; Anandamayee Majumdar; Stephen M. Miller
2012-01-01
This paper uses small set of variables-- real GDP, the inflation rate, and the short-term interest rate -- and a rich set of models -- athoeretical and theoretical, linear and nonlinear, as well as classical and Bayesian models -- to consider whether we could have predicted the recent downturn of the US real GDP. Comparing the performance by root mean squared errors of the models to the benchmark random-walk model, the two theoretical models, especially the nonlinear model, perform well on th...
International Nuclear Information System (INIS)
Vishwanath, Karthik; Mycek, Mary-Ann; Pogue, Brian
2002-01-01
A Monte Carlo model developed to simulate time-resolved fluorescence propagation in a semi-infinite turbid medium was validated against previously reported theoretical and computational results. Model simulations were compared to experimental measurements of fluorescence spectra and lifetimes on tissue-simulating phantoms for single and dual fibre-optic probe geometries. Experiments and simulations using a single probe revealed that scattering-induced artefacts appeared in fluorescence emission spectra, while fluorescence lifetimes were unchanged. Although fluorescence lifetime measurements are generally more robust to scattering artefacts than are measurements of fluorescence spectra, in the dual-probe geometry scattering-induced changes in apparent lifetime were predicted both from diffusion theory and via Monte Carlo simulation, as well as measured experimentally. In all cases, the recovered apparent lifetime increased with increasing scattering and increasing source-detector separation. Diffusion theory consistently underestimated the magnitude of these increases in apparent lifetime (predicting a maximum increase of ∼15%), while Monte Carlo simulations and experiment were closely matched (showing increases as large as 30%). These results indicate that quantitative simulations of time-resolved fluorescence propagation in turbid media will be important for accurate recovery of fluorophore lifetimes in biological spectroscopy and imaging applications. (author)
Mechanical properties of jennite: A theoretical and experimental study
Energy Technology Data Exchange (ETDEWEB)
Moon, Juhyuk, E-mail: juhyuk.moon@stonybrook.edu [Civil Engineering Program, Department of Mechanical Engineering, Stony Brook University, NY 11794 (United States); Yoon, Seyoon [School of Engineering, Kings College, University of Aberdeen, Aberdeen AB24 3UE (United Kingdom); Monteiro, Paulo J.M. [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States)
2015-05-15
The objective of this study is to determine the mechanical properties of jennite. To date, several hypotheses have been proposed to predict the structural properties of jennite. For the first time as reported herein, the isothermal bulk modulus of jennite was measured experimentally. Synchrotron-based high-pressure x-ray diffraction experiments were performed to observe the variation of lattice parameters under pressure. First-principles calculations were applied to compare with the experimental results and predict additional structural properties. Accurately measured isothermal bulk modulus herein (K{sub 0} = 64(2) GPa) and the statistical assessment on experimental and theoretical results suggest reliable mechanical properties of shear and Young's modulus, Poisson's ratio, and elastic tensor coefficients. Determination of these fundamental structural properties is the first step toward greater understanding of calcium–silicate–hydrate, as well as provides a sound foundation for forthcoming atomic level simulations.
The art of predicting nuclear masses
International Nuclear Information System (INIS)
Hirsch, J.G.; Morales, I.; Mendoza-Temis, J.; Frank, A.; Lopez-Vieyra, J.C.; Barea, J.; Pittel, S.; Van Isacker, P.; Velazquez, V.
2008-01-01
A review of recent advances in the theoretical analysis of nuclear mass models and their predictive power is presented. After introducing two tests which probe the ability of nuclear mass models to extrapolate, three models are analyzed in detail: the liquid drop model (LDM), the liquid drop model plus empirical shell corrections (LDMM) and the Duflo–Zuker mass formula (DZ). The DZ model is exhibited as the most predictive model. The Garvey–Kelson mass relations are also discussed. It is shown that their fulfillment probes the consistency of the most commonly used mass formulae, and that they can be used in an iterative process to predict nuclear masses in the neighborhood of nuclei with measured masses, offering a simple and reproducible procedure for short range mass predictions. (author)
Directory of Open Access Journals (Sweden)
Weiguo Li
2012-01-01
Full Text Available A thermodamage strength theoretical model taking into account the effect of residual stress was established and applied to each temperature phase based on the study of effects of various physical mechanisms on the fracture strength of ultrahigh-temperature ceramics. The effects of SiC particle size, crack size, and SiC particle volume fraction on strength corresponding to different temperatures were studied in detail. This study showed that when flaw size is not large, the bigger SiC particle size results in the greater effect of tensile residual stress in the matrix grains on strength reduction, and this prediction coincides with experimental results; and the residual stress and the combined effort of particle size and crack size play important roles in controlling material strength.
Dissociation of the Phenylarsane Molecular Ion: A Theoretical Study
Energy Technology Data Exchange (ETDEWEB)
Kim, Sun Young; Choe, Joong Chul [Dongguk University, Seoul (Korea, Republic of)
2010-09-15
The potential energy surfaces (PESs) for the primary and secondary dissociations of the phenylarsane molecular ion (1a) were determined from the quantum chemical calculations using the G3(MP2)//B3LYP method. Several pathways for the loss of H· were determined and occurred though rearrangements as well as through direct bond cleavages. The kinetic analysis based on the PES for the primary dissociation showed that the loss of H{sub 2} was more favored than the loss of H·, but the H· loss competed with the H{sub 2} loss at high energies. The bicyclic isomer, 7-arsa-norcaradiene radical cation, was formed through the 1,2 shift of an α-H of 1a and played an important role as an intermediate for the further rearrangements in the loss of H· and the losses of As· and AsH. The reaction pathways for the formation of the major products in the secondary dissociations of [M-H]{sup +} and [M-H{sub 2}]{sup +·} were examined. The theoretical prediction explained the previous experimental results for the dissociation at high energies but not the dissociation at low energies.
Wind Power Prediction Considering Nonlinear Atmospheric Disturbances
Directory of Open Access Journals (Sweden)
Yagang Zhang
2015-01-01
Full Text Available This paper considers the effect of nonlinear atmospheric disturbances on wind power prediction. A Lorenz system is introduced as an atmospheric disturbance model. Three new improved wind forecasting models combined with a Lorenz comprehensive disturbance are put forward in this study. Firstly, we define the form of the Lorenz disturbance variable and the wind speed perturbation formula. Then, different artificial neural network models are used to verify the new idea and obtain better wind speed predictions. Finally we separately use the original and improved wind speed series to predict the related wind power. This proves that the corrected wind speed provides higher precision wind power predictions. This research presents a totally new direction in the wind prediction field and has profound theoretical research value and practical guiding significance.
Francis, Jill J; Stockton, Charlotte; Eccles, Martin P; Johnston, Marie; Cuthbertson, Brian H; Grimshaw, Jeremy M; Hyde, Chris; Tinmouth, Alan; Stanworth, Simon J
2009-11-01
Many theories of behaviour are potentially relevant to predictive and intervention studies but most studies investigate a narrow range of theories. Michie et al. (2005) agreed 12 'theoretical domains' from 33 theories that explain behaviour change. They developed a 'Theoretical Domains Interview' (TDI) for identifying relevant domains for specific clinical behaviours, but the framework has not been used for selecting theories for predictive studies. It was used here to investigate clinicians' transfusion behaviour in intensive care units (ICU). Evidence suggests that red blood cells transfusion could be reduced for some patients without reducing quality of care. (1) To identify the domains relevant to transfusion practice in ICUs and neonatal intensive care units (NICUs), using the TDI. (2) To use the identified domains to select appropriate theories for a study predicting transfusion behaviour. An adapted TDI about managing a patient with borderline haemoglobin by watching and waiting instead of transfusing red blood cells was used to conduct semi-structured, one-to-one interviews with 18 intensive care consultants and neonatologists across the UK. Relevant theoretical domains were: knowledge, beliefs about capabilities, beliefs about consequences, social influences, behavioural regulation. Further analysis at the construct level resulted in selection of seven theoretical approaches relevant to this context: Knowledge-Attitude-Behaviour Model, Theory of Planned Behaviour, Social Cognitive Theory, Operant Learning Theory, Control Theory, Normative Model of Work Team Effectiveness and Action Planning Approaches. This study illustrated, the use of the TDI to identify relevant domains in a complex area of inpatient care. This approach is potentially valuable for selecting theories relevant to predictive studies and resulted in greater breadth of potential explanations than would be achieved if a single theoretical model had been adopted.
Johnson, Kennita A.; Vormohr, Hannah R.; Doinikov, Alexander A.; Bouakaz, Ayache; Shields, C. Wyatt; López, Gabriel P.; Dayton, Paul A.
2016-05-01
Acoustophoresis uses acoustic radiation force to remotely manipulate particles suspended in a host fluid for many scientific, technological, and medical applications, such as acoustic levitation, acoustic coagulation, contrast ultrasound imaging, ultrasound-assisted drug delivery, etc. To estimate the magnitude of acoustic radiation forces, equations derived for an inviscid host fluid are commonly used. However, there are theoretical predictions that, in the case of a traveling wave, viscous effects can dramatically change the magnitude of acoustic radiation forces, which make the equations obtained for an inviscid host fluid invalid for proper estimation of acoustic radiation forces. To date, experimental verification of these predictions has not been published. Experimental measurements of viscous effects on acoustic radiation forces in a traveling wave were conducted using a confocal optical and acoustic system and values were compared with available theories. Our results show that, even in a low-viscosity fluid such as water, the magnitude of acoustic radiation forces is increased manyfold by viscous effects in comparison with what follows from the equations derived for an inviscid fluid.
Towards A Theoretical Biology: Reminiscences
Indian Academy of Sciences (India)
engaged in since the start of my career at the University of Chicago. Theoretical biology was ... research on theoretical problems in biology. Waddington, an ... aimed at stimulating the development of such a theoretical biology. The role the ...
A theoretical model of job retention for home health care nurses.
Ellenbecker, Carol Hall
2004-08-01
Predicted severe nursing shortages and an increasing demand for home health care services have made the retention of experienced, qualified nursing staff a priority for health care organizations. The purpose of this paper is to describe a theoretical model of job retention for home health care nurses. The theoretical model is an integration of the findings of empirical research related to intent to stay and retention, components of Neal's theory of home health care nursing practice and findings from earlier work to develop an instrument to measure home health care nurses' job satisfaction. The theoretical model identifies antecedents to job satisfaction of home health care nurses. The antecedents are intrinsic and extrinsic job characteristics. The model also proposes that job satisfaction is directly related to retention and indirectly related to retention though intent to stay. Individual nurse characteristics are indirectly related to retention through intent to stay. The individual characteristic of tenure is indirectly related to retention through autonomy, as an intrinsic characteristic of job satisfaction, and intent to stay. The proposed model can be used to guide research that explores gaps in knowledge about intent to stay and retention among home health care nurses.
Parallel processing streams for motor output and sensory prediction during action preparation.
Stenner, Max-Philipp; Bauer, Markus; Heinze, Hans-Jochen; Haggard, Patrick; Dolan, Raymond J
2015-03-15
Sensory consequences of one's own actions are perceived as less intense than identical, externally generated stimuli. This is generally taken as evidence for sensory prediction of action consequences. Accordingly, recent theoretical models explain this attenuation by an anticipatory modulation of sensory processing prior to stimulus onset (Roussel et al. 2013) or even action execution (Brown et al. 2013). Experimentally, prestimulus changes that occur in anticipation of self-generated sensations are difficult to disentangle from more general effects of stimulus expectation, attention and task load (performing an action). Here, we show that an established manipulation of subjective agency over a stimulus leads to a predictive modulation in sensory cortex that is independent of these factors. We recorded magnetoencephalography while subjects performed a simple action with either hand and judged the loudness of a tone caused by the action. Effector selection was manipulated by subliminal motor priming. Compatible priming is known to enhance a subjective experience of agency over a consequent stimulus (Chambon and Haggard 2012). In line with this effect on subjective agency, we found stronger sensory attenuation when the action that caused the tone was compatibly primed. This perceptual effect was reflected in a transient phase-locked signal in auditory cortex before stimulus onset and motor execution. Interestingly, this sensory signal emerged at a time when the hemispheric lateralization of motor signals in M1 indicated ongoing effector selection. Our findings confirm theoretical predictions of a sensory modulation prior to self-generated sensations and support the idea that a sensory prediction is generated in parallel to motor output (Walsh and Haggard 2010), before an efference copy becomes available. Copyright © 2015 the American Physiological Society.
Activity systems modeling as a theoretical lens for social exchange studies
Directory of Open Access Journals (Sweden)
Ernest Jones
2016-01-01
Full Text Available The social exchange perspective seeks to acknowledge, understand and predict the dynamics of social interactions. Empirical research involving social exchange constructs have grown to be highly technical including confirmatory factor analysis to assess construct distinctiveness and structural equation modeling to assess construct causality. Each study seemingly strives to assess how underlying social exchange theoretic constructs interrelate. Yet despite this methodological depth and resultant explanatory and predictive power, a significant number of studies report findings that, once synthesized, suggest an underlying persistent threat of conceptual or construct validity brought about by a search for epistemological parsimony. Further, it is argued that a methodological approach that embraces inherent complexity such as activity systems modeling facilitates the search for simplified models while not ignoring contextual factors.
Collective motion of predictive swarms.
Directory of Open Access Journals (Sweden)
Nathaniel Rupprecht
Full Text Available Theoretical models of populations and swarms typically start with the assumption that the motion of agents is governed by the local stimuli. However, an intelligent agent, with some understanding of the laws that govern its habitat, can anticipate the future, and make predictions to gather resources more efficiently. Here we study a specific model of this kind, where agents aim to maximize their consumption of a diffusing resource, by attempting to predict the future of a resource field and the actions of other agents. Once the agents make a prediction, they are attracted to move towards regions that have, and will have, denser resources. We find that the further the agents attempt to see into the future, the more their attempts at prediction fail, and the less resources they consume. We also study the case where predictive agents compete against non-predictive agents and find the predictors perform better than the non-predictors only when their relative numbers are very small. We conclude that predictivity pays off either when the predictors do not see too far into the future or the number of predictors is small.
Katariya, Santosh B.; Patil, Dinesh; Rhyman, Lydia; Alswaidan, Ibrahim A.; Ramasami, Ponnadurai; Sekar, Nagaiyan
2017-12-01
The static first and second hyperpolarizability and their related properties were calculated for triphenylamine-based "push-pull" dyes using the B3LYP, CAM-B3LYP and BHHLYP functionals in conjunction with the 6-311+G(d,p) basis set. The electronic coupling for the electron transfer reaction of the dyes were calculated with the generalized Mulliken-Hush method. The results obtained were correlated with the polarizability parameter αCT , first hyperpolarizability parameter βCT, and the solvatochromic descriptor of 〈 γ〉 SD obtained by the solvatochromic method. The dyes studied show a high total first order hyperpolarizability (70-238 times) and second order hyperpolarizability (412-778 times) compared to urea. Among the three functionals, the CAM-B3LYP and BHHLYP functionals show hyperpolarizability values closer to experimental values. Experimental absorption and emission wavelengths measured for all the synthesized dyes are in good agreement with those predicted using the time-dependent density functional theory. The theoretical examination on non-linear optical properties was performed on the key parameters of polarizability and hyperpolarizability. A remarkable increase in non-linear optical response is observed on insertion of benzothiazole unit compared to benzimidazole unit.
A Unified Theoretical Framework for Cognitive Sequencing.
Savalia, Tejas; Shukla, Anuj; Bapi, Raju S
2016-01-01
The capacity to sequence information is central to human performance. Sequencing ability forms the foundation stone for higher order cognition related to language and goal-directed planning. Information related to the order of items, their timing, chunking and hierarchical organization are important aspects in sequencing. Past research on sequencing has emphasized two distinct and independent dichotomies: implicit vs. explicit and goal-directed vs. habits. We propose a theoretical framework unifying these two streams. Our proposal relies on brain's ability to implicitly extract statistical regularities from the stream of stimuli and with attentional engagement organizing sequences explicitly and hierarchically. Similarly, sequences that need to be assembled purposively to accomplish a goal require engagement of attentional processes. With repetition, these goal-directed plans become habits with concomitant disengagement of attention. Thus, attention and awareness play a crucial role in the implicit-to-explicit transition as well as in how goal-directed plans become automatic habits. Cortico-subcortical loops basal ganglia-frontal cortex and hippocampus-frontal cortex loops mediate the transition process. We show how the computational principles of model-free and model-based learning paradigms, along with a pivotal role for attention and awareness, offer a unifying framework for these two dichotomies. Based on this framework, we make testable predictions related to the potential influence of response-to-stimulus interval (RSI) on developing awareness in implicit learning tasks.
A Unified Theoretical Framework for Cognitive Sequencing
Directory of Open Access Journals (Sweden)
Tejas Savalia
2016-11-01
Full Text Available The capacity to sequence information is central to human performance. Sequencing ability forms the foundation stone for higher order cognition related to language and goal-directed planning. Information related to the order of items, their timing, chunking and hierarchical organization are important aspects in sequencing. Past research on sequencing has emphasized two distinct and independent dichotomies: implicit versus explicit and goal-directed versus habits. We propose a theoretical framework unifying these two streams. Our proposal relies on brain's ability to implicitly extract statistical regularities from the stream of stimuli and with attentional engagement organizing sequences explicitly and hierarchically. Similarly, sequences that need to be assembled purposively to accomplish a goal require engagement of attentional processes. With repetition, these goal-directed plans become habits with concomitant disengagement of attention. Thus attention and awareness play a crucial role in the implicit-to-explicit transition as well as in how goal-directed plans become automatic habits. Cortico-subcortical loops ─ basal ganglia-frontal cortex and hippocampus-frontal cortex loops ─ mediate the transition process. We show how the computational principles of model-free and model-based learning paradigms, along with a pivotal role for attention and awareness, offer a unifying framework for these two dichotomies. Based on this framework, we make testable predictions related to the potential influence of response-to-stimulus interval (RSI on developing awareness in implicit learning tasks.
A theoretical analysis of flow through the nucleating stage in a low pressure steam turbine
International Nuclear Information System (INIS)
Skillings, S.A.; Walters, P.T.; Jackson, R.
1989-01-01
In order to improve steam turbine efficiency and reliability, the phenomena associated with the formation and growth of water droplets must be understood. This report describes a theoretical investigation into flow behaviour in the nucleating stage, where the predictions of a one-dimensional theory are compared with measured turbine data. Results indicate that droplet sizes predicted by homogeneous condensation theory cannot be reconciled with measurements unless fluctuating shock waves arise. Heterogeneous effects and flow turbulence are also discussed along with their implications for the condensation process. (author)
Salomone, Horacio D.; Olivieri, Néstor A.; Véliz, Maximiliano E.; Raviola, Lisandro A.
2018-05-01
In the context of fluid mechanics courses, it is customary to consider the problem of a sphere falling under the action of gravity inside a viscous fluid. Under suitable assumptions, this phenomenon can be modelled using Stokes’ law and is routinely reproduced in teaching laboratories to determine terminal velocities and fluid viscosities. In many cases, however, the measured physical quantities show important deviations with respect to the predictions deduced from the simple Stokes’ model, and the causes of these apparent ‘anomalies’ (for example, whether the flow is laminar or turbulent) are seldom discussed in the classroom. On the other hand, there are various variable-mass problems that students tackle during elementary mechanics courses and which are discussed in many textbooks. In this work, we combine both kinds of problems and analyse—both theoretically and experimentally—the evolution of a system composed of a sphere pulled by a chain of variable length inside a tube filled with water. We investigate the effects of different forces acting on the system such as weight, buoyancy, viscous friction and drag force. By means of a sequence of mathematical models of increasing complexity, we obtain a progressive fit that accounts for the experimental data. The contrast between the various models exposes the strengths and weaknessess of each one. The proposed experience can be useful for integrating concepts of elementary mechanics and fluids, and is suitable as laboratory practice, stressing the importance of the experimental validation of theoretical models and showing the model-building processes in a didactic framework.
International Nuclear Information System (INIS)
This report is a survey of the studies done in the Theoretical Physics Division of the Nuclear Physics Institute; the subjects studied in theoretical nuclear physics were the few-nucleon problem, nuclear structure, nuclear reactions, weak interactions, intermediate energy and high energy physics. In this last field, the subjects studied were field theory, group theory, symmetry and strong interactions [fr
The Predictiveness of Achievement Goals
Directory of Open Access Journals (Sweden)
Huy P. Phan
2013-11-01
Full Text Available Using the Revised Achievement Goal Questionnaire (AGQ-R (Elliot & Murayama, 2008, we explored first-year university students’ achievement goal orientations on the premise of the 2 × 2 model. Similar to recent studies (Elliot & Murayama, 2008; Elliot & Thrash, 2010, we conceptualized a model that included both antecedent (i.e., enactive learning experience and consequence (i.e., intrinsic motivation and academic achievement of achievement goals. Two hundred seventy-seven university students (151 women, 126 men participated in the study. Structural equation modeling procedures yielded evidence that showed the predictive effects of enactive learning experience and mastery goals on intrinsic motivation. Academic achievement was influenced intrinsic motivation, performance-approach goals, and enactive learning experience. Enactive learning experience also served as an antecedent of the four achievement goal types. On the whole, evidence obtained supports the AGQ-R and contributes, theoretically, to 2 × 2 model.
Review of prediction for thermal contact resistance
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
Theoretical prediction research on thermal contact resistance is reviewed in this paper. In general, modeling or simulating the thermal contact resistance involves several aspects, including the descriptions of surface topography, the analysis of micro mechanical deformation, and the thermal models. Some key problems are proposed for accurately predicting the thermal resistance of two solid contact surfaces. We provide a perspective on further promising research, which would be beneficial to understanding mechanisms and engineering applications of the thermal contact resistance in heat transport phenomena.
Sound transmission through lightweight double-leaf partitions: theoretical modelling
Wang, J.; Lu, T. J.; Woodhouse, J.; Langley, R. S.; Evans, J.
2005-09-01
This paper presents theoretical modelling of the sound transmission loss through double-leaf lightweight partitions stiffened with periodically placed studs. First, by assuming that the effect of the studs can be replaced with elastic springs uniformly distributed between the sheathing panels, a simple smeared model is established. Second, periodic structure theory is used to develop a more accurate model taking account of the discrete placing of the studs. Both models treat incident sound waves in the horizontal plane only, for simplicity. The predictions of the two models are compared, to reveal the physical mechanisms determining sound transmission. The smeared model predicts relatively simple behaviour, in which the only conspicuous features are associated with coincidence effects with the two types of structural wave allowed by the partition model, and internal resonances of the air between the panels. In the periodic model, many more features are evident, associated with the structure of pass- and stop-bands for structural waves in the partition. The models are used to explain the effects of incidence angle and of the various system parameters. The predictions are compared with existing test data for steel plates with wooden stiffeners, and good agreement is obtained.
Theoretical and numerical study of thermo-hydro-mechanical damage in unsaturated porous media
International Nuclear Information System (INIS)
Arson, Ch.
2009-09-01
Nuclear waste disposals are designed in multi-phase porous media. A new damage model, formulated in independent state variables (net stress, suction and thermal stress), is proposed for such geo-materials. The damage variable is a second-order tensor, which principal values grow with tensile strains. The stress/strain relations are derived from a postulated expression of the free energy. The degraded rigidities are computed by applying the Principle of Equivalent Elastic Energy for each stress state variable. Cracking effects are taken into account in transfers by introducing internal length parameters in the expressions of moisture conductivities. The damage model has been implemented in Θ-Stock Finite Element code. The mechanical model has been validated by comparing numerical results to experimental data and theoretical predictions. The qualitative evolutions given by the model in the parametric studies performed on realistic complex configurations show good trends. (author)
International Nuclear Information System (INIS)
Naito, Susumu; Hirata, Yosuke; Izumi, Mikio; Sano, Akira; Miyamoto, Yasuaki; Aoyama, Yoshio; Yamaguchi, Hiromi
2007-01-01
We present a reinforced ion current prediction model in alpha radioactivity measurement using ionized air transportation. Although our previous model explained the qualitative trend of the measured ion current values, the absolute values of the theoretical curves were about two times as large as the measured values. In order to accurately predict the measured values, we reinforced our model by considering columnar recombination and turbulent diffusion, which affects columnar recombination. Our new model explained the considerable ion loss in the early stage of ion diffusion and narrowed the gap between the theoretical and measured values. The model also predicted suppression of ion loss due to columnar recombination by spraying a high-speed air flow near a contaminated surface. This suppression was experimentally investigated and confirmed. In conclusion, we quantitatively clarified the theoretical relation between alpha radioactivity and ion current in laminar flow and turbulent pipe flow. (author)
A field theoretic model for static friction
Mahyaeh, I.; Rouhani, S.
2013-01-01
We present a field theoretic model for friction, where the friction coefficient between two surfaces may be calculated based on elastic properties of the surfaces. We assume that the geometry of contact surface is not unusual. We verify Amonton's laws to hold that friction force is proportional to the normal load.This model gives the opportunity to calculate the static coefficient of friction for a few cases, and show that it is in agreement with observed values. Furthermore we show that the ...
Spatial Economics Model Predicting Transport Volume
Directory of Open Access Journals (Sweden)
Lu Bo
2016-10-01
Full Text Available It is extremely important to predict the logistics requirements in a scientific and rational way. However, in recent years, the improvement effect on the prediction method is not very significant and the traditional statistical prediction method has the defects of low precision and poor interpretation of the prediction model, which cannot only guarantee the generalization ability of the prediction model theoretically, but also cannot explain the models effectively. Therefore, in combination with the theories of the spatial economics, industrial economics, and neo-classical economics, taking city of Zhuanghe as the research object, the study identifies the leading industry that can produce a large number of cargoes, and further predicts the static logistics generation of the Zhuanghe and hinterlands. By integrating various factors that can affect the regional logistics requirements, this study established a logistics requirements potential model from the aspect of spatial economic principles, and expanded the way of logistics requirements prediction from the single statistical principles to an new area of special and regional economics.
The beautiful invisible creativity, imagination, and theoretical physics
Vignale, Giovanni
2011-01-01
Challenging the image of theoretical physics as a dry discipline, The Beautiful Invisible shows that this highly abstract science is in fact teeming with beautiful concepts, and the task of imagining them demands profound creativity, just as creative as the work of poets or magical realist novelists such as Borges and Musil. "A good scientific theory is like a symbolic tale, an allegory of reality," writes Giovanni Vignale, as he uncovers the unexpected links between theoretical physics and artistic creativity. In engaging and at times poetic prose, and with ample quotations from many of the writers he admires, Vignale presents his own unorthodox accounts of fundamental theoretical concepts such as Newtonian mechanics, superconductivity, and Einstein's theory of relativity, illuminating their profound implications. Throughout, the author treats readers to glimpses of physics as "exercised in the still night, when only the moon rages." Indeed, as we delve behind now-familiar concepts such as "electron spin" an...
Theoretical study of elastic, mechanical and thermodynamic properties of MgRh intermetallic compound
Directory of Open Access Journals (Sweden)
S. Boucetta
2014-03-01
Full Text Available In the last years, Magnesium alloys are known to be of great technological importance and high scientific interest. In this work, density functional theory plane-wave pseudo potential method, with local density approximation (LDA and generalized gradient approximation (GGA are used to perform first-principles quantum mechanics calculations in order to investigate the structural, elastic and mechanical properties of the intermetallic compound MgRh with a CsCl-type structure. Comparison of the calculated equilibrium lattice constant and experimental data shows good agreement. The elastic constants were determined from a linear fit of the calculated stress–strain function according to Hooke's law. From the elastic constants, the bulk modulus B, shear modulus G, Young's modulus E, Poisson's ratio σ, anisotropy factor A and the ratio B/G for MgRh compound are obtained. The sound velocities and Debye temperature are also predicted from elastic constants. Finally, the linear response method has been used to calculate the thermodynamic properties. The temperature dependence of the enthalpy H, free energy F, entropy S, and heat capacity at constant volume Cv of MgRh crystal in a quasi-harmonic approximation have been obtained from phonon density of states and discussed for the first report. This is the first quantitative theoretical prediction of these properties.
Bauduin, Sophie; Clarisse, Lieven; Theunissen, Michael; George, Maya; Hurtmans, Daniel; Clerbaux, Cathy; Coheur, Pierre-François
2017-03-01
Separating concentrations of carbon monoxide (CO) in the boundary layer from the rest of the atmosphere with nadir satellite measurements is of particular importance to differentiate emission from transport. Although thermal infrared (TIR) satellite sounders are considered to have limited sensitivity to the composition of the near-surface atmosphere, previous studies show that they can provide information on CO close to the ground in case of high thermal contrast. In this work we investigate the capability of IASI (Infrared Atmospheric Sounding Interferometer) to retrieve near-surface CO concentrations, and we quantitatively assess the influence of thermal contrast on such retrievals. We present a 3-part analysis, which relies on both theoretical forward simulations and retrievals on real data, performed for a large range of negative and positive thermal contrast situations. First, we derive theoretically the IASI detection threshold of CO enhancement in the boundary layer, and we assess its dependence on thermal contrast. Then, using the optimal estimation formalism, we quantify the role of thermal contrast on the error budget and information content of near-surface CO retrievals. We demonstrate that, contrary to what is usually accepted, large negative thermal contrast values (ground cooler than air) lead to a better decorrelation between CO concentrations in the low and the high troposphere than large positive thermal contrast (ground warmer than the air). In the last part of the paper we use Mexico City and Barrow as test cases to contrast our theoretical predictions with real retrievals, and to assess the accuracy of IASI surface CO retrievals through comparisons to ground-based in-situ measurements.
RNA folding: structure prediction, folding kinetics and ion electrostatics.
Tan, Zhijie; Zhang, Wenbing; Shi, Yazhou; Wang, Fenghua
2015-01-01
Beyond the "traditional" functions such as gene storage, transport and protein synthesis, recent discoveries reveal that RNAs have important "new" biological functions including the RNA silence and gene regulation of riboswitch. Such functions of noncoding RNAs are strongly coupled to the RNA structures and proper structure change, which naturally leads to the RNA folding problem including structure prediction and folding kinetics. Due to the polyanionic nature of RNAs, RNA folding structure, stability and kinetics are strongly coupled to the ion condition of solution. The main focus of this chapter is to review the recent progress in the three major aspects in RNA folding problem: structure prediction, folding kinetics and ion electrostatics. This chapter will introduce both the recent experimental and theoretical progress, while emphasize the theoretical modelling on the three aspects in RNA folding.
Energy Technology Data Exchange (ETDEWEB)
Muhrer, G., E-mail: muhrer@lanl.gov [Los Alamos National Laboratory, Los Alamos, 87545 NM (United States); Hartl, M.; Mocko, M.; Tovesson, F.; Daemen, L. [Los Alamos National Laboratory, Los Alamos, 87545 NM (United States)
2012-07-21
In the search for moderator materials encapsulated materials have been discussed, but very little is known regarding the effect of encapsulation on neutron moderation properties. As a first step toward a better understanding, we present the measured total neutron cross-section of water confined in silica microspheres and compare the measured data to the predicted theoretical cross-section.
Corbala-Robles, L; Volcke, E I P; Samijn, A; Ronsse, F; Pieters, J G
2016-05-15
Heat is an important resource in wastewater treatment plants (WWTPs) which can be recovered. A prerequisite to determine the theoretical heat recovery potential is an accurate heat balance model for temperature prediction. The insulating effect of foam present on the basin surface and its influence on temperature prediction were assessed in this study. Experiments were carried out to characterize the foam layer and its insulating properties. A refined dynamic temperature prediction model, taking into account the effect of foam, was set up. Simulation studies for a WWTP treating highly concentrated (manure) wastewater revealed that the foam layer had a significant effect on temperature prediction (3.8 ± 0.7 K over the year) and thus on the theoretical heat recovery potential (30% reduction when foam is not considered). Seasonal effects on the individual heat losses and heat gains were assessed. Additionally, the effects of the critical basin temperature above which heat is recovered, foam thickness, surface evaporation rate reduction and the non-absorbed solar radiation on the theoretical heat recovery potential were evaluated. Copyright © 2016 Elsevier Ltd. All rights reserved.
Ruzziconi, Laura
2013-11-15
This study deals with an experimental and theoretical investigation of an electrically actuated micro-electromechanical system (MEMS). The experimental nonlinear dynamics are explored via frequency sweeps in a neighborhood of the first symmetric natural frequency, at increasing values of electrodynamic excitation. Both the non-resonant branch, the resonant one, the jump between them, and the presence of a range of inevitable escape (dynamic pull-in) are observed. To simulate the experimental behavior, a single degree-offreedom spring mass model is derived, which is based on the information coming from the experimentation. Despite the apparent simplicity, the model is able to catch all the most relevant aspects of the device response. This occurs not only at low values of electrodynamic excitation, but also at higher ones. Nevertheless, the theoretical predictions are not completely fulfilled in some aspects. In particular, the range of existence of each attractor is smaller in practice than in the simulations. This is because, under realistic conditions, disturbances are inevitably encountered (e.g. discontinuous steps when performing the sweeping, approximations in the modeling, etc.) and give uncertainties to the operating initial conditions. A reliable prediction of the actual (and not only theoretical) response is essential in applications. To take disturbances into account, we develop a dynamical integrity analysis. Integrity profiles and integrity charts are performed. They are able to detect the parameter range where each branch can be reliably observed in practice and where, instead, becomes vulnerable. Moreover, depending on the magnitude of the expected disturbances, the integrity charts can serve as a design guideline, in order to effectively operate the device in safe condition, according to the desired outcome. Copyright © 2013 by ASME.
Ruzziconi, Laura; Ramini, Abdallah H.; Younis, Mohammad I.; Lenci, Stefano
2013-01-01
This study deals with an experimental and theoretical investigation of an electrically actuated micro-electromechanical system (MEMS). The experimental nonlinear dynamics are explored via frequency sweeps in a neighborhood of the first symmetric natural frequency, at increasing values of electrodynamic excitation. Both the non-resonant branch, the resonant one, the jump between them, and the presence of a range of inevitable escape (dynamic pull-in) are observed. To simulate the experimental behavior, a single degree-offreedom spring mass model is derived, which is based on the information coming from the experimentation. Despite the apparent simplicity, the model is able to catch all the most relevant aspects of the device response. This occurs not only at low values of electrodynamic excitation, but also at higher ones. Nevertheless, the theoretical predictions are not completely fulfilled in some aspects. In particular, the range of existence of each attractor is smaller in practice than in the simulations. This is because, under realistic conditions, disturbances are inevitably encountered (e.g. discontinuous steps when performing the sweeping, approximations in the modeling, etc.) and give uncertainties to the operating initial conditions. A reliable prediction of the actual (and not only theoretical) response is essential in applications. To take disturbances into account, we develop a dynamical integrity analysis. Integrity profiles and integrity charts are performed. They are able to detect the parameter range where each branch can be reliably observed in practice and where, instead, becomes vulnerable. Moreover, depending on the magnitude of the expected disturbances, the integrity charts can serve as a design guideline, in order to effectively operate the device in safe condition, according to the desired outcome. Copyright © 2013 by ASME.
Drug-Target Interaction Prediction through Label Propagation with Linear Neighborhood Information.
Zhang, Wen; Chen, Yanlin; Li, Dingfang
2017-11-25
Interactions between drugs and target proteins provide important information for the drug discovery. Currently, experiments identified only a small number of drug-target interactions. Therefore, the development of computational methods for drug-target interaction prediction is an urgent task of theoretical interest and practical significance. In this paper, we propose a label propagation method with linear neighborhood information (LPLNI) for predicting unobserved drug-target interactions. Firstly, we calculate drug-drug linear neighborhood similarity in the feature spaces, by considering how to reconstruct data points from neighbors. Then, we take similarities as the manifold of drugs, and assume the manifold unchanged in the interaction space. At last, we predict unobserved interactions between known drugs and targets by using drug-drug linear neighborhood similarity and known drug-target interactions. The experiments show that LPLNI can utilize only known drug-target interactions to make high-accuracy predictions on four benchmark datasets. Furthermore, we consider incorporating chemical structures into LPLNI models. Experimental results demonstrate that the model with integrated information (LPLNI-II) can produce improved performances, better than other state-of-the-art methods. The known drug-target interactions are an important information source for computational predictions. The usefulness of the proposed method is demonstrated by cross validation and the case study.
Energy Technology Data Exchange (ETDEWEB)
Moral, Monica; Garcia, Gregorio [Departamento de Quimica Fisica y Analitica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain); Penas, Antonio [Departamento de Quimica Inorganica y Organica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain); Garzon, Andres; Granadino-Roldan, Jose M. [Departamento de Quimica Fisica y Analitica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain); Melguizo, Manuel [Departamento de Quimica Inorganica y Organica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain); Fernandez-Gomez, Manuel, E-mail: mfg@ujaen.es [Departamento de Quimica Fisica y Analitica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain)
2012-10-26
Highlights: Black-Right-Pointing-Pointer We study properties of Ph{sub 2}Tz and (PhTz){sub n}Ph as candidates for organic electronics. Black-Right-Pointing-Pointer The synthesis of Ph{sub 2}Tz was performed through a modified Pinner-type reaction. Black-Right-Pointing-Pointer IR/Raman spectra allowed to conclude that Ph{sub 2}Tz is nearly planar in liquid phase. Black-Right-Pointing-Pointer Electronic structure was studied by UV-Vis/TD-DFT methods in different solvents. Black-Right-Pointing-Pointer Bandgap, E{sub LUMO}, electron mobility predict some n-type character for limit polymer. -- Abstract: This work presents a theoretical and spectroscopic study on the electronic and structural properties of the diphenyl-s-tetrazine molecule (Ph{sub 2}Tz) and some oligomeric derivatives. Ph{sub 2}Tz was synthesized through a variation of Pinner-type reaction which uses N-acetylcysteine as catalyst. Insight into the structure and electronic properties of the title compound was obtained through IR, Raman, UV-Vis spectra in different solvents, and theoretical calculations. Theoretical studies have been extended to different n-mers derivatives up to an ideal molecular wire through the oligomeric approximation, predicting this way electronic properties such as LUMO energy levels, electron affinity and reorganization energy in order to assess their possible applications in molecular electronics.
Information-theoretic metamodel of organizational evolution
Sepulveda, Alfredo
2011-12-01
Social organizations are abstractly modeled by holarchies---self-similar connected networks---and intelligent complex adaptive multiagent systems---large networks of autonomous reasoning agents interacting via scaled processes. However, little is known of how information shapes evolution in such organizations, a gap that can lead to misleading analytics. The research problem addressed in this study was the ineffective manner in which classical model-predict-control methods used in business analytics attempt to define organization evolution. The purpose of the study was to construct an effective metamodel for organization evolution based on a proposed complex adaptive structure---the info-holarchy. Theoretical foundations of this study were holarchies, complex adaptive systems, evolutionary theory, and quantum mechanics, among other recently developed physical and information theories. Research questions addressed how information evolution patterns gleamed from the study's inductive metamodel more aptly explained volatility in organization. In this study, a hybrid grounded theory based on abstract inductive extensions of information theories was utilized as the research methodology. An overarching heuristic metamodel was framed from the theoretical analysis of the properties of these extension theories and applied to business, neural, and computational entities. This metamodel resulted in the synthesis of a metaphor for, and generalization of organization evolution, serving as the recommended and appropriate analytical tool to view business dynamics for future applications. This study may manifest positive social change through a fundamental understanding of complexity in business from general information theories, resulting in more effective management.
Ruzziconi, Laura
2013-02-20
In this study we deal with a microelectromechanical system (MEMS) and develop a dynamical integrity analysis to interpret and predict the experimental response. The device consists of a clamped-clamped polysilicon microbeam, which is electrostatically and electrodynamically actuated. It has non-negligible imperfections, which are a typical consequence of the microfabrication process. A single-mode reduced-order model is derived and extensive numerical simulations are performed in a neighborhood of the first symmetric natural frequency, via frequency response diagrams and behavior chart. The typical softening behavior is observed and the overall scenario is explored, when both the frequency and the electrodynamic voltage are varied. We show that simulations based on direct numerical integration of the equation of motion in time yield satisfactory agreement with the experimental data. Nevertheless, these theoretical predictions are not completely fulfilled in some aspects. In particular, the range of existence of each attractor is smaller in practice than in the simulations. This is because these theoretical curves represent the ideal limit case where disturbances are absent, which never occurs under realistic conditions. A reliable prediction of the actual (and not only theoretical) range of existence of each attractor is essential in applications. To overcome this discrepancy and extend the results to the practical case where disturbances exist, a dynamical integrity analysis is developed. After introducing dynamical integrity concepts, integrity profiles and integrity charts are drawn. They are able to describe if each attractor is robust enough to tolerate the disturbances. Moreover, they detect the parameter range where each branch can be reliably observed in practice and where, instead, becomes vulnerable, i.e. they provide valuable information to operate the device in safe conditions according to the desired outcome and depending on the expected disturbances
Energy Technology Data Exchange (ETDEWEB)
Yavuz, Murat; Ozer, Zehra Nur, E-mail: zehraerengil@aku.edu.tr; Ulu, Melike; Dogan, Mevlut [e-COL Laboratory, Department of Physics, Afyon Kocatepe University, Afyonkarahisar 03200 (Turkey); Champion, Christophe [Centre d’Etudes Nucléaires de Bordeaux Gradignan, CNRS/IN2P3, Université de Bordeaux, Gradignan 33170 (France)
2016-04-28
Experimental and theoretical double differential cross sections (DDCSs) for electron-induced ionization of methane (CH{sub 4}) are here reported for primary energies ranging from 50 eV to 350 eV and ejection angles between 25° and 130°. Experimental DDCSs are compared with theoretical predictions performed within the first Born approximation Coulomb wave. In this model, the initial molecular state is described by using single center wave functions, the incident (scattered) electron being described by a plane wave, while a Coulomb wave function is used for modeling the secondary ejected electron. A fairly good agreement may be observed between theory and experiment with nevertheless an expected systematic overestimation of the theory at low-ejection energies (<50 eV).
International Nuclear Information System (INIS)
Lappin, A. R.
1980-07-01
Performance of both near- and far-field thermomechanical calculations to assess the feasibility of waste disposal in silicic tuffs requires a formalism for predicting thermal conductivity of a broad range of tuffs. This report summarizes the available thermal conductivity data for silicate phases that occur in tuffs and describes several grain-density and conductivity trends which may be expected to result from post-emplacement alteration. A bounding curve is drawn that predicts the minimum theoretical matrix (zero-porosity) conductivity for most tuffs as a function of grain density. Comparison of experimental results with this curve shows that experimental conductivities are consistently lower at any given grain density. Use of the lowered bounding curve and an effective gas conductivity of 0.12 W/m 0 C allows conservative prediction of conductivity for a broad range of tuff types. For the samples measured here, use of the predictive curve allows estimation of conductivity to within 15% or better, with one exception. Application and possible improvement of the formalism are also discussed
Predictability of Mobile Phone Associations
DEFF Research Database (Denmark)
Jensen, Bjørn Sand; Larsen, Jan; Hansen, Lars Kai
2010-01-01
Prediction and understanding of human behavior is of high importance in many modern applications and research areas ranging from context-aware services, wireless resource allocation to social sciences. In this study we collect a novel dataset using standard mobile phones and analyze how the predi...... representation, and general behavior. This is of vital interest in the development of context-aware services which rely on forecasting based on mobile phone sensors.......Prediction and understanding of human behavior is of high importance in many modern applications and research areas ranging from context-aware services, wireless resource allocation to social sciences. In this study we collect a novel dataset using standard mobile phones and analyze how...... the predictability of mobile sensors, acting as proxies for humans, change with time scale and sensor type such as GSM and WLAN. Applying recent information theoretic methods, it is demonstrated that an upper bound on predictability is relatively high for all sensors given the complete history (typically above 90...
Inference of ICF Implosion Core Mix using Experimental Data and Theoretical Mix Modeling
International Nuclear Information System (INIS)
Welser-Sherrill, L.; Haynes, D.A.; Mancini, R.C.; Cooley, J.H.; Tommasini, R.; Golovkin, I.E.; Sherrill, M.E.; Haan, S.W.
2009-01-01
The mixing between fuel and shell materials in Inertial Confinement Fusion (ICF) implosion cores is a current topic of interest. The goal of this work was to design direct-drive ICF experiments which have varying levels of mix, and subsequently to extract information on mixing directly from the experimental data using spectroscopic techniques. The experimental design was accomplished using hydrodynamic simulations in conjunction with Haan's saturation model, which was used to predict the mix levels of candidate experimental configurations. These theoretical predictions were then compared to the mixing information which was extracted from the experimental data, and it was found that Haan's mix model performed well in predicting trends in the width of the mix layer. With these results, we have contributed to an assessment of the range of validity and predictive capability of the Haan saturation model, as well as increased our confidence in the methods used to extract mixing information from experimental data.
A Combined Theoretical and Experimental Study for Silver Electroplating
Liu, Anmin; Ren, Xuefeng; An, Maozhong; Zhang, Jinqiu; Yang, Peixia; Wang, Bo; Zhu, Yongming; Wang, Chong
2014-01-01
A novel method combined theoretical and experimental study for environmental friendly silver electroplating was introduced. Quantum chemical calculations and molecular dynamic (MD) simulations were employed for predicting the behaviour and function of the complexing agents. Electronic properties, orbital information, and single point energies of the 5,5-dimethylhydantoin (DMH), nicotinic acid (NA), as well as their silver(I)-complexes were provided by quantum chemical calculations based on density functional theory (DFT). Adsorption behaviors of the agents on copper and silver surfaces were investigated using MD simulations. Basing on the data of quantum chemical calculations and MD simulations, we believed that DMH and NA could be the promising complexing agents for silver electroplating. The experimental results, including of electrochemical measurement and silver electroplating, further confirmed the above prediction. This efficient and versatile method thus opens a new window to study or design complexing agents for generalized metal electroplating and will vigorously promote the level of this research region.
A Combined Theoretical and Experimental Study for Silver Electroplating
Liu, Anmin; Ren, Xuefeng; An, Maozhong; Zhang, Jinqiu; Yang, Peixia; Wang, Bo; Zhu, Yongming; Wang, Chong
2014-01-01
A novel method combined theoretical and experimental study for environmental friendly silver electroplating was introduced. Quantum chemical calculations and molecular dynamic (MD) simulations were employed for predicting the behaviour and function of the complexing agents. Electronic properties, orbital information, and single point energies of the 5,5-dimethylhydantoin (DMH), nicotinic acid (NA), as well as their silver(I)-complexes were provided by quantum chemical calculations based on density functional theory (DFT). Adsorption behaviors of the agents on copper and silver surfaces were investigated using MD simulations. Basing on the data of quantum chemical calculations and MD simulations, we believed that DMH and NA could be the promising complexing agents for silver electroplating. The experimental results, including of electrochemical measurement and silver electroplating, further confirmed the above prediction. This efficient and versatile method thus opens a new window to study or design complexing agents for generalized metal electroplating and will vigorously promote the level of this research region. PMID:24452389
Research in theoretical physics: Annual progress report for period April 1, 1988--March 31, 1989
International Nuclear Information System (INIS)
Domokos, G.; Kovesi-Domokos, S.
1988-11-01
This report contains a summary of research carried out in order to search for a substructure of quarks and leptons. Theoretical predictions valid for a large class of composite models suggest enhanced muon production in high energy lepton-induced reactions. A tentative analysis of some cosmic ray data indicates that the predictions of such models are in accordance with the data. In order to move towards the construction of satisfactory composite models, a study of gauge invariant effective actions and phase transitions in gauge theories was begun. 20 refs., 1 fig
International Nuclear Information System (INIS)
Kerveno, Maelle; Dupuis, Marc; Bauge, E.; Hilaire, S.; Romain, P.; Morillon, B.; Delaroche, J.P.; Dupuis, M.; Peru, S.; Belier, G.; Bonnet, T.; Laborie, J.M.; Laurent, B.; Ledoux, X.; Varignon, C.; Meot, V.; Bernard, David; Capote, Roberto; Kawano, T.; Bond, E.; Vieira, D.J.; Wilhelmy, J.B.; Raynal, J.; Plompen, Arjan J.M.; Drohe, J.C.; Nankov, N.; Nyman, M.; Rouki, C.; Bacquias, A.; Dessagne, Ph.; Henning, G.; Karam, H.; Kerveno, M.; Rudolf, G.; Thiry, J.C.; Borcea, C.; Negret, A.; Stanoiu, M.; Bucurescu, D.; Deleanu, D.; Filipescu, D.; Ghita, D.; Glodariu, T.; Marginean, N.; Marginean, R.; Mihai, C.; Olacel, A.; Pascu, S.; Sava, T.; Stroe, L.; Goriely, S.; Pavlik, A.; Jericha, E.; Ledoux, X.; Becker, J.A.; Macri, R.; Authier, N.; Hyneck, D.; Jansen, Y.; Legendre, J.; Jacquet, X.; Gunsing, Frank; Henning, Greg
2014-03-01
Since the two last decades, in the framework of general researches on future reactors, strong efforts have been devoted to improve the quantity and quality of nuclear data. Indeed, in order to improve safety margins and fuel optimization, but also to develop new kind of reactors or fuel cycles, accurate nuclear data are mandatory. At the end of the twentieth century, nuclear data bases did not reach the required quality level to be used in future reactor simulations. Therefore, both experimentalists and theoreticians, in the framework of several European research programs (HINDAS, NUDATRA, ANDES, CHANDA...), have tried to make the situation better. New sets of precise data measurements concerning fission, capture, (n,xn),..., reaction cross sections for a large variety of nuclei have been initiated. From evaluation point of view, the JEFF project has also improved the quality of nuclear data bases for several nuclei. In parallel, on the theoretical side, progress has also been made concerning cross section modeling in a wide range of energy (eV to GeV). The goal was to provide theoretical models with a good predictive power to feed data bases where experimental data are still missing and where the measurement is too complex. In this context, for example, a new nuclear reaction code TALYS has been developed. Collaboration between experimentalists, theoreticians and evaluators are then of strong interest to make progress. The number of problems to be solved covers various fields of nuclear reactions such as fission, capture or inelastic scattering. In order to avoid too large an audience we have decided, as a first step, to focus on inelastic scattering on actinides. Experimentally, three main methods exist to measure the total inelastic cross section: activation, detection of the emitted neutrons and prompt-gamma spectroscopy. This last method is, nevertheless, dependent on theoretical models since it provides (n,xn γ) cross sections and not the total inelastic
Foreign direct investment and economic growth: A theoretical framework
Directory of Open Access Journals (Sweden)
Edmore Mahembe
2014-05-01
Full Text Available The relationship between FDI and economic growth has attracted considerable attention over the years. Despite the important role played by FDI in economic growth, a number of policy-makers have not fully understood the theoretical linkage between FDI and economic growth. The aim of this paper, therefore, is to review the theoretical literature on the relationship between FDI and economic growth in a stylized fashion. The theoretical literature reviewed in this study show that FDI is a key contributor to the economic growth of the host country. FDI affects economic growth through two broad channels: (i FDI can encourage the adoption of new technologies in the production process through technological spillovers; and (ii FDI may stimulate knowledge transfers, both in terms of labour training and skill acquisition, and also by introducing alternative management practices and better organisational arrangements.
Size-based predictions of food web patterns
DEFF Research Database (Denmark)
Zhang, Lai; Hartvig, Martin; Knudsen, Kim
2014-01-01
We employ size-based theoretical arguments to derive simple analytic predictions of ecological patterns and properties of natural communities: size-spectrum exponent, maximum trophic level, and susceptibility to invasive species. The predictions are brought about by assuming that an infinite number...... of species are continuously distributed on a size-trait axis. It is, however, an open question whether such predictions are valid for a food web with a finite number of species embedded in a network structure. We address this question by comparing the size-based predictions to results from dynamic food web...... simulations with varying species richness. To this end, we develop a new size- and trait-based food web model that can be simplified into an analytically solvable size-based model. We confirm existing solutions for the size distribution and derive novel predictions for maximum trophic level and invasion...
Predictability of Conversation Partners
Takaguchi, Taro; Nakamura, Mitsuhiro; Sato, Nobuo; Yano, Kazuo; Masuda, Naoki
2011-08-01
Recent developments in sensing technologies have enabled us to examine the nature of human social behavior in greater detail. By applying an information-theoretic method to the spatiotemporal data of cell-phone locations, [C. Song , ScienceSCIEAS0036-8075 327, 1018 (2010)] found that human mobility patterns are remarkably predictable. Inspired by their work, we address a similar predictability question in a different kind of human social activity: conversation events. The predictability in the sequence of one’s conversation partners is defined as the degree to which one’s next conversation partner can be predicted given the current partner. We quantify this predictability by using the mutual information. We examine the predictability of conversation events for each individual using the longitudinal data of face-to-face interactions collected from two company offices in Japan. Each subject wears a name tag equipped with an infrared sensor node, and conversation events are marked when signals are exchanged between sensor nodes in close proximity. We find that the conversation events are predictable to a certain extent; knowing the current partner decreases the uncertainty about the next partner by 28.4% on average. Much of the predictability is explained by long-tailed distributions of interevent intervals. However, a predictability also exists in the data, apart from the contribution of their long-tailed nature. In addition, an individual’s predictability is correlated with the position of the individual in the static social network derived from the data. Individuals confined in a community—in the sense of an abundance of surrounding triangles—tend to have low predictability, and those bridging different communities tend to have high predictability.
Predictability of Conversation Partners
Directory of Open Access Journals (Sweden)
Taro Takaguchi
2011-09-01
Full Text Available Recent developments in sensing technologies have enabled us to examine the nature of human social behavior in greater detail. By applying an information-theoretic method to the spatiotemporal data of cell-phone locations, [C. Song et al., Science 327, 1018 (2010SCIEAS0036-8075] found that human mobility patterns are remarkably predictable. Inspired by their work, we address a similar predictability question in a different kind of human social activity: conversation events. The predictability in the sequence of one’s conversation partners is defined as the degree to which one’s next conversation partner can be predicted given the current partner. We quantify this predictability by using the mutual information. We examine the predictability of conversation events for each individual using the longitudinal data of face-to-face interactions collected from two company offices in Japan. Each subject wears a name tag equipped with an infrared sensor node, and conversation events are marked when signals are exchanged between sensor nodes in close proximity. We find that the conversation events are predictable to a certain extent; knowing the current partner decreases the uncertainty about the next partner by 28.4% on average. Much of the predictability is explained by long-tailed distributions of interevent intervals. However, a predictability also exists in the data, apart from the contribution of their long-tailed nature. In addition, an individual’s predictability is correlated with the position of the individual in the static social network derived from the data. Individuals confined in a community—in the sense of an abundance of surrounding triangles—tend to have low predictability, and those bridging different communities tend to have high predictability.
Energy Technology Data Exchange (ETDEWEB)
Becker, Kurt M; Jahnberg, S; Haga, I; Hansson, P T; Mathisen, R P
1964-09-15
A theoretical model for predicting the threshold of instability for two phase flow in a natural circulation loop is presented. The model calculates the flow transient caused by a step disturbance of the heat input, and is based upon the conservation laws of mass, momentum and energy in one dimensional form. Empirical correlations are used in the model for estimating the void fractions and the two-phase flow pressure drops. The equations are solved numerically in a finite difference approximation coded for a digital computer. An experimental study of the hydrodynamic instability and dynamic burnout in two-phase flow has been performed in a natural circulation loop in the pressure range from 10 to 70 atg. The test sections were round ducts of 20, 30 and 36 mm inner diameter and 4890 mm heated length. The experimental results showed that within the ranges tested, the stability of the flow increases with increasing pressure and increasing throttling before the test section, but decreases with increasing Inlet subcooling and increasing throttling after the test section. Comparing the natural circulation burnout steam qualities with corresponding forced circulation data shoved that the former data were low by a factor up to 2.5. However, by applying inlet throttling of the flow the burnout values approached and finally coincided with the forced circulation data. The present experimental results as well as data available from other sources have been compared with the stability thresholds obtained with the theoretical model. The comparisons included circular, annular and rod cluster geometries, and the agreement between the experimental and theoretical stability limits was good. Finally the application of the experimental and theoretical results on the assessment of boiling heavy water reactor design is discussed.
International Nuclear Information System (INIS)
Becker, Kurt M.; Jahnberg, S.; Haga, I.; Hansson, P.T.; Mathisen, R.P.
1964-09-01
A theoretical model for predicting the threshold of instability for two phase flow in a natural circulation loop is presented. The model calculates the flow transient caused by a step disturbance of the heat input, and is based upon the conservation laws of mass, momentum and energy in one dimensional form. Empirical correlations are used in the model for estimating the void fractions and the two-phase flow pressure drops. The equations are solved numerically in a finite difference approximation coded for a digital computer. An experimental study of the hydrodynamic instability and dynamic burnout in two-phase flow has been performed in a natural circulation loop in the pressure range from 10 to 70 atg. The test sections were round ducts of 20, 30 and 36 mm inner diameter and 4890 mm heated length. The experimental results showed that within the ranges tested, the stability of the flow increases with increasing pressure and increasing throttling before the test section, but decreases with increasing Inlet subcooling and increasing throttling after the test section. Comparing the natural circulation burnout steam qualities with corresponding forced circulation data shoved that the former data were low by a factor up to 2.5. However, by applying inlet throttling of the flow the burnout values approached and finally coincided with the forced circulation data. The present experimental results as well as data available from other sources have been compared with the stability thresholds obtained with the theoretical model. The comparisons included circular, annular and rod cluster geometries, and the agreement between the experimental and theoretical stability limits was good. Finally the application of the experimental and theoretical results on the assessment of boiling heavy water reactor design is discussed
Estimating Human Predictability From Mobile Sensor Data
DEFF Research Database (Denmark)
Jensen, Bjørn Sand; Larsen, Jakob Eg; Jensen, Kristian
2010-01-01
Quantification of human behavior is of prime interest in many applications ranging from behavioral science to practical applications like GSM resource planning and context-aware services. As proxies for humans, we apply multiple mobile phone sensors all conveying information about human behavior....... Using a recent, information theoretic approach it is demonstrated that the trajectories of individual sensors are highly predictable given complete knowledge of the infinite past. We suggest using a new approach to time scale selection which demonstrates that participants have even higher predictability...
Directory of Open Access Journals (Sweden)
Wang Yong
2011-10-01
Full Text Available Abstract Background With the development of genome-sequencing technologies, protein sequences are readily obtained by translating the measured mRNAs. Therefore predicting protein-protein interactions from the sequences is of great demand. The reason lies in the fact that identifying protein-protein interactions is becoming a bottleneck for eventually understanding the functions of proteins, especially for those organisms barely characterized. Although a few methods have been proposed, the converse problem, if the features used extract sufficient and unbiased information from protein sequences, is almost untouched. Results In this study, we interrogate this problem theoretically by an optimization scheme. Motivated by the theoretical investigation, we find novel encoding methods for both protein sequences and protein pairs. Our new methods exploit sufficiently the information of protein sequences and reduce artificial bias and computational cost. Thus, it significantly outperforms the available methods regarding sensitivity, specificity, precision, and recall with cross-validation evaluation and reaches ~80% and ~90% accuracy in Escherichia coli and Saccharomyces cerevisiae respectively. Our findings here hold important implication for other sequence-based prediction tasks because representation of biological sequence is always the first step in computational biology. Conclusions By considering the converse problem, we propose new representation methods for both protein sequences and protein pairs. The results show that our method significantly improves the accuracy of protein-protein interaction predictions.
Niu, Yingli; Li, Wenqiang; Peng, Qian; Geng, Hua; Yi, Yuanping; Wang, Linjun; Nan, Guangjun; Wang, Dong; Shuai, Zhigang
2018-04-01
MOlecular MAterials Property Prediction Package (MOMAP) is a software toolkit for molecular materials property prediction. It focuses on luminescent properties and charge mobility properties. This article contains a brief descriptive introduction of key features, theoretical models and algorithms of the software, together with examples that illustrate the performance. First, we present the theoretical models and algorithms for molecular luminescent properties calculation, which includes the excited-state radiative/non-radiative decay rate constant and the optical spectra. Then, a multi-scale simulation approach and its algorithm for the molecular charge mobility are described. This approach is based on hopping model and combines with Kinetic Monte Carlo and molecular dynamics simulations, and it is especially applicable for describing a large category of organic semiconductors, whose inter-molecular electronic coupling is much smaller than intra-molecular charge reorganisation energy.
Elliott, D. G.
1977-01-01
Measurements of reaction rail currents, reaction rail voltages, and airgap magnetic fields in tests of the Linear Induction Motor Research Vehicle (LIMRV) were compared with theoretical calculations from the mesh/matrix theory. It was found that the rail currents and magnetic fields predicted by the theory are within 20 percent of the measured currents and fields at most motor locations in most of the runs, but differ by as much as a factor of two in some cases. The most consistent difference is a higher experimental than theoretical magnetic field near the entrance of the motor and a lower experimental than theoretical magnetic field near the exit. The observed differences between the theoretical and experimental magnetic fields and currents do not account for the differences of as much as 26 percent between the theoretical and experimental thrusts.
Directory of Open Access Journals (Sweden)
Brown Robert H
2010-11-01
Full Text Available Abstract Background Bronchial thermoplasty is a novel technique designed to reduce an airway's ability to contract by reducing the amount of airway smooth muscle through controlled heating of the airway wall. This method has been examined in animal models and as a treatment for asthma in human subjects. At the present time, there has been little research published about how radiofrequency (RF energy and heat is transferred to the airways of the lung during bronchial thermoplasty procedures. In this manuscript we describe a computational, theoretical model of the delivery of RF energy to the airway wall. Methods An electro-thermal finite-element-analysis model was designed to simulate the delivery of temperature controlled RF energy to airway walls of the in vivo lung. The model includes predictions of heat generation due to RF joule heating and transfer of heat within an airway wall due to thermal conduction. To implement the model, we use known physical characteristics and dimensions of the airway and lung tissues. The model predictions were tested with measurements of temperature, impedance, energy, and power in an experimental canine model. Results Model predictions of electrode temperature, voltage, and current, along with tissue impedance and delivered energy were compared to experiment measurements and were within ± 5% of experimental averages taken over 157 sample activations. The experimental results show remarkable agreement with the model predictions, and thus validate the use of this model to predict the heat generation and transfer within the airway wall following bronchial thermoplasty. Conclusions The model also demonstrated the importance of evaporation as a loss term that affected both electrical measurements and heat distribution. The model predictions showed excellent agreement with the empirical results, and thus support using the model to develop the next generation of devices for bronchial thermoplasty. Our results suggest
Gall, P. D.
1984-01-01
Improving the aerodynamic characteristics of an airplane with respect to maximizing lift and minimizing induced and parasite drag are of primary importance in designing lighter, faster, and more efficient aircraft. Previous research has shown that a properly designed biplane wing system can perform superiorly to an equivalent monoplane system with regard to maximizing the lift-to-drag ratio and efficiency factor. Biplanes offer several potential advantages over equivalent monoplanes, such as a 60-percent reduction in weight, greater structural integrity, and increased roll response. The purpose of this research is to examine, both theoretically and experimentally, the possibility of further improving the aerodynamic characteristics of the biplanes configuration by adding winglets. Theoretical predictions were carried out utilizing vortex-lattice theory, which is a numerical method based on potential flow theory. Experimental data were obtained by testing a model in the Pennsylvania State University's subsonic wind tunnel at a Reynolds number of 510,000. The results showed that the addition of winglets improved the performance of the biplane with respect to increasing the lift-curve slope, increasing the maximum lift coefficient, increasing the efficiency factor, and decreasing the induced drag. A listing of the program is included in the Appendix.
Directory of Open Access Journals (Sweden)
R. Melnyk
2015-03-01
Full Text Available Mean spherical approximation (MSA, second-order Barker-Henderson (BH perturbation theory and thermodynamic perturbation theory (TPT for associating fluids in combination with BH perturbation theory are applied to the study of the structural properties and phase behaviour of the Derjaguin-Landau-Verwey-Overbeek (DLVO model of lysozyme and γ-cristalline aqueous electrolyte solutions. Predictions of the MSA for the structure factors are in good agreement with the corresponding computer simulation predictions. The agreement between theoretical results for the liquid-gas phase diagram and the corresponding results of the experiment and computer simulation is less satisfactory, with predictions of the combined BH-TPT approach being the most accurate.
Effects prediction guidelines for structures subjected to ground motion
International Nuclear Information System (INIS)
1975-07-01
Part of the planning for an underground nuclear explosion (UNE) is determining the effects of expected ground motion on exposed structures. Because of the many types of structures and the wide variation in ground motion intensity typically encountered, no single prediction method is both adequate and feasible for a complete evaluation. Furthermore, the nature and variability of ground motion and structure damage prescribe effects predictions that are made probabilistically. Initially, prediction for a UNE involves a preliminary assessment of damage to establish overall project feasibility. Subsequent efforts require more detailed damage evaluations, based on structure inventories and analyses of specific structures, so that safety problems can be identified and safety and remedial measures can be recommended. To cover this broad range of effects prediction needs for a typical UNE project, three distinct but interrelated methods have been developed and are described. First, the fundamental practical and theoretical aspects of predicting the effects of dynamic ground motion on structures are summarized. Next, experimentally derived and theoretically determined observations of the behavior of typical structures subjected to ground motion are presented. Then, based on these fundamental considerations and on the observed behavior of structures, the formulation of the three effects prediction procedures is described, along with guidelines regarding their applicability. Example damage predictions for hypothetical UNEs demonstrate these procedures. To aid in identifying the vibration properties of complex structures, one chapter discusses alternatives in vibration testing, instrumentation, and data analysis. Finally, operational guidelines regarding data acquisition procedures, safety criteria, and remedial measures involved in conducting structure effects evaluations are discussed. (U.S.)
A Comparison Between Measured and Predicted Hydrodynamic Damping for a Jack-Up Rig Model
DEFF Research Database (Denmark)
Laursen, Thomas; Rohbock, Lars; Jensen, Jørgen Juncher
1996-01-01
An extensive set of measurements funded by the EU project Large Scale Facilities Program has been carried out on a model of a jack-up rig at the Danish Hydraulic Institute. The test serieswere conducted by MSC and include determination of base shears and overturning moments in both regular...... methods.In the comparison between the model test results and the theoretical predictions, thehydro-dynamic damping proves to be the most important uncertain parameter. It is shown thata relative large hydrodynamic damping must be assumed in the theoretical calculations in orderto predict the measured...
A Markov game theoretic data fusion approach for cyber situational awareness
Shen, Dan; Chen, Genshe; Cruz, Jose B., Jr.; Haynes, Leonard; Kruger, Martin; Blasch, Erik
2007-04-01
This paper proposes an innovative data-fusion/ data-mining game theoretic situation awareness and impact assessment approach for cyber network defense. Alerts generated by Intrusion Detection Sensors (IDSs) or Intrusion Prevention Sensors (IPSs) are fed into the data refinement (Level 0) and object assessment (L1) data fusion components. High-level situation/threat assessment (L2/L3) data fusion based on Markov game model and Hierarchical Entity Aggregation (HEA) are proposed to refine the primitive prediction generated by adaptive feature/pattern recognition and capture new unknown features. A Markov (Stochastic) game method is used to estimate the belief of each possible cyber attack pattern. Game theory captures the nature of cyber conflicts: determination of the attacking-force strategies is tightly coupled to determination of the defense-force strategies and vice versa. Also, Markov game theory deals with uncertainty and incompleteness of available information. A software tool is developed to demonstrate the performance of the high level information fusion for cyber network defense situation and a simulation example shows the enhanced understating of cyber-network defense.
International Nuclear Information System (INIS)
Jegou, Ch.; Gin, St.; Advocat, Th.; Vernaz, E.
1997-01-01
Work carried out since the early 1980's to predict the long-term behavior of nuclear containment glasses has revealed the inadequacy of existing models, notably in accounting for the fundamental mechanisms involved in some complex systems (e.g. glass-water-clay), inciting us to examine and discuss the theoretical basis for the hypotheses generally assumed in our models. This paper discusses the theoretical basis for the Aagaard-Helgeson law and its application to nuclear glasses. The contribution of other types of kinetic laws is also considered to describe the alteration kinetics of nuclear glasses. (authors)
International Nuclear Information System (INIS)
Yang Tianxing; Ye Xiang; Huang Lei; Xie Yiqun; Ke Sanhuang
2012-01-01
Highlights: ► We simulate the reversible vertical single-atom manipulations on several metal surfaces. ► We propose a method to predict whether a reversible vertical single-atom manipulation can be successful on several metal surfaces. ► A 3-dimensional Ni nanocluster is assembled on the Ni(1 1 1) surface using a Ni trimer-apex tip. - Abstract: We propose a theoretical model to show that pulling up an adatom from an atomic step requires a weaker force than from the flat surfaces of Al(0 0 1), Ni(1 1 1), Pt(1 1 0) and Au(1 1 0). Single adatom in the atomic step can be extracted vertically by a trimer-apex tip while can be released to the flat surface. This reversible vertical manipulation can then be used to fabricate a supported three-dimensional (3D) nanostructure on the Ni(1 1 1) surface. The present modeling can be used to predict whether the reversible vertical single-atom manipulation and thus the assembling of 3D nanostructures can be achieved on a metal surface.
Theoretical isochrones for old, super-metal-rich stars
International Nuclear Information System (INIS)
Vandenberg, D.A.; Laskarides, P.G.; National Capodistrian Univ., Athens, Greece)
1987-01-01
A new and up-to-date set of theoretical evolutionary sequences and isochrones for super-metal-rich stars is presented. Models have been constructed for metallicities as high as Z = 0.10 and masses in the range of mass/solar mass = 0.6-1.5, in order to calculate isochrones for ages from 6 to 18 Gyr. The latest Los Alamos opacities are utilized, which have a pronounced effect on predicted mass-luminosity relations, and a value of 1.5 is adopted for the mixing-length parameter, which is required to reproduce the properties of the sun. The detailed numerical results are expected to be particularly useful in the construction of population synthesis models. 48 references
The theoretical tensile strength of fcc crystals predicted from shear strength calculations
International Nuclear Information System (INIS)
Cerny, M; Pokluda, J
2009-01-01
This work presents a simple way of estimating uniaxial tensile strength on the basis of theoretical shear strength calculations, taking into account its dependence on a superimposed normal stress. The presented procedure enables us to avoid complicated and time-consuming analyses of elastic stability of crystals under tensile loading. The atomistic simulations of coupled shear and tensile deformations in cubic crystals are performed using first principles computational code based on pseudo-potentials and the plane wave basis set. Six fcc crystals are subjected to shear deformations in convenient slip systems and a special relaxation procedure controls the stress tensor. The obtained dependence of the ideal shear strength on the normal tensile stress seems to be almost linearly decreasing for all investigated crystals. Taking these results into account, the uniaxial tensile strength values in three crystallographic directions were evaluated by assuming a collapse of the weakest shear system. Calculated strengths for and loading were found to be mostly lower than previously calculated stresses related to tensile instability but rather close to those obtained by means of the shear instability analysis. On the other hand, the strengths for loading almost match the stresses related to tensile instability.
Predictions for mt and MW in minimal supersymmetric models
International Nuclear Information System (INIS)
Buchmueller, O.; Ellis, J.R.; Flaecher, H.; Isidori, G.
2009-12-01
Using a frequentist analysis of experimental constraints within two versions of the minimal supersymmetric extension of the Standard Model, we derive the predictions for the top quark mass, m t , and the W boson mass, m W . We find that the supersymmetric predictions for both m t and m W , obtained by incorporating all the relevant experimental information and state-of-the-art theoretical predictions, are highly compatible with the experimental values with small remaining uncertainties, yielding an improvement compared to the case of the Standard Model. (orig.)
McClure, Timothy E.; May, David C.
2008-01-01
To test and compare theoretical explanations of the use of corporal punishment in school, the authors examine how well county-level measures of culture, socioeconomic strain, and social capital predict the prevalence and incidence of corporal punishment in Kentucky schools. Although several variables are significantly correlated with corporal…
Ellis, Stephen R.; Adelstein, Bernard D.; Yeom, Kiwon
2013-01-01
The Misalignment Effect Function (MEF) describes the decrement in manual performance associated with a rotation between operators' visual display frame of reference and that of their manual control. It now has been empirically determined for rotation axes oblique to canonical body axes and is compared with the MEF previously measured for rotations about canonical axes. A targeting rule, called the Secant Rule, based on these earlier measurements is derived from a hypothetical process and shown to describe some of the data from three previous experiments. It explains the motion trajectories determined for rotations less than 65deg in purely kinematic terms without the need to appeal to a mental rotation process. Further analysis of this rule in three dimensions applied to oblique rotation axes leads to a somewhat surprising expectation that the difficulty posed by rotational misalignment should get harder as the required movement is shorter. This prediction is confirmed. Geometry underlying this rule also suggests analytic extensions for predicting more generally the difficulty of making movements in arbitrary directions subject to arbitrary misalignments.
Simen, Patrick; Contreras, David; Buck, Cara; Hu, Peter; Holmes, Philip; Cohen, Jonathan D
2009-12-01
The drift-diffusion model (DDM) implements an optimal decision procedure for stationary, 2-alternative forced-choice tasks. The height of a decision threshold applied to accumulating information on each trial determines a speed-accuracy tradeoff (SAT) for the DDM, thereby accounting for a ubiquitous feature of human performance in speeded response tasks. However, little is known about how participants settle on particular tradeoffs. One possibility is that they select SATs that maximize a subjective rate of reward earned for performance. For the DDM, there exist unique, reward-rate-maximizing values for its threshold and starting point parameters in free-response tasks that reward correct responses (R. Bogacz, E. Brown, J. Moehlis, P. Holmes, & J. D. Cohen, 2006). These optimal values vary as a function of response-stimulus interval, prior stimulus probability, and relative reward magnitude for correct responses. We tested the resulting quantitative predictions regarding response time, accuracy, and response bias under these task manipulations and found that grouped data conformed well to the predictions of an optimally parameterized DDM.
Muñoz-Silva, A; Sánchez-García, M; Nunes, C; Martins, A
2007-10-01
There is much evidence that demonstrates that programs and interventions based on the theoretical models of the Theory of Reasoned Action (TRA) and the Theory of Planned Behaviour (TPB) have been effective in the prevention of the sexual transmission of HIV. The objective of this work is to compare the effectiveness of both models in the prediction of condom use, distinguishing two components inside the variable Perceived Behavioural Control of the TPB model: self-efficacy and control. The perspective of gender differences is also added. The study was carried out in a sample of 601 Portuguese and Spanish university students. The results show that the females have a higher average in all the TPB variables than males, except in the frequency of condom use: females request the use of condoms less frequently than males. On the other hand, for both females and males the TPB model predicts better condom-use intention than the TRA. However there are no differences between the two models in relation to the prediction of condom-use behaviour. For prediction of intention, the most outstanding variable among females is attitude, while among males they are subjective norm and self-efficacy. Finally, we analyze the implications of these data from a theoretical and practical point of view.
A hybrid model to predict the onset of gas entrainment with surface tension effects
International Nuclear Information System (INIS)
Saleh, W.; Bowden, R.C.; Hassan, I.G.; Kadem, L.
2008-01-01
The onset of gas entrainment, in a single downward oriented discharge from a stratified gas-liquid region with was modeled. The assumptions made in the development of the model reduced the problem to that of a potential flow. The discharge was modeled as a point-sink. Through use of the Kelvin-Laplace equation the model included the effects of surface tension. The resulting model required further knowledge of the flow field, specifically the dip radius of curvature prior to the onset of gas entrainment. The dip shape and size was investigated experimentally and correlations were provided to characterize the dip in terms of the discharge Froude number. The experimental correlation was used in conjunction with the theoretical model to predict the critical height. The results showed that by including surface tension effects the predicted critical height showed excellent agreement with experimental data. Surface tension reduces the critical height through the Bond number
Directory of Open Access Journals (Sweden)
Mohsen Oftadeh
2014-02-01
Full Text Available Nowadays, the bidentate ligands 3-hydroxypyridin-4-ones (HPOs as orally active iron chelating agents have been demonstrated to possess potentials for the treatment of some of the human diseases such as iron-overload in thalassaemia patients and malaria. In this research, a series of HPOs with different substitutes and positions were theoretically investigated in order to extract and predict their partition coefficient values (LogP which were experimentally determined in an aqueous/octanol system. The effective electronic parameters on logP were also investigated. The results show that the type of method, basis set, and the solvent do not basically affect on the logP values. But some parameters such as hydrophobicity, polarizability, and orbital electronic charge density (HOMO and LUMO are effective on logP values.
Adding propensity scores to pure prediction models fails to improve predictive performance
Directory of Open Access Journals (Sweden)
Amy S. Nowacki
2013-08-01
Full Text Available Background. Propensity score usage seems to be growing in popularity leading researchers to question the possible role of propensity scores in prediction modeling, despite the lack of a theoretical rationale. It is suspected that such requests are due to the lack of differentiation regarding the goals of predictive modeling versus causal inference modeling. Therefore, the purpose of this study is to formally examine the effect of propensity scores on predictive performance. Our hypothesis is that a multivariable regression model that adjusts for all covariates will perform as well as or better than those models utilizing propensity scores with respect to model discrimination and calibration.Methods. The most commonly encountered statistical scenarios for medical prediction (logistic and proportional hazards regression were used to investigate this research question. Random cross-validation was performed 500 times to correct for optimism. The multivariable regression models adjusting for all covariates were compared with models that included adjustment for or weighting with the propensity scores. The methods were compared based on three predictive performance measures: (1 concordance indices; (2 Brier scores; and (3 calibration curves.Results. Multivariable models adjusting for all covariates had the highest average concordance index, the lowest average Brier score, and the best calibration. Propensity score adjustment and inverse probability weighting models without adjustment for all covariates performed worse than full models and failed to improve predictive performance with full covariate adjustment.Conclusion. Propensity score techniques did not improve prediction performance measures beyond multivariable adjustment. Propensity scores are not recommended if the analytical goal is pure prediction modeling.
Singular vectors, predictability and ensemble forecasting for weather and climate
International Nuclear Information System (INIS)
Palmer, T N; Zanna, Laure
2013-01-01
The local instabilities of a nonlinear dynamical system can be characterized by the leading singular vectors of its linearized operator. The leading singular vectors are perturbations with the greatest linear growth and are therefore key in assessing the system’s predictability. In this paper, the analysis of singular vectors for the predictability of weather and climate and ensemble forecasting is discussed. An overview of the role of singular vectors in informing about the error growth rate in numerical models of the atmosphere is given. This is followed by their use in the initialization of ensemble weather forecasts. Singular vectors for the ocean and coupled ocean–atmosphere system in order to understand the predictability of climate phenomena such as ENSO and meridional overturning circulation are reviewed and their potential use to initialize seasonal and decadal forecasts is considered. As stochastic parameterizations are being implemented, some speculations are made about the future of singular vectors for the predictability of weather and climate for theoretical applications and at the operational level. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Lyapunov analysis: from dynamical systems theory to applications’. (review)
NOx PREDICTION FOR FBC BOILERS USING EMPIRICAL MODELS
Directory of Open Access Journals (Sweden)
Jiří Štefanica
2014-02-01
Full Text Available Reliable prediction of NOx emissions can provide useful information for boiler design and fuel selection. Recently used kinetic prediction models for FBC boilers are overly complex and require large computing capacity. Even so, there are many uncertainties in the case of FBC boilers. An empirical modeling approach for NOx prediction has been used exclusively for PCC boilers. No reference is available for modifying this method for FBC conditions. This paper presents possible advantages of empirical modeling based prediction of NOx emissions for FBC boilers, together with a discussion of its limitations. Empirical models are reviewed, and are applied to operation data from FBC boilers used for combusting Czech lignite coal or coal-biomass mixtures. Modifications to the model are proposed in accordance with theoretical knowledge and prediction accuracy.
THE DEVELOPMENT AND USE OF A MODEL TO PREDICT SUSTAINABILITY OF CHANGE IN HEALTH CARE SETTINGS.
Molfenter, Todd; Ford, James H; Bhattacharya, Abhik
2011-01-01
Innovations adopted through organizational change initiatives are often not sustained leading to diminished quality, productivity, and consumer satisfaction. Research explaining variance in the use of adopted innovations in health care settings is sparse, suggesting the need for a theoretical model to guide research and practice. In this article, we describe the development of a hybrid conjoint decision theoretic model designed to predict the sustainability of organizational change in health care settings. An initial test of the model's predictive validity using expert scored hypothetic profiles resulted in an r-squared value of .77. The test of this model offers a theoretical base for future research on the sustainability of change in health care settings.
Ab-initio theoretical predictions of structure properties of semiconductors
International Nuclear Information System (INIS)
Rodriguez, C.O.; Peltzer y Blanca, E.L.; Cappannini, O.M.
1983-01-01
In this paper, calculations of the total energies and related structural properties of Si, GaP and C are presented showing good agreement with experimental values. The total energy is calculated within the local-density functional formalism using first principles non-local pseudopotentials. (A.C.A.S.) [pt
Theoretical study on loss of coolant accident of a research reactor
International Nuclear Information System (INIS)
Lee, Kwon-Yeong; Kim, Wan-Soo
2016-01-01
Highlights: • A theoretical model of siphon breaking phenomena was developed. • A general formula using Chisholm coefficient B was proposed. • The safety requirements regarding a loss of coolant accident of research reactors could be found out. - Abstract: Under the design conditions of a research reactor, the siphon phenomenon induced by pipe rupture can cause continuous efflux of water. In order to prevent water efflux, an additional facility is necessary. A siphon breaker is a type of safety facility that can resist the loss of coolant effectively. However, analysis of siphon breaking is complex since it comprises two-phase flow and there are many inputs to be considered. For this reason, we analyzed the experimental results to develop a theoretical model of siphon breaking phenomena. Developed model is based on fluid mechanics and Chisholm model. From Bernoulli’s equation, the velocity and quantity as well as undershooting height, water level, pressure, friction coefficient, and factors related to the two-phase flow could be calculated. The Chisholm model, which is able to analyze the two-phase flow, can predict the results in a manner similar to those obtained from a real-scale experiment, and a general formula using Chisholm coefficient B was proposed in this study. Also, we verified the theoretical model and concluded that it is possible to analyze the siphon breaking. Moreover, the design conditions that can satisfy the safety requirements regarding a loss of coolant accident of research reactors could be found out by using the theoretical model. In conclusion, we propose the theoretical model which can analyze the siphon breaking as real, and it is helpful not only to analyze but also to design the siphon breaker.
A predictive model for e-commerce consumer expenditure in EC countries
Kovačić, Zlatko
2004-01-01
Describing and predicting consumer expenditure on a country or cross-national level has a long tradition in theoretical and applied economics and econometrics. This paper is a first attempt in describing aggregate eCommerce consumer expenditure among European Commission (EC) countries. After brief introduction of possible theoretical models which explain the variation in eCommerce consumer expenditure among observed countries, a list of important predictors has been discussed. The results gen...
Malak, Malak Fouad; Hamed, Awatef; Tabakoff, Widen
1990-01-01
A two-color LDV system was used in the measurement of three orthogonal velocity components at 758 points located throughout the scroll and the unvaned portion of the nozzle of a radial inflow turbine scroll. The cold flow experimental results are presented for the velocity field at the scroll tongue. In addition, a total pressure loss of 3.5 percent for the scroll is revealed from the velocity measurements combined with the static pressure readings. Moreover, the measurement of the three normal stresses of the turbulence has showed that the flow is anisotropic. Furthermore, the mean velocity components are compared with a numerical solution of the potential flow field using the finite element technique. The theoretical prediction of the exit flow angle variation agrees well with the experimental results. This variation leads to a higher scroll pattern factor which can be avoided by controlling the scroll cross sectional area distribution.
Computational predictions of zinc oxide hollow structures
Tuoc, Vu Ngoc; Huan, Tran Doan; Thao, Nguyen Thi
2018-03-01
Nanoporous materials are emerging as potential candidates for a wide range of technological applications in environment, electronic, and optoelectronics, to name just a few. Within this active research area, experimental works are predominant while theoretical/computational prediction and study of these materials face some intrinsic challenges, one of them is how to predict porous structures. We propose a computationally and technically feasible approach for predicting zinc oxide structures with hollows at the nano scale. The designed zinc oxide hollow structures are studied with computations using the density functional tight binding and conventional density functional theory methods, revealing a variety of promising mechanical and electronic properties, which can potentially find future realistic applications.
Marrella, Alessandra; Aiello, Maurizio; Quarto, Rodolfo; Scaglione, Silvia
2016-10-01
Porous multiphase scaffolds have been proposed in different tissue engineering applications because of their potential to artificially recreate the heterogeneous structure of hierarchically complex tissues. Recently, graded scaffolds have been also realized, offering a continuum at the interface among different phases for an enhanced structural stability of the scaffold. However, their internal architecture is often obtained empirically and the architectural parameters rarely predetermined. The aim of this work is to offer a theoretical model as tool for the design and fabrication of functional and structural complex graded scaffolds with predicted morphological and chemical features, to overcome the time-consuming trial and error experimental method. This developed mathematical model uses laws of motions, Stokes equations, and viscosity laws to describe the dependence between centrifugation speed and fiber/particles sedimentation velocity over time, which finally affects the fiber packing, and thus the total porosity of the 3D scaffolds. The efficacy of the theoretical model was tested by realizing engineered graded grafts for osteochondral tissue engineering applications. The procedure, based on combined centrifugation and freeze-drying technique, was applied on both polycaprolactone (PCL) and collagen-type-I (COL) to test the versatility of the entire process. A functional gradient was combined to the morphological one by adding hydroxyapatite (HA) powders, to mimic the bone mineral phase. Results show that 3D bioactive morphologically and chemically graded grafts can be properly designed and realized in agreement with the theoretical model. Biotechnol. Bioeng. 2016;113: 2286-2297. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
Energy Technology Data Exchange (ETDEWEB)
Yanagisawa, Susumu, E-mail: shou@sci.u-ryukyu.ac.jp [Department of Physics and Earth Sciences, Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213 (Japan); Okuma, Koji; Inaoka, Takeshi [Department of Physics and Earth Sciences, Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213 (Japan); Hamada, Ikutaro, E-mail: Hamada.Ikutaro@nims.go.jp [International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Tsukuba 305-0044 (Japan)
2015-10-01
Highlights: • Review of theoretical studies on organic solids with the density-functional methods. • van der Waals (vdW)-inclusive methods to predict cohesive properties of oligoacenes. • A variant of the vdW density functional describes the structures accurately. • The molecular configuration and conformation crucially affects the band dispersion. - Abstract: We review recent studies on electronic properties of the organic solids with the first-principles electronic structure methods, with the emphasis on the roles of the intermolecular van der Waals (vdW) interaction in electronic properties of the organic semiconductors. After a brief summary of the recent vdW inclusive first-principle theoretical methods, we discuss their performance in predicting cohesive properties of oligoacene crystals as examples of organic crystals. We show that a variant of the van der Waals density functional describes structure and energetics of organic crystals accurately. In addition, we review our recent study on the zinc phthalocyanine crystal and discuss the importance of the intermolecular distance and orientational angle in the band dispersion. Finally, we draw some general conclusions and the future perspectives.
International Nuclear Information System (INIS)
Yanagisawa, Susumu; Okuma, Koji; Inaoka, Takeshi; Hamada, Ikutaro
2015-01-01
Highlights: • Review of theoretical studies on organic solids with the density-functional methods. • van der Waals (vdW)-inclusive methods to predict cohesive properties of oligoacenes. • A variant of the vdW density functional describes the structures accurately. • The molecular configuration and conformation crucially affects the band dispersion. - Abstract: We review recent studies on electronic properties of the organic solids with the first-principles electronic structure methods, with the emphasis on the roles of the intermolecular van der Waals (vdW) interaction in electronic properties of the organic semiconductors. After a brief summary of the recent vdW inclusive first-principle theoretical methods, we discuss their performance in predicting cohesive properties of oligoacene crystals as examples of organic crystals. We show that a variant of the van der Waals density functional describes structure and energetics of organic crystals accurately. In addition, we review our recent study on the zinc phthalocyanine crystal and discuss the importance of the intermolecular distance and orientational angle in the band dispersion. Finally, we draw some general conclusions and the future perspectives.
Theoretical Aeroacoustics: Compiled Mathematical Derivations of Fereidoun 'Feri' Farassat
Miller, Steven A. E.
2016-01-01
Dr. Fereidoun 'Feri' Farassat was a theoretical aero-acoustician at the National Aeronautics and Space Administration (NASA) Langley Research Center. This book contains technical derivations, notes, and classes that Dr. Farassat produced during his professional career. The layout of the book has been carefully crafted so that foundational ideas through advanced theories, which altered the technical discipline of aeroacoustics, build upon one another. The book can be used to understand the theories of acoustics and learn one contemporary aeroacoustic prediction approach made popular by Dr. Farassat. Most importantly, this book gives the general reader insight into how one of NASA's best aeroacoustics theoreticians thought, constructed, and solved problems throughout his career.
Vallo, Claudia I
2002-01-01
The present work is concerned with applications of a kinetic model for free-radical polymerization of a polymethylmethacrylate-based bone cement. Autocatalytic behavior at the first part of the reaction as well as a diffusion control phenomenon near vitrification are described by the model. Comparison of theoretical computations with experimental measurements for the temperature evolution during batch casting demonstrated the capacity of the proposed model to represent the kinetic behavior of the polymerization reaction. Temperature evolution and monomer conversion were simulated for the cure of the cement in molds made of different materials. The maximum monomer conversion fraction was markedly influenced by the physical properties of the mold material. The unreacted monomer acts as a plasticizer that influences the mechanical behavior of the cement. Hence, the same cement formulation cured in molds of different materials may result in different mechanical response because of the differences in the amounts of residual monomer. Standardization of the mold type to prepare specimens for the mechanical characterization of bone cements is recommended. Theoretical prediction of temperature evolution during hip replacement indicated that for cement thickness lower than 6 mm the peak temperature at the bone-cement interface was below the limit stated for thermal injury (50 degrees C for more than 1 min). The use of thin cement layers is recommended to diminish the risk of thermal injury; however, it is accompanied by an increase in the amount of unreacted monomer present in the cured material. Copyright 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 627-642, 2002