Dual absorptive model and np elastic scattering at high energies
Energy Technology Data Exchange (ETDEWEB)
Saleem, M.; Fazal-e-Aleem
1980-06-01
The most recent measurements of the angular distribution and total cross-sections in np elastic scattering at high energies from 70 to 400 GeV/c have been fitted by using the dual absorptive model. Comparison has also been made with the Kane-Siedl model and the simple Regge pole model.
A two-dimensional mathematical model of non-linear dual-sorption of percutaneous drug absorption
Directory of Open Access Journals (Sweden)
George K
2005-07-01
Full Text Available Abstract Background Certain drugs, for example scopolamine and timolol, show non-linear kinetic behavior during permeation process. This non-linear kinetic behavior is due to two mechanisms; the first mechanism being a simple dissolution producing mobile and freely diffusible molecules and the second being an adsorption process producing non-mobile molecules that do not participate in the diffusion process. When such a drug is applied on the skin surface, the concentration of the drug accumulated in the skin and the amount of the drug eliminated into the blood vessel depend on the value of a parameter, C, the donor concentration. The present paper studies the effect of the parameter value, C, when the region of the contact of the skin with drug, is a line segment on the skin surface. To confirm that dual-sorption process gives an explanation to non-linear kinetic behavior, the characteristic features that are used in one-dimensional models are (1 prolongation of half-life if the plot of flux versus time are straight lines soon after the vehicle removal, (2 the decrease in half-life with increase in donor concentration. This paper introduces another feature as a characteristic to confirm that dual-sorption model gives an explanation to the non-linear kinetic behavior of the drug. This new feature is "the prolongation of half-life is not a necessary feature if the plots of drug flux versus time is a non-linear curve, soon after the vehicle removal". Methods From biological point of view, a drug absorption model is said to be nonlinear if the sorption isotherm is non-linear. When a model is non-linear the relationship between lag-time and donor concentration is non-linear and the lag time decreases with increase in donor concentration. A two-dimensional dual-sorption model is developed for percutaneous absorption of a drug, which shows non-linear kinetic behavior in the permeation process. This model may be used when the diffusion of the drug in
DEFF Research Database (Denmark)
Marklund, Matti; Strömberg, Eric A,; Lærke, Helle Nygaard;
2014-01-01
Alkylresorcinols have proven to be useful biomarkers of whole-grain wheat and rye intake in many nutritional studies. To improve their utility, more knowledge regarding the fate of alkylresorcinols and their metabolites after consumption is needed.Objective: The objective of this study was to dev......Alkylresorcinols have proven to be useful biomarkers of whole-grain wheat and rye intake in many nutritional studies. To improve their utility, more knowledge regarding the fate of alkylresorcinols and their metabolites after consumption is needed.Objective: The objective of this study...... a single dose (120 g) of rye bran and validated against fasting plasma concentrations from 8 women and 7 men with controlled rye bran intake (23, 45, or 90 g/d). Alkylresorcinols in the lymph and plasma of a pig fed a single alkylresorcinol dose (1.3 mmol) were quantified to assess absorption. Human......% of the alkylresorcinol dose was recovered in the lymph. DHPPA was identified in both human ileostomal effluent and pig bile, indicating availability of DHPPA for absorption and enterohepatic circulation.Conclusion: Intact alkylresorcinols have advantages over DHBA and DHPPA as plasma biomarkers for whole-grain wheat...
Taniguchi, Tadahiro; Sawaragi, Tetsuo
In this paper, a new machine-learning method, called Dual-Schemata model, is presented. Dual-Schemata model is a kind of self-organizational machine learning methods for an autonomous robot interacting with an unknown dynamical environment. This is based on Piaget's Schema model, that is a classical psychological model to explain memory and cognitive development of human beings. Our Dual-Schemata model is developed as a computational model of Piaget's Schema model, especially focusing on sensori-motor developing period. This developmental process is characterized by a couple of two mutually-interacting dynamics; one is a dynamics formed by assimilation and accommodation, and the other dynamics is formed by equilibration and differentiation. By these dynamics schema system enables an agent to act well in a real world. This schema's differentiation process corresponds to a symbol formation process occurring within an autonomous agent when it interacts with an unknown, dynamically changing environment. Experiment results obtained from an autonomous facial robot in which our model is embedded are presented; an autonomous facial robot becomes able to chase a ball moving in various ways without any rewards nor teaching signals from outside. Moreover, emergence of concepts on the target movements within a robot is shown and discussed in terms of fuzzy logics on set-subset inclusive relationships.
Absorption enhancement of a dual-band metamaterial absorber
Zhong, Min; Han, Gui Ming; Liu, Shui Jie; Xu, Bang Li; Wang, Jie; Huang, Hua Qing
2017-02-01
In this paper, we propose and fabricate a dual-band metamaterial absorber in 6-24 THz region. Electric field distribution reveal that the first absorption band is obtained from localized surface plasmon (LSP) modes which are excited both on inside and outside edges of each circular-patterned metal-dielectric stack, while the second absorption band is excited by LSP modes on outside edges of each stack. Measured results indicate that the absorption band width can be tuned by increasing the radius of circular-patterned layers or reducing the thickness of dielectric spacing layers. Moreover, the designed dual-band metamaterial absorber is independent on circular-patterned dielectric layer combinations.
Absorption in dielectric models
Churchill, R J
2015-01-01
We develop a classical microscopic model of a dielectric. The model features nonlinear interaction terms between polarizable dipoles and lattice vibrations. The lattice vibrations are found to act as a pseudo-reservoir, giving broadband absorption of electromagnetic radiation without the addition of damping terms in the dynamics. The effective permittivity is calculated using a perturbative iteration method and is found to have the form associated with real dielectrics. Spatial dispersion is naturally included in the model and we also calculate the wavevector dependence of the permittivity.
Gamma ray absorption of cylindrical fissile material with dual shields
Institute of Scientific and Technical Information of China (English)
WU Chen-Yan; TIAN Dong-Feng; CHENG Yi-Ying; HUANG Yong-Yi; LU Fu-Quan; YANG Fu-Jia
2005-01-01
This work analyzed the gamma ray attenuation effect from the self-absorption and shield attenuation perspectively. An exact mathematical equation was given for the geometric factor of the cylindrical fissile material with dual shields. In addition, several approximation approaches suitable for real situation were discussed, especially in the radial and axial directions of the cylinders, since the G-factors have simple forms. Then the space distribution patterns of the G-factor were analyzed based on numerical result and effective ways to solve the geometric information of the cylindrical fissile material, the radii and the heights, were deduced. This method was checked and verified by numerical calculation. Because of the efficiency of the method, it is ideal for application in real situations, such as nuclear safeguards, which demands speed of detection and accuracy of geometric analysis.
Zhao, Pengfei; Ni, Ran; Wang, Kexin; Hong, Xia; Ding, Yadan; Cong, Tie; Liu, Junping; Zhao, Huiying
2017-07-01
Silica nanorods were synthesized through a simple one-pot emulsion-droplet-based growth method, in which tetraethylorthosilicate (TEOS) was used as the silica source, ammonia as the catalyst, and polyvinylpyrrolidone (PVP) as the structure-directing agent and stabilizer. By controlling hydrolysis and condensation in the reaction process, we regulated the aspect ratios and the infrared (IR) absorption fingerprint signals (the transverse optical and the longitudinal optical phonon modes) of the silica nanorods. Based on this, a dual-mode immunoassay was performed for detecting model target analyte, human IgG. The shape code of the silica nanorods was used for simple, rapid qualitative, and sensitive semi-quantitative immunoassay by using a conventional optical microscope. The characteristic IR absorption fingerprint signals of the silica nanorods allowed for reliable quantitative immunoassay with good selectivity and high specificity. The detection limit and the linear range were found out to be 0.5 pM and 1 pM-10 nM, respectively. We expect that such dual-mode immunoassay could be applied for the detection of other analytes, such as protein, nucleic acids, bacteria, viruses, explosives, toxins, and so on. Graphical abstract A simple dual-mode immunoassay was performed using the shape code and infrared absorption fingerprint signals of silica nanorods as detection signals.
Improving the mid-infrared energy absorption efficiency by using a dual-band metamaterial absorber
Institute of Scientific and Technical Information of China (English)
Nan Zhang; Peiheng Zhoun; Shifeng Zou; Xiaolong Weng; Jianliang Xie; Longjiang Deng
2014-01-01
In this paper, a dual-band mid-infrared metamaterial absorber was proposed to improve the energy absorption efficiency. Up to 99%absorption was obtained at 9.03 and 11.83μm in the simulation, and each absorption band can be tuned by the dielectric spacing layer, i.e., the dielectric constant and its thickness. The dual-band absorption mechanism was analyzed, and the quite well absorption performance at large incident angles was also presented. The results of this study can be applied in the field of thermal absorbing and solar energy harvesting.
Dual beam light profile microscopy: a new technique for optical absorption depth profilometry.
Power, J F; Fu, S W
2004-02-01
Light profile microscopy (LPM) is a recently developed technique of optical inspection that is used to record micrometer-scale images of thin-film cross-sections on a direct basis. In single beam mode, LPM provides image contrast based on luminescence, elastic, and/or inelastic scatter. However, LPM may also be used to depth profile the optical absorption coefficient of a thin film based on a method of dual beam irradiation presented in this work. The method uses a pair of collimated laser beams to consecutively irradiate a film from two opposing directions along the depth axis. An average profile of the beam's light intensity variation through the material is recovered for each direction and used to compute a depth-dependent differential absorbance profile. This latter quantity is shown from theory to be related to the film's depth-dependent optical absorption coefficient through a simple linear model that may be inverted by standard methods of numerical linear algebra. The inverse problem is relatively well posed, showing good immunity to data errors. This profilometry method is experimentally applied to a set of well-characterized materials with known absorption properties over a scale of tens of micrometers, and the reconstructed absorption profiles were found to be highly consistent with the reference data.
Li, Zhong-Jun; Hou, Zhi-Ling; Song, Wei-Li; Liu, Xing-Da; Cao, Wen-Qiang; Shao, Xiao-Hong; Cao, Mao-Sheng
2016-05-01
Electromagnetic absorption materials have received increasing attention owing to their wide applications in aerospace, communication and the electronics industry, and multiferroic materials with both polarization and magnetic properties are considered promising ceramics for microwave absorption application. However, the insufficient absorption intensity coupled with the narrow effective absorption bandwidth has limited the development of high-performance multiferroic materials for practical microwave absorption. To address such issues, in the present work, we utilize interfacial engineering in BiFeO3 nanoparticles via Ca doping, with the purpose of tailoring the phase boundary. Upon Ca-substitution, the co-existence of both R3c and P4mm phases has been confirmed to massively enhance both dielectric and magnetic properties via manipulating the phase boundary and the destruction of the spiral spin structure. Unlike the commonly reported magnetic/dielectric hybrid microwave absorption composites, Bi0.95Ca0.05FeO3 has been found to deliver unusual continuous dual absorption peaks at a small thickness (1.56 mm), which has remarkably broadened the effective absorption bandwidth (8.7-12.1 GHz). The fundamental mechanisms based on the phase boundary engineering have been discussed, suggesting a novel platform for designing advanced multiferroic materials with wide applications.Electromagnetic absorption materials have received increasing attention owing to their wide applications in aerospace, communication and the electronics industry, and multiferroic materials with both polarization and magnetic properties are considered promising ceramics for microwave absorption application. However, the insufficient absorption intensity coupled with the narrow effective absorption bandwidth has limited the development of high-performance multiferroic materials for practical microwave absorption. To address such issues, in the present work, we utilize interfacial engineering in BiFeO3
Li, Zhong-Jun; Hou, Zhi-Ling; Song, Wei-Li; Liu, Xing-Da; Cao, Wen-Qiang; Shao, Xiao-Hong; Cao, Mao-Sheng
2016-05-21
Electromagnetic absorption materials have received increasing attention owing to their wide applications in aerospace, communication and the electronics industry, and multiferroic materials with both polarization and magnetic properties are considered promising ceramics for microwave absorption application. However, the insufficient absorption intensity coupled with the narrow effective absorption bandwidth has limited the development of high-performance multiferroic materials for practical microwave absorption. To address such issues, in the present work, we utilize interfacial engineering in BiFeO3 nanoparticles via Ca doping, with the purpose of tailoring the phase boundary. Upon Ca-substitution, the co-existence of both R3c and P4mm phases has been confirmed to massively enhance both dielectric and magnetic properties via manipulating the phase boundary and the destruction of the spiral spin structure. Unlike the commonly reported magnetic/dielectric hybrid microwave absorption composites, Bi0.95Ca0.05FeO3 has been found to deliver unusual continuous dual absorption peaks at a small thickness (1.56 mm), which has remarkably broadened the effective absorption bandwidth (8.7-12.1 GHz). The fundamental mechanisms based on the phase boundary engineering have been discussed, suggesting a novel platform for designing advanced multiferroic materials with wide applications.
DUAL RANDOM MODEL OF INCREASING ANNUITY
Institute of Scientific and Technical Information of China (English)
HeWenjiong; ZhangYi
2001-01-01
The dual random models about the life insurance and social pension insurance have received considerable attention in the recent articles on actuarial theory and applications. This paper discusses a general kind of increasing annuity based on its force of interest accumulationfunction as a general random process. The dual random model of the present value of the benefits of the increasing annuity has been set, and their moments have been calculated under certainconditions.
Dual-gated tunable absorption in graphene-based hyperbolic metamaterial
Directory of Open Access Journals (Sweden)
Renxia Ning
2015-06-01
Full Text Available The use of a dual-gated tunable absorber in graphene-based hyperbolic metamaterial (GHMM in the near-infrared frequency range was investigated. The horizontal and vertical parts for relative permittivity of GHMM, which consists of monolayer graphene and conventional dielectric, were tuned using the chemical potential. To obtain a large absorption, GHMM was placed on top of a stacked structure containing dielectric and graphene layers and a copper reflector was placed at the bottom. The dual-gated absorber had multiband absorption, which was tuned using the chemical potential of graphene and GHMM. This study focuses on the variation of the absorption with change in the chemical potential and dielectric thickness. The results show that multiband absorption could be attained when chemical potential and dielectric thickness was changed. Broadband absorption could be generated when the frequency ranged from 215 THz to 250 THz. This phenomenon may be valuable for a variety of important applications including optical communication technology and near-infrared stealth communication.
Dual-Band Perfect Absorption by Breaking the Symmetry of Metamaterial Structure
Hai, Le Dinh; Qui, Vu Dinh; Dinh, Tiep Hong; Hai, Pham; Giang, Trinh Thị; Cuong, Tran Manh; Tung, Bui Son; Lam, Vu Dinh
2017-02-01
Since the first proposal of Landy et al. (Phys Rev Lett 100:207402, 2008), the metamaterial perfect absorber (MPA) has rapidly become one of the most crucial research trends. Recently, dual-band, multi-band and broadband MPA have been highly desirable in electronic applications. In this paper, we demonstrate and evaluate a MPA structure which can generate dual-band absorption operating at the microwave frequency by breaking the symmetry of structure. There is an agreement between simulation and experimental results. The results can be explained by using the equivalent LC circuit and the electric field distribution of this structure. In addition, various structures with different symmetry configurations were studied to gain greater insight into the absorption.
Two-Photon Absorption Spectroscopy of Rubidium with a Dual-Comb Tequnique
Nishiyama, Akiko; Yoshida, Satoru; Hariki, Takuya; Nakajima, Yoshiaki; Minoshima, Kaoru
2017-06-01
Dual-comb spectroscopies have great potential for high-resolution molecular and atomic spectroscopies, thanks to the broadband comb spectrum consisting of dense narrow modes. In this study, we apply the dual-comb system to Doppler-free two-photon absorption spectroscopy. The outputs of two frequency combs excite several two-photon transitions of rubidium, and we obtained broadband Doppler-free spectra from dual-comb fluorescence signals. The fluorescence detection scheme circumvents the sensitivity limit which is effectively determined by the dynamic range of photodetectors in absorption-based dual-comb spectroscopies. Our system realized high-sensitive, Doppler-free high-resolution and broadband atomic spectroscopy. A part of observed spectra of 5S_{1/2} - 5D_{5/2} transition is shown in the figure. The hyperfine structures of the F" = 1 - F' = 3,2,1 transitions are fully-resolved and the spectral widths are approximately 5 MHz. The absolute frequency axis is precisely calibrated from comb mode frequencies which were stabilized to a GPS-disciplined clock. This work was supported by JST through the ERATO MINOSHIMA Intelligent Optical Synthesizer Project and Grant-in-Aid for JSPS Fellows (16J02345). A. Nishiyama, S. Yoshida, Y. Nakajima, H. Sasada, K. Nakagawa, A. Onae, K. and Minoshima, Opt. Express 24, 25894 (2016). A. Hipke, S. A. Meek, T. Ideguchi, T.W. Hänsch, and N. Picqué, Phys. Rev. A 90, 011805(R) (2014).
Integrable Deformations of T -Dual σ Models
Borsato, Riccardo; Wulff, Linus
2016-12-01
We present a method to deform (generically non-Abelian) T duals of two-dimensional σ models, which preserves classical integrability. The deformed models are identified by a linear operator ω on the dualized subalgebra, which satisfies the 2-cocycle condition. We prove that the so-called homogeneous Yang-Baxter deformations are equivalent, via a field redefinition, to our deformed models when ω is invertible. We explain the details for deformations of T duals of principal chiral models, and present the corresponding generalization to the case of supercoset models.
Tunable dual-band light trapping and absorption enhancement with graphene concentric ring arrays
Xiao, Shuyuan; Liu, Yuebo; Han, Xu; Yan, Xicheng
2016-01-01
Surface plasmon resonance (SPR) has been intensively studied and widely employed for light trapping and absorption enhancement. In the mid-infrared and terahertz (THz) regime, graphene supports the tunable SPR via manipulating its Fermi energy and enhances light-matter interaction at the selective wavelength. In this paper, a pair of graphene concentric rings has been proposed to introduce tunable dual-band light trapping with good angle polarization tolerance and enhance the absorption in the low light-absorbing efficiency materials nearby to more than one order. Moreover, the design principle here could be set as a template to achieve multi-band plasmonic absorption enhancement by introducing more graphene concentric rings into each unit cell. This work not only opens up new ways of employing graphene SPR, but also leads to practical applications in high-performance simultaneous multi-color photodetection with high efficiency and tunable spectral selectivity.
Gap Model for Dual Customer Values
Institute of Scientific and Technical Information of China (English)
HOU Lun; TANG Xiaowo
2008-01-01
The customer value, the key problem in customer relationship management (CRM), was studied to construct a gap model for dual customer values. A basic description of customer values is given, and then the gaps between products and services in different periods for the customers and companies are analyzed based on the product or service life-cycle. The main factors that influence the perceived customer value were analyzed to define the "recognized value gap" and a gap model for the dual customer values was constructed to supply companies with a tool to analyze existing customer value gaps and improve customer relationship management.
Absorption spectroscopy of EBT model GAFCHROMIC film.
Devic, Slobodan; Tomic, Nada; Pang, Zhiyu; Seuntjens, Jan; Podgorsak, Ervin B; Soares, Christopher G
2007-01-01
The introduction of radiochromic films has solved some of the problems associated with conventional 2D radiation detectors. Their high spatial resolution, low energy dependence, and near-tissue equivalence make them ideal for measurement of dose distributions in radiation fields with high dose gradients. Precise knowledge of the absorption spectra of these detectors can help to develop more suitable optical densitometers and potentially extend the use of these films to other areas such as the measurement of the radiation beam spectral information. The goal of this study is to present results of absorption spectra measurements for the new GAFCHROMIC film, EBT type, exposed to 6 MV photon beam in the dose range from 0 to 6 Gy. Spectroscopic analysis reveals that in addition to the two main absorption peaks, centered at around 583 and 635 nm, the absorption spectrum in the spectral range from 350 to 800 nm contains six more absorption bands. Comparison of the absorption spectra reveals that previous HD-810, MD-55, as well as HS GAFCHROMIC film models, have nearly the same sensitive layer base material, whereas the new EBT model, GAFCHROMIC film has a different composition of its sensitive layer. We have found that the two most prominent absorption bands in EBT model radiochromic film do not change their central wavelength position with change in a dose deposited to the film samples.
Dual-Retrieval Models and Neurocognitive Impairment
Brainerd, C. J.; Reyna, V. F.; Gomes, C. F. A.; Kenney, A. E.; Gross, C. J.; Taub, E. S.; Spreng, R. N.
2014-01-01
Advances in dual-retrieval models of recall make it possible to use clinical data to test theoretical hypotheses about mild cognitive impairment (MCI) and Alzheimer's dementia (AD), the most common forms of neurocognitive impairment. Hypotheses about the nature of the episodic memory declines in these diseases, about decline versus sparing of…
Dual-Retrieval Models and Neurocognitive Impairment
Brainerd, C. J.; Reyna, V. F.; Gomes, C. F. A.; Kenney, A. E.; Gross, C. J.; Taub, E. S.; Spreng, R. N.
2014-01-01
Advances in dual-retrieval models of recall make it possible to use clinical data to test theoretical hypotheses about mild cognitive impairment (MCI) and Alzheimer's dementia (AD), the most common forms of neurocognitive impairment. Hypotheses about the nature of the episodic memory declines in these diseases, about decline versus sparing of…
Distributed Model Predictive Control via Dual Decomposition
DEFF Research Database (Denmark)
Biegel, Benjamin; Stoustrup, Jakob; Andersen, Palle
2014-01-01
This chapter presents dual decomposition as a means to coordinate a number of subsystems coupled by state and input constraints. Each subsystem is equipped with a local model predictive controller while a centralized entity manages the subsystems via prices associated with the coupling constraints...
Deformable surface modeling based on dual subdivision
Institute of Scientific and Technical Information of China (English)
WANG Huawei; SUN Hanqiu; QIN Kaihuai
2005-01-01
Based on dual Doo-Sabin subdivision and the corresponding parameterization, a modeling technique of deformable surfaces is presented in this paper. In the proposed model, all the dynamic parameters are computed in a unified way for both non-defective and defective subdivision matrices, and central differences are used to discretize the Lagrangian dynamics equation instead of backward differences. Moreover, a local scheme is developed to solve the dynamics equation approximately, thus the order of the linear equation is reduced greatly. Therefore, the proposed model is more efficient and faster than the existing dynamic models. It can be used for deformable surface design, interactive surface editing, medical imaging and simulation.
Institute of Scientific and Technical Information of China (English)
LI Zhi-biao; LI Dong-hui; WU Ying-xiang
2005-01-01
This paper discusses the principle and mathematical method to measure the phase fractions of multiphase flows by using a dual-energy gamma-ray system. The dual-energy gamma-ray device is composed of radioactive isotopes of 241Am and 137Cs with emission energies of 59.5 keV and 662 keV respectively. A rational method to calibrate the absorption coefficient was introduced in detail. The statistical error has been analyzed on the basis of the accurate absorption coefficient which enables determination phrase fractions almost independent of the flow regime. Improvement has been achieved on the measurement accuracy of phase fractions.
Dual-scale multimedia dynamic synchronization model
Institute of Scientific and Technical Information of China (English)
李乃祥
2009-01-01
Multimedia synchronization is the key technology in application of distributed multimedia.Solution of synchronization conflicts insides and among streams as well as that of user interaction,synchronization granularity refinement and synchronization precision improvement remain great challenges although great efforts have been invested by the academic circle.The construction method of a dual-scale dynamic synchronous model of multimedia presented in this article realizes multimedia synchronization on two sca...
Dual interface gratings design for absorption enhancement in thin crystalline silicon solar cells
Zhang, Jinqiannan; Yu, Zhongyuan; Liu, Yumin; Chai, Hongyu; Hao, Jing; Ye, Han
2017-09-01
We numerically study and analyze the light absorption enhancement in thin crystalline silicon solar cell with dual interface gratings. The structure combines the front dielectric nanowalls and the sinusoidal plasmonic grating at back reflector. We show that having specific interfaces with well-chosen period, fill factor and height can allow more efficient dielectric and plasmonic modes coupling into active layer and can improve the solar cell performance. For 1 μm active layer case, the optimal result for the proposed structure achieves short-circuit current of 23.6 mA/cm2, which performs over 50% better than flat solar cell structure, the short-circuit current of which is 15.5 mA/cm2. In addition, the active layer thickness and angular analysis show that the proposed structure maintains its advantage over flat structure.
A new model for quasar absorption clouds
Energy Technology Data Exchange (ETDEWEB)
Doroshkevich, A.G. (Academy of Sciences of USSR, Moscow (USSR). Inst. of Applied Mathematics); Muecket, J.P.; Mueller, V. (Academy of Sciences of GDR, Potsdam (German Democratic Republic). Central Inst. for Astrophysics)
1990-09-15
A local model for intervening absorption clouds in quasar spectra is discussed. At the boundary of cold clouds in the hot intergalactic gas a non-linear temperature profile results from electron heat conductivity and radiative energy losses both depending on ionization rates. This transition region causes the excitation of a wide range of ionization levels in the heavy elements of the gas. The predicted column densities along the line-of-sight are comparable with data from identified metal absorption systems at high redshifts. (author).
Bouwman, C.A.; Naber, T.H.J.; Breemen, van R.B.; Zhu, D.; Dicke, H.; Siebelink, E.; Hulshof, P.J.M.; Russel, F.G.M.; Schaafsma, G.; West, C.E.
2010-01-01
The objective was to quantify the vitamin A equivalency of ß-carotene in two diets using a dual-isotope dilution technique and the apparent ß-carotene absorption as measured by the oral–faecal balance technique. Seventeen healthy adults with an ileostomy completed the 4-week diet-controlled, cross-o
Loo-Bouwman, C.A. Van; Naber, T.H.; Breemen, R.B. van; Zhu, D.; Dicke, H.; Siebelink, E.; Hulshof, P.J.; Russel, F.G.M.; Schaafsma, G.; West, C.E.
2010-01-01
The objective was to quantify the vitamin A equivalency of beta-carotene in two diets using a dual-isotope dilution technique and the apparent beta-carotene absorption as measured by the oral-faecal balance technique. Seventeen healthy adults with an ileostomy completed the 4-week diet-controlled, c
Scale Factor Self-Dual Cosmological Models
dS, U Camara; Sotkov, G M
2015-01-01
We implement a conformal time scale factor duality for Friedmann-Robertson-Walker cosmological models, which is consistent with the weak energy condition. The requirement for self-duality determines the equations of state for a broad class of barotropic fluids. We study the example of a universe filled with two interacting fluids, presenting an accelerated and a decelerated period, with manifest UV/IR duality. The associated self-dual scalar field interaction turns out to coincide with the "radiation-like" modified Chaplygin gas models. We present an equivalent realization of them as gauged K\\"ahler sigma models (minimally coupled to gravity) with very specific and interrelated K\\"ahler- and super-potentials. Their applications in the description of hilltop inflation and also as quintessence models for the late universe are discussed.
The Gravity Dual of the Ising Model
Castro, Alejandra; Hartman, Thomas; Maloney, Alexander; Volpato, Roberto
2011-01-01
We evaluate the partition function of three dimensional theories of gravity in the quantum regime, where the AdS radius is Planck scale and the central charge is of order one. The contribution from the AdS vacuum sector can - with certain assumptions - be computed and equals the vacuum character of a minimal model CFT. The torus partition function is given by a sum over geometries which is finite and computable. For generic values of Newton's constant G and the AdS radius L the result has no Hilbert space interpretation, but in certain cases it agrees with the partition function of a known CFT. For example, the partition function of pure Einstein gravity with G=3L equals that of the Ising model, providing evidence that these theories are dual. We also present somewhat weaker evidence that the 3-state and tricritical Potts models are dual to pure higher spin theories of gravity based on SL(3) and E_6, respectively.
String-like dual models for scalar theories
Baadsgaard, Christian; Bjerrum-Bohr, N. E. J.; Bourjaily, Jacob; Damgaard, Poul H.
2016-12-01
We show that all tree-level amplitudes in φ p scalar field theory can be represented as the α ' → 0 limit of an SL(2, ℝ)-invariant, string-theory-like dual model integral. These dual models are constructed according to constraints that admit families of solutions. We derive these dual models, and give closed formulae for all tree-level amplitudes of any φ p scalar field theory.
String-Like Dual Models for Scalar Theories
Baadsgaard, Christian; Bourjaily, Jacob L; Damgaard, Poul H
2016-01-01
We show that all tree-level amplitudes in $\\varphi^p$ scalar field theory can be represented as the $\\alpha'\\to0$ limit of an $SL(2,R)$-invariant, string-theory-like dual model integral. These dual models are constructed according to constraints that admit families of solutions. We derive these dual models, and give closed formulae for all tree-level amplitudes of any $\\varphi^p$ scalar field theory.
Dual Enrollment in Spanish: One Working Model
Bloom, Melanie; Chambers, Laura
2009-01-01
Dual enrollment is now a nation-wide phenomenon as all 50 states currently offer some form of dual-enrollment program to secondary-school students (Karp, Bailey, Hughes, and Fermin 2005). However, dual enrollment itself is often difficult to define as programs vary from school to school (Jordan, Cavalluzzo, and Corallo 2006). Therefore, language…
Dual Enrollment in Spanish: One Working Model
Bloom, Melanie; Chambers, Laura
2009-01-01
Dual enrollment is now a nation-wide phenomenon as all 50 states currently offer some form of dual-enrollment program to secondary-school students (Karp, Bailey, Hughes, and Fermin 2005). However, dual enrollment itself is often difficult to define as programs vary from school to school (Jordan, Cavalluzzo, and Corallo 2006). Therefore, language…
Dual Numbers Approach in Multiaxis Machines Error Modeling
Directory of Open Access Journals (Sweden)
Jaroslav Hrdina
2014-01-01
Full Text Available Multiaxis machines error modeling is set in the context of modern differential geometry and linear algebra. We apply special classes of matrices over dual numbers and propose a generalization of such concept by means of general Weil algebras. We show that the classification of the geometric errors follows directly from the algebraic properties of the matrices over dual numbers and thus the calculus over the dual numbers is the proper tool for the methodology of multiaxis machines error modeling.
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
In this article, principle and mathematical method of determining the phase fractions of multiphase flows by using a dual-energy γ-ray system have been described. The dual-energy γ-ray device is composed of radioactive isotopes of 241Am and 137Cs with γ-ray energies of 59.5 and 662 keV, respectively. A rational method to calibrate the absorption coefficient was introduced in detail. The modified arithmetic is beneficial to removing the extra Compton scattering from the measured value. The result shows that the dual-energy γ-ray technique can be used in three-phase flow with average accuracy greater than 95%, which enables us to determine phase fractions almost independent of the flow regime. Improvement has been achieved on measurement accuracy of phase fractions.
On quantum equivalence of dual $\\sigma$ models $SL(3)$ examples
Horváth, Z; Palla, L
1996-01-01
The equivalence of several $SL(3)$ sigma models and their special Abelian duals is investigated in the two loop order of perturbation theory. The investigation is based on extracting and comparing various $\\beta$ functions of the original and dual models. The role of the discrete global symmetries is emphasized.
On quantum equivalence of dual sigma models: SL(3) examples
Energy Technology Data Exchange (ETDEWEB)
Horvath, Z. [Lorand Eoetvoes Univ., Budapest (Hungary). Inst. for Theoretical Physics; Karp, R.L. [Lorand Eoetvoes Univ., Budapest (Hungary). Inst. for Theoretical Physics; Palla, L. [Lorand Eoetvoes Univ., Budapest (Hungary). Inst. for Theoretical Physics
1997-04-14
The equivalence of several SL(3) sigma models and their special Abelian duals is investigated in two-loop order of perturbation theory. The investigation is based on extracting and comparing various {beta}-functions of the original and dual models. The role of discrete global symmetries is emphasized. (orig.).
Slow Steps Towards Dual Earner/ Dual Carer Family Model: Why Fathers do not Take Parental Leave
Karu, Marre; Kasearu, Kairi
2011-01-01
"The article looks at the transition of Estonian society towards dual earner/ dual carer family model and focuses on fathers' decision regarding taking their parental leave. Based on theory of planned behaviour by Ajzen, data from 20 qualitative interviews with fathers of small children are analysed to explore the beliefs fathers have when it comes to parental leave. The analysis distinguishes between two images of 'good parenting' that play a role in the fathers' intention to take parental l...
Miller, Leland V; Krebs, Nancy F; Hambidge, K Michael
2013-02-28
A previously described mathematical model of Zn absorption as a function of total daily dietary Zn and phytate was fitted to data from studies in which dietary Ca, Fe and protein were also measured. An analysis of regression residuals indicated statistically significant positive relationships between the residuals and Ca, Fe and protein, suggesting that the presence of any of these dietary components enhances Zn absorption. Based on the hypotheses that (1) Ca and Fe both promote Zn absorption by binding with phytate and thereby making it unavailable for binding Zn and (2) protein enhances the availability of Zn for transporter binding, the model was modified to incorporate these effects. The new model of Zn absorption as a function of dietary Zn, phytate, Ca, Fe and protein was then fitted to the data. The proportion of variation in absorbed Zn explained by the new model was 0·88, an increase from 0·82 with the original model. A reduced version of the model without Fe produced an equally good fit to the data and an improved value for the model selection criterion, demonstrating that when dietary Ca and protein are controlled for, there is no evidence that dietary Fe influences Zn absorption. Regression residuals and testing with additional data supported the validity of the new model. It was concluded that dietary Ca and protein modestly enhanced Zn absorption and Fe had no statistically discernable effect. Furthermore, the model provides a meaningful foundation for efforts to model nutrient interactions in mineral absorption.
Absorptive Capacity of Information Technology and Its Conceptual Model
Institute of Scientific and Technical Information of China (English)
BI Xinhua; YU Cuiling
2008-01-01
In order to examine the problem of how to improve the use of information technology (IT) in enterprises, this paper makes an exploration from the perspective of organizational absorptive capacity. We propose the concept of IT absorptive capacity from an organizational level. A dynamic process model is developed to further analyze IT absorption. IT absorptive capacity of this process is embodied as six forms: identification, adoption, adaptation, acceptance, infusion, and knowledge management. By means of questionnaire surveys of 76 Chinese enterprises, the main factors that favor or disable the capacity of each stage are discovered. Using the method of system dynamics, a conceptual model of IT absorptive capacity is developed to analyze the action mechanism of the factors in detail. The model indicates that the critical factors are embodied in the aspect of management. Furthermore, it demonstrates that IT absorption is a spiral process, during which IT absorptive capacity evolves dynamically and, consequently, promotes IT use.
Dual model of vocational education: Austrian example
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Tomić Milica
2015-01-01
Full Text Available Dual education, as a form of secondary vocational education means that education and practical training are held on two locations - in school and in a company (organization, factory and that these two institutions jointly participate in the realization of vocational education. The paper presents an account of the functioning of dual education in Austria. In that framework special attention was paid to law regulations in this field, the modes of dual education, progression through the system and the perspectives of the young in the labour market. Among the key features of dual education which are, at the same time, considered the factors of its successfulness, the following stand out: active role of social partners in the conceptualization and realization of vocational education; intensive practical training of high quality; systemic interrelatedness of vocational schools and firms where practical training is provided, the compliance of the offer of educational profiles and the needs of labour market; the system of stimulation for the firms that provide professional training for students, clear legislation and the system of professional qualifications. Yet, the challenges of dual educations are not neglected in the paper.
Absorption of acoustic waves by sunspots. II - Resonance absorption in axisymmetric fibril models
Rosenthal, C. S.
1992-01-01
Analytical calculations of acoustic waves scattered by sunspots which concentrate on the absorption at the magnetohydrodynamic Alfven resonance are extended to the case of a flux-tube embedded in a uniform atmosphere. The model is based on a flux-tubes of varying radius that are highly structured, translationally invariant, and axisymmetric. The absorbed fractional energy is determined for different flux-densities and subphotospheric locations with attention given to the effects of twist. When the flux is highly concentrated into annuli efficient absorption is possible even when the mean magnetic flux density is low. The model demonstrates low absorption at low azimuthal orders even in the presence of twist which generally increases the range of wave numbers over which efficient absorption can occur. Resonance absorption is concluded to be an efficient mechanism in monolithic sunspots, fibril sunspots, and plage fields.
Establishment of animal model of dual liver transplantation in rat.
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Ying Zhang
Full Text Available The animal model of the whole-size and reduced-size liver transplantation in both rat and mouse has been successfully established. Because of the difficulties and complexities in microsurgical technology, the animal model of dual liver transplantation was still not established for twelve years since the first human dual liver transplantation has been made a success. There is an essential need to establish this animal model to lay a basic foundation for clinical practice. To study the physiological and histopathological changes of dual liver transplantation, "Y" type vein from the cross part between vena cava and two iliac of donor and "Y' type prosthesis were employed to recanalize portal vein and the bile duct between dual liver grafts and recipient. The dual right upper lobes about 45-50% of the recipient liver volume were taken as donor, one was orthotopically implanted at its original position, the other was rotated 180° sagitally and heterotopically positioned in the left upper quadrant. Microcirculation parameters, liver function, immunohistochemistry and survival were analyzed to evaluate the function of dual liver grafts. No significant difference in the hepatic microcirculatory flow was found between two grafts in the first 90 minutes after reperfusion. Light and electronic microscope showed the liver architecture was maintained without obvious features of cellular destruction and the continuity of the endothelium was preserved. Only 3 heterotopically positioned graft appeared patchy desquamation of endothelial cell, mitochondrial swelling and hepatocytes cytoplasmic vacuolization. Immunohistochemistry revealed there is no difference in hepatocyte activity and the ability of endothelia to contract and relax after reperfusion between dual grafts. Dual grafts made a rapid amelioration of liver function after reperfusion. 7 rats survived more than 7 days with survival rate of 58.3.%. Using "Y" type vein and bile duct prosthesis, we
Pritchard, Stephen C; Coltheart, Max; Palethorpe, Sallyanne; Castles, Anne
2012-10-01
Two prominent dual-route computational models of reading aloud are the dual-route cascaded (DRC) model, and the connectionist dual-process plus (CDP+) model. While sharing similarly designed lexical routes, the two models differ greatly in their respective nonlexical route architecture, such that they often differ on nonword pronunciation. Neither model has been appropriately tested for nonword reading pronunciation accuracy to date. We argue that empirical data on the nonword reading pronunciation of people is the ideal benchmark for testing. Data were gathered from 45 Australian-English-speaking psychology undergraduates reading aloud 412 nonwords. To provide contrast between the models, the nonwords were chosen specifically because DRC and CDP+ disagree on their pronunciation. Both models failed to accurately match the experiment data, and both have deficiencies in nonword reading performance. However, the CDP+ model performed significantly worse than the DRC model. CDP++, the recent successor to CDP+, had improved performance over CDP+, but was also significantly worse than DRC. In addition to highlighting performance shortcomings in each model, the variety of nonword responses given by participants points to a need for models that can account for this variety.
On two-parameter models of photon cross sections: application to dual-energy CT imaging.
Williamson, Jeffrey F; Li, Sicong; Devic, Slobodan; Whiting, Bruce R; Lerma, Fritz A
2006-11-01
The goal of this study is to evaluate the theoretically achievable accuracy in estimating photon cross sections at low energies (20-1000 keV) from idealized dual-energy x-ray computed tomography (CT) images. Cross-section estimation from dual-energy measurements requires a model that can accurately represent photon cross sections of any biological material as a function of energy by specifying only two characteristic parameters of the underlying material, e.g., effective atomic number and density. This paper evaluates the accuracy of two commonly used two-parameter cross-section models for postprocessing idealized measurements derived from dual-energy CT images. The parametric fit model (PFM) accounts for electron-binding effects and photoelectric absorption by power functions in atomic number and energy and scattering by the Klein-Nishina cross section. The basis-vector model (BVM) assumes that attenuation coefficients of any biological substance can be approximated by a linear combination of mass attenuation coefficients of two dissimilar basis substances. Both PFM and BVM were fit to a modern cross-section library for a range of elements and mixtures representative of naturally occurring biological materials (Z = 2-20). The PFM model, in conjunction with the effective atomic number approximation, yields estimated the total linear cross-section estimates with mean absolute and maximum error ranges of 0.6%-2.2% and 1%-6%, respectively. The corresponding error ranges for BVM estimates were 0.02%-0.15% and 0.1%-0.5%. However, for photoelectric absorption frequency, the PFM absolute mean and maximum errors were 10.8%-22.4% and 29%-50%, compared with corresponding BVM errors of 0.4%-11.3% and 0.5%-17.0%, respectively. Both models were found to exhibit similar sensitivities to image-intensity measurement uncertainties. Of the two models, BVM is the most promising approach for realizing dual-energy CT cross-section measurement.
Integrable deformations of T-dual $\\sigma$ models
Borsato, Riccardo
2016-01-01
We present a method to deform (generically non-abelian) T duals of two-dimensional $\\sigma$ models, which preserves classical integrability. The deformed models are identified by a linear operator $\\omega$ on the dualised subalgebra, which satisfies the 2-cocycle condition. We prove that the so-called homogeneous Yang-Baxter deformations are equivalent, via a field redefinition, to our deformed models when $\\omega$ is invertible. We explain the details for deformations of T duals of Principal Chiral Models, and present the corresponding generalisation to the case of supercoset models.
Nonlinear dynamical model of an automotive dual mass flywheel
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Lei Chen
2015-06-01
Full Text Available The hysteresis, stick–slip, and rotational speed-dependent characteristics in a basic dual mass flywheel are obtained from a static and a dynamic experiments. Based on the experimental results, a nonlinear model of the transferred torque in this dual mass flywheel is developed, with the overlying form of nonlinear elastic torque and frictional torque. The nonlinearities of stiffness are investigated, deriving a nonlinear model to describe the rotational speed-dependent stiffness. In addition, Bouc–Wen model is used to model the hysteretic frictional torque. Thus, the nonlinear 2-degree-of-freedom system of this dual mass flywheel is set up. Then, the Levenberg–Marquardt method is adopted for the parameter estimation of the frictional torque. Finally, taking the nonlinear stiffness in this model into account, the parameters of Bouc–Wen model are estimated based on the dynamic test data.
Using Live Dual Modeling to Help Preservice Teachers Develop TPACK
Lu, Liangyue; Lei, Jing
2012-01-01
To help preservice teachers learn about teaching with technology--specifically, technological pedagogical content knowledge (TPACK)--the researchers designed and implemented a Live Dual Modeling strategy involving both live behavior modeling and cognitive modeling in this study. Using qualitative research methods, the researchers investigated…
An extended dual search space model of scientific discovery learning
Joolingen, van Wouter R.; Jong, de Ton
1997-01-01
This article describes a theory of scientific discovery learning which is an extension of Klahr and Dunbar''s model of Scientific Discovery as Dual Search (SDDS) model. We present a model capable of describing and understanding scientific discovery learning in complex domains in terms of the SDDS fr
Model systems for understanding absorption tuning by opsin proteins
DEFF Research Database (Denmark)
Nielsen, Mogens Brøndsted
2009-01-01
This tutorial review reports on model systems that have been synthesised and investigated for elucidating how opsin proteins tune the absorption of the protonated retinal Schiff base chromophore. In particular, the importance of the counteranion is highlighted. In addition, the review advocates...... is avoided, and it becomes clear that opsin proteins induce blueshifts in the chromophore absorption rather than redshifts....
An in silico skin absorption model for fragrance materials.
Shen, Jie; Kromidas, Lambros; Schultz, Terry; Bhatia, Sneha
2014-12-01
Fragrance materials are widely used in cosmetics and other consumer products. The Research Institute for Fragrance Materials (RIFM) evaluates the safety of these ingredients and skin absorption is an important parameter in refining systemic exposure. Currently, RIFM's safety assessment process assumes 100% skin absorption when experimental data are lacking. This 100% absorption default is not supportable and alternate default values were proposed. This study aims to develop and validate a practical skin absorption model (SAM) specific for fragrance material. It estimates skin absorption based on the methodology proposed by Kroes et al. SAM uses three default absorption values based on the maximum flux (J(max)) - namely, 10%, 40%, and 80%. J(max) may be calculated by using QSAR models that determine octanol/water partition coefficient (K(ow)), water solubility (S) and permeability coefficient (K(p)). Each of these QSAR models was refined and a semi-quantitative mechanistic model workflow is presented. SAM was validated with a large fragrance-focused data set containing 131 materials. All resulted in predicted values fitting the three-tiered absorption scenario based on Jmax ranges. This conservative SAM may be applied when fragrance material lack skin absorption data. Copyright © 2014 Elsevier Ltd. All rights reserved.
Modelling absorption and photoluminescence of TPD
Energy Technology Data Exchange (ETDEWEB)
Vragovic, Igor [Dpto. de Fisica Aplicada and Inst. Universitario de Materiales de Alicante, Universidad de Alicante, E-03080 Alicante (Spain)], E-mail: igor.vragovic@ua.es; Calzado, Eva M.; Diaz Garcia, Maria A.; Himcinschi, C. [Max-Planck-Institut fuer Mikrostrukturphysik, D-06120 Halle (Germany); Gisslen, L.; Scholz, R. [Walter Schottky Institut, Technische Universitaet Muenchen, D-85748 Garching (Germany)
2008-05-15
We analyse the optical spectra of N,N{sup '}-diphenyl-N,N{sup '}-bis(3-methyl-phenyl)-(1,1{sup '}-biphenyl)-4,4{sup '}-diamine (TPD) doped polystyrene films. The aim of the present paper is to give a microscopic interpretation of the significant Stokes shift between absorption and photoluminescence, which makes this material suitable for stimulated emission. The optimized geometric structures and energies of a neutral TPD monomer in ground and excited states are obtained by ab initio calculations using Hartree-Fock and density functional theory. The results indicate that the second distinct peak observed in absorption may arise either from a group of higher electronic transitions of the monomer or from the lowest optical transitions of a TPD dimer.
Proposing a model for absorption capacity of technology
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Hossein Gholizadeh
2015-01-01
Full Text Available Absorption capacity of knowledge is the concept which is been introduced in this situation. This phenomenon describes why some countries are in a better condition with a view to technology. Many countries believe that the power to stay in the battle and excel other competitors directly depends on their abilities in taking knowledge. Many countries have used their technological gap with developed countries as an accelerator for improving their absorption capacity. In this study, authors tried to produce a complete definition for absorption capacity through analyzing different research. Then with using expert opinions, a categorization for dimensions of absorption capacity will be prepared by using the structural equation modeling analysis, and finally a model for measuring absorption capacity is suggested. The results show effective dimensions in 5 different section. Studies depict that the most important one is keeping which could be a fundamental for long-term policies of 1404.
On the dual equivalence of the self-dual and topologically massive p-form models
Menezes, R; Ribeiro, R F; Wotzasek, C
2003-01-01
We study the duality symmetry in p-form models containing a generalized $B_q\\wedge F_{p+1}$ term in spacetime manifolds of arbitrary dimensions. The equivalence between the $B_q\\wedge F_{p+1}$ self-dual ($SD_{B\\wedge F}$) and the $B_q\\wedge F_{p+1}$ topologically massive ($TM_{B\\wedge F}$) models is established using a gauge embedding procedure, including the minimal coupling to conserved charged matter current. The minimal coupling adopted for both tensor fields in the self-dual representation is transformed into a non minimal magnetic like coupling in the topologically massive representation but with the currents swapped. It is known that to establish this equivalence a current-current interaction term is needed to render the matter sector unchanged. We show that both terms arise naturally from the embedding adopted. Comparison with Higgs/Julia-Toulouse duality is established.
Estimation of the Human Absorption Cross Section Via Reverberation Models
DEFF Research Database (Denmark)
Steinböck, Gerhard; Pedersen, Troels; Fleury, Bernard Henri;
2016-01-01
Since the presence of persons affects the reverberation time observed for in-room channels, the absorption cross section of a person can be estimated from measurements via Sabine's and Eyring's models for the reverberation time. We propose an estimator relying on the more accurate model by Eyring...... and compare the obtained results to those of Sabine's model. We find that the absorption by persons is large enough to be measured with a wideband channel sounder and that estimates of the human absorption cross section differ for the two models. The obtained values are comparable to values reported...... in the literature. We also suggest the use of controlled environments with low average absorption coefficients to obtain more reliable estimates. The obtained values can be used to predict the change of reverberation time with persons in the propagation environment. This allows prediction of channel characteristics...
Directory of Open Access Journals (Sweden)
Steven A. Abrams
2010-07-01
Full Text Available With the use of stable isotopes, this study aimed to compare the bioavailability of active absorbable algal calcium (AAACa, obtained from oyster shell powder heated to a high temperature, with an additional heated seaweed component (Heated Algal Ingredient, HAI, with that of calcium carbonate. In 10 postmenopausal women volunteers aged 59 to 77 years (mean ± S.D., 67 ± 5.3, the fractional calcium absorption of AAACa and CaCO3 was measured by a dual stable isotope method. 44Ca-enriched CaCO3 and AAACa were administered in all subjects one month apart. After a fixed-menu breakfast and pre-test urine collection (Urine 0, 42Ca-enriched CaCl2 was intravenously injected, followed by oral administration of 44Ca-enriched CaCO3 without carrier 15 minutes later, and complete urine collection for the next 24 hours (Urine 24. The fractional calcium absorption was calculated as the ratio of Augmentation of 44Ca from Urine 0 to Urine 24/ augmentation of 42Ca from Urine 0 to Urine 24. Differences and changes of 44Ca and 42Ca were corrected by comparing each with 43Ca. Fractional absorption of AAACa (mean ± S.D., 23.1 ± 6.4, was distinctly and significantly higher than that of CaCO3 (14.7 ± 6.4; p = 0.0060 by paired t-test. The mean fractional absorption was approximately 1.57-times higher for AAACa than for CaCO3. The serum 25(OH vitamin D level was low (mean ± S.D., 14.2 ± 4.95 ng/ml, as is common in this age group in Japan. Among the parameters of the bone and mineral metabolism measured, none displayed a significant correlation with the fractional absorption of CaCO3 and AAACa. Higher fractional absorption of AAACa compared with CaCO3 supports previous reports on the more beneficial effect of AAACa than CaCO3 for osteoporosis.
Analyzing radiation absorption difference of dental substance by using Dual CT
Yu, H.; Lee, H. K.; Cho, J. H.; Yang, H. J.; Ju, Y. S.
2015-07-01
The purpose of this study was to evaluate the changes of noise and computer tomography (CT) number in each dental substance, by using the metal artefact reduction algorithm; we used dual CT for this study. For the study, we produced resin, titanium, gypsum, and wax that are widely used by dentists. In addition, we made nickel to increase the artefact. While making the study materials, we made sure that there is no difficulty when inserting the substances inside phantom. In order to study, we scanned before and after using the metal artefact reduction algorithm. We conducted an average analysis of CT number and noise, before and after using the metal artefact reduction algorithm. As a result, there was no difference in CT number and noise before and after using the metal artefact reduction algorithm. However, when it comes to the noise value in each substance, wax's noise value was the lowest whereas titanium's noise value was the highest, after applying the metal artefact reduction algorithm. In nickel, CT number and noise value from artefact area showed a decreased noise value when applying the metal artefact reduction algorithm. In conclusion, we assumed that we could increase the effectiveness of CT examination by applying dual energy's metal artefact reduction algorithm.
International Family Migration and the Dual-Earner Model
DEFF Research Database (Denmark)
Munk, Martin D.; Nikolka, Till; Poutvaara, Panu
2017-01-01
Gender differences in labor force participation are exceptionally small in Nordic countries. We investigate how couples emigrating from Denmark self-select and sort into different destinations and whether couples pursue the dual-earner model, in which both partners work, when abroad. Female labor...
Duals for classical inventory models via generalized geometric programming
Carlton H. Scott; Thomas R. Jefferson; Soheila Jorjani
2004-01-01
Inventory problems generally have a structure that can be exploited for computational purposes. Here, we look at the duals of two seemingly unrelated inventory models that suggest an interesting duality between discrete time optimal control and optimization over an ordered sequence of variables. Concepts from conjugate duality and generalized geometric programming are used to establish the duality.
Dual equivalence in models with higher-order derivatives
Bazeia, D; Nascimento, J R S; Ribeiro, R F; Wotzasek, C
2003-01-01
We introduce a class of higher-order derivative models in (2,1) space-time dimensions. The models are described by a vector field, and contain a Proca-like mass term which prevents gauge invariance. We use the gauge embedding procedure to generate another class of higher-order derivative models, gauge-invariant and dual to the former class. We also show that the gauge embedding approach works appropriately when the vector field couples with fermionic matter.
Van Loo-Bouwman, Carolien A; Naber, Ton H J; van Breemen, Richard B; Zhu, Dongwei; Dicke, Heleen; Siebelink, Els; Hulshof, Paul J M; Russel, Frans G M; Schaafsma, Gertjan; West, Clive E
2010-06-01
The objective was to quantify the vitamin A equivalency of beta-carotene in two diets using a dual-isotope dilution technique and the apparent beta-carotene absorption as measured by the oral-faecal balance technique. Seventeen healthy adults with an ileostomy completed the 4-week diet-controlled, cross-over intervention study. Each subject followed both diets for 2 weeks: a diet containing vegetables low in beta-carotene content with supplemental beta-carotene in salad dressing oil ('oil diet'; mean beta-carotene intake 3.1 mg/d) and a diet containing vegetables and fruits high in beta-carotene content ('mixed diet'; mean beta-carotene intake 7.6 mg/d). Daily each subject consumed a mean of 190 microg [13C10]beta-carotene and 195 microg [13C10]retinyl palmitate in oil capsules. The vitamin A equivalency of beta-carotene was calculated as the dose-corrected ratio of [13C5]retinol to [13C10]retinol in serum. Apparent absorption of beta-carotene was determined with oral-faecal balance. Isotopic data quantified a vitamin A equivalency of [13C10]beta-carotene in oil of 3.6:1 (95 % CI 2.8, 4.6) regardless of dietary matrices differences. The apparent absorption of (labelled and dietary) beta-carotene from the 'oil diet' (30 %) was 1.9-fold higher than from the 'mixed diet' (16 %). This extrinsic labelling technique can measure precisely the vitamin A equivalency of beta-carotene in oil capsules, but it does not represent the effect of different dietary matrices.
Anacleto, M A; Nascimento, J R S; Ribeiro, R F; Wotzasek, C
2001-01-01
We study the equivalence between the self-dual and the Maxwell-Chern-Simons (MCS) models coupled to dynamical, U(1) charged matter, both fermionic and bosonic. This is done through an iterative procedure of gauge embedding that produces the dual mapping of the self-dual vector field theory into a Maxwell-Chern-Simons version. In both cases, to establish this equivalence a current-current interaction term is needed to render the matter sector unchanged. Moreover, the minimal coupling of the original self-dual model is replaced by a non-minimal magnetic like coupling in the MCS side. Unlike the fermionic instance however, in the bosonic example the dual mapping proposed here leads to a Maxwell-Chern-Simons theory immersed in a field dependent medium.
The space of signed points and the Self Dual Model
Leal, L C
2002-01-01
We study a generalization of the group of loops based on sets of signed points, instead of paths or loops. This geometrical setting incorporates the kinematical constraints of the Sigma Model, inasmuch as the the group of loops does with the Bianchi identities of Yang-Mills theories. We employ an Abelian version of this construction to quantize the Self-Dual Model, which allows us to relate this theory with that of a massless scalar field obeying non-trivial boundary conditions.
Water Transport Models of Moisture Absorption and Sweat Discharge Yarns
Institute of Scientific and Technical Information of China (English)
WANG Fa-ming; ZHOU Xiao-hong; WANG Shan-yuan
2008-01-01
An important property of moisture absorption and sweat discharge yams is their water transport property. In the paper, two water transport models of moisture absorption and sweat discharge yams were developed to investigate the influence factors on their wicking rate. In parallel Column Pores Model, wicking rate is determined by the equivalent capillary radius R and length of the capillary tube L. In Pellets Accumulation Model, wicking rate is decided by the capillary radius r and length of the fiber unit assemble L0.
Finiteness of PST self-dual models
Monteiro del Cima, O; Sarandy, M S; Cima, Oswaldo M. Del; Piguet, Olivier; Sarandy, Marcelo S.
2001-01-01
The Pasti-Sorokin-Tonin model for describing chiral forms is considered at the quantum level. We study the ultraviolet and infrared behaviour of the model in two, four and six dimensions in the framework of algebraic renormalization. The absence of anomalies, as well as the finiteness, up to non-physical renormalizations, are shown in all dimensions analyzed.
Moisture Absorption Model of Composites Considering Water Temperature Effect
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HUI Li
2016-11-01
Full Text Available The influence of water temperature on composite moisture absorption parameters was investigated in temperature-controlled water bath. Experiments of carbon fiber/bismaleimide resin composites immersed in water of 60℃, 70℃and 80℃ were developed respectively. According to the moisture content-time curves obtained from the experimental results, the diffusion coefficient and the balanced moisture content of the composites immersed in different water temperature could be calculated. What's more, the effect of water temperature on the diffusion coefficient and the balanced moisture content were discussed too. According to the Arrhenius equation and the law of Fick, a moisture absorption model was proposed to simulate the hygroscopic behaviour of the composite laminates immersed in different water temperature which can predict the absorption rate of water of the composites immersed in distilled water of 95℃ at any time precisely and can calculate how long it will take to reach the specific absorption rate.
A dual porosity model of nutrient uptake by root hairs
Zygalakis, K. C.
2011-08-09
Summary: • The importance of root hairs in the uptake of sparingly soluble nutrients is understood qualitatively, but not quantitatively, and this limits efforts to breed plants tolerant of nutrient-deficient soils. • Here, we develop a mathematical model of nutrient uptake by root hairs allowing for hair geometry and the details of nutrient transport through soil, including diffusion within and between soil particles. We give illustrative results for phosphate uptake. • Compared with conventional \\'single porosity\\' models, this \\'dual porosity\\' model predicts greater root uptake because more nutrient is available by slow release from within soil particles. Also the effect of soil moisture is less important with the dual porosity model because the effective volume available for diffusion in the soil is larger, and the predicted effects of hair length and density are different. • Consistent with experimental observations, with the dual porosity model, increases in hair length give greater increases in uptake than increases in hair density per unit main root length. The effect of hair density is less in dry soil because the minimum concentration in solution for net influx is reached more rapidly. The effect of hair length is much less sensitive to soil moisture. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.
Dual imputation model for incomplete longitudinal data
Jolani, S.; Frank, L.E.; Buuren, S. van
2014-01-01
Missing values are a practical issue in the analysis of longitudinal data. Multiple imputation (MI) is a well-known likelihood-based method that has optimal properties in terms of efficiency and consistency if the imputation model is correctly specified. Doubly robust (DR) weighing-based methods pro
Models to predict intestinal absorption of therapeutic peptides and proteins.
Antunes, Filipa; Andrade, Fernanda; Ferreira, Domingos; Nielsen, Hanne Morck; Sarmento, Bruno
2013-01-01
Prediction of human intestinal absorption is a major goal in the design, optimization, and selection of drugs intended for oral delivery, in particular proteins, which possess intrinsic poor transport across intestinal epithelium. There are various techniques currently employed to evaluate the extension of protein absorption in the different phases of drug discovery and development. Screening protocols to evaluate protein absorption include a range of preclinical methodologies like in silico, in vitro, in situ, ex vivo and in vivo. It is the careful and critical use of these techniques that can help to identify drug candidates, which most probably will be well absorbed from the human intestinal tract. It is well recognized that the human intestinal permeability cannot be accurately predicted based on a single preclinical method. However, the present social and scientific concerns about the animal well care as well as the pharmaceutical industries need for rapid, cheap and reliable models predicting bioavailability give reasons for using methods providing an appropriate correlation between results of in vivo and in vitro drug absorption. The aim of this review is to describe and compare in silico, in vitro, in situ, ex vivo and in vivo methods used to predict human intestinal absorption, giving a special attention to the intestinal absorption of therapeutic peptides and proteins.
Dual coupling effective band model for polarons
Marchand, Dominic J. J.; Stamp, Philip C. E.; Berciu, Mona
2017-01-01
Nondiagonal couplings to a bosonic bath completely change polaronic dynamics, from the usual diagonally coupled paradigm of smoothly varying properties. We study, using analytic and numerical methods, a model having both diagonal Holstein and nondiagonal Su-Schrieffer-Heeger (SSH) couplings. The critical coupling found previously in the pure SSH model, at which the k =0 effective mass diverges, now becomes a transition line in the coupling constant plane—the form of the line depends on the adiabaticity parameter. Detailed results are given for the quasiparticle and ground-state properties, over a wide range of couplings and adiabaticity ratios. The new paradigm involves a destabilization, at the transition line, of the simple Holstein polaron to one with a finite ground-state momentum, but with everywhere a continuously evolving band shape. No "self-trapping transition" exists in any of these models. The physics may be understood entirely in terms of competition between different hopping terms in a simple renormalized effective band theory. The possibility of further transitions is suggested by the results.
Mathematical Modeling of Dual Intake Transparent Transpired Solar Collector
Thomas Semenou; Rousse, Daniel R.; Brice Le Lostec; Hervé F. Nouanegue; Pierre-Luc Paradis
2015-01-01
Nowadays, in several types of commercial or institutional buildings, a significant rise of transpired solar collectors used to preheat the fresh air of the building can be observed. Nevertheless, when the air mass flow rate is low, the collector efficiency collapses and a large amount of energy remains unused. This paper presents a simple yet effective mathematical model of a transparent transpired solar collector (TTC) with dual intake in order to remove stagnation problems in the plenum and...
Functional mathematical model of dual pathway AV nodal conduction.
Climent, A M; Guillem, M S; Zhang, Y; Millet, J; Mazgalev, T N
2011-04-01
Dual atrioventricular (AV) nodal pathway physiology is described as two different wave fronts that propagate from the atria to the His bundle: one with a longer effective refractory period [fast pathway (FP)] and a second with a shorter effective refractory period [slow pathway (SP)]. By using His electrogram alternance, we have developed a mathematical model of AV conduction that incorporates dual AV nodal pathway physiology. Experiments were performed on five rabbit atrial-AV nodal preparations to develop and test the presented model. His electrogram alternances from the inferior margin of the His bundle were used to identify fast and slow wave front propagations. The ability to predict AV conduction time and the interaction between FP and SP wave fronts have been analyzed during regular and irregular atrial rhythms (e.g., atrial fibrillation). In addition, the role of dual AV nodal pathway wave fronts in the generation of Wenckebach periodicities has been illustrated. Finally, AV node ablative modifications have been evaluated. The model accurately reproduced interactions between FP and SP during regular and irregular atrial pacing protocols. In all experiments, specificity and sensitivity higher than 85% were obtained in the prediction of the pathway responsible for conduction. It has been shown that, during atrial fibrillation, the SP ablation significantly increased the mean HH interval (204 ± 39 vs. 274 ± 50 ms, P AV node mechanisms and should be considered as a step forward in the studies of AV nodal conduction.
Li, L; Zhang, J; Gao, C
2001-08-01
Catalyst samples are digested in a microwave digestion system. The optimum parameters for microwave digestion are selected. Cobalt and nickel in the mixture of Co2+ and Ni2+ with 4-(2-pyridylazo) resorcinol (PAR) can be determined simultaneously by dual-wavelength equal absorption spectrophotometry. By means of the combination of two methods, Co2+ and Ni2+ in catalyst can be determined rapidly, accurately, and contamination problems avoided. The linear ranges are 0-30 micrograms.25 mL-1 for Co2+ and 0-25 micrograms.25 mL-1 for Ni2+. The recoveries of Co2+ and Ni2+ in synthetic samples are between 98.2%-103.6% and between 97.9%-103.7%, respectively. The relative standard deviations of analytical results in catalyst samples are less than 2.2% for Co2+ and less than 1.8% for Ni2+, and relative errors are less than +/- 2.5% for Co2+ and Ni2+.
A dynamic model of digestion and absorption in pigs
DEFF Research Database (Denmark)
Strathe, Anders Bjerring; Danfær, Allan Christian; Chwalibog, Andrzej
2008-01-01
The paper describes and evaluates the construction of a mathematical model to study the kinetics of digestion and absorption in growing pigs. The core of the model is based on a compartmental structure, which divides the gastro-intestinal tract into four anatomical segments: the stomach, two part......, starch, sugars and dietary fibre. Besides a chemical description of the feed, the model further requires information about daily dry matter intake and feeding frequency....
Modelling and Analysis of Dual-Stator Induction Motors
Razik, Hubert; Rezzoug, Abderrezak; Hadiouche, Djafar
In this paper, the analysis and the modelling of a Dual-Stator Induction Motor (DSIM) are presented. In particular, the effects of the shift angle between its three-phase windings are studied. A complex steady state model is first established in order to analyse its harmonic behavior when it is supplied by a non-sinusoidal voltage source. Then, a new transformation matrix is proposed to develop a suitable dynamic model. In both cases, the study is made using an arbitrary shift angle. Simulation results of its PWM control are also presented and compared in order to confirm our theoretical observations.
Abdel Hafiz, Moustafa; Brazhnikov, Denis; Coget, Grégoire; Taichenachev, Alexei; Yudin, Valeriy; de Clercq, Emeric; Boudot, Rodolphe
2017-07-01
The saturated absorption technique is an elegant method widely used in atomic and molecular physics for high-resolution spectroscopy, laser frequency standards and metrology purposes. We have recently discovered that a saturated absorption scheme with a dual-frequency laser can lead to a significant sign reversal of the usual Doppler-free dip, yielding a deep enhanced-absorption spike. In this paper, we report detailed experimental investigations of this phenomenon, together with a full in-depth theoretical description. It is shown that several physical effects can support or oppose the formation of the high-contrast central spike in the absorption profile. The physical conditions for which all these effects act constructively and result in very bright Doppler-free resonances are revealed. Apart from their theoretical interest, results obtained in this manuscript are of great interest for laser spectroscopy and laser frequency stabilization purposes, with applications in laser cooling, matter-wave sensors, atomic clocks or quantum optics.
Velis, Costas A; Franco-Salinas, Claudia; O'Sullivan, Catherine; Najorka, Jens; Boccaccini, Aldo R; Cheeseman, Christopher R
2014-07-01
Mixed color waste glass extracted from municipal solid waste is either not recycled, in which case it is an environmental and financial liability, or it is used in relatively low value applications such as normal weight aggregate. Here, we report on converting it into a novel glass-ceramic lightweight aggregate (LWA), potentially suitable for high added value applications in structural concrete (upcycling). The artificial LWA particles were formed by rapidly sintering (waste glass powder with clay mixes using sodium silicate as binder and borate salt as flux. Composition and processing were optimized using response surface methodology (RSM) modeling, and specifically (i) a combined process-mixture dual RSM, and (ii) multiobjective optimization functions. The optimization considered raw materials and energy costs. Mineralogical and physical transformations occur during sintering and a cellular vesicular glass-ceramic composite microstructure is formed, with strong correlations existing between bloating/shrinkage during sintering, density and water adsorption/absorption. The diametrical expansion could be effectively modeled via the RSM and controlled to meet a wide range of specifications; here we optimized for LWA structural concrete. The optimally designed LWA is sintered in comparatively low temperatures (825-835 °C), thus potentially saving costs and lowering emissions; it had exceptionally low water adsorption/absorption (6.1-7.2% w/wd; optimization target: 1.5-7.5% w/wd); while remaining substantially lightweight (density: 1.24-1.28 g.cm(-3); target: 0.9-1.3 g.cm(-3)). This is a considerable advancement for designing effective environmentally friendly lightweight concrete constructions, and boosting resource efficiency of waste glass flows.
Daksha, M.; Derzsi, A.; Wilczek, S.; Trieschmann, J.; Mussenbrock, T.; Awakowicz, P.; Donkó, Z.; Schulze, J.
2017-08-01
In particle-in-cell/Monte Carlo collisions (PIC/MCC) simulations of capacitively coupled plasmas (CCPs), the plasma-surface interaction is generally described by a simple model in which a constant secondary electron emission coefficient (SEEC) is assumed for ions bombarding the electrodes. In most PIC/MCC studies of CCPs, this coefficient is set to γ = 0.1, independent of the energy of the incident particle, the electrode material, and the surface conditions. Here, the effects of implementing energy-dependent secondary electron yields for ions, fast neutrals, and taking surface conditions into account in PIC/MCC simulations is investigated. Simulations are performed using self-consistently calculated effective SEECs, {γ }* , for ‘clean’ (e.g., heavily sputtered) and ‘dirty’ (e.g., oxidized) metal surfaces in single- and dual-frequency discharges in argon and the results are compared to those obtained by assuming a constant secondary electron yield of γ =0.1 for ions. In single-frequency (13.56 MHz) discharges operated under conditions of low heavy particle energies at the electrodes, the pressure and voltage at which the transition between the α- and γ-mode electron power absorption occurs are found to strongly depend on the surface conditions. For ‘dirty’ surfaces, the discharge operates in α-mode for all conditions investigated due to a low effective SEEC. In classical dual-frequency (1.937 MHz + 27.12 MHz) discharges {γ }* significantly increases with increasing low-frequency voltage amplitude, {V}{LF}, for dirty surfaces. This is due to the effect of {V}{LF} on the heavy particle energies at the electrodes, which negatively influences the quality of the separate control of ion properties at the electrodes. The new results on the separate control of ion properties in such discharges indicate significant differences compared to previous results obtained with different constant values of γ.
An Empirical Investigation into a Subsidiary Absorptive Capacity Process Model
DEFF Research Database (Denmark)
Schleimer, Stephanie; Pedersen, Torben
2011-01-01
and empirically test a process model of absorptive capacity. The setting of our empirical study is 213 subsidiaries of multinational enterprises and the focus is on the capacity of these subsidiaries to successfully absorb best practices in marketing strategy from their headquarters. This setting allows us...
Dual Superconductivity in Abelian Higgs Model of QCD
Rajput, B. S.
2017-04-01
The study of generalized field associated with Abelian dyons has been undertaken and it has been demonstrated that topologically, a non-Abelian gauge theory is equivalent to a set of Abelian gauge theories supplemented by dyons which undergo condensation leading to confinement and consequently to superconducting model of QCD vacuum, where the Higgs field plays the role of a regulator only. Constructing the effective action for dyonic field in Abelian projection of QCD, it has been demonstrated that any charge (electrical or magnetic) of dyon screens its own direct potential to which it minimally couples and anti-screens the dual potential leading to dual superconductivity in accordance with generalized Meissner effect. In this Abelian projection of QCD an Abelian Higgs model (AHM) has been successfully constructed and it has been shown to incorporate dual superconductivity and confinement as the consequence of dyonic condensation. It has been demonstrated that in AHM t' Hooft loop creates the string (AHM-string) around which the monopole current under London limit leads to vanishing coherence length in the chromo-magnetic superconductor. It has also been shown that in London limit the squared density of monopole current around AHM-string has a maximum at the distance of the order of penetration length.
Theoretical modeling of the absorption spectrum of aqueous riboflavin
Zanetti-Polzi, Laura; Aschi, Massimiliano; Daidone, Isabella; Amadei, Andrea
2017-02-01
In this study we report the modeling of the absorption spectrum of riboflavin in water using a hybrid quantum/classical mechanical approach, the MD-PMM methodology. By means of MD-PMM calculations, with which the effect of riboflavin internal motions and of solvent interactions on the spectroscopic properties can be explicitly taken into account, we obtain an absorption spectrum in very good agreement with the experimental spectrum. In particular, the calculated peak maxima show a consistent improvement with respect to previous computational approaches. Moreover, the calculations show that the interaction with the environment may cause a relevant recombination of the gas-phase electronic states.
Slow Steps towards Dual Earner/Dual Carer Family Model: Why Do Fathers Not Take Parental Leave
Marre Karu; Kairi Kasearu
2011-01-01
The article looks at the transition of Estonian society towards dual earner/dual carer family model and focuses on fathers’ decision regarding taking their parental leave. Based on theory of planned behaviour by Ajzen, data from 20 qualitative interviews with fathers of small children are analysed to explore the beliefs fathers have when it comes to parental leave. The analysis distinguishes between two images of ‘good parenting’ that play a role in the fathers’ intention to take parental lea...
Exclusive J/Psi electroproduction in a dual model
Energy Technology Data Exchange (ETDEWEB)
R. Fiore, L.L. Jenkovszky, V.K. Magas, S. Melis, A. Prokudin
2009-12-01
Exclusive J/Psi electroproduction is studied in the framework of the analytic S-matrix theory. The differential and integrated elastic cross sections are calculated using the Modified Dual Amplitude with Mandelstam Analyticity (M-DAMA) model. The model is applied to the description of the available experimantal data and proves to be valid in a wide region of the kinematical variables s, t and Q^2. Our amplitude can be used also as a universal background parametrization for the extraction of tiny resonance signals.
Energy Technology Data Exchange (ETDEWEB)
Lottin, O.; Feidt, M.; Benelmir, R. [LEMTA-UHP Nancy-1, 54 - Vandoeuvre-les-Nancy (France)
1997-12-31
This paper is a series of transparencies presenting a comparative study of the thermal performances of different types of refrigerating machineries: di-thermal with vapor compression, tri-thermal with moto-compressor, with ejector, with free piston, adsorption-type, resorption-type, absorption-type, compression-absorption-type. A prototype of ammonia-water compression-absorption heat pump is presented and modeled. (J.S.)
Yáñez-Araque, Benito; Hernández-Perlines, Felipe; Moreno-Garcia, Juan
2017-01-01
The training of human resources improves business performance: myth or reality? While the literature has extensively addressed this issue, the transfer that occurs from training to performance still remains unresolved. The present study suggests an empirical solution to this gap, through a multiple mediation model of dynamic capabilities. Accordingly, the study makes a major contribution to the effectiveness of an organizational-level training: the "true" relationship between training and performance is mediated by absorptive and innovative capacities. It is difficult from training to directly affect the results: it must be done through a chain of intermediate variables. Training can be argued to be indirectly related to performance, through absorptive capacity in the first place, and innovative capacity in the second, sequentially in this order (three-path mediated effect). Of all immediate relationships received by performance, its explained variance is achieved partly via absorptive capacity and partly via innovation. The direct relationship through training is not significant and only explains a small percentage of the variance in performance. These results have been corroborated by combining two methods of analysis: PLS-SEM and fsQCA, using data from an online survey. This dual methodology in the study of the same phenomenon allows overcoming the limitations of each method, which would not have been possible with a single methodological approach, and confirming the findings obtained by any of them.
Computational Model of a Biomass Driven Absorption Refrigeration System
Directory of Open Access Journals (Sweden)
Munyeowaji Mbikan
2017-02-01
Full Text Available The impact of vapour compression refrigeration is the main push for scientists to find an alternative sustainable technology. Vapour absorption is an ideal technology which makes use of waste heat or renewable heat, such as biomass, to drive absorption chillers from medium to large applications. In this paper, the aim was to investigate the feasibility of a biomass driven aqua-ammonia absorption system. An estimation of the solid biomass fuel quantity required to provide heat for the operation of a vapour absorption refrigeration cycle (VARC is presented; the quantity of biomass required depends on the fuel density and the efficiency of the combustion and heat transfer systems. A single-stage aqua-ammonia refrigeration system analysis routine was developed to evaluate the system performance and ascertain the rate of energy transfer required to operate the system, and hence, the biomass quantity needed. In conclusion, this study demonstrated the results of the performance of a computational model of an aqua-ammonia system under a range of parameters. The model showed good agreement with published experimental data.
Ray tracing and ECRH absorption modeling in the HSX stellarator
Weir, G. M.; Likin, K. M.; Marushchenko, N. B.; Turkin, Y.
2015-09-01
To increase flexibility in ECRH experiments on the helically symmetric experiment (HSX), a second gyrotron and transmission line have been installed. The second antenna includes a steerable mirror for off-axis heating, and the launched power may be modulated for use in heat pulse propagation experiments. The extraordinary wave at the second harmonic of the electron gyrofrequency or the ordinary wave at the fundamental resonance are used for plasma start-up and heating on HSX. The tracing visualized ray tracing code (Marushchenko et al 2007 Plasma Fusion Res. 2 S1129) is used to estimate single-pass absorption and to model multi-pass wave damping in the three-dimensional HSX geometry. The single-pass absorption of the ordinary wave at the fundamental resonance is calculated to be as high as 30%, while measurements of the total absorption indicate that 45% of the launched power is absorbed. A multi-pass ray tracing model correctly predicts the experimental absorption and indicates that the launched power is absorbed within the plasma core (r/a≤slant 0.2 ).
[Dual neural circuit model of reading and writing].
Iwata, Makoto
2011-08-01
In the hypothetical neural circuit model of reading and writing that was initially proposed by Dejerine and subsequently confirmed by Geschwind, the left angular gyrus was considered as a unique center for processing letters. Japanese investigators, however, have repeatedly pointed out that this angular gyrus model cannot fully explain the disturbances observed in reading and writing Kanji letters in Japanese patients with various types of alexia with or without agraphia. In 1982, I proposed a dual neural circuit model of reading and writing Japanese on the basis of neuropsychological studies on the various types of alexia with or without agraphia without aphasia. This dual neural circuit model proposes that apart from the left angular gyrus which was thought to be a node for phonological processing of letters, the left posterior inferior temporal area, also acts as a node for semantic processing of letters. Further investigations using O15-PET activation on normal subjects revealed that the left middle occipital gyrus (area 19 of Brodmann) and the posterior portion of the left inferior temporal gyrus (area 37 of Brodmann) are the cortical areas responsible for reading Japanese letters; the former serving for phonological reading and the latter for semantic reading. This duality of the neural circuit in processing letters was later applied to explain disturbances in reading English, and was finally accepted as a valid model for other alphabetic letter systems too.
Holographic Model of Dual Superconductor for Quark Confinement
Huang, Tsung-Sheng
2016-01-01
We show that a hairy black hole solution can provide a holographically dual description of quark confinement. There exists a one-parameter sensible metric which receives the backreaction of matter contents in the holographic action, where the scalar and gauge field are responsible for the condensation of chromomagnetic monopoles. This model features a preconfining phase triggered by second-order monopole condensation and a first-order confinement/deconfinement phase transition. To confirm the confinement, the quark-antiquark potential is calculated by probing a QCD string in both phases. At last, contribution from Kaluza-Klein monopoles in the confining phase is discussed.
Parameterized reduced-order models using hyper-dual numbers.
Energy Technology Data Exchange (ETDEWEB)
Fike, Jeffrey A.; Brake, Matthew Robert
2013-10-01
The goal of most computational simulations is to accurately predict the behavior of a real, physical system. Accurate predictions often require very computationally expensive analyses and so reduced order models (ROMs) are commonly used. ROMs aim to reduce the computational cost of the simulations while still providing accurate results by including all of the salient physics of the real system in the ROM. However, real, physical systems often deviate from the idealized models used in simulations due to variations in manufacturing or other factors. One approach to this issue is to create a parameterized model in order to characterize the effect of perturbations from the nominal model on the behavior of the system. This report presents a methodology for developing parameterized ROMs, which is based on Craig-Bampton component mode synthesis and the use of hyper-dual numbers to calculate the derivatives necessary for the parameterization.
Mathematical Modeling of Dual Intake Transparent Transpired Solar Collector
Directory of Open Access Journals (Sweden)
Thomas Semenou
2015-01-01
Full Text Available Nowadays, in several types of commercial or institutional buildings, a significant rise of transpired solar collectors used to preheat the fresh air of the building can be observed. Nevertheless, when the air mass flow rate is low, the collector efficiency collapses and a large amount of energy remains unused. This paper presents a simple yet effective mathematical model of a transparent transpired solar collector (TTC with dual intake in order to remove stagnation problems in the plenum and ensure a better thermal efficiency and more heat recovery. A thermal model and a pressure loss model were developed. Then, the combined model was validated with experimental data from the Solar Rating and Certification Corporation (SRCC. The results show that the collector efficiency can be up to 70% and even 80% regardless of operating conditions. The temperature gain is able to reach 20°K when the solar irradiation is high.
Remark on: the neutron spherical optical-model absorption.
Energy Technology Data Exchange (ETDEWEB)
Smith, A. B.; Nuclear Engineering Division
2007-06-30
The energy-dependent behavior of the absorption term of the spherical neutron optical potential for doubly magic {sup 208}Pb and the neighboring {sup 209}Bi is examined. These considerations suggest a phenomenological model that results in an intuitively attractive energy dependence of the imaginary potential that provides a good description of the observed neutron cross sections and that is qualitatively consistent with theoretical concepts. At the same time it provides an alternative to some of the arbitrary assumptions involved in many conventional optical-model interpretations reported in the literature and reduces the number of the parameters of the model.
Cascaded process model based control: packed absorption column application.
Govindarajan, Anand; Jayaraman, Suresh Kumar; Sethuraman, Vijayalakshmi; Raul, Pramod R; Rhinehart, R Russell
2014-03-01
Nonlinear, adaptive, process-model based control is demonstrated in a cascaded single-input-single-output mode for pressure drop control in a pilot-scale packed absorption column. The process is shown to be nonlinear. Control is demonstrated in both servo and regulatory modes, for no wind-up in a constrained situation, and for bumpless transfer. Model adaptation is demonstrated and shown to provide process insight. The application procedure is revealed as a design guide to aid others in implementing process-model based control.
Intergalactic Helium Absorption in Cold Dark Matter Models
Croft, R A C; Katz, N; Hernquist, L E; Croft, Rupert A. C.; Weinberg, David H.; Katz, Neal; Hernquist, Lars
1996-01-01
Observations from the HST and the HUT have recently detected HeII absorption along the lines of sight to two high redshift quasars. We use cosmological simulations with gas dynamics to investigate HeII absorption in the cold dark matter (CDM) theory of structure formation. We consider two Omega=1 CDM models with different normalizations and one Omega_0=0.4 CDM model, all incorporating the photoionizing UV background spectrum computed by Haardt & Madau (1996). The simulated gas distribution, combined with the H&M spectral shape, accounts for the relative observed values of taubar_HI and taubar_HeII, the effective mean optical depths for HI and HeII absorption. If the background intensity is as high as H&M predict, then matching the absolute values of taubar_HI and taubar_HeII requires a baryon abundance larger (by factors between 1.5 and 3 for the various CDM models) than our assumed value of Omega_b h^2=0.0125. The simulations reproduce the evolution of taubar_heII over the observed redshift range...
A Simple Disk Wind Model for Broad Absorption Line Quasars
Higginbottom, N; Long, K S; Sim, S A; Matthews, J H
2013-01-01
Approximately 20% of quasi-stellar objects (QSOs) exhibit broad, blue-shifted absorption lines in their ultraviolet spectra. Such features provide clear evidence for significant outflows from these systems, most likely in the form of accretion disk winds. These winds may represent the "quasar" mode of feedback that is often invoked in galaxy formation/evolution models, and they are also key to unification scenarios for active galactic nuclei (AGN) and QSOs. To test these ideas, we construct a simple benchmark model of an equatorial, biconical accretion disk wind in a QSO and use a Monte Carlo ionization/radiative transfer code to calculate the ultraviolet spectra as a function of viewing angle. We find that for plausible outflow parameters, sightlines looking directly into the wind cone do produce broad, blue-shifted absorption features in the transitions typically seen in broad absorption line QSOs. However, our benchmark model is intrinsically X-ray weak in order to prevent overionization of the outflow, an...
Generalized self-dual Maxwell-Chern-Simons-Higgs model
Bazeia, D; da Hora, E; Menezes, R
2012-01-01
We present a consistent BPS framework for a generalized Maxwell-Chern-Simons-Higgs model. The overall model, including its self-dual potential, depends on three different functions, h(|{\\phi}|,N), w(|{\\phi}|) and G(|{\\phi}|), which are functions of the scalar fields only. The BPS energy is proportional to the magnetic flux when w(|{\\phi}|) and G(|{\\phi}|) are related to each other by a differential constraint. We present an explicit non-standard model and its topologically non-trivial static configurations, which are described by the usual radially symmetric profile. Finally, we note that the non-standard results behave in a similar way as their standard counterparts, as expected, reinforcing the consistence of the overall construction.
Generalized self-dual Maxwell-Chern-Simons-Higgs model
Bazeia, D.; Casana, R.; da Hora, E.; Menezes, R.
2012-06-01
We present a consistent Bogomol’nyi-Prasad-Sommerfield (BPS) framework for a generalized Maxwell-Chern-Simons-Higgs model. The overall model, including its self-dual potential, depends on three different functions, h(|ϕ|,N), w(|ϕ|), and G(|ϕ|), which are functions of the scalar fields only. The BPS energy is proportional to the magnetic flux when w(|ϕ|) and G(|ϕ|) are related to each other by a differential constraint. We present an explicit nonstandard model and its topologically nontrivial static configurations, which are described by the usual radially symmetric profile. Finally, we note that the nonstandard results behave in a similar way as their standard counterparts, as expected, reinforcing the consistence of the overall construction.
A dual modelling of evolving political opinion networks
Wang, Ru
2012-01-01
We present the result of a dual modeling of opinion network. The model complements the agent-based opinion models by attaching to the social agent (voters) network a political opinion (party) network having its own intrinsic mechanisms of evolution. These two sub-networks form a global network which can be either isolated from or dependent on the external influence. Basically, the evolution of the agent network includes link adding and deleting, the opinion changes influenced by social validation, the political climate, the attractivity of the parties and the interaction between them. The opinion network is initially composed of numerous nodes representing opinions or parties which are located on a one dimensional axis according to their political positions. The mechanism of evolution includes union, splitting, change of position and of attractivity, taken into account the pairwise node interaction decaying with node distance in power law. The global evolution ends in a stable distribution of the social agent...
The dual systems model: Review, reappraisal, and reaffirmation
Directory of Open Access Journals (Sweden)
Elizabeth P. Shulman
2016-02-01
Full Text Available According to the dual systems perspective, risk taking peaks during adolescence because activation of an early-maturing socioemotional-incentive processing system amplifies adolescents’ affinity for exciting, pleasurable, and novel activities at a time when a still immature cognitive control system is not yet strong enough to consistently restrain potentially hazardous impulses. We review evidence from both the psychological and neuroimaging literatures that has emerged since 2008, when this perspective was originally articulated. Although there are occasional exceptions to the general trends, studies show that, as predicted, psychological and neural manifestations of reward sensitivity increase between childhood and adolescence, peak sometime during the late teen years, and decline thereafter, whereas psychological and neural reflections of better cognitive control increase gradually and linearly throughout adolescence and into the early 20s. While some forms of real-world risky behavior peak at a later age than predicted, this likely reflects differential opportunities for risk-taking in late adolescence and young adulthood, rather than neurobiological differences that make this age group more reckless. Although it is admittedly an oversimplification, as a heuristic device, the dual systems model provides a far more accurate account of adolescent risk taking than prior models that have attributed adolescent recklessness to cognitive deficiencies.
The dual systems model: Review, reappraisal, and reaffirmation.
Shulman, Elizabeth P; Smith, Ashley R; Silva, Karol; Icenogle, Grace; Duell, Natasha; Chein, Jason; Steinberg, Laurence
2016-02-01
According to the dual systems perspective, risk taking peaks during adolescence because activation of an early-maturing socioemotional-incentive processing system amplifies adolescents' affinity for exciting, pleasurable, and novel activities at a time when a still immature cognitive control system is not yet strong enough to consistently restrain potentially hazardous impulses. We review evidence from both the psychological and neuroimaging literatures that has emerged since 2008, when this perspective was originally articulated. Although there are occasional exceptions to the general trends, studies show that, as predicted, psychological and neural manifestations of reward sensitivity increase between childhood and adolescence, peak sometime during the late teen years, and decline thereafter, whereas psychological and neural reflections of better cognitive control increase gradually and linearly throughout adolescence and into the early 20s. While some forms of real-world risky behavior peak at a later age than predicted, this likely reflects differential opportunities for risk-taking in late adolescence and young adulthood, rather than neurobiological differences that make this age group more reckless. Although it is admittedly an oversimplification, as a heuristic device, the dual systems model provides a far more accurate account of adolescent risk taking than prior models that have attributed adolescent recklessness to cognitive deficiencies.
Mathematical Model of Natural Gas Desulfurization Based on Membrane Absorption
Institute of Scientific and Technical Information of China (English)
Wang Shuli; Ma Jun; Wang Ganyu; Zhou Heng
2014-01-01
Models of mass transfer kinetics combined with mass transfer differential equation and mass transfer resistance equation were established on the basis of double-iflm theory. Mass transfer process of H2S absorption by means of polypro-pylene hydrophobic microporous hollow ifber membrane contactor was simulated using MDEA (N-methyldiethanolamine) as the absorption liquid and corresponding experiments of natural gas desulfurization were performed. The simulation re-sults indicated that the removal rate of hydrogen sulifde showed positive dependence on the absorption liquid concentration and gas pressure. However, the desulfurization rate showed negative dependence on gas lfow. The simulated values were in good agreement with the experimental results. The in-tube concentration of hydrogen sulifde at the same point increased with increase in the gas velocity. Axial concentration of hydrogen sulifde decreased rapidly at the beginning, and the de-crease saw a slowdown during the latter half period. Hydrogen sulifde concentration dropped quickly in the radial direction, and the reduction in the radial direction was weakened with the increase of axial length due to the gradual reduction of hy-drogen sulifde concentration along the tube. The desulfurization rate under given operating conditions can be predicted by this model, and the theoretical basis for membrane module design can also be provided.
Absorption Cycle Heat Pump Model for Control Design
DEFF Research Database (Denmark)
Vinther, Kasper; Just Nielsen, Rene; Nielsen, Kirsten Mølgaard
2015-01-01
Heat pumps have recently received increasing interest due to green energy initiatives and increasing energy prices. In this paper, a nonlinear dynamic model of a single-effect LiBr-water absorption cycle heat pump is derived for simulation and control design purposes. The model is based...... on an actual heat pump located at a larger district heating plant. The model is implemented in Modelica and is based on energy and mass balances, together with thermodynamic property functions for LiBr and water and staggered grid representations for heat exchangers. Model parameters have been fitted...... to operational data and different scenarios are simulated to investigate the operational stability of the heat pump. Finally, this paper provides suggestions and examples of derivation of lower order linear models for control design. © Copyright IEEE - All rights reserved....
Sensitivity analysis of a sound absorption model with correlated inputs
Chai, W.; Christen, J.-L.; Zine, A.-M.; Ichchou, M.
2017-04-01
Sound absorption in porous media is a complex phenomenon, which is usually addressed with homogenized models, depending on macroscopic parameters. Since these parameters emerge from the structure at microscopic scale, they may be correlated. This paper deals with sensitivity analysis methods of a sound absorption model with correlated inputs. Specifically, the Johnson-Champoux-Allard model (JCA) is chosen as the objective model with correlation effects generated by a secondary micro-macro semi-empirical model. To deal with this case, a relatively new sensitivity analysis method Fourier Amplitude Sensitivity Test with Correlation design (FASTC), based on Iman's transform, is taken into application. This method requires a priori information such as variables' marginal distribution functions and their correlation matrix. The results are compared to the Correlation Ratio Method (CRM) for reference and validation. The distribution of the macroscopic variables arising from the microstructure, as well as their correlation matrix are studied. Finally the results of tests shows that the correlation has a very important impact on the results of sensitivity analysis. Assessment of correlation strength among input variables on the sensitivity analysis is also achieved.
A two-dimensional mathematical model of percutaneous drug absorption
Directory of Open Access Journals (Sweden)
Kubota K
2004-06-01
Full Text Available Abstract Background When a drug is applied on the skin surface, the concentration of the drug accumulated in the skin and the amount of the drug eliminated into the blood vessel depend on the value of a parameter, r. The values of r depend on the amount of diffusion and the normalized skin-capillary clearence. It is defined as the ratio of the steady-state drug concentration at the skin-capillary boundary to that at the skin-surface in one-dimensional models. The present paper studies the effect of the parameter values, when the region of contact of the skin with the drug, is a line segment on the skin surface. Methods Though a simple one-dimensional model is often useful to describe percutaneous drug absorption, it may be better represented by multi-dimensional models. A two-dimensional mathematical model is developed for percutaneous absorption of a drug, which may be used when the diffusion of the drug in the direction parallel to the skin surface must be examined, as well as in the direction into the skin, examined in one-dimensional models. This model consists of a linear second-order parabolic equation with appropriate initial conditions and boundary conditions. These boundary conditions are of Dirichlet type, Neumann type or Robin type. A finite-difference method which maintains second-order accuracy in space along the boundary, is developed to solve the parabolic equation. Extrapolation in time is applied to improve the accuracy in time. Solution of the parabolic equation gives the concentration of the drug in the skin at a given time. Results Simulation of the numerical methods described is carried out with various values of the parameter r. The illustrations are given in the form of figures. Conclusion Based on the values of r, conclusions are drawn about (1 the flow rate of the drug, (2 the flux and the cumulative amount of drug eliminated into the receptor cell, (3 the steady-state value of the flux, (4 the time to reach the steady
Reale, Lucia; Kaiser, Jozef; Pace, Loretta; Lai, Antonia; Flora, Francesco; Angelosante Bruno, Antonella; Tucci, Adele; Zuppella, Paola; Mancini, Lucia; Tromba, Giuliana; Ruggieri, Fabrizio; Fanelli, Maria; Malina, Radomir; Liska, Miroslav; Poma, Anna
2010-06-01
This study is related to the application of the X-ray dual-energy microradiography technique together with the atomic absorption spectroscopy (AAS) for the detection of lead on Zea mays stem, ear, root, and leaf samples. To highlight the places with lead intake, the planar radiographs taken with monochromatic X-ray radiation in absorption regime with photon energy below and above the absorption edge of a given chemical element, respectively, are analyzed and processed. To recognize the biological structures involved in the intake, the dual-energy images with the lead signal have been compared with the optical images of the same Z. mays stem. The ear, stem, root, and leaf samples have also been analyzed with the AAS technique to measure the exact amount of the hyperaccumulated lead. The AAS measurement revealed that the highest intake occurred in the roots while the lowest in the maize ears and in the leaf. It seems there is a particular mechanism that protects the seeds and the leaves in the intake process.
Obara, Yuki; Katayama, Tetsuo; Ogi, Yoshihiro; Suzuki, Takayuki; Kurahashi, Naoya; Karashima, Shutaro; Chiba, Yuhei; Isokawa, Yusuke; Togashi, Tadashi; Inubushi, Yuichi; Yabashi, Makina; Suzuki, Toshinori; Misawa, Kazuhiko
2014-01-13
We present femtosecond time-resolved X-ray absorption spectroscopy of aqueous solution using a hard x-ray free electron laser (SACLA) and a synchronized Ti:sapphire laser. The instrumental response time is 200 fs, and the repetition rate of measurement is 10 Hz. A cylindrical liquid beam 100 μm in diameter of aqueous ammonium iron(III) oxalate solution is photoexcited at 400 nm, and the transient X-ray absorption spectra are measured in the K-edge region of iron, 7.10 - 7.26 keV, using a dual X-ray beam dispersive detection method. Each of the dual beams has the pulse energy of 1.4 μJ, and pump-induced absorbance change on the order of 10(-3) is successfully detected. The photoexcited iron complex exhibits a red shifted iron K-edge with the appearance time constant of 260 fs. The X-ray absorption difference spectra, with and without the pump pulses, are independent of time delay after 1.5 ps up to 100 ps, indicating that the photoexcited species is long-lived.
Mathematical Modeling of Intestinal Iron Absorption Using Genetic Programming
Colins, Andrea; Gerdtzen, Ziomara P.; Nuñez, Marco T.; Salgado, J. Cristian
2017-01-01
Iron is a trace metal, key for the development of living organisms. Its absorption process is complex and highly regulated at the transcriptional, translational and systemic levels. Recently, the internalization of the DMT1 transporter has been proposed as an additional regulatory mechanism at the intestinal level, associated to the mucosal block phenomenon. The short-term effect of iron exposure in apical uptake and initial absorption rates was studied in Caco-2 cells at different apical iron concentrations, using both an experimental approach and a mathematical modeling framework. This is the first report of short-term studies for this system. A non-linear behavior in the apical uptake dynamics was observed, which does not follow the classic saturation dynamics of traditional biochemical models. We propose a method for developing mathematical models for complex systems, based on a genetic programming algorithm. The algorithm is aimed at obtaining models with a high predictive capacity, and considers an additional parameter fitting stage and an additional Jackknife stage for estimating the generalization error. We developed a model for the iron uptake system with a higher predictive capacity than classic biochemical models. This was observed both with the apical uptake dataset used for generating the model and with an independent initial rates dataset used to test the predictive capacity of the model. The model obtained is a function of time and the initial apical iron concentration, with a linear component that captures the global tendency of the system, and a non-linear component that can be associated to the movement of DMT1 transporters. The model presented in this paper allows the detailed analysis, interpretation of experimental data, and identification of key relevant components for this complex biological process. This general method holds great potential for application to the elucidation of biological mechanisms and their key components in other complex
Electrostatic modelling of dual frequency rf plasma discharges
Energy Technology Data Exchange (ETDEWEB)
Boyle, P C; Ellingboe, A R; Turner, M M [Plasma Research Laboratory, National Centre for Plasma Science and Technology and School of Physical Sciences, Dublin City University, Dublin 9 (Ireland)
2004-08-01
Particle-in-cell simulations have been used to study the nature of dual frequency plasma discharges. It is observed that both the ion flux on to the electrodes and the ion bombardment energy on to the electrodes can be controlled independently. There are two separate regimes in which this occurs. At large electrode separation, the ion current is controlled by varying the total discharge current, J{sub lf} + J{sub hf}. At small electrode separations, the ion flux can be controlled by varying the high frequency power source. In both regimes, the energy of the ions bombarding the electrodes is then determined by the low frequency voltage. A consequence of using dual frequencies to power the device is that the sheath width increases linearly as the low frequency power source is increased. This results in the dimensions of the bulk plasma decreasing, causing the electron temperature to increase for devices with electrode separations that are of comparable size to the electrode separation. In order to better understand the underlying physics involved within these devices an analytical global model has been developed which can explain many of the characteristics observed in the simulations.
A simple disc wind model for broad absorption line quasars
Higginbottom, N.; Knigge, C.; Long, K. S.; Sim, S. A.; Matthews, J. H.
2013-12-01
Approximately 20 per cent of quasi-stellar objects (QSOs) exhibit broad, blue-shifted absorption lines in their ultraviolet spectra. Such features provide clear evidence for significant outflows from these systems, most likely in the form of accretion disc winds. These winds may represent the `quasar' mode of feedback that is often invoked in galaxy formation/evolution models, and they are also key to unification scenarios for active galactic nuclei (AGN) and QSOs. To test these ideas, we construct a simple benchmark model of an equatorial, biconical accretion disc wind in a QSO and use a Monte Carlo ionization/radiative transfer code to calculate the ultraviolet spectra as a function of viewing angle. We find that for plausible outflow parameters, sightlines looking directly into the wind cone do produce broad, blue-shifted absorption features in the transitions typically seen in broad absorption line (BAL) QSOs. However, our benchmark model is intrinsically X-ray weak in order to prevent overionization of the outflow, and the wind does not yet produce collisionally excited line emission at the level observed in non-BAL QSOs. As a first step towards addressing these shortcomings, we discuss the sensitivity of our results to changes in the assumed X-ray luminosity and mass-loss rate, Ṁwind. In the context of our adopted geometry, Ṁwind ˜ Ṁacc is required in order to produce significant BAL features. The kinetic luminosity and momentum carried by such outflows would be sufficient to provide significant feedback.
A Comprehensive X-Ray Absorption Model for Atomic Oxygen
Gorczyca, T. W.; Bautista, M. A.; Hasoglu, M. F.; Garcia, J.; Gatuzz, E.; Kaastra, J. S.; Kallman, T. R.; Manson, S. T.; Mendoza, C.; Raassen, A. J. J.; de Vries, C. P.; Zatsarinny, O.
2013-01-01
An analytical formula is developed to accurately represent the photoabsorption cross section of atomic Oxygen for all energies of interest in X-ray spectral modeling. In the vicinity of the K edge, a Rydberg series expression is used to fit R-matrix results, including important orbital relaxation effects, that accurately predict the absorption oscillator strengths below threshold and merge consistently and continuously to the above-threshold cross section. Further, minor adjustments are made to the threshold energies in order to reliably align the atomic Rydberg resonances after consideration of both experimental and observed line positions. At energies far below or above the K-edge region, the formulation is based on both outer- and inner-shell direct photoionization, including significant shake-up and shake-off processes that result in photoionization-excitation and double-photoionization contributions to the total cross section. The ultimate purpose for developing a definitive model for oxygen absorption is to resolve standing discrepancies between the astronomically observed and laboratory-measured line positions, and between the inferred atomic and molecular oxygen abundances in the interstellar medium from XSTAR and SPEX spectral models.
Application of Dual Model to Animal Feed Formulation Optimizing System
Institute of Scientific and Technical Information of China (English)
XIONG Ben-hai; LUO Qing-yao; PANG Zhi-hong
2003-01-01
This study introduced a dual model on an original linear programming to obtain those shadowprices of resources that take part in optimizing. Of feed formulation, the shadow prices of nutrient resourcesshow their influencing degree on a diet last cost when increasing or decreasing expected diet nutrient values.The higher the shadow price of one nutrient resource, the more obvious its influencing action on a diet lastcost. When the shadow price of a kind of resource equals "zero", it means that reaching of this nutrient valuedoes not have influence on a special diet last cost within a particular value range. At the same time, this paperdiscussed the future development direction of feed formulation optimizing techniques in China.
Modelling of electron beam absorption in complex geometries
Klassen, Alexander; Bauereiß, Andreas; Körner, Carolin
2014-02-01
Computational modelling of processes that involve highly energetic electrons like electron beam melting, welding, drilling or electron beam lithography, to name but a few, requires information about the attenuation of the electron beam as it passes through the sample. Depth-dose curves as a function of electron energy, target material as well as local surface obliquity have to be provided in situ during the calculation. The most efficient way to address this issue is by employing mathematical expressions. Therefore, we propose an electron beam model based on a set of semi-empirical equations available from different published literature and on theoretical considerations. Particular stress is thereby put on accuracy and the range of validity of the theoretical approach by comparison with experimental data. Finally, we apply our model to powder-bed based additive manufacturing. The numerical results demonstrate that electron beam absorption and depth of penetration have a strong influence on the quality of the fabricated product.
SU(5) monopoles and the dual standard model
Liu, H; Liu, Hong; Vachaspati, Tanmay
1997-01-01
We find the spectrum of magnetic monopoles produced in the symmetry breaking SU(5) \\rightarrow [SU(3)\\times SU(2)\\times U(1)']/Z_6 by constructing classical bound states of the fundamental monopoles. The spectrum of monopoles is found to correspond to the spectrum of one family of standard model fermions and hence, is a starting point for constructing the dual standard model. At this level, however, there is an extra monopole state - the ``diquark'' monopole - with no corresponding standard model fermion. If the SU(3) factor now breaks down to Z_3, the monopoles with non-trivial SU(3) charge get confined by strings in SU(3) singlets. Another outcome of this symmetry breaking is that the diquark monopole becomes unstable (metastable) to fragmentation into fundamental monopoles and the one-one correspondence with the standard model fermions is restored. We discuss the fate of the monopoles if the [SU(2)\\times U(1)']/Z_2 factor breaks down to U(1)_Q by a Higgs mechanism as in the electroweak model. Here we find ...
The Linked Dual Representation model of vocal perception and production
Directory of Open Access Journals (Sweden)
Sean eHutchins
2013-11-01
Full Text Available The voice is one of the most important media for communication, yet there is a wide range of abilities in both the perception and production of the voice. In this article, we review this range of abilities, focusing on pitch accuracy as a particularly informative case, and look at the factors underlying these abilities. Several classes of models have been posited describing the relationship between vocal perception and production, and we review the evidence for and against each class of model. We look at how the voice is different from other musical instruments and review evidence about both the association and the dissociation between vocal perception and production abilities. Finally, we introduce the Linked Dual Representation model, a new approach which can account for the broad patterns in prior findings, including trends in the data which might seem to be countervailing. We discuss how this model interacts with higher-order cognition and examine its predictions about several aspects of vocal perception and production.
Dyon Condensation and Dual Superconductivity in Abelian Higgs Model of QCD
Directory of Open Access Journals (Sweden)
B. S. Rajput
2010-01-01
Full Text Available Constructing the effective action for dyonic field in Abelian projection of QCD, it has been demonstrated that any charge (electrical or magnetic of dyon screens its own direct potential to which it minimally couples and antiscreens the dual potential leading to dual superconductivity in accordance with generalized Meissner effect. Taking the Abelian projection of QCD, an Abelian Higgs model, incorporating dual superconductivity and confinement, has been constructed and its representation has been obtained in terms of average of Wilson loop.
Modelling polarization dependent absorption: The vectorial Lambert-Beer law
Franssens, G.
2014-07-01
The scalar Lambert-Beer law, describing the absorption of unpolarized light travelling through a linear non-scattering medium, is simple, well-known, and mathematically trivial. However, when we take the polarization of light into account and consider a medium with polarization dependent absorption, we now need a Vectorial Lambert-Beer Law (VLBL) to quantify this interaction. Such a generalization of the scalar Lambert-Beer law appears not to be readily available. A careful study of this topic reveals that it is not a trivial problem. We will see that the VLBL is not and cannot be a straightforward vectorized version of its scalar counterpart. The aim of the work is to present the general form of the VLBL and to explain how it arises. A reasonable starting point to derive the VLBL is the Vectorial Radiative Transfer Equation (VRTE), which models the absorption and scattering of (partially) polarized light travelling through a linear medium. When we turn off scattering, the VRTE becomes an infinitesimal model for the VLBL holding in the medium. By integrating this equation, we expect to find the VLBL. Surprisingly, this is not the end of the story. It turns out that light propagation through a medium with polarization-dependent absorption is mathematically not that trivial. The trickiness behind the VLBL can be understood in the following terms. The matrix in the VLBL, relating any input Stokes vector to the corresponding output Stokes vector, must necessarily be a Mueller matrix. The subset of invertible Mueller matrices forms a Lie group. It is known that this Lie group contains the ortho-chronous Lorentz group as a subgroup. The group manifold of this subgroup has a (well-known) non-trivial topology. Consequently, the manifold of the Lie group of Mueller matrices also has (at least the same, but likely a more general) non-trivial topology (the full extent of which is not yet known). The type of non-trivial topology, possessed by the manifold of (invertible
Device Scale Modeling of Solvent Absorption using MFIX-TFM
Energy Technology Data Exchange (ETDEWEB)
Carney, Janine E. [National Energy Technology Lab. (NETL), Albany, OR (United States); Finn, Justin R. [National Energy Technology Lab. (NETL), Albany, OR (United States); Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States)
2016-10-01
Recent climate change is largely attributed to greenhouse gases (e.g., carbon dioxide, methane) and fossil fuels account for a large majority of global CO_{2} emissions. That said, fossil fuels will continue to play a significant role in the generation of power for the foreseeable future. The extent to which CO_{2} is emitted needs to be reduced, however, carbon capture and sequestration are also necessary actions to tackle climate change. Different approaches exist for CO_{2} capture including both post-combustion and pre-combustion technologies, oxy-fuel combustion and/or chemical looping combustion. The focus of this effort is on post-combustion solvent-absorption technology. To apply CO_{2 technologies at commercial scale, the availability and maturity and the potential for scalability of that technology} need to be considered. Solvent absorption is a proven technology but not at the scale needed by typical power plant. The scale up and down and design of laboratory and commercial packed bed reactors depends heavily on the specific knowledge of two-phase pressure drop, liquid holdup, the wetting efficiency and mass transfer efficiency as a function of operating conditions. Simple scaling rules often fail to provide proper design. Conventional reactor design modeling approaches will generally characterize complex non-ideal flow and mixing patterns using simplified and/or mechanistic flow assumptions. While there are varying levels of complexity used within these approaches, none of these models resolve the local velocity fields. Consequently, they are unable to account for important design factors such as flow maldistribution and channeling from a fundamental perspective. Ideally design would be aided by development of predictive models based on truer representation of the physical and chemical processes that occur at different scales. Computational fluid dynamic (CFD) models are based on multidimensional flow equations with first
Modeling of light absorption in tissue during infrared neural stimulation.
Thompson, Alexander C; Wade, Scott A; Brown, William G A; Stoddart, Paul R
2012-07-01
A Monte Carlo model has been developed to simulate light transport and absorption in neural tissue during infrared neural stimulation (INS). A range of fiber core sizes and numerical apertures are compared illustrating the advantages of using simulations when designing a light delivery system. A range of wavelengths, commonly used for INS, are also compared for stimulation of nerves in the cochlea, in terms of both the energy absorbed and the change in temperature due to a laser pulse. Modeling suggests that a fiber with core diameter of 200 μm and NA=0.22 is optimal for optical stimulation in the geometry used and that temperature rises in the spiral ganglion neurons are as low as 0.1°C. The results show a need for more careful experimentation to allow different proposed mechanisms of INS to be distinguished.
Magnetospheres of hot Jupiters: hydrodynamic models & ultraviolet absorption
Alexander, R D; Mohammed, H; Nichols, J D; Ercolano, B
2015-01-01
We present hydrodynamic simulations of stellar wind-magnetosphere interactions in hot Jupiters such as WASP-12b. For fiducial stellar wind rates we find that a planetary magnetic field of a few G produces a large magnetospheric cavity, which is typically 6-9 planetary radii in size. A bow shock invariably forms ahead of the magnetosphere, but the pre-shock gas is only mildly supersonic (with typical Mach numbers of $\\simeq$1.6-1.8) so the shock is weak. This results in a characteristic signature in the ultraviolet light curve: a broad absorption feature that leads the optical transit by 10-20% in orbital phase. The shapes of our synthetic light-curves are consistent with existing observations of WASP-12b, but the required near-UV optical depth ($\\tau \\sim 0.1$) can only be achieved if the shocked gas cools rapidly. We further show that radiative cooling is inefficient, so we deem it unlikely that a magnetospheric bow shock is responsible for the observed near-UV absorption. Finally, we apply our model to two ...
Twinlike models for self-dual Maxwell-Higgs theories
Energy Technology Data Exchange (ETDEWEB)
Bazeia, D.; Hora, E. da [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Dept. de Fisica; Menezes, R. [Universidade Federal da Paraiba (UFPB), Rio Tinto, PB (Brazil). Dept. de Ciencias Exatas
2012-07-01
Full text: We present the development of a coherent first-order theoretical framework that allows for the existence of twinlike models in the context of a generalized self-dual Maxwell-Higgs theories. Here, the generalized model is controlled by two dimensionless functions, h (|{phi}|) and w (|{phi}|) , which are functions of the Higgs field only. Furthermore, these functions are assumed to be positive, in order to avoid problems with the energy of the overall model. In this context, for a given constraint between h (|{phi}|), w (|{phi}|) and the symmetry breaking Higgs potential V (|{phi}|), we found BPS equations by minimizing the generalized total energy. Here, even in the presence of non-trivial choices to h (|{phi}|), w (|{phi}|) and V (|{phi}|), the resulting equations mimic the standard first-order ones. Therefore, given the usual finite-energy boundary conditions, the generalized model engenders the very same topologically non-trivial configurations as the standard Maxwell-Higgs theory. The energy of such configurations is bounded from below, this bound being equal to the magnetic flux, which is quantized according the winding number, as expected. Even in this case, it is important to note that the generalized model is not a parametrization of the usual Maxwell-Higgs one. We study the resulting BPS configurations via the canonical radially symmetric Ansatz, and we found electrically non-charged time-independent vortex solutions which engender the very same magnetic field. In this sense, since this field is related to the topological stability of the usual vortex configurations, we believe the stability of the generalized model can be achieve in the same way. We use a combination of theoretical and numerical techniques to show that different choices to h (|{phi}|) and w (|{phi}|) engender different energy densities, even in the presence of the very same field solutions. In this case, we show that all these densities give the very same total energy. (author)
Infinitesimal dividing modeling method for dual suppliers inventory model with random lead times
Institute of Scientific and Technical Information of China (English)
Ji Pengcheng; Song Shiji; Wu Cheng
2009-01-01
As one of the basic inventory cost models, the (Q, r) inventory cost model of dual suppliers with random procurement lead time is mostly formulated by using the concepts of "effective lead time" and "lead time demand", which may lead to an imprecise inventory cost. Through the real-time statistic of the inventory quantities, this paper considers the precise (Q, r) inventory cost model of dual supplier procurement by using an infinitesimal dividing method. The traditional modeling method of the inventory cost for dual supplier procurement includes complex procedures. To reduce the complexity effectively, the presented method investigates the statistics properties in real-time of the inventory quantities with the application of the infinitesimal dividing method. It is proved that the optimal holding and shortage costs of dual supplier procurement are less than those of single supplier procurement respectively. With the assumption that both suppliers have the same distribution of lead times, the convexity of the cost function per unit time is proved. So the optimal solution can be easily obtained by applying the classical convex optimization methods. The numerical examples are given to verify the main conclusions.
Poisson-Lie T-duals of the bi-Yang-Baxter models
Klimcik, C
2016-01-01
We prove the conjecture of Sfetsos, Siampos and Thompson that suitable analytic continuations of the Poisson-Lie T-duals of the bi-Yang-Baxter sigma models coincide with the recently introduced generalized lambda models.
New simulation model of absorption pump with internal storage
Energy Technology Data Exchange (ETDEWEB)
San Juan, Cristina; Soutullo, Silvia; Enriquez, Ricardo; Ferrer, Jose Antonio; Heras, M Rosario [Energy Efficiency in Buildings R and D Unit. CIEMAT., Avenida Complutense 22, 28040 Madrid, (Spain)], email: cristina.sanjuan@ciemat.es
2010-07-01
In hot climates, such as in Spain, conditioning systems are used to provide a good level of thermal comfort during summer. Systems are usually composed of one liquid absorption pump and external storage in a water tank. The aim of this study is to present a new technology whereby energy is stored in crystallized salts through the use of 4 heat pumps. A case study was carried out in the Plataforma Solar de Almeria, Spain, where the performance of both conventional and new cooling systems were analyzed through the use of a dynamic model in TRNSYS. Results showed that for the new system, adaptability increases with the number of independent blocks and its performance is influenced by the control strategy. In addition it was found that 15m3 of external storage are required in conventional systems to achieve the same performance as the new system. This study showed that the new system requires less storage room than conventional systems.
Models of ionospheric VLF absorption of powerful ground based transmitters
Cohen, M. B.; Lehtinen, N. G.; Inan, U. S.
2012-12-01
Ground based Very Low Frequency (VLF, 3-30 kHz) radio transmitters play a role in precipitation of energetic Van Allen electrons. Initial analyses of the contribution of VLF transmitters to radiation belt losses were based on early models of trans-ionospheric propagation known as the Helliwell absorption curves, but some recent studies have found that the model overestimates (by 20-100 dB) the VLF energy reaching the magnetosphere. It was subsequently suggested that conversion of wave energy into electrostatic modes may be responsible for the error. We utilize a newly available extensive record of VLF transmitter energy reaching the magnetosphere, taken from the DEMETER satellite, and perform a direct comparison with a sophisticated full wave model of trans-ionospheric propagation. Although the model does not include the effect of ionospheric irregularities, it correctly predicts the average total power injected into the magnetosphere within several dB. The results, particularly at nighttime, appear to be robust against the variability of the ionospheric electron density. We conclude that the global effect of irregularity scattering on whistler mode conversion to quasi-electrostatic may be no larger than 6 dB.
Jam-absorption driving with a car-following model
Taniguchi, Yohei; Nishi, Ryosuke; Ezaki, Takahiro; Nishinari, Katsuhiro
2015-09-01
Jam-absorption driving (JAD) refers to the action performed by a single car to dynamically change its headway to remove a traffic jam. Because of its irregular motion, a car performing JAD perturbs other cars following it, and these perturbations may grow to become the so-called secondary traffic jams. A basic theory for JAD (Nishi et al. 2013) does not consider accelerations of cars or the stability of traffic flow. In this paper, by introducing car-following behaviors, we implement these elements in JAD. Numerous previous studies on the instability of traffic flow showed that even in a region whose density is below a critical density, perturbation may grow if its initial magnitude is large. According to these previous studies, we expect that the perturbations caused by JAD, if they are sufficiently small, do not grow to become secondary traffic jams. Using a microscopic car-following model, we numerically confirmed that the stability of a flow obeying the model depends on the magnitude of JAD perturbations. On the basis of this knowledge, numerical results indicate that parameter regions exist where JAD allows traffic jams to be removed without causing secondary traffic jams. Moreover, JAD is robust against a parameter of acceleration in the model, as well as the choice of car-following models.
Institute of Scientific and Technical Information of China (English)
Jing CHEN; Rui-feng DING
2014-01-01
Based on the work in Ding and Ding (2008), we develop a modifi ed stochastic gradient (SG) parameter estimation algorithm for a dual-rate Box-Jenkins model by using an auxiliary model. We simplify the complex dual-rate Box-Jenkins model to two fi nite impulse response (FIR) models, present an auxiliary model to estimate the missing outputs and the unknown noise variables, and compute all the unknown parameters of the system with colored noises. Simulation results indicate that the proposed method is effective.
New self-dual $k$-generalized Abelian-Higgs models
Casana, R; Santos, A C
2015-01-01
We have shown the existence of self-dual solutions in new Maxwell-Higgs scenarios whose gauge field possess $k$-generalized dynamics, i.e., the kinetic part of the gauge action being highly nonlinear. We have implemented the BPS formalism providing highly nonlinear generalized self-dual equations whose solutions possess a total energy proportional to the magnetic flux. However, there is a key condition which allows to express the self-dual equations in a form mathematically similar those arising in the Maxwell-Higgs model. Under such a key condition, we have analyzed the general properties of the self-dual axially symmetric vortices. We have observed the generalization modifies the vortex core, the magnetic field amplitude and the bosonic masses but the total energy remains proportional to the quantized magnetic flux. Finally, we have established a prescription which allows to obtain different $k$-generalized Abelian Higgs models providing self-dual configurations.
Modelling Alkali Line Absorption and Molecular Bands in Cool DAZs
Homeier, D; Allard, F; Hauschildt, P H; Schweitzer, A; Stancil, P C; Weck, P F; Homeier, Derek; Allard, Nicole F.; Allard, France; Hauschildt, Peter H.; Schweitzer, Andreas; Stancil, Phillip C.; Weck, Philippe F.
2005-01-01
Two peculiar stars showing an apparent extremely broadened and strong NaI D absorption have been discovered in surveys for cool white dwarfs by Oppenheimer et al. (2001) and Harris et al. (SDSS, 2003). We discuss the nature of these objects using PHOENIX atmosphere models for metal-poor brown dwarfs/very low mass stars, and new white dwarf LTE and NLTE models for hydrogen- and helium-dominated atmospheres with metals. These include complete molecular formation in chemical equilibrium and a model for the alkali resonance line broadening based on the damping profiles of Allard et al. (2003), as well as new molecular line opacities for metal hydrides. First results of our calculations indicate good agreement with a hydrogen-dominated WD atmosphere with a Na abundance roughly consistent with a state of high accretion. We analyse deviations of the abundances of Na, K, Mg and Ca from the cosmic pattern and comment on implications of these results for standard accretion scenarios.
Slow Steps towards Dual Earner/Dual Carer Family Model: Why Do Fathers Not Take Parental Leave
Directory of Open Access Journals (Sweden)
Marre Karu
2011-06-01
Full Text Available The article looks at the transition of Estonian society towards dual earner/dual carer family model and focuses on fathers’ decision regarding taking their parental leave. Based on theory of planned behaviour by Ajzen, data from 20 qualitative interviews with fathers of small children are analysed to explore the beliefs fathers have when it comes to parental leave. The analysis distinguishes between two images of ‘good parenting’ that play a role in the fathers’ intention to take parental leave. First, there is an image of an outcome-oriented ‘project manager’ aﬀected by failure anxiety, and second, there is a much more relaxed image of a ‘good parent’ as a ‘companion’ who values everyday contact and a close relationship with the child(ren.
Optimization of absorption placement using geometrical acoustic models and least squares.
Saksela, Kai; Botts, Jonathan; Savioja, Lauri
2015-04-01
Given a geometrical model of a space, the problem of optimally placing absorption in a space to match a desired impulse response is in general nonlinear. This has led some to use costly optimization procedures. This letter reformulates absorption assignment as a constrained linear least-squares problem. Regularized solutions result in direct distribution of absorption in the room and can accommodate multiple frequency bands, multiple sources and receivers, and constraints on geometrical placement of absorption. The method is demonstrated using a beam tracing model, resulting in the optimal absorption placement on the walls and ceiling of a classroom.
Dual permeability FEM models for distributed fiber optic sensors development
Aguilar-López, Juan Pablo; Bogaard, Thom
2017-04-01
Fiber optic cables are commonly known for being robust and reliable mediums for transferring information at the speed of light in glass. Billions of kilometers of cable have been installed around the world for internet connection and real time information sharing. Yet, fiber optic cable is not only a mean for information transfer but also a way to sense and measure physical properties of the medium in which is installed. For dike monitoring, it has been used in the past for detecting inner core and foundation temperature changes which allow to estimate water infiltration during high water events. The DOMINO research project, aims to develop a fiber optic based dike monitoring system which allows to directly sense and measure any pore pressure change inside the dike structure. For this purpose, questions like which location, how many sensors, which measuring frequency and which accuracy are required for the sensor development. All these questions may be initially answered with a finite element model which allows to estimate the effects of pore pressure change in different locations along the cross section while having a time dependent estimation of a stability factor. The sensor aims to monitor two main failure mechanisms at the same time; The piping erosion failure mechanism and the macro-stability failure mechanism. Both mechanisms are going to be modeled and assessed in detail with a finite element based dual permeability Darcy-Richards numerical solution. In that manner, it is possible to assess different sensing configurations with different loading scenarios (e.g. High water levels, rainfall events and initial soil moisture and permeability conditions). The results obtained for the different configurations are later evaluated based on an entropy based performance evaluation. The added value of this kind of modelling approach for the sensor development is that it allows to simultaneously model the piping erosion and macro-stability failure mechanisms in a time
Sjögren, Erik; Westergren, Jan; Grant, Iain; Hanisch, Gunilla; Lindfors, Lennart; Lennernäs, Hans; Abrahamsson, Bertil; Tannergren, Christer
2013-07-16
Oral drug delivery is the predominant administration route for a major part of the pharmaceutical products used worldwide. Further understanding and improvement of gastrointestinal drug absorption predictions is currently a highly prioritized area of research within the pharmaceutical industry. The fraction absorbed (fabs) of an oral dose after administration of a solid dosage form is a key parameter in the estimation of the in vivo performance of an orally administrated drug formulation. This study discloses an evaluation of the predictive performance of the mechanistic physiologically based absorption model GI-Sim. GI-Sim deploys a compartmental gastrointestinal absorption and transit model as well as algorithms describing permeability, dissolution rate, salt effects, partitioning into micelles, particle and micelle drifting in the aqueous boundary layer, particle growth and amorphous or crystalline precipitation. Twelve APIs with reported or expected absorption limitations in humans, due to permeability, dissolution and/or solubility, were investigated. Predictions of the intestinal absorption for different doses and formulations were performed based on physicochemical and biopharmaceutical properties, such as solubility in buffer and simulated intestinal fluid, molecular weight, pK(a), diffusivity and molecule density, measured or estimated human effective permeability and particle size distribution. The performance of GI-Sim was evaluated by comparing predicted plasma concentration-time profiles along with oral pharmacokinetic parameters originating from clinical studies in healthy individuals. The capability of GI-Sim to correctly predict impact of dose and particle size as well as the in vivo performance of nanoformulations was also investigated. The overall predictive performance of GI-Sim was good as >95% of the predicted pharmacokinetic parameters (C(max) and AUC) were within a 2-fold deviation from the clinical observations and the predicted plasma AUC
Directory of Open Access Journals (Sweden)
E. Majchrzak
2008-12-01
Full Text Available The dual reciprocity boundary element method is applied for numerical modelling of solidification process. This variant of the BEM is connected with the transformation of the domain integral to the boundary integrals. In the paper the details of the dual reciprocity boundary element method are presented and the usefulness of this approach to solidification process modelling is demonstrated. In the final part of the paper the examples of computations are shown.
2014-11-01
based reverse saturable absorption (RSA) [1,2] events of both the C60 cage and antenna units in the combined wide UV-visible‒NIR region and effective...is available at http://spiedigitallibrary.org. 14. ABSTRACT Synthesis of several C60-( antenna )x conjugates was performed to demonstrate high...range of wavelengths. It was achieved by covalent attachment of a hybrid combination of two types of light- harvesting fluorescent antenna
Topological self-dual configurations in a Lorentz-violating gauged O(3) sigma model
Casana, R; Ferreira, M M
2015-01-01
We have studied the existence of topological BPS or self-dual configurations in a Lorentz-violating gauged O(3) nonlinear sigma model, where CPT-even Lorentz-violating (LV) terms were introduced in both the gauge and {\\sigma}-field sectors. Such as it happens in the usual gauged {\\sigma}-model, purely magnetic self-dual configurations are allowed, maintaining some qualitative features of the standard ones. In a more involved configuration, Lorentz-violation provides new self-dual magnetic solutions carrying electric field but null total electric charge. In both cases, the total energy of the self-dual configurations turns out proportional to the topological charge of the model and to the LV parameters introduced in the {\\sigma}-sector. It is shown that the LV terms yield magnetic flux reversion as well.
Topological self-dual configurations in a Lorentz-violating gauged O (3 ) sigma model
Casana, R.; Farias, C. F.; Ferreira, M. M.
2015-12-01
We have studied the existence of topological Bogomol'nyi-Prasad-Sommerfield or self-dual configurations in a Lorentz-violating gauged O (3 ) nonlinear sigma model, where C P T -even Lorentz-violating (LV) terms were introduced in both the gauge and σ -field sectors. As happens in the usual gauged σ model, purely magnetic self-dual configurations are allowed, maintaining some qualitative features of the standard ones. In a more involved configuration, Lorentz violation provides new self-dual magnetic solutions carrying an electric field but a null total electric charge. In both cases, the total energy of the self-dual configurations turns out to be proportional to the topological charge of the model and to the LV parameters introduced in the σ sector. It is shown that the LV terms yield magnetic flux reversion as well.
A new three-dimensional electromechanical impedance model for an embedded dual-PZT transducer
Wang, Dansheng; Li, Zhi; Zhu, Hongping
2016-07-01
In the past twenty years, the electromechanical (EM) impedance technique has been investigated extensively in the mechanical, aviation and civil engineering fields. Many different EM impedance models have been proposed to characterize the interaction between the surface-bonded PZT transducer and the host structure. This paper formulates a new three-dimensional EM impedance model characterizing the interaction between an embedded circle dual-PZT transducer and the host structure based on the effective impedance concept. The proposed model is validated by experimental results from a group of smart cement cubes, in which three circle dual-PZT transducers are embedded respectively. In addition, a new EM impedance measuring method for the dual-PZT transducer is also introduced. In the measuring method, only a common signal generator and an oscilloscope are needed, by which the exciting and receiving voltage signals are obtained respectively. Combined with fast Fourier transform the EM impedance signatures of the dual-PZT transducers are obtained.
Measurements of the Absorption by Auditorium SEATING—A Model Study
BARRON, M.; COLEMAN, S.
2001-01-01
One of several problems with seat absorption is that only small numbers of seats can be tested in standard reverberation chambers. One method proposed for reverberation chamber measurements involves extrapolation when the absorption coefficient results are applied to actual auditoria. Model seat measurements in an effectively large model reverberation chamber have allowed the validity of this extrapolation to be checked. The alternative barrier method for reverberation chamber measurements was also tested and the two methods were compared. The effect on the absorption of row-row spacing as well as absorption by small numbers of seating rows was also investigated with model seats.
Simulation Model for Dynamic Operation of Double-Effect Absorption Chillers
Ahmed Mojahid Sid Ahmed Mohammed Salih; Gilani Syed Ihtsham Ul-Haq
2014-01-01
The development in the field of refrigeration and air conditioning systems driven by absorption cycles acquired a considerable importance recently. For commercial absorption chillers, an essential challenge for creating chiller model certainly is the shortage of components technical specifications. These kinds of specifications are usually proprietary for chillers producers. In this paper, a double-effect parallel-flow-type steam absorption chiller model based on thermodynamic and energy equa...
The research on the modeling of dual-cone double enveloping hourglass worm gear pair
Directory of Open Access Journals (Sweden)
LI Shaoxiang
2013-04-01
Full Text Available Up to now there is no specialized,efficient,general-purpose modeling method of dual-cone double enveloping hourglass worm gear pair.In this paper,based on the spatial meshing theory,a parameterized mathematical model of the dual-cone double enveloping hourglass worm gear pair is established,which is simplified as a digitized modeling method based on six basic parameters of the worm gear pair.Virtual machining modeling plug-in programming is achieved through the solidworks development platform.The results show that this modeling method can make the hourglass worm modeling more convenient,accurate and fast.
The research on the modeling of dual-cone double enveloping hourglass worm gear pair
Directory of Open Access Journals (Sweden)
LI Shaoxiang
2013-04-01
Full Text Available Up to now there is no specialized,efficient,general-purpose modeling method of dual-cone double enveloping hourglass worm gear pair.In this paper,based on the spatial meshing theory,a parameterized mathematical model of the dual-cone double enveloping hourglass worm gear pair is established,which is simplified as a digitized modeling method based on six basic parameters of the worm gear pair.Virtual machining modeling plug-in programming is achieved through the solidworks development platform.The results show that this modeling method can make the hourglass worm modeling more convenient,accurate and fast.
3D modeling of dual wind-up extensional rheometers
DEFF Research Database (Denmark)
Yu, Kaijia; Román Marín, José Manuel; Rasmussen, Henrik K.
2010-01-01
Fully three-dimensional numerical simulations of a dual wind-up drum rheometer of the Sentmanat Extensional Rheometer (SER; Sentmanat, 2004 [1]) or the Extensional Viscosity Fixture (EVF; Garritano and Berting, 2006 [2]) type have been performed. In the SER and EVF a strip of rectangular shape is...
Direct Evidence for a Dual Process Model of Deductive Inference
Markovits, Henry; Brunet, Marie-Laurence; Thompson, Valerie; Brisson, Janie
2013-01-01
In 2 experiments, we tested a strong version of a dual process theory of conditional inference (cf. Verschueren et al., 2005a, 2005b) that assumes that most reasoners have 2 strategies available, the choice of which is determined by situational variables, cognitive capacity, and metacognitive control. The statistical strategy evaluates inferences…
Model: A Dual Focused Intervention for Depression and Addiction.
Lysaught, Eileen; Wodarski, John S.
1996-01-01
Describes how adolescents are affected by depression and alcohol dependence and offers a treatment plan for a dual diagnosis. The plan consists of an adolescent group and family program to facilitate and maintain behavioral changes in treatment. The benefits of this treatment and rationale for its application are discussed. (LSR)
Arain, Salma Aslam; Kazi, Tasneem G; Afridi, Hassan Imran; Abbasi, Abdul Rasool; Panhwar, Abdul Haleem; Naeemullah; Shanker, Bhawani; Arain, Mohammad Balal
2014-12-10
An efficient, innovative preconcentration method, dual-cloud point extraction (d-CPE) has been developed for the extraction and preconcentration of copper (Cu(2+)) in serum samples of different viral hepatitis patients prior to couple with flame atomic absorption spectrometry (FAAS). The d-CPE procedure was based on forming complexes of elemental ions with complexing reagent 1-(2-pyridylazo)-2-naphthol (PAN), and subsequent entrapping the complexes in nonionic surfactant (Triton X-114). Then the surfactant rich phase containing the metal complexes was treated with aqueous nitric acid solution, and metal ions were back extracted into the aqueous phase, as second cloud point extraction stage, and finally determined by flame atomic absorption spectrometry using conventional nebulization. The multivariate strategy was applied to estimate the optimum values of experimental variables for the recovery of Cu(2+) using d-CPE. In optimum experimental conditions, the limit of detection and the enrichment factor were 0.046μgL(-1) and 78, respectively. The validity and accuracy of proposed method were checked by analysis of Cu(2+) in certified sample of serum (CRM) by d-CPE and conventional CPE procedure on same CRM. The proposed method was successfully applied to the determination of Cu(2+) in serum samples of different viral hepatitis patients and healthy controls.
Arain, Salma Aslam; Kazi, Tasneem G.; Afridi, Hassan Imran; Abbasi, Abdul Rasool; Panhwar, Abdul Haleem; Naeemullah; Shanker, Bhawani; Arain, Mohammad Balal
2014-12-01
An efficient, innovative preconcentration method, dual-cloud point extraction (d-CPE) has been developed for the extraction and preconcentration of copper (Cu2+) in serum samples of different viral hepatitis patients prior to couple with flame atomic absorption spectrometry (FAAS). The d-CPE procedure was based on forming complexes of elemental ions with complexing reagent 1-(2-pyridylazo)-2-naphthol (PAN), and subsequent entrapping the complexes in nonionic surfactant (Triton X-114). Then the surfactant rich phase containing the metal complexes was treated with aqueous nitric acid solution, and metal ions were back extracted into the aqueous phase, as second cloud point extraction stage, and finally determined by flame atomic absorption spectrometry using conventional nebulization. The multivariate strategy was applied to estimate the optimum values of experimental variables for the recovery of Cu2+ using d-CPE. In optimum experimental conditions, the limit of detection and the enrichment factor were 0.046 μg L-1 and 78, respectively. The validity and accuracy of proposed method were checked by analysis of Cu2+ in certified sample of serum (CRM) by d-CPE and conventional CPE procedure on same CRM. The proposed method was successfully applied to the determination of Cu2+ in serum samples of different viral hepatitis patients and healthy controls.
Solving the sign problems of the massless lattice Schwinger model with a dual formulation
Directory of Open Access Journals (Sweden)
Christof Gattringer
2015-08-01
Full Text Available We derive an exact representation of the massless Schwinger model on the lattice in terms of dual variables which are configurations of loops, dimers and plaquette occupation numbers. When expressed with the dual variables the partition sum has only real and positive terms also when a chemical potential or a topological term are added – situations where the conventional representation has a complex action problem. The dual representation allows for Monte Carlo simulations without restrictions on the values of the chemical potential or the vacuum angle.
Solving the sign problems of the massless lattice Schwinger model with a dual formulation
Gattringer, Christof; Sazonov, Vasily
2015-01-01
We derive an exact representation of the massless Schwinger model on the lattice in terms of dual variables which are configurations of loops, dimers and plaquette occupation numbers. When expressed with the dual variables the partition sum has only real and positive terms also when a chemical potential or a topological term are added -- situations where the conventional representation has a complex action problem. The dual representation allows for Monte Carlo simulations without restrictions on the values of the chemical potential or the vacuum angle.
A mechanism-based approach for absorption modeling: the Gastro-Intestinal Transit Time (GITT) model.
Hénin, Emilie; Bergstrand, Martin; Standing, Joseph F; Karlsson, Mats O
2012-06-01
Absorption models used in the estimation of pharmacokinetic drug characteristics from plasma concentration data are generally empirical and simple, utilizing no prior information on gastro-intestinal (GI) transit patterns. Our aim was to develop and evaluate an estimation strategy based on a mechanism-based model for drug absorption, which takes into account the tablet movement through the GI transit. This work is an extension of a previous model utilizing tablet movement characteristics derived from magnetic marker monitoring (MMM) and pharmacokinetic data. The new approach, which replaces MMM data with a GI transit model, was evaluated in data sets where MMM data were available (felodipine) or not available (diclofenac). Pharmacokinetic profiles in both datasets were well described by the model according to goodness-of-fit plots. Visual predictive checks showed the model to give superior simulation properties compared with a standard empirical approach (first-order absorption rate + lag-time). This model represents a step towards an integrated mechanism-based NLME model, where the use of physiological knowledge and in vitro–in vivo correlation helps fully characterize PK and generate hypotheses for new formulations or specific populations.
Dual random circuit breaker network model with equivalent thermal circuit network
Kim, Kwanyong; Yoon, Seong Jun; Choi, Woo Young
2014-02-01
A SPICE-based dual random circuit breaker (RCB) network model with an equivalent thermal circuit network has been proposed in order to emulate resistance switching (RS) of unipolar resistive random access memory (RRAM). The dual RCB network model consists of the electrical RCB network model for the forming and set operations and the equivalent thermal circuit network model for the reset operation. In addition, the proposed model can explain the effects of heat dissipation on the memory and threshold RS with the variation in electrode thickness.
Duality equivalence between nonlinear self-dual and topologically massive models
Ilha, A; Ilha, Anderson; Wotzasek, Clovis
2001-01-01
In this report we study the dual equivalence between the generalized self-dual (SD) and topologically massive (TM) models. To this end we linearize the model using an auxiliary field and apply a gauge embedding procedure to construct a gauge equivalent model. We clearly show that, under the above conditions, a nonlinear SD model always has a duality equivalent TM action.The general result obtained is then particularized for a number of examples, including the Born-Infeld-Chern-Simons (BICS) model recently discussed in the literature.
A 5-DOF Model for Aeroengine Spindle Dual-rotor System Analysis
Institute of Scientific and Technical Information of China (English)
HU Qinghua; DENG Sier; TENG Hongfei
2011-01-01
This paper develops a five degrees of freedom (5-DOF) model for aeroengine spindle dual-rotor system dynamic analysis.In this system, the dual rotors are supported on two angular contact ball bearings and two deep groove ball bearings, one of the latter-mentioned bearings works as the inter-shaft bearing.Driven by respective motors, the dual rotors have different co-rotating speeds.The proposed model mathematically formulates the nonlinear displacements, elastic deflections and contact forces of beatings with consideration of 5-DOF and coupling of dual rotors.The nonlinear equations of motions of dual rotors with 5-DOF are solved using Runge-Kutta-Fehlberg algorithm.In order to investigate the effect of the introduced 5-DOF and nonlinear dynamic bearing model, we compare the proposed model with two models: the 3-DOF model of this system only considering three translational degrees of freedom (Gupta, 1993, rotational freedom is neglected); the 5-DOF model where the deep groove ball bearings are simplified as linear elastic spring (Guskov, 2007).The simulation results verify Gupta's prediction (1993) and show that the rotational freedom of rotors and nonlinear dynamic model of bearings have great effect on the system dynamic simulation.The quantitative results are given as well.
Indian Academy of Sciences (India)
Pier A Mello; Eugene Kogan
2002-02-01
We present a maximum-entropy model for the transport of waves through a classically chaotic cavity in the presence of absorption. The entropy of the -matrix statistical distribution is maximized, with the constraint $\\langle {\\rm Tr}SS^{\\dagger}\\rangle = n: n$ is the dimensionality of , and 0 ≤ ≤ 1. For = 1 the -matrix distribution concentrates on the unitarity sphere and we have no absorption; for = 0 the distribution becomes a delta function at the origin and we have complete absorption. For strong absorption our result agrees with a number of analytical calculations already given in the literature. In that limit, the distribution of the individual (angular) transmission and reﬂection coefﬁcients becomes exponential – Rayleigh statistics – even for = 1. For ≫ 1 Rayleigh statistics is attained even with no absorption; here we extend the study to < 1. The model is compared with random-matrix-theory numerical simulations: it describes the problem very well for strong absorption, but fails for moderate and weak absorptions. The success of the model for strong absorption is understood in the light of a central-limit theorem. For weak absorption, some important physical constraint is missing in the construction of the model.
Poisson-Lie T-duals of the bi-Yang-Baxter models
Klimčík, Ctirad
2016-09-01
We prove the conjecture of Sfetsos, Siampos and Thompson that suitable analytic continuations of the Poisson-Lie T-duals of the bi-Yang-Baxter sigma models coincide with the recently introduced generalized λ-models. We then generalize this result by showing that the analytic continuation of a generic σ-model of ;universal WZW-type; introduced by Tseytlin in 1993 is nothing but the Poisson-Lie T-dual of a generic Poisson-Lie symmetric σ-model introduced by Klimčík and Ševera in 1995.
Tassin, Philippe; Zhao, Rongkuo; Jain, Aditya; Koschny, Thomas; Soukoulis, Costas M
2012-01-01
Several classical analogues of electromagnetically induced transparency (EIT) in metamaterials have been demonstrated. A simple two-resonator model can describe their absorption spectrum qualitatively, but fails to provide information about the scattering properties-e.g., transmission and group delay. Here we develop an alternative model that rigourously includes the coupling of the radiative resonator to the external electromagnetic fields. This radiating two-oscillator model can describe both the absorption spectrum and the scattering parameters quantitatively. The model also predicts metamaterials with a narrow spectral feature in the absorption larger than the background absorption of the radiative element. This classical analogue of electromagnetically induced absorption (EIA) is shown to occur when both the dissipative loss of the radiative resonator and the coupling strength are small. These predictions are subsequently demonstrated in experiments.
A Dual-Process Model of the Alcohol-Behavior Link for Social Drinking
Moss, Antony C.; Albery, Ian P.
2009-01-01
A dual-process model of the alcohol-behavior link is presented, synthesizing 2 of the major social-cognitive approaches: expectancy and myopia theories. Substantial evidence has accrued to support both of these models, and recent neurocognitive models of the effects of alcohol on thought and behavior have provided evidence to support both as well.…
Logical Reasoning versus Information Processing in the Dual-Strategy Model of Reasoning
Markovits, Henry; Brisson, Janie; de Chantal, Pier-Luc
2017-01-01
One of the major debates concerning the nature of inferential reasoning is between counterexample-based strategies such as mental model theory and statistical strategies underlying probabilistic models. The dual-strategy model, proposed by Verschueren, Schaeken, & d'Ydewalle (2005a, 2005b), which suggests that people might have access to both…
Modeling of Ad-hoc and Infrastructure Dual Mode Mobile Networks
Institute of Scientific and Technical Information of China (English)
Yi-Hung Chen; Hui-Nien Hung; Yi-Bing Lin; Nan-Fu Peng
2005-01-01
This paper investigates a mobile telecommunications system that supports both ad hoc and infrastructure mode operations. Based on analytic and simulation models, our study investigates how base station (BS) and ad hoc channel capacity, and the mobility and locality of mobile stations affect the performance of a dual mode system. We show that a dual mode system can significantly outperform a single mode (infrastructure) system when the degree of locality is high. Furthermore, a dual mode system can support much faster mobile users with less BS channels in comparison to an infrastructure mode system. Our study quantitatively identifies the threshold value for the number of ad hoc channels such that beyond this threshold, increasing ad hoc channel capacity will not improve the performance of a dual mode system.
Energy Technology Data Exchange (ETDEWEB)
Henager, Charles H.; Nguyen, Ba Nghiep; Kurtz, Richard J.; Ferraris, M.; Katoh, Y.
2016-03-31
Finite element continuum damage models (FE-CDM) have been developed to simulate and model dual-phase joints and cracked joints for improved analysis of SiC materials in nuclear environments. This report extends the analysis from the last reporting cycle by including results from dual-phase models and from cracked joint models.
Self-Dual Vortices in Abelian Higgs Models with Dielectric Function on the Noncommutative Plane
Fuertes, W García
2014-01-01
We show that Abelian Higgs Models with dielectric function defined on the noncommutative plane enjoy self-dual vorticial solutions. By choosing a particular form of the dielectric function, we provide a family of solutions whose Higgs and magnetic fields interpolate between the profiles of the noncommutative Nielsen-Olesen and Chern-Simons vortices. This is done both for the usual $U(1)$ model and for the $SU(2)\\times U(1)$ semilocal model with a doublet of complex scalar fields. The variety of known noncommutative self-dual vortices which display a regular behaviour when the noncommutativity parameter tends to zero results in this way considerably enlarged.
No-ghost theorem for the Pomeron sector of the dual model
Olive, D
1973-01-01
The Pomeron sector of the dual model comprises a spectrum of states obtained by factorizing the residues of poles occurring in a certain channel (with vacuum quantum numbers) of the orientable non-planar single loop graphs of the conventional dual model considered in 26 space-time dimensions. The authors show that the spectrum of Pomeron states which couple between external physical particle states are transverse and hence positive definite and thus ghost-free. The same states also factorize the Virasoro-Shapiro model which now appears very likely to be the scattering theory of Pomeron ground states. (17 refs).
Absorption of beta-carotene and other carotenoids in humans and animal models : a review
Vliet, T. van
1996-01-01
Objective: To review available information on absorption and further metabolism of different carotenoids in man and to discuss animal models and approaches in the study of carotenoid absorption and metabolism in man. Conclusions: Humans appear to absorb various carotenoids in a relatively non-specif
Absorption of beta-carotene and other carotenoids in humans and animal models : a review
Vliet, T. van
1996-01-01
Objective: To review available information on absorption and further metabolism of different carotenoids in man and to discuss animal models and approaches in the study of carotenoid absorption and metabolism in man. Conclusions: Humans appear to absorb various carotenoids in a relatively
Energy Technology Data Exchange (ETDEWEB)
Gregory Flach; Mary Harris; Susan Hubbard; Camelia Knapp; Mike Kowalsky; Maggie Millings; John Shafer; Mike Waddell
2006-06-01
Our research project is motivated by the observations that conventional characterization approaches capture only a fraction of heterogeneity affecting field-scale transport, and that conventional modeling approaches, which use this sparse data, typically do not successfully predict long term plume behavior with sufficient accuracy to guide remedial strategies. Our working hypotheses are that improved prediction of contaminant transport can be achieved using a dual-domain transport approach and field-scale characterization approaches. Our overall objectives are to: (1) develop a dual-domain modeling approach using the TOUGH2 family of codes that incorporates the key interactions between mobile and immobile transport regions that are expected to play a role in long term plume behavior; (2) develop a facies-based multi-scale characterization approach that utilizes log, crosshole, and surface-based characterization information and that is guided by the parameterization needs of the dual domain modeling; and (3) evaluate the approaches by applying them to the prediction of plume behavior at the P-Area at the Savannah River Site (Figure 1). Our three-year project scope includes development of multi-scale characterization and dual-domain modeling approach and field-scale data acquisition (Year 1); Numerical simulations and field-scale characterization (Year 2); and Plume transport simulations and exploration of optimal dual-domain parameters (Year 3).
A Dual Coding Theoretical Model of Decoding in Reading: Subsuming the LaBerge and Samuels Model
Sadoski, Mark; McTigue, Erin M.; Paivio, Allan
2012-01-01
In this article we present a detailed Dual Coding Theory (DCT) model of decoding. The DCT model reinterprets and subsumes The LaBerge and Samuels (1974) model of the reading process which has served well to account for decoding behaviors and the processes that underlie them. However, the LaBerge and Samuels model has had little to say about…
DRC: a dual route cascaded model of visual word recognition and reading aloud.
Coltheart, M; Rastle, K; Perry, C; Langdon, R; Ziegler, J
2001-01-01
This article describes the Dual Route Cascaded (DRC) model, a computational model of visual word recognition and reading aloud. The DRC is a computational realization of the dual-route theory of reading, and is the only computational model of reading that can perform the 2 tasks most commonly used to study reading: lexical decision and reading aloud. For both tasks, the authors show that a wide variety of variables that influence human latencies influence the DRC model's latencies in exactly the same way. The DRC model simulates a number of such effects that other computational models of reading do not, but there appear to be no effects that any other current computational model of reading can simulate but that the DRC model cannot. The authors conclude that the DRC model is the most successful of the existing computational models of reading.
DEFF Research Database (Denmark)
Faramarzi, Leila; Kontogeorgis, Georgios; Thomsen, Kaj
2009-01-01
The extended UNIQUAC model [K. Thomsen, R Rasmussen, Chem. Eng. Sci. 54 (1999) 1787-1802] was applied to the thermodynamic representation of carbon dioxide absorption in aqueous monoethanolamine (MEA), methyldiethanolamine (MDEA) and varied strength mixtures of the two alkanolamines (MEA-MDEA). F......The extended UNIQUAC model [K. Thomsen, R Rasmussen, Chem. Eng. Sci. 54 (1999) 1787-1802] was applied to the thermodynamic representation of carbon dioxide absorption in aqueous monoethanolamine (MEA), methyldiethanolamine (MDEA) and varied strength mixtures of the two alkanolamines (MEA......) are included in the parameter estimation process. The previously unavailable standard state properties of the alkanolamine ions appearing in this work, i.e. MEA protonate, MEA carbamate and MDEA protonate are determined. The concentration of the species in both MEA and MDEA solutions containing CO2...
A Dual-Stage Two-Phase Model of Selective Attention
Hubner, Ronald; Steinhauser, Marco; Lehle, Carola
2010-01-01
The dual-stage two-phase (DSTP) model is introduced as a formal and general model of selective attention that includes both an early and a late stage of stimulus selection. Whereas at the early stage information is selected by perceptual filters whose selectivity is relatively limited, at the late stage stimuli are selected more efficiently on a…
Dual Mission: An Innovative Field Model for Training Social Work Students for Work with Veterans
Selber, Katherine; Chavkin, Nancy Feyl; Biggs, Mary Jo Garcia
2015-01-01
This descriptive article explores a collaborative model that blends the dual missions of training social work students to work with military personnel, veterans, and their families while serving student veterans on campus. The model consists of 2 main components: (1) a nationally recognized service component for providing academic, health and…
Glöckner, A.; Witteman, C.L.M.
2010-01-01
Intuitive-automatic processes are crucial for making judgements and decisions. The fascinating complexity of these processes has attracted many decision researchers, prompting them to start investigating intuition empirically and to develop numerous models. Dual-process models assume a clear distinc
Knock prediction for dual fuel engines by using a simplified combustion model
Institute of Scientific and Technical Information of China (English)
费少梅; 刘震涛; 严兆大
2003-01-01
The present work used a methane-air mixture chemical kinetics scheme consisting of 119 elementary reaction steps and 41 chemical species to develop a simplified combustion model for prediction of the knock in dual fuel engines. Calculated values by the model for natural gas operation showed good agreement with corresponding experimental values over a broad range of operating conditions.
Reliable dual tensor model estimation in single and crossing fibers based on jeffreys prior
J. Yang (Jianfei); D.H.J. Poot; M.W.A. Caan (Matthan); Su, T. (Tanja); C.B. Majoie (Charles); L.J. van Vliet (Lucas); F. Vos (Frans)
2016-01-01
textabstractPurpose This paper presents and studies a framework for reliable modeling of diffusion MRI using a data-acquisition adaptive prior. Methods Automated relevance determination estimates the mean of the posterior distribution of a rank-2 dual tensor model exploiting Jeffreys prior (JARD).
Dual Mission: An Innovative Field Model for Training Social Work Students for Work with Veterans
Selber, Katherine; Chavkin, Nancy Feyl; Biggs, Mary Jo Garcia
2015-01-01
This descriptive article explores a collaborative model that blends the dual missions of training social work students to work with military personnel, veterans, and their families while serving student veterans on campus. The model consists of 2 main components: (1) a nationally recognized service component for providing academic, health and…
Energy Technology Data Exchange (ETDEWEB)
Lembcke, B.; Loesler, A.C.; Caspary, W.F.; Schuernbrand, P.E.; Emrich, D.; Creutzfeldt, W.
1986-08-01
In order to delineate the clinical value of a dual-isotope fat absorption test system (FATS) using glycerol (/sup 75/Se)triether as lipid-phase marker and glycerol (/sup 125/I)trioleate as the test lipid, fecal isotope ratios from single stools (and a 72-hr stool homogenate) were compared to quantitative fecal fat excretion. The study included 11 patients without and 24 patients with steatorrhea. With a figure of 0.8% as the upper limit of normal, the test was a reliable indicator of steatorrhea with 87.5% sensitivity and 81.8% specificity; efficiency was 85.7%. Related to a prevalence of steatorrhea of 45.9% as the mean value of 1269 consecutive 72-hr specimens investigated for steatorrhea during 1978-1982, the positive (negative) predictive value of the FATS is 80.3% (87.2%). With 2% as the upper limit of normal, no false positive results ensued. It is concluded that a two-step interpretation of the FATS (0.8% limit and 2% limit) may be regarded a valid qualitative index for steatorrhea. The FATS isotope ratio using single stools correlated well with FATS ratios in the 72-hr stool homogenates (r = 0.97). FATS therefore allows a convenient estimate of steatorrhea from measuring single stools. As a quantitative measure of fecal fat excretion, the FATS is unreliable.
State of charge modeling of lithium-ion batteries using dual exponential functions
Kuo, Ting-Jung; Lee, Kung-Yen; Huang, Chien-Kang; Chen, Jau-Horng; Chiu, Wei-Li; Huang, Chih-Fang; Wu, Shuen-De
2016-05-01
A mathematical model is developed by fitting the discharging curve of LiFePO4 batteries and used to investigate the relationship between the state of charge and the closed-circuit voltage. The proposed mathematical model consists of dual exponential terms and a constant term which can fit the characteristics of dual equivalent RC circuits closely, representing a LiFePO4 battery. One exponential term presents the stable discharging behavior and the other one presents the unstable discharging behavior and the constant term presents the cut-off voltage.
Topological B-Model on Weighted Projective Spaces and Self-Dual Models in Four Dimensions
Popov, A D; Popov, Alexander D.; Wolf, Martin
2004-01-01
It was recently shown by Witten on the basis of several examples that the topological B-model whose target space is a Calabi-Yau (CY) supermanifold is equivalent to holomorphic Chern-Simons (hCS) theory on the same supermanifold. Moreover, for the supertwistor space CP^{3|4} as target space, it has been demonstrated that hCS theory on CP^{3|4} is equivalent to self-dual N=4 super Yang-Mills (SYM) theory in four dimensions. We consider as target spaces for the B-model the weighted projective spaces WCP^{3|2}(1,1,1,1|p,q) with two fermionic coordinates of weight p and q, respectively - which are CY supermanifolds for p+q=4 - and discuss hCS theory on them. By using twistor techniques, we obtain certain field theories in four dimensions which are equivalent to hCS theory. These theories turn out to be self-dual truncations of N=4 SYM theory or of its twisted (topological) version.
Directory of Open Access Journals (Sweden)
Pawel Boguslawski
2016-02-01
Full Text Available There is an increasing need for building models that permit interior navigation, e.g., for escape route analysis. This paper presents a non-manifold Computer-Aided Design (CAD data structure, the dual half-edge based on the Poincaré duality that expresses both the geometric representations of individual rooms and their topological relationships. Volumes and faces are expressed as vertices and edges respectively in the dual space, permitting a model just based on the storage of primal and dual vertices and edges. Attributes may be attached to all of these entities permitting, for example, shortest path queries between specified rooms, or to the exterior. Storage costs are shown to be comparable to other non-manifold models, and construction with local Euler-type operators is demonstrated with two large university buildings. This is intended to enhance current developments in 3D Geographic Information Systems for interior and exterior city modelling.
Absorptive capacity, technological innovation, and product life cycle: a system dynamics model
National Research Council Canada - National Science Library
Zou, Bo; Guo, Feng; Guo, Jinyu
2016-01-01
.... Based on interviews with 24 Chinese firms, this study develops a system-dynamics model that incorporates an important feedback loop among absorptive capacity, technological innovation, and product life cycle (PLC...
Dual geometric worm algorithm for two-dimensional discrete classical lattice models
Hitchcock, Peter; Sørensen, Erik S.; Alet, Fabien
2004-07-01
We present a dual geometrical worm algorithm for two-dimensional Ising models. The existence of such dual algorithms was first pointed out by Prokof’ev and Svistunov [N. Prokof’ev and B. Svistunov, Phys. Rev. Lett. 87, 160601 (2001)]. The algorithm is defined on the dual lattice and is formulated in terms of bond variables and can therefore be generalized to other two-dimensional models that can be formulated in terms of bond variables. We also discuss two related algorithms formulated on the direct lattice, applicable in any dimension. These latter algorithms turn out to be less efficient but of considerable intrinsic interest. We show how such algorithms quite generally can be “directed” by minimizing the probability for the worms to erase themselves. Explicit proofs of detailed balance are given for all the algorithms. In terms of computational efficiency the dual geometrical worm algorithm is comparable to well known cluster algorithms such as the Swendsen-Wang and Wolff algorithms, however, it is quite different in structure and allows for a very simple and efficient implementation. The dual algorithm also allows for a very elegant way of calculating the domain wall free energy.
Drug Absorption Modeling as a Tool to Define the Strategy in Clinical Formulation Development
Kuentz, Martin
2008-01-01
The purpose of this mini review is to discuss the use of physiologically-based drug absorption modeling to guide the formulation development. Following an introduction to drug absorption modeling, this article focuses on the preclinical formulation development. Case studies are presented, where the emphasis is not only the prediction of absolute exposure values, but also their change with altered input values. Sensitivity analysis of technologically relevant parameters, like the drug’s partic...
Directory of Open Access Journals (Sweden)
Orlando Arévalo
Full Text Available In everyday life, humans interact with a dynamic environment often requiring rapid adaptation of visual perception and motor control. In particular, new visuo-motor mappings must be learned while old skills have to be kept, such that after adaptation, subjects may be able to quickly change between two different modes of generating movements ('dual-adaptation'. A fundamental question is how the adaptation schedule determines the acquisition speed of new skills. Given a fixed number of movements in two different environments, will dual-adaptation be faster if switches ('phase changes' between the environments occur more frequently? We investigated the dynamics of dual-adaptation under different training schedules in a virtual pointing experiment. Surprisingly, we found that acquisition speed of dual visuo-motor mappings in a pointing task is largely independent of the number of phase changes. Next, we studied the neuronal mechanisms underlying this result and other key phenomena of dual-adaptation by relating model simulations to experimental data. We propose a simple and yet biologically plausible neural model consisting of a spatial mapping from an input layer to a pointing angle which is subjected to a global gain modulation. Adaptation is performed by reinforcement learning on the model parameters. Despite its simplicity, the model provides a unifying account for a broad range of experimental data: It quantitatively reproduced the learning rates in dual-adaptation experiments for both direct effect, i.e. adaptation to prisms, and aftereffect, i.e. behavior after removal of prisms, and their independence on the number of phase changes. Several other phenomena, e.g. initial pointing errors that are far smaller than the induced optical shift, were also captured. Moreover, the underlying mechanisms, a local adaptation of a spatial mapping and a global adaptation of a gain factor, explained asymmetric spatial transfer and generalization of prism
Modeling moisture absorption kinetics of barley grain using viscoelastic model and neural networks
Directory of Open Access Journals (Sweden)
M Kamali
2015-09-01
Full Text Available Introduction: Barley is one of the most important grains with high digestible starch making it a main source of energy in human nutrition as well as in livestock rations formulation and feeding. Starch is the main part of barley grain and it has an inverse relation with its protein. It has a digestible foodstuff of 80 to 84 percent of its dry matter content. Barley as livestock foodstuff should be processed and it is done in several ways. A customary method for processing barley in dairy farms is its size reduction by milling (Hunt, 1996. An alternative method of barley processing is steam rolling. However, because of the high cost of steam generators a method of soaking with heating has been considered as an alternative method for steam rolling (Yang et al., 2000. The rate of moisture absorption by grains during the soaking process varies considerably and depends on the size of the grain, water temperature and the length of soaking. High temperature water soaking is an ordinary way to reduce the time duration for reaching a high rate of moisture absorption during the soaking process (Kashaninejad et al., 2009. Various studies have shown that these models have adequate accuracy in analyzing drying and moisture absorption processes for most agricultural products (Abu-Ghannam and McKenna, 1997. Some researchers have modeled beans moisture absorption behavior using 14 mathematical models and found that the Weibull model had the most conformity with variations in experimental data (Shafaei and Masoumi, 2014c. Observations made by researchers indicate that the moisture absorption process in various materials encompasses a primary phase with a fast rate and a second phase with a lower rate. The second phase in moisture absorption is called the relaxation phase. The main problem with all the mathematical and experimental models is the lack of the model’s ability to evaluate the rate of moisture absorption in the secondary phase. Artificial Neural
DOUBLE SHELL TANK (DST) HYDROXIDE DEPLETION MODEL FOR CARBON DIOXIDE ABSORPTION
Energy Technology Data Exchange (ETDEWEB)
OGDEN DM; KIRCH NW
2007-10-31
This document generates a supernatant hydroxide ion depletion model based on mechanistic principles. The carbon dioxide absorption mechanistic model is developed in this report. The report also benchmarks the model against historical tank supernatant hydroxide data and vapor space carbon dioxide data. A comparison of the newly generated mechanistic model with previously applied empirical hydroxide depletion equations is also performed.
Moisan, John R.; Moisan, Tiffany A. H.; Linkswiler, Matthew A.
2011-01-01
Phytoplankton absorption spectra and High-Performance Liquid Chromatography (HPLC) pigment observations from the Eastern U.S. and global observations from NASA's SeaBASS archive are used in a linear inverse calculation to extract pigment-specific absorption spectra. Using these pigment-specific absorption spectra to reconstruct the phytoplankton absorption spectra results in high correlations at all visible wavelengths (r(sup 2) from 0.83 to 0.98), and linear regressions (slopes ranging from 0.8 to 1.1). Higher correlations (r(sup 2) from 0.75 to 1.00) are obtained in the visible portion of the spectra when the total phytoplankton absorption spectra are unpackaged by multiplying the entire spectra by a factor that sets the total absorption at 675 nm to that expected from absorption spectra reconstruction using measured pigment concentrations and laboratory-derived pigment-specific absorption spectra. The derived pigment-specific absorption spectra were further used with the total phytoplankton absorption spectra in a second linear inverse calculation to estimate the various phytoplankton HPLC pigments. A comparison between the estimated and measured pigment concentrations for the 18 pigment fields showed good correlations (r(sup 2) greater than 0.5) for 7 pigments and very good correlations (r(sup 2) greater than 0.7) for chlorophyll a and fucoxanthin. Higher correlations result when the analysis is carried out at more local geographic scales. The ability to estimate phytoplankton pigments using pigment-specific absorption spectra is critical for using hyperspectral inverse models to retrieve phytoplankton pigment concentrations and other Inherent Optical Properties (IOPs) from passive remote sensing observations.
Asymmetric and common absorption of shocks in nonlinear autoregressive models
Dijk, Dick van; Franses, Philip Hans; Boswijk, Peter
2000-01-01
textabstractA key feature of many nonlinear time series models is that they allow for the possibility that the model structure experiences changes, depending on for example the state of the economy or of the financial market. A common property of these models is that it generally is not possible to fully understand the structure of the model by considering the estimated values of the model parameters only. Put differently, it often is difficult to interpret a specific nonlinear model. To shed...
A polar cap absorption model optimization based on the vertical ionograms analysis
Zaalov, N. Y.; Moskaleva, E. V.
2016-11-01
Space weather events significantly affect the high frequency (HF) radio wave propagation. The now-casting and forecasting of HF radio wave absorption is important for the HF communication industries. This paper assimilates vertical sounding data into an absorption model to improve its performance as a now-casting tool. The approach is a modification of the algorithm elaborated by Sauer and Wilkinson, which is based on the riometer data. The optimization is focused on accounting for short timescale variation of the absorption. It should be noted that the expression of the frequency dependence of absorption induced by the energetic particle precipitation employed in Sauer and Wilkinson model is based on the riometer data at frequencies of 20, 30, and 50 MHz. The approach suggested in this paper provides an opportunity for expanding the frequency dependence of the absorption for frequencies below 10 MHz. The simulation of the vertical ionograms in the polar cap region uses a computational model designed to overcome the high frequency wave propagation problem in high latitude of the Earth. HF radio wave absorption induced by solar UV illumination, X-ray flares and energetic particles precipitation is taken into consideration in our model. The absorption caused by the energetic particle precipitation is emphasized, because the study is focused on HF wave propagation in polar cap region. A comparison of observed and simulated vertical ionograms enables the coefficients, which relate absorption (day-time and night-time) to integral proton flux to be refined. The values of these coefficients determined from evaluation of the data recorded by any reliable ionosonde are valid for absorption calculation in high-latitude region.
Theoretical analysis of electronic absorption spectra of vitamin B12 models
Andruniow, Tadeusz; Kozlowski, Pawel M.; Zgierski, Marek Z.
2001-10-01
Time-dependent density-functional theory (TD-DFT) is applied to analyze the electronic absorption spectra of vitamin B12. To accomplish this two model systems were considered: CN-[CoIII-corrin]-CN (dicyanocobinamide, DCC) and imidazole-[CoIII-corrin]-CN (cyanocobalamin, ImCC). For both models 30 lowest excited states were calculated together with transition dipole moments. When the results of TD-DFT calculations were directly compared with experiment it was found that the theoretical values systematically overestimate experimental data by approximately 0.5 eV. The uniform adjustment of the calculated transition energies allowed detailed analysis of electronic absorption spectra of vitamin B12 models. All absorption bands in spectral range 2.0-5.0 eV were readily assigned. In particular, TD-DFT calculations were able to explain the origin of the shift of the lowest absorption band caused by replacement of the-CN axial ligand by imidazole.
Simulation Model for Dynamic Operation of Double-Effect Absorption Chillers
Directory of Open Access Journals (Sweden)
Ahmed Mojahid Sid Ahmed Mohammed Salih
2014-07-01
Full Text Available The development in the field of refrigeration and air conditioning systems driven by absorption cycles acquired a considerable importance recently. For commercial absorption chillers, an essential challenge for creating chiller model certainly is the shortage of components technical specifications. These kinds of specifications are usually proprietary for chillers producers. In this paper, a double-effect parallel-flow-type steam absorption chiller model based on thermodynamic and energy equations is presented. The chiller studied is Lithium bromide-water with capacity of 1250 RT (Refrigeration Tons. The governing equations of the dynamic operation of the chiller are developed. From available design information, the values of the overall heat transfer coefficients multiplied by the surface area are computed. The dynamic operation of the absorption chiller is simulated to study the performance of the system. The model is able to provide essential details of the temperature, concentration, and flow rate at each state point in the chiller.
Tylka, Tracy L
2011-06-01
Although muscularity and body fat concerns are central to conceptualizing men's body image, they have not been examined together within existing structural models. This study refined the tripartite influence model (Thompson, Heinberg, Altabe, & Tantleff-Dunn, 1999) by including dual body image pathways (muscularity and body fat dissatisfaction) to engagement in muscular enhancement and disordered eating behaviors, respectively, and added dating partners as a source of social influence. Latent variable structural equation modeling analyses supported this quadripartite model in 473 undergraduate men. Nonsignificant paths were trimmed and two unanticipated paths were added. Muscularity dissatisfaction and body fat dissatisfaction represented dual body image pathways to men's engagement in muscularity enhancement behaviors and disordered eating behaviors, respectively. Pressures to be mesomorphic from friends, family, media, and dating partners made unique contributions to the model. Internalization of the mesomorphic ideal, muscularity dissatisfaction, and body fat dissatisfaction played key meditational roles within the model.
DEFF Research Database (Denmark)
Gong, M.; Zhang, Y.; Weschler, Charles J.
2014-01-01
A transient model is developed to predict dermal absorption of gas-phase chemicals via direct air-to-skin-to-blood transport under non-steady-state conditions. It differs from published models in that it considers convective mass-transfer resistance in the boundary layer of air adjacent to the skin....... Results calculated with this transient model are in good agreement with the limited experimental results that are available for comparison. The sensitivity of the modeled estimates to key parameters is examined. The model is then used to estimate air-to-skin-to-blood absorption of six phthalate esters...
Game Perspectives of DEA Models and Their Duals
Directory of Open Access Journals (Sweden)
Fang Xu
2013-01-01
Full Text Available We present a series of two-person games, which lead to various DEA models. The relationship between the DEA models and the games is explicit in our setting, although the Nash equilibrium solutions do not generally exist. Besides the classic DEA models, we also establish an explicit relationship between the games and some extended DEA models, such as free disposable hull DEA models and “negative” or “inverted” DEA models.
An Image Fusion Method Based on NSCT and Dual-channel PCNN Model
Nianyi Wang; Yide Ma; Weilan Wang; Shijie Zhou
2014-01-01
NSCT is one of useful multiscale geometric analysis tools, which takes full advantage of geometric regularity of image intrinsic structures. The dual-channel PCNN is a simplified PCNN model, which can process multiple images by a single PCNN. This saves time in the process of image fusion and cuts down computational complexity. In this paper, we present a new image fusion scheme based on NSCT and dual-channel PCNN. Firstly, the fusion rules of subband coefficients of NSCT are discussed. For t...
Self-Dual Chern-Simons Solitons and Generalized Heisenberg Ferromagnet Models
Oh, P; Oh, Phillial
1996-01-01
We consider the (2+1)-dimensional gauged Heisenberg ferromagnet model coupled with the Chern-Simons gauge fields. Self-dual Chern-Simons solitons, the static zero energy solution saturating Bogomol'nyi bounds, are shown to exist when the generalized spin variable is valued in the Hermitian symmetric spaces G/H. By gauging the maximal torus subgroup of H, we obtain self-dual solitons which satisfy vortex-type nonlinear equations thereby extending the two dimensional instantons in a nontrivial way. An explicit example for the CP(N) case is given.
Genetic and Environmental Bases of Reading and Spelling: A Unified Genetic Dual Route Model
Bates, Timothy C.; Castles, Anne; Luciano, Michelle; Wright, Margaret J.; Coltheart, Max; Martin, Nicholas G.
2007-01-01
We develop and test a dual-route model of genetic effects on reading aloud and spelling, based on irregular and non-word reading and spelling performance assessed in 1382 monozygotic and dizygotic twins. As in earlier research, most of the variance in reading was due to genetic effects. However, there were three more specific conclusions: the…
van Zomeren, Martijn; Leach, Colin Wayne; Spears, Russell
To explain the psychology behind individuals' motivation to participate in collective action against collective disadvantage (e.g., protest marches), the authors introduce a dynamic dual pathway model of approach coping that integrates many common explanations of collective action (i.e., group
Sibley, Chris G.; Overall, Nickola C.
2011-01-01
We tested a dual process motivational model of ambivalent sexism and gender differences in intimate partner preferences. Meta-analysis of 32 samples (16 with men, 16 with women; N = 5,459) indicated that Benevolent Sexism (BS) in women was associated with greater preferences for high-resource partners (r = 0.24), whereas Hostile Sexism (HS) in men…
Saab, Rim; Tausch, Nicole; Spears, Russell; Cheung, Wing-Yee
2015-01-01
We examined predictors of collective action among bystander group members in solidarity with a disadvantaged group by extending the dual pathway model of collective action, which proposes one efficacy-based and one emotion-based path to collective action (Van Zomeren, Spears, Fischer, & Leach, 2004)
Experimental evidence for a dual pathway model analysis of coping with the climate crisis
van Zomeren, Martijn; Spears, Russell; Leach, Colinn Wayne
2010-01-01
Two experiments examined the psychological power of fear and group efficacy beliefs to increase environmental action intentions against the climate crisis Extending a dual pathway model of coping with collective disadvantage results showed evidence for emotion-focused approach coping Environmental a
Applicability of the Dual-Factor Model of Mental Health for College Students
Eklund, Katie; Dowdy, Erin; Jones, Camille; Furlong, Michael
2011-01-01
This study explores the utility of a dual-factor model of mental health in which the concepts of mental illness and mental wellness are integrated. Life satisfaction, emotional symptoms, personal adjustment, and clinical symptoms were assessed with a sample of 240 college students. Participants were organized into four groups based on levels of…
An engineering treatise on the CARE II dual mode and coverage models
1976-01-01
A mathematical model used to calculate the reliability of any dual-mode, spare-switching computer system was described, and some illustrative examples were presented. The possibility of extending the resultant computer program further was also examined, enabling it, in particular, to accommodate computer configurations involving more than two modes of operation.
Shao, W.; Bogaard, T.A.; Bakker, M.
2014-01-01
Preferential flow paths, such as cracks, macropores, fissures, pipes etc. are common features of highly heterogeneous slopes. During intense rainstorms, preferential flow has a significant influence on subsurface flow and slope stability. Dual-permeability models are widely used to simulate
Shao, W.; Bogaard, T.A.; Bakker, M.
2014-01-01
Preferential flow paths, such as cracks, macropores, fissures, pipes etc. are common features of highly heterogeneous slopes. During intense rainstorms, preferential flow has a significant influence on subsurface flow and slope stability. Dual-permeability models are widely used to simulate preferen
Nijstad, B.A.; De Dreu, C.K.W.; Rietzschel, E.F.; Baas, M.
2010-01-01
The dual pathway to creativity model argues that creativity-the generation of original and appropriate ideas-is a function of cognitive flexibility and cognitive persistence, and that dispositional or situational variables may influence creativity either through their effects on flexibility, on pers
Longitudinal Study of a Dual-Factor Model of Mental Health in Chinese Youth
Xiong, Junmei; Qin, Yi; Gao, Miaomiao; Hai, Man
2017-01-01
By incorporating psychopathology and subjective well-being (SWB), the dual-factor model of mental health (DFM) can comprehensively measure psychological health. We examined the utility of the DFM among 1,293 Chinese adolescents (Grades 7-12). Furthermore, we examined the dynamics of mental health group membership via a two-wave longitudinal study…
Jixiang Zhou; Yong Wang; Xiaoming Yan
2014-01-01
We investigate a joint pricing and purchasing problem for the dual-channel newsvendor model with the assumption that only the mean and variance of the demand are known. The newsvendor in our model simultaneously distributes a single product through traditional retail and Internet. A robust optimization approach that maximizes the worst-case profit is adapted under the aforementioned conditions to model demand uncertainty and linear clearing functions that characterize the relationship between...
Dual lattice representations for O(N and CP(N−1 models with a chemical potential
Directory of Open Access Journals (Sweden)
Falk Bruckmann
2015-10-01
Full Text Available We derive dual representations for O(N and CP(N−1 models on the lattice. In terms of the dual variables the partition sums have only real and positive contributions also at finite chemical potential. Thus the complex action problem of the conventional formulation is overcome and using the dual variables Monte Carlo simulations are possible at arbitrary chemical potential.
Four-State Model for Three-Branch Molecule's Two-Photon Absorption Properties
Institute of Scientific and Technical Information of China (English)
SU Yan; WANG Pei-Ji; ZHAO Peng; RONG Zhen-Yu
2006-01-01
@@ We present a four-state model for calculating the two-photon absorption of multi-branched molecules by using the time-depended function method. The numerical results indicate that the two-photon absorption cross section has a strong enhancement for three-branch molecules compared to two-branch structures. The maximal two-photon-absorption cross section is 2.358 × 10-47 cm 4 s/photon. At the same time, the charge-transfer process for the charge-transfer states is visualized in order to explain mechanism about the maximal TPA cross section.
Asymmetric and common absorption of shocks in nonlinear autoregressive models
D.J.C. van Dijk (Dick); Ph.H.B.F. Franses (Philip Hans); H.P. Boswijk (Peter)
2000-01-01
textabstractA key feature of many nonlinear time series models is that they allow for the possibility that the model structure experiences changes, depending on for example the state of the economy or of the financial market. A common property of these models is that it generally is not possible to
Asymmetric and common absorption of shocks in nonlinear autoregressive models
D.J.C. van Dijk (Dick); Ph.H.B.F. Franses (Philip Hans); H.P. Boswijk (Peter)
2000-01-01
textabstractA key feature of many nonlinear time series models is that they allow for the possibility that the model structure experiences changes, depending on for example the state of the economy or of the financial market. A common property of these models is that it generally is not possible to
DEFF Research Database (Denmark)
Cokpekin, Özge
recognize potentially valuable external knowledge to be able to start the knowledge absorption process has not been discussed. This paper suggests creativity management and argues that stimulating meaningfully novel behavior positively influences the recognition ability and the communication it enhances......The benefits of the open innovation business model and the absorptive capacity necessary to acquire and utilize external knowledge have been discussed extensively. An emerging literature stream has identified certain intra-organizational antecedents of absorptive capacity. However how firms...... alleviates the Not-Invented-Here syndrome. Based on the absorptive capacity and organizational creativity literature a model consists of five hypotheses is derived and tested on a sample of 346 Danish SMEs. The results indicate that creativity management plays a positive role in the development...
Liu, Ying; Yi, Tao; Di, Huan; Xiao, Lu; He, Ji-Kui
2011-08-01
A new dynamic in vitro intestinal absorption model for screening and evaluating lipid formulations was established by means of the characteristics of the intestinal digestion and absorption of the lipid formulations. This model was composed of two systems, including intestinal digestion and the intestinal tissue culture, which drew the evaluation method of intestinal absorption into the in vitro lipolysis model. The influence of several important model parameters such as Ca2+, D-glucose, K+ on the two systems of this model has been investigated. The results showed that increasing of Ca2+ concentration could be significantly conductive to intestinal digestion. The increasing of D-glucose concentration could stepped significantly down the decay of the intestinal activity. K+ was able to maintain intestinal activity, but the influence of different concentration levels on the decay of the intestinal activity was of no significant difference. Thus the model parameters were set up as follows: Ca2+ for 10 mmol x L(-1), D-glucose for 15 mmol x L(-1) and K+ for 5.5 mmol x L(-1). Type I lipid formulation was evaluated with this model, and there was a significant correlation between the absorption curve in vitro and absorption curve in vivo of rats (r = 0.995 6, P lipid formulations.
Atomistic modeling of H absorption in Pd nanoparticles
Energy Technology Data Exchange (ETDEWEB)
Ruda, M., E-mail: ruda@cab.cnea.gov.a [Centro Atomico Bariloche, 8400 Bariloche (Argentina); Centro Regional Universitario Bariloche, U.N. Comahue (Argentina); Crespo, E.A., E-mail: crespo@uncoma.edu.a [Depto. de Fisica, Fac. de Ingenieria, Universidad Nacional del Comahue, Buenos Aires 1400, 8300 Neuquen (Argentina); Debiaggi, S. Ramos de, E-mail: ramos@uncoma.edu.a [Depto. de Fisica, Fac. de Ingenieria, Universidad Nacional del Comahue, Buenos Aires 1400, 8300 Neuquen (Argentina); CONICET (Argentina)
2010-04-16
Size affects the properties of absorption of H in Palladium nanoparticles. Because of their higher proportion of surface atoms compared to the bulk, the pressure-composition (P-C) isotherms of the nanoparticles are modified. We performed atomistic simulations for different-sized Pd nanoparticles and for the bulk at different H concentrations using the Monte Carlo technique in the TP{mu}N ensemble to calculate the P-C isotherms. The Pd-H interatomic potentials are of the Embedded Atom (EAM) type and have been recently developed by Zhou et al. . From the related van't Hoff equation we obtained |{Delta}H{sup o}| = (28 {+-} 7) kJ/0.5 mol of H{sub 2} and |{Delta}S{sup o}| = (71 {+-} 19) J/0.5 mol of H{sub 2}.K for the PdH formation in the bulk. For Pd nanoparticles previous simulations results based on a different set of EAM potentials showed that H was absorbed primarily in the surface before diffusing into the inside of small Pd clusters . Considering the better performance of Zhou's potentials for the bulk, in this work we analyzed the evolution of the equilibrium microstructure of Pd nanoparticles as a function of their size and H concentration. Our simulations predict enhanced hydrogen solubilities and vanishing plateaux when compared to the bulk and that H is absorbed in the subsurface of the nanoparticles.
National Research Council Canada - National Science Library
NOMIYAMA, Ryosuke; SAGO, Yuki; YASUTAKE, Daisuke; KITANO, Masaharu
2012-01-01
.... The rate of root salt absorption of corn and sunflower plants under the salinized condition were analyzed by applying the transpiration-integrated model of root ion absorption affected by leaf transpiration...
Chen, Sheng-Hui; Wang, Hsuan-Wen; Chang, Ting-Wei
2012-03-12
Considering the Mott-Davis density of state model and Rayleigh scattering effect, we present an approach to model the absorption profile of microcrystalline silicon thin films in this paper. Maxwell-Garnett effective medium theory was applied to analyze the absorption curves. To validate the model, several experimental profiles have been established and compared with those results from the model. With the assistance of the genetic algorithm, our results show that the absorption curves from the model are in good agreement with the experiments. Our findings also indicate that, as the crystal volume fraction increases, not only do the defects in amorphous silicon reduce, but the bulk scattering effect is gradually enhanced as well.
Thermodynamic Modeling of an Ammonia-Water Absorption System Associated with a Microturbine
Edson Bazzo; Janilson Arcangelo Rossa
2009-01-01
Thermodynamic modeling and Second Law analysis of a small-scale cogeneration system consisting of a 5 refrigerant ton absorption chiller connected by a thermosyphon heat exchanger to a 28 kWe natural gas microturbine are presented. The proposed configuration changes the heat source of the absorption chiller, replacing the original natural gas burning system. A computational algorithm was programmed to analyze the global efficiency of the combined cooling and power plant and the coefficient of...
Modeling of dual gradient elution in ion exchange and mixed-mode chromatography.
Lee, Yi Feng; Schmidt, Michael; Graalfs, Heiner; Hafner, Mathias; Frech, Christian
2015-10-23
Protein retention using dual gradient elution in ion exchange- and mixed-mode chromatography can be modeled using the combination of a modified Yamamoto's LGE model and a conversion term to correlate the elution salt concentration and pH at any given gradient slope. Incorporation of the pH dependence of the binding charges into the model also provides some insights on the dual effects of salt and pH in protein-ligand interaction. The fitted thermodynamic parameters (ΔGP(0)/RT, ΔGS(0)/RT, number of charged amino acids involved in binding) of the dual gradient elution data using lysozyme and mAbs on SP Sepharose(®) FF, Eshmuno(®) HCX, and Capto(®) MMC ImpRes were consistent to the results of mono gradient data. This gives rise to an approach to perform thermodynamic modeling of protein retention in ion exchange- and mixed-mode chromatography by combining both salt and pH gradient into a single run of dual gradient elution which will increase time and cost efficiency. The dual gradients used in this study encompassed a wide range of pH (4-8) and NaCl concentrations (0-1M). Curve fits showed that ΔGP(0)/RT is protein type and ligand dependent. ΔGS(0)/RT is strongly dependent on the stationary phase but not the protein. For mAb04 on mixed-mode resin Capto(®) MMC, ΔGS(0)/RT is 5-6 times higher than the result reported for the same protein on cation exchanger Fractogel(®) EMD SO3(-) (S).
Crum, Matthew F; Trevaskis, Natalie L; Williams, Hywel D; Pouton, Colin W; Porter, Christopher J H
2016-04-01
In vitro lipid digestion models are commonly used to screen lipid-based formulations (LBF), but in vitro-in vivo correlations are in some cases unsuccessful. Here we enhance the scope of the lipid digestion test by incorporating an absorption 'sink' into the experimental model. An in vitro model of lipid digestion was coupled directly to a single pass in situ intestinal perfusion experiment in an anaesthetised rat. The model allowed simultaneous real-time analysis of the digestion and absorption of LBFs of fenofibrate and was employed to evaluate the influence of formulation digestion, supersaturation and precipitation on drug absorption. Formulations containing higher quantities of co-solvent and surfactant resulted in higher supersaturation and more rapid drug precipitation in vitro when compared to those containing higher quantities of lipid. In contrast, when the same formulations were examined using the coupled in vitro lipid digestion - in vivo absorption model, drug flux into the mesenteric vein was similar regardless of in vitro formulation performance. For some drugs, simple in vitro lipid digestion models may underestimate the potential for absorption from LBFs. Consistent with recent in vivo studies, drug absorption for rapidly absorbed drugs such as fenofibrate may occur even when drug precipitation is apparent during in vitro digestion.
Predicting Anticancer Drug Responses Using a Dual-Layer Integrated Cell Line-Drug Network Model.
Directory of Open Access Journals (Sweden)
Naiqian Zhang
Full Text Available The ability to predict the response of a cancer patient to a therapeutic agent is a major goal in modern oncology that should ultimately lead to personalized treatment. Existing approaches to predicting drug sensitivity rely primarily on profiling of cancer cell line panels that have been treated with different drugs and selecting genomic or functional genomic features to regress or classify the drug response. Here, we propose a dual-layer integrated cell line-drug network model, which uses both cell line similarity network (CSN data and drug similarity network (DSN data to predict the drug response of a given cell line using a weighted model. Using the Cancer Cell Line Encyclopedia (CCLE and Cancer Genome Project (CGP studies as benchmark datasets, our single-layer model with CSN or DSN and only a single parameter achieved a prediction performance comparable to the previously generated elastic net model. When using the dual-layer model integrating both CSN and DSN, our predicted response reached a 0.6 Pearson correlation coefficient with observed responses for most drugs, which is significantly better than the previous results using the elastic net model. We have also applied the dual-layer cell line-drug integrated network model to fill in the missing drug response values in the CGP dataset. Even though the dual-layer integrated cell line-drug network model does not specifically model mutation information, it correctly predicted that BRAF mutant cell lines would be more sensitive than BRAF wild-type cell lines to three MEK1/2 inhibitors tested.
Feasibility of a 3D human airway epithelial model to study respiratory absorption.
Reus, Astrid A; Maas, Wilfred J M; Jansen, Harm T; Constant, Samuel; Staal, Yvonne C M; van Triel, Jos J; Kuper, C Frieke
2014-03-01
The respiratory route is an important portal for human exposure to a large variety of substances. Consequently, there is an urgent need for realistic in vitro strategies for evaluation of the absorption of airborne substances with regard to safety and efficacy assessment. The present study investigated feasibility of a 3D human airway epithelial model to study respiratory absorption, in particular to differentiate between low and high absorption of substances. Bronchial epithelial models (MucilAir™), cultured at the air-liquid interface, were exposed to eight radiolabeled model substances via the apical epithelial surface. Absorption was evaluated by measuring radioactivity in the apical compartment, the epithelial cells and the basolateral culture medium. Antipyrine, caffeine, naproxen and propranolol were highly transported across the epithelial cell layer (>5%), whereas atenolol, mannitol, PEG-400 and insulin were limitedly transported (absorption. The intra-experimental reproducibility of the results was considered adequate based on an average coefficient of variation (CV) of 15%. The inter-experimental reproducibility of highly absorbed compounds was in a similar range (CV of 15%), but this value was considerably higher for those compounds that were limitedly absorbed. No statistical significant differences between different donors and experiments were observed. The present study provides a simple method transposable in any lab, which can be used to rank the absorption of chemicals and pharmaceuticals, and is ready for further validation with respect to reproducibility and capacity of the method to predict respiratory transport in humans.
Alvarado, Matthew J.; Lonsdale, Chantelle R.; Macintyre, Helen L.; Bian, Huisheng; Chin, Mian; Ridley, David A.; Heald, Colette L.; Thornhill, Kenneth L.; Anderson, Bruce E.; Cubison, Michael J.; Jimenez, Jose L.; Kondo, Yutaka; Sahu, Lokesh K.; Dibb, Jack E.; Wang, Chien
2016-07-01
Accurate modeling of the scattering and absorption of ultraviolet and visible radiation by aerosols is essential for accurate simulations of atmospheric chemistry and climate. Closure studies using in situ measurements of aerosol scattering and absorption can be used to evaluate and improve models of aerosol optical properties without interference from model errors in aerosol emissions, transport, chemistry, or deposition rates. Here we evaluate the ability of four externally mixed, fixed size distribution parameterizations used in global models to simulate submicron aerosol scattering and absorption at three wavelengths using in situ data gathered during the 2008 Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) campaign. The four models are the NASA Global Modeling Initiative (GMI) Combo model, GEOS-Chem v9-02, the baseline configuration of a version of GEOS-Chem with online radiative transfer calculations (called GC-RT), and the Optical Properties of Aerosol and Clouds (OPAC v3.1) package. We also use the ARCTAS data to perform the first evaluation of the ability of the Aerosol Simulation Program (ASP v2.1) to simulate submicron aerosol scattering and absorption when in situ data on the aerosol size distribution are used, and examine the impact of different mixing rules for black carbon (BC) on the results. We find that the GMI model tends to overestimate submicron scattering and absorption at shorter wavelengths by 10-23 %, and that GMI has smaller absolute mean biases for submicron absorption than OPAC v3.1, GEOS-Chem v9-02, or GC-RT. However, the changes to the density and refractive index of BC in GC-RT improve the simulation of submicron aerosol absorption at all wavelengths relative to GEOS-Chem v9-02. Adding a variable size distribution, as in ASP v2.1, improves model performance for scattering but not for absorption, likely due to the assumption in ASP v2.1 that BC is present at a constant mass fraction
Directory of Open Access Journals (Sweden)
Jiang-Tao Li
2015-01-01
Full Text Available The nonlinear dual-porosity flow model, specifically considering the quadratic pressure gradient term, wellbore storage coefficient, well skin factor, and interporosity flow of matrix to natural fractures, was established for well production in a naturally fractured formation and then solved using a semianalytical method, including Laplace transform and a transformation of the pressure function. Analytical solution of the model in Laplace space was converted to numerical solution in real space using Stehfest numerical inversion. Nonlinear flow process for well production in a naturally fractured formation with different external boundaries was simulated and analyzed using standard pressure curves. Influence of the quadratic pressure gradient coefficient on pressure curves was studied qualitatively and quantitatively in conditions of a group of fixed model parameters. The research results show that the semianalytical modelling method is applicable in simulating the nonlinear dual-porosity flow behavior.
Pang, Yafei; Yang, Ming; Chen, Xuying; He, Wei; Li, Shiyang; Li, Chaodong
2011-08-01
An analytical model is presented to explain the effects of dual-frequency drive on the plate ultrasonic motor in this paper. The experimental prototype is a plate ultrasonic motor using single-phase asymmetric excitation, which can work under a single vibration or multiple vibration modes. Based on the linear superposition of vibrations with two different excitation frequencies, an analytical model is established using the classic Coulomb friction model, and the non-load rotation speed and maximum stall torque are deduced. Moreover, some crucial parameters such as preload and dead-zone in dual-frequency superposition model are identified or modified automatically by searching for the maximum correlation coefficient between simulation and experimental data using single-frequency drive. It is found that simulation and experiment results agree well when no excitation frequency component is at resonance.
Fiori, R. A. D.; Danskin, D. W.
2016-11-01
Energetic protons can penetrate into the ionosphere increasing ionization in the D region causing polar cap absorption that may potentially block high-frequency radio communications for transpolar flights. The protons are guided by the geomagnetic field into the high-latitude polar cap region. Riometers monitor variations in ionospheric absorption by observing the level of background cosmic radio noise. Current polar cap absorption modeling techniques are based on the linear relationship between absorption and the square root of the integral proton flux, which has previously only been demonstrated using data from a single high-latitude polar station. The proportionality constant describing this relationship is evaluated for two different polar cap absorption events occurring 7-11 March 2012 and 23 January 2012 to 1 February 2012. Examination of the proportionality constant using data from riometers distributed between 60° and 90° magnetic latitude reveals a previously unreported latitudinal dependence for data at magnetic latitudes of ≤66.8° on the dayside and ≤70.8° on the nightside. Incorporating the latitudinal dependence into the current D Region Absorption Prediction absorption model improves the agreement between measurement-derived and modeled parameters by increasing the correlation coefficient between data sets, reducing the root-mean-square error, and reducing the bias.
Prediction models for performance and emissions of a dual fuel CI engine using ANFIS
Indian Academy of Sciences (India)
A Adarsh Rai; P Srinivasa Pai; B R Shrinivasa Rao
2015-04-01
Dual fuel engines are being used these days to overcome shortage of fossil fuels and fulfill stringent exhaust gas emission regulations. They have several advantages over conventional diesel engines. In this context, this paper makes use of experimental results obtained from a dual fuel engine for developing models to predict performance and emission parameters. Conventional modelling efforts to understand the relationships between the input and the output variables, requires thermodynamic analysis which is complex and time consuming. As a result, efforts have been made to use artificial intelligence modelling techniques like fuzzy logic, Artificial Neural Network (ANN), Genetic Algorithm (GA), etc. This paper uses a neuro fuzzy modelling technique, Adaptive Neuro Fuzzy Inference System (ANFIS) for developing prediction models for performance and emission parameter of a dual fuel engine. Percentage load, percentage Liquefied Petroleum Gas (LPG) and Injection Timing (IT) have been used as input parameters, whereas output parameters include Brake Specific Energy Consumption (BSEC), Brake Thermal Efficiency (BTE), Exhaust Gas Temperature (EGT) and smoke. In order to further improve the prediction accuracy of the model, GA has been used to optimize ANFIS. GA optimized ANFIS gives higher prediction accuracy of more than 90% for all parameters except for smoke, where there is a substantial improvement from 46.67% to 73.33%, when compared to conventional ANFIS model.
Zhang, Ruoqiao; Thibault, Jean-Baptiste; Bouman, Charles A; Sauer, Ken D; Hsieh, Jiang
2014-01-01
Dual-energy X-ray CT (DECT) has the potential to improve contrast and reduce artifacts as compared to traditional CT. Moreover, by applying model-based iterative reconstruction (MBIR) to dual-energy data, one might also expect to reduce noise and improve resolution. However, the direct implementation of dual-energy MBIR requires the use of a nonlinear forward model, which increases both complexity and computation. Alternatively, simplified forward models have been used which treat the material-decomposed channels separately, but these approaches do not fully account for the statistical dependencies in the channels. In this paper, we present a method for joint dual-energy MBIR (JDE-MBIR), which simplifies the forward model while still accounting for the complete statistical dependency in the material-decomposed sinogram components. The JDE-MBIR approach works by using a quadratic approximation to the polychromatic log-likelihood and a simple but exact nonnegativity constraint in the image domain. We demonstrate that our method is particularly effective when the DECT system uses fast kVp switching, since in this case the model accounts for the inaccuracy of interpolated sinogram entries. Both phantom and clinical results show that the proposed model produces images that compare favorably in quality to previous decomposition-based methods, including FBP and other statistical iterative approaches.
Dual pairs and jetlet methods for ideal incompressible fluid models in $n\\geq 2$ dimensions
Cotter, C J; Holm, D D; Jacobs, H O; Meier, D M
2015-01-01
We review the role of dual pairs in mechanics and use them to derive particle-like solutions to regularized incompressible fluid systems. These dual pairs result from the action of diffeomorphisms on point particles (essentially by moving the points). We then augment our dual pairs by considering the action of diffeomorphisms on Taylor series, also known as jets. The augmented dual pairs induce a hierarchy of particle-like solutions and conservation laws with particles carrying a copy of a jet group. We call these augmented particles jetlets. The jet groups serve as finite-dimensional models of the diffeomorphism group itself, and so the jetlet particles serve as a finite-dimensional model of the self-similarity exhibited by ideal incompressible fluids. The conservation law associated to jetlet solutions is shown to be a shadow of Kelvin's circulation theorem. Finally, we study the dynamics of infinite time particle mergers. We prove that two merging particles at the zeroth level in the hierarchy yield dynami...
Subthreshold current model of fully depleted dual material gate SOI MOSFET
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
Dual material gate SOI MOSFET with asymmetrical halo can suppress short channel effect and increase carriers transport efficiency. The analytical model of its subthreshold drain current is derived based on the explicit solution of two-dimensional Poisson's equation in the depletion region. The model takes into consideration the channel length modulation effect and the contribution of the back channel current component. Its validation is verified by comparision with two dimensional device simulator MEDICI.
Stillhart, Cordula; Imanidis, Georgios; Griffin, Brendan T; Kuentz, Martin
2014-12-01
In vitro lipolysis is widely utilized for predicting in vivo performance of oral lipid-based formulations (LBFs). However, evaluation of LBFs in the absence of an absorption sink may have limited in vivo relevance. This study aimed at employing biopharmaceutical modeling to simulate LBF digestion and drug supersaturation in a continuous absorptive environment. Three fenofibrate-loaded LBFs were characterized in vitro (dispersion and lipolysis) and drug precipitation was monitored using in-line Raman spectroscopy. In vitro data were combined with pharmacokinetic data derived from an in vivo study in pigs to simulate intestinal LBF transit. This biopharmaceutical model allowed calculation of lipolysis-triggered drug supersaturation while drug and lipolysis products are absorbed from the intestine. The biopharmaceutical model predicted that, in a continuous absorption environment, fenofibrate supersaturation was considerably lower compared to in vitro lipolysis (non-sink). Hence, the extensive drug precipitation observed in vitro was predicted to be unlikely in vivo. The absorption of lipolysis products increased drug supersaturation, but drug precipitation was unlikely for highly permeable drugs. Biopharmaceutical modeling is a valuable approach for predicting LBFs performance in vivo. In the absence of in vitro tools simulating absorptive conditions, modeling strategies should be further considered.
Rezenda, R; Sabado, M; Kasjanovs, V; Baptista, L.; da Silva, K; Noritomi, P; Sena, F.; Wen, X.; Da Silva, J; Mironov, V.
2013-01-01
The dual-scaled hydrid scaffold fabrication technology based on combination of 3D printing (fused deposition modeling) and electrospining have been recently introduced. We report here the design, fabrication, mechanical testing, in vitro and in vivo biocompatibility testing of novel auricular implants for treatment microtia fabricated by dual scaled hydbrid scaffold fabrication technology.
models for predicting compressive strength and water absorption of ...
African Journals Online (AJOL)
user
combine laterite and quarry dust in sandcrete blocks or concrete are few. One of ... model for optimization of compressive strength of sand- laterite blocks using ..... compressive strength of Pulverise fuel Ash-Cement concrete''. IOSR Journal of ...
Directory of Open Access Journals (Sweden)
V. S. Zarubin
2016-01-01
Full Text Available A temperature state of the solid body may depend both on the conditions of heat exchange with external environment surrounding its surface and on the energy release within the body volume, caused, for example, by the processes in nuclear reactor elements or exothermic chemical reactions, absorption of penetrating radiation energy or transformation of a part of the electrical power into heat with flowing electric current (so-called Joule heat.If with growing temperature the intensity of bulk power density increases, a limited steady temperature state can emerge at which heat extracted to the body surface and released within its volume reaches maximum. Thus, small increments of temperature lead to an increase of heat release, which can not be extracted to the body surface by conduction without further temperature increase. As a result, the steady temperature distribution in the body becomes impossible that determines the state of the thermal explosion, so named due to the fact that in this case the appropriate mathematical model predicts an unlimited temperature increase.A lot of published papers and monographs concerning the study of the combustion and explosion processes in a stationary medium analyse the thermal explosion state. The most famous papers consider a mathematical model to describe a temperature distribution in the case when heat release is because of exothermic chemical reactions the rate of which increases with temperature growth. The dependence of the chemical reaction rate on temperature is usually described by the exponential Arrhenius law, which makes it necessary to consider an essentially nonlinear mathematical model containing differential equation, which includes the term, nonlinearly rising with increasing temperature. Even with simplifying assumptions, this model allows an exact closed form solution only in the case of one-dimensional temperature distributions in the two areas of the canonical form: in the plate, infinite
Menezes, R; Ribeiro, R F; Wotzasek, C
2002-01-01
We study the equivalence between the $B\\wedge F$ self-dual ($SD_{B\\wedge F}$) and the $B\\wedge F$ topologically massive ($TM_{B\\wedge F}$) models including the coupling to dynamical, U(1) charged fermionic matter. This is done through an iterative procedure of gauge embedding that produces the dual mapping. In the interactive cases, the minimal coupling adopted for both vector and tensor fields in the self-dual representation is transformed into a non minimal magnetic like coupling in the topologically massive representation but with the currents swapped. It is known that to establish this equivalence a current-current interaction term is needed to render the matter sector unchanged. We show that both terms arise naturally from the embedding procedure.
DEFF Research Database (Denmark)
Vigeant, Michelle C.; Wang, Lily M.; Rindel, Jens Holger
2006-01-01
recording, and a final auralization is created by mixing all individual channel auralizations together. This study evaluates the objective and subjective effects of using four and thirteen channel IRs in an ODEON model of Queen’s Hall, a hall located in Copenhagen with variable absorption. Analyses...... of the results reveal great differences in the objective parameters of reverberation time (T30), clarity index (C50), sound pressure level (SPL) and lateral energy fraction (LF80) for each channel’s impulse response across the room absorption variations. Subjective studies were conducted to see the effect...... on auralizations of changing source orientation in various configurations of the room with different amounts of absorption. The results show that subjects could more easily identify source orientation with an increasing number of recording channels in the auralizations, but a significant effect with absorption...
Experimental measurement and modeling of the rate of absorption of carbon dioxide by aqueous ammonia
DEFF Research Database (Denmark)
Darde, Victor Camille Alfred; van Well, Willy J.M.; Fosbøl, Philip Loldrup
2011-01-01
In this work, the rate of absorption of carbon dioxide by aqueous ammonia solvent has been studied by applying a newly built wetted wall column. The absorption rate in aqueous ammonia was measured at temperatures from 279 to 304K for 1 to 10wt% aqueous ammonia with loadings varying from 0 to 0.8mol......CO2/molNH3. The absorption rate in 30wt% aqueous mono-ethanolamine (MEA) was measured at 294 and 314K with loadings varying from 0 to 0.4 as comparison.It was found that at 304K, the rate of absorption of carbon dioxide by 10wt% NH3 solvent was comparable to the rates for 30wt% MEA at 294 and 314K (a.......The rate of absorption decreases strongly with decreasing ammonia concentrations and increasing CO2 loadings.The rate of absorption of carbon dioxide by aqueous ammonia solvent was modeled using the measurements of the unloaded solutions and the zwitter-ion mechanism. The model could successfully predict...
Tamin, Jacques
2013-08-01
In the United Kingdom (UK), ethical guidance for doctors assumes a therapeutic setting and a normal doctor-patient relationship. However, doctors with dual obligations may not always operate on the basis of these assumptions in all aspects of their role. In this paper, the situation of UK occupational physicians is described, and a set of models to characterise their different practices is proposed. The interaction between doctor and worker in each of these models is compared with the normal doctor-patient relationship, focusing on the different levels of trust required, the possible power imbalance and the fiduciary obligations that apply. This approach highlights discrepancies between what the UK General Medical Council guidance requires and what is required of a doctor in certain roles or functions. It is suggested that using this modelling approach could also help in clarifying the sources of moral conflict for other doctors with "dual obligations" in their various roles.
Enhancement Factors in Ozone Absorption Based on the Surface Renewal Model and its Application
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
Based on the Danckwerts surface renewal model, a simple explicit expression of theenhancement factor in ozone absorption with a first order ozone self-decomposition and parallel secondorder ozonation reactions has been derived. The results are compared with our previous work based onthe film theory. The 2,4-dichlorophenol destruction rate by ozonation is predicted using the enhancementfactor model in this paper.
Modelling of the Absorption and Desorption Process of Chemical Heat Pumps
Institute of Scientific and Technical Information of China (English)
Gui－PingLin; Xiu－GanYuan
1993-01-01
A simple model for the desorption and absorption process of the chemical heat pump is presented in this paper .It is based on the assumption of a definite reaction front.The results from this model are compared with those obtained by finite difference method and it is observed that there is almost no difference between them.
Self-dual configurations in Abelian Higgs models with k-generalized gauge field dynamics
Casana, R.; Cavalcante, A.; da Hora, E.
2016-12-01
We have shown the existence of self-dual solutions in new Maxwell-Higgs scenarios where the gauge field possesses a k-generalized dynamic, i.e., the kinetic term of gauge field is a highly nonlinear function of F μν F μν . We have implemented our proposal by means of a k-generalized model displaying the spontaneous symmetry breaking phenomenon. We implement consistently the Bogomol'nyi-Prasad-Sommerfield formalism providing highly nonlinear self-dual equations whose solutions are electrically neutral possessing total energy proportional to the magnetic flux. Among the infinite set of possible configurations, we have found families of k-generalized models whose self-dual equations have a form mathematically similar to the ones arising in the Maxwell-Higgs or Chern-Simons-Higgs models. Furthermore, we have verified that our proposal also supports infinite twinlike models with | ϕ|4-potential or | ϕ|6-potential. With the aim to show explicitly that the BPS equations are able to provide well-behaved configurations, we have considered a test model in order to study axially symmetric vortices. By depending of the self-dual potential, we have shown that the k-generalized model is able to produce solutions that for long distances have a exponential decay (as Abrikosov-Nielsen-Olesen vortices) or have a power-law decay (characterizing delocalized vortices). In all cases, we observe that the generalization modifies the vortex core size, the magnetic field amplitude and the bosonic masses but the total energy remains proportional to the quantized magnetic flux.
Self-dual configurations in Abelian Higgs models with k-generalized gauge field dynamics
Energy Technology Data Exchange (ETDEWEB)
Casana, R.; Cavalcante, A. [Departamento de Física, Universidade Federal do Maranhão,65080-805, São Luís, Maranhão (Brazil); Hora, E. da [Departamento de Física, Universidade Federal do Maranhão,65080-805, São Luís, Maranhão (Brazil); Coordenadoria Interdisciplinar de Ciência e Tecnologia, Universidade Federal do Maranhão,65080-805, São Luís, Maranhão (Brazil)
2016-12-14
We have shown the existence of self-dual solutions in new Maxwell-Higgs scenarios where the gauge field possesses a k-generalized dynamic, i.e., the kinetic term of gauge field is a highly nonlinear function of F{sub μν}F{sup μν}. We have implemented our proposal by means of a k-generalized model displaying the spontaneous symmetry breaking phenomenon. We implement consistently the Bogomol’nyi-Prasad-Sommerfield formalism providing highly nonlinear self-dual equations whose solutions are electrically neutral possessing total energy proportional to the magnetic flux. Among the infinite set of possible configurations, we have found families of k-generalized models whose self-dual equations have a form mathematically similar to the ones arising in the Maxwell-Higgs or Chern-Simons-Higgs models. Furthermore, we have verified that our proposal also supports infinite twinlike models with |ϕ|{sup 4}-potential or |ϕ|{sup 6}-potential. With the aim to show explicitly that the BPS equations are able to provide well-behaved configurations, we have considered a test model in order to study axially symmetric vortices. By depending of the self-dual potential, we have shown that the k-generalized model is able to produce solutions that for long distances have a exponential decay (as Abrikosov-Nielsen-Olesen vortices) or have a power-law decay (characterizing delocalized vortices). In all cases, we observe that the generalization modifies the vortex core size, the magnetic field amplitude and the bosonic masses but the total energy remains proportional to the quantized magnetic flux.
Institute of Scientific and Technical Information of China (English)
ZikangWu; ArneJakobsen; 等
1994-01-01
The pupose of this paper is to investigate the validity of a lumped model,i.e.a reaction front model,for the simulation of solid absorption process.A distributed model is developed for solid absorption process,and a dimensionless RF number is suggested to predict the qualitative shape of reaction degree profile.The simulation results from the reaction front model are compared with those from the distributed model solved by a finite difference scheme,and it is shown that they are in good agreement in almost all cased.no matter whether there is reaction front or not.
Cornaton, F
2011-01-01
One dimensional analytical porosity-weighted solutions of the dual-porosity model are derived, providing insights on how to relate exchange and storage coefficients to the volumetric density of the high-permeability medium. It is shown that porosity-weighted storage and exchange coefficients are needed when handling highly heterogeneous systems - such as karstic aquifers - using equivalent dual-porosity models. The sensitivity of these coefficients is illustrated by means of numerical experiments with theoretical karst systems. The presented 1-D dual-porosity analytical model is used to reproduce the hydraulic responses of reference 3-D karst aquifers, modelled by a discrete single-continuum approach. Under various stress conditions, simulation results show the relations between the dual-porosity model coefficients and the structural features of the discrete single-continuum model. The calibration of the equivalent 1-D analytical dual-porosity model on reference hydraulic responses confirms the dependence of ...
One dimensional modeling of a diesel-CNG dual fuel engine
Azman, Putera Adam; Fawzi, Mas; Ismail, Muammar Mukhsin; Osman, Shahrul Azmir
2017-04-01
Some of the previous studies have shown that the use of compressed natural gas (CNG) in diesel engines potentially produce engine performance improvement and exhaust gas emission reduction, especially nitrogen oxides, unburned hydrocarbons, and carbon dioxide. On the other hand, there are other researchers who claimed that the use of CNG increases exhaust gas emissions, particularly nitrogen oxides. In this study, a one-dimensional model of a diesel-CNG dual fuel engine was made based on a 4-cylinder 2.5L common rail direct injection diesel engine. The software used is GT-Power, and it was used to analyze the engine performance and exhaust gas emissions of several diesel-CNG dual fuel blend ratios, i.e. 100:0, 90:10, 80:20, 70:30, 60:40 and 50:50. The effect of 100%, 75%, 50% engine loads on the exhaust gas emissions were also studied. The result shows that all diesel-CNG fuel blends produces higher brake torque and brake power at engine speed of 2000-3000 rpm compared with 100% diesel. The 50:50 diesel-CNG blend produces the highest brake torque and brake power, but also has the highest brake specific fuel consumption. As a higher percentage of CNG added to the dual fuel blend, unburned hydrocarbons and carbon monoxide emission increased while carbon dioxide emission decreased. The nitrogen oxides emission concentration is generally unaffected by any change of the dual fuel ratio.
Duality Equivalence Between Self-Dual And Topologically Massive Non-Abelian Models
Ilha, A
2001-01-01
The non-abelian version of the self-dual model proposed by Townsend, Pilch and van Nieuwenhuizen presents some well known difficulties not found in the abelian case, such as well defined duality operation leading to self-duality and dual equivalence with the Yang-Mills-Chern-Simons theory, for the full range of the coupling constant. These questions are tackled in this work using a distinct gauge lifting technique that is alternative to the master action approach first proposed by Deser and Jackiw. The master action, which has proved useful in exhibiting the dual equivalence between theories in diverse dimensions, runs into trouble when dealing with the non-abelian case apart from the weak coupling regime. This new dualization technique on the other hand, is insensitive of the non-abelian character of the theory and generalize straightforwardly from the abelian case. It also leads, in a simple manner, to the dual equivalence for the case of couplings with dynamical fermionic matter fields. As an application, ...
Dual states estimation of a subsurface flow-transport coupled model using ensemble Kalman filtering
El Gharamti, Mohamad
2013-10-01
Modeling the spread of subsurface contaminants requires coupling a groundwater flow model with a contaminant transport model. Such coupling may provide accurate estimates of future subsurface hydrologic states if essential flow and contaminant data are assimilated in the model. Assuming perfect flow, an ensemble Kalman filter (EnKF) can be used for direct data assimilation into the transport model. This is, however, a crude assumption as flow models can be subject to many sources of uncertainty. If the flow is not accurately simulated, contaminant predictions will likely be inaccurate even after successive Kalman updates of the contaminant model with the data. The problem is better handled when both flow and contaminant states are concurrently estimated using the traditional joint state augmentation approach. In this paper, we introduce a dual estimation strategy for data assimilation into a one-way coupled system by treating the flow and the contaminant models separately while intertwining a pair of distinct EnKFs, one for each model. The presented strategy only deals with the estimation of state variables but it can also be used for state and parameter estimation problems. This EnKF-based dual state-state estimation procedure presents a number of novel features: (i) it allows for simultaneous estimation of both flow and contaminant states in parallel; (ii) it provides a time consistent sequential updating scheme between the two models (first flow, then transport); (iii) it simplifies the implementation of the filtering system; and (iv) it yields more stable and accurate solutions than does the standard joint approach. We conducted synthetic numerical experiments based on various time stepping and observation strategies to evaluate the dual EnKF approach and compare its performance with the joint state augmentation approach. Experimental results show that on average, the dual strategy could reduce the estimation error of the coupled states by 15% compared with the
Modeling the heterogeneous intestinal absorption of propiverine extended-release.
Weiss, Michael; Sermsappasuk, Pakawadee; Siegmund, Werner
2015-08-30
Propiverine is a widely used antimuscarinic drug with bioavailability that is limited by intestinal first-pass extraction. To study the apparent heterogeneity in intestinal first-pass extraction, we performed a population analysis of oral concentration-time data measured after administration of an extended-release formulation of propiverine in ten healthy subjects. Using an inverse Gaussian function as input model, the assumption that the systemically available fraction increases as a sigmoidal function of time considerably improved the fit. The step-like increase in this fraction at time t=3.7h predicted by the model suggests that propiverine is predominantly absorbed in colon. A nearly perfect correlation was found between the estimates of bioavailability and mean dissolution time. Copyright © 2015 Elsevier B.V. All rights reserved.
A Multilevel Testlet Model for Dual Local Dependence
Jiao, Hong; Kamata, Akihito; Wang, Shudong; Jin, Ying
2012-01-01
The applications of item response theory (IRT) models assume local item independence and that examinees are independent of each other. When a representative sample for psychometric analysis is selected using a cluster sampling method in a testlet-based assessment, both local item dependence and local person dependence are likely to be induced.…
Modeling biofilms with dual extracellular electron transfer mechanisms
Renslow, Ryan; Babauta, Jerome; Kuprat, Andrew; Schenk, Jim; Ivory, Cornelius; Fredrickson, Jim; Beyenal, Haluk
2013-01-01
Electrochemically active biofilms have a unique form of respiration in which they utilize solid external materials as terminal electron acceptors for their metabolism. Currently, two primary mechanisms have been identified for long-range extracellular electron transfer (EET): a diffusion- and a conduction-based mechanism. Evidence in the literature suggests that some biofilms, particularly Shewanella oneidensis, produce the requisite components for both mechanisms. In this study, a generic model is presented that incorporates the diffusion- and the conduction-based mechanisms and allows electrochemically active biofilms to utilize both simultaneously. The model was applied to S. oneidensis and Geobacter sulfurreducens biofilms using experimentally generated data found in the literature. Our simulation results show that 1) biofilms having both mechanisms available, especially if they can interact, may have a metabolic advantage over biofilms that can use only a single mechanism; 2) the thickness of G. sulfurreducens biofilms is likely not limited by conductivity; 3) accurate intrabiofilm diffusion coefficient values are critical for current generation predictions; and 4) the local biofilm potential and redox potential are two distinct parameters and cannot be assumed to have identical values. Finally, we determined that simulated cyclic and squarewave voltammetry based on our model are currently not capable of determining the specific percentages of extracellular electron transfer mechanisms in a biofilm. The developed model will be a critical tool for designing experiments to explain EET mechanisms. PMID:24113651
Lee, Dongchul; Gillespie, Ewan; Bradley, Kerry
2011-02-10
In spinal cord stimulation (SCS), concordance of stimulation-induced paresthesia over painful body regions is a necessary condition for therapeutic efficacy. Since patient pain patterns can be unique, a common stimulation configuration is the placement of two leads in parallel in the dorsal epidural space. This construct provides flexibility in steering stimulation current mediolaterally over the dorsal column to achieve better pain-paresthesia overlap. Using a mathematical model with an accurate fiber diameter distribution, we studied the ability of dual parallel leads to steer stimulation between adjacent contacts on dual parallel leads using (1) a single source system, and (2) a multi-source system, with a dedicated current source for each contact. The volume conductor model of a low-thoracic spinal cord with epidurally-positioned dual parallel (2 mm separation) percutaneous leads was first created, and the electric field was calculated using ANSYS, a finite element modeling tool. The activating function for 10 um fibers was computed as the second difference of the extracellular potential along the nodes of Ranvier on the nerve fibers in the dorsal column. The volume of activation (VOA) and the central point of the VOA were computed using a predetermined threshold of the activating function. The model compared the field steering results with single source versus dedicated power source systems on dual 8-contact stimulation leads. The model predicted that the multi-source system can target more central points of stimulation on the dorsal column than a single source system (100 vs. 3) and the mean steering step for mediolateral steering is 0.02 mm for multi-source systems vs 1 mm for single source systems, a 50-fold improvement. The ability to center stimulation regions in the dorsal column with high resolution may allow for better optimization of paresthesia-pain overlap in patients.
Dual of 3-dimensional pure SU(2) Lattice Gauge Theory and the Ponzano-Regge Model
Anishetty, R; Sharatchandra, H S; Mathur, M; Anishetty, Ramesh; Cheluvaraja, Srinath; Mathur, Manu
1993-01-01
By carrying out character expansion and integration over all link variables, the partition function of 3-dimensional pure SU(2) lattice gauge theory is rewritten in terms of 6j symbols. The result is Ponzano-Regge model of 3-dimensional gravity with a term that explicitly breaks general coordinate invariance. Conversely, we show that dual of Ponzano-Regge model is an SU(2) lattice gauge theory where all plaquette variables are constrained to the identity matrix and therefore the model needs no further regularization. Our techniques are applicable to other models with non-abelian symmetries in any dimension and provide duality transform for the partition function.
A multiple fractal model for estimating permeability of dual-porosity media
Li, Bo; Liu, Richeng; Jiang, Yujing
2016-09-01
A multiple fractal model that considers the fractal properties of both porous matrices and fracture networks is proposed for the permeability of dual-porosity media embedded with randomly distributed fractures. In this model, the aperture distribution is verified to follow the fractal scaling law, and the porous matrix is assumed to comprise a bundle of tortuous capillaries that also follow the fractal scaling law. Analytical expressions for fractal aperture distribution, total flow rate, total equivalent permeability, and dimensionless permeability are established, where the dimensionless permeability is defined as the ratio of permeability of the porous matrices to that of the fracture networks. The dimensionless permeability is closely correlated to the structural parameters (i.e., α, θ, Dtf, Dtp, De, Dp, emax, λmax) of the dual-porosity media, and it is more sensitive to the fractal dimension for the size distribution of fracture aperture than to that for the size distribution of pore/capillary diameter. The maximum pore/capillary diameter has a greater impact on the dimensionless permeability than that of the maximum fracture aperture. The dimensionless permeability of fracture networks constructed by the fractal aperture distribution has close values with those of models with lognormal aperture distribution. The proposed multiple fractal model does not involve any empirical constants that do not have clear physical meanings, which could serve as a quick estimation method for assessing permeability of dual-porosity media.
Parallel LC circuit model for multi-band absorption and preliminary design of radiative cooling.
Feng, Rui; Qiu, Jun; Liu, Linhua; Ding, Weiqiang; Chen, Lixue
2014-12-15
We perform a comprehensive analysis of multi-band absorption by exciting magnetic polaritons in the infrared region. According to the independent properties of the magnetic polaritons, we propose a parallel inductance and capacitance(PLC) circuit model to explain and predict the multi-band resonant absorption peaks, which is fully validated by using the multi-sized structure with identical dielectric spacing layer and the multilayer structure with the same strip width. More importantly, we present the application of the PLC circuit model to preliminarily design a radiative cooling structure realized by merging several close peaks together. This omnidirectional and polarization insensitive structure is a good candidate for radiative cooling application.
Cheminformatics Modeling of Amine Solutions for Assessing their CO2 Absorption Properties.
Kuenemann, Melaine A; Fourches, Denis
2017-03-07
As stricter regulations on CO2 emissions are adopted worldwide, identifying efficient chemical processes to capture and recycle CO2 is of critical importance for industry. The most common process known as amine scrubbing suffers from the lack of available amine solutions capable of capturing CO2 efficiently. Tertiary amines characterized by low heats of reaction are considered good candidates but their absorption properties can significantly differ from one analogue to another despite high structural similarity. Herein, after collecting and curating experimental data from the literature, we have built a modeling set of 41 amine structures with their absorption properties. Then we analyzed their chemical composition using molecular descriptors and non-supervised clustering. Furthermore, we developed a series of quantitative structure-property relationships (QSPR) to assess amines' CO2 absorption properties from their structural characteristics. These models afforded reasonable prediction performances (e. g., Q(2)LOO =0.63 for CO2 absorption amount) even though they are solely based on 2D chemical descriptors and individual machine learning techniques (random forest and neural network). Overall, we believe the chemical analysis and the series of QSPR models presented in this proof-of-concept study represent new knowledge and innovative tools that could be very useful for screening and prioritizing hypothetical amines to be synthesized and tested experimentally for their CO2 absorption properties.
Institute of Scientific and Technical Information of China (English)
2009-01-01
Objective To study the intestinal absorption and transepithelial transport of three limoninoids: evodol (EVO), limonin (LIM), and shihulimonin A (SHIA), isolated from Fructus Evodiae [the unripe fruit of Evodia rutaecarpa and Evodia rutaecarpa var. bodinieri] in the human intestine. Methods The in vitro cultured human colon carcinoma cell line, Caco-2 cell monolayer model, was applied to studying the absorption and transepithelial transport of the three limoninoids from apical (AP) to basolateral (BL) side and from BL to AP side. The three limoninoids were measured by reversed-phase high performance liquid chromatography coupled with ultraviolet absorption detector. Transport parameters and apparent permeability coefficients (Papp) were then calculated and compared with those of Propranolol as a control substance of high permeability and Atenolol as a control substance of poor permeability. Results The Papp value of EVO and LIM from AP to BL side for absorption and transport were 1.78 × 10-5 cm/s and 1.16 × 10-5 cm/s, respectively, which was comparable to that of Propranolol with Papp 2.18 × 10-5 cm/s. Conclusion The absorption and transport of both EVO and LIM are main passive diffusion as the dominating process in Caco-2 cell monolayer model, and they were estimated to be high absorbed compounds. SHIA in Caco-2 cell monolayer model may be involved in metabolism in the transport processes.
Absorptive capacity, technological innovation, and product life cycle: a system dynamics model.
Zou, Bo; Guo, Feng; Guo, Jinyu
2016-01-01
While past research has recognized the importance of the dynamic nature of absorptive capacity, there is limited knowledge on how to generate a fair and comprehensive analytical framework. Based on interviews with 24 Chinese firms, this study develops a system-dynamics model that incorporates an important feedback loop among absorptive capacity, technological innovation, and product life cycle (PLC). The simulation results reveal that (1) PLC affects the dynamic process of absorptive capacity; (2) the absorptive capacity of a firm peaks in the growth stage of PLC, and (3) the market demand at different PLC stages is the main driving force in firms' technological innovations. This study also explores a sensitivity simulation using the variables of (1) time spent in founding an external knowledge network, (2) research and development period, and (3) knowledge diversity. The sensitivity simulation results show that the changes of these three variables have a greater impact on absorptive capacity and technological innovation during growth and maturity stages than in the introduction and declining stages of PLC. We provide suggestions on how firms can adjust management policies to improve their absorptive capacity and technological innovation performance during different PLC stages.
Photon absorption models in nanostructured semiconductor solar cells and devices
Luque, Antonio
2015-01-01
This book is intended to be used by materials and device physicists and also solar cells researchers. It models the performance characteristics of nanostructured solar cells and resolves the dynamics of transitions between several levels of these devices. An outstanding insight into the physical behaviour of these devices is provided, which complements experimental work. This therefore allows a better understanding of the results, enabling the development of new experiments and optimization of new devices. It is intended to be accessible to researchers, but also to provide engineering tools w
Investigation of degenerate dual-pump phase sensitive amplifier using multi-wave model
Xie, Weilin; Labidi, Tarek; Bretenaker, Fabien
2015-01-01
Operation of a degenerate dual-pump phase sensitive amplifier (PSA) is thoroughly numerically investigated using a multi-wave model, taking into account high-order waves associated with undesired four-wave mixing (FWM) processes. More accurate phase-sensitive signal gain spectra are obtained compared to the conventional 3-wave model, leading to the precise optimization of the pump configuration in a dual-pump PSA. The signal gain spectra, as well as the phase sensitivity, are obtained and interpreted by investigating the dominant FWM processes in terms of corresponding phase matching. Moreover, the relation between dispersion slope and gain spectra is revealed, permitting the application-oriented arbitrary tailoring of the gain spectra by manipulating the dispersion profile and pump wavelength allocation.
D-dimensional Conformal Field Theories with anomalous dimensions as Dual Resonance Models
Mack, Gerhard
2009-01-01
An exact correspondence is pointed out between conformal field theories in D dimensions and dual resonance models in D' dimensions, where D' may differ from D. Dual resonance models, pioneered by Veneziano, were forerunners of string theory. The analog of scattering amplitudes are called Mellin amplitudes; they depend on complex variables which substitute for the Mandelstam variables on which scattering amplitudes depend. The Mellin amplitudes satisfy exact duality - i.e. meromorphy with simple poles in single variables, and crossing symmetry - and an appropriate form of factorization which is implied by operator product expansions (OPE). Duality is a D-independent property. The positions of the leading poles are given by the dimensions of fields in the OPE; their residues depend on D and determine satellites. Dimensional reduction and induction D goes to D-1 and D+1 are discussed. Dimensional reduction leads to the appearence of Anti de Sitter space.
A Dual Hesitant Fuzzy Multigranulation Rough Set over Two-Universe Model for Medical Diagnoses.
Zhang, Chao; Li, Deyu; Yan, Yan
2015-01-01
In medical science, disease diagnosis is one of the difficult tasks for medical experts who are confronted with challenges in dealing with a lot of uncertain medical information. And different medical experts might express their own thought about the medical knowledge base which slightly differs from other medical experts. Thus, to solve the problems of uncertain data analysis and group decision making in disease diagnoses, we propose a new rough set model called dual hesitant fuzzy multigranulation rough set over two universes by combining the dual hesitant fuzzy set and multigranulation rough set theories. In the framework of our study, both the definition and some basic properties of the proposed model are presented. Finally, we give a general approach which is applied to a decision making problem in disease diagnoses, and the effectiveness of the approach is demonstrated by a numerical example.
Abbas, Ibrahim A.
2016-09-01
In the present paper, the theory of generalized photo-thermoelasticity under dual phase lag model has been applied to study the coupled thermal, plasma and elastic waves on unbounded semiconductor medium with cylindrical cavity. The bounding surface of the cavity is traction free and loaded thermally by exponentially decaying pulse boundary heat flux. By using Laplace transform and the eigenvalue approach methodology, the solutions of all variables have been obtained analytically. Numerical computations have been done for silicon-like semiconductor material, and the results are displayed graphically to show the difference between the dual phase lag (DPL) model, Lord and Shulman’s theory (LS) and the classical dynamical coupled theory (CT).
Monte Carlo markovian modeling of modal competition in dual-wavelength semiconductor lasers
Chusseau, Laurent; Philippe, Fabrice; Jean-Marie, Alain
2014-03-01
Monte Carlo markovian models of a dual-mode semiconductor laser with quantum well (QW) or quantum dot (QD) active regions are proposed. Accounting for carriers and photons as particles that may exchange energy in the course of time allows an ab initio description of laser dynamics such as the mode competition and intrinsic laser noise. We used these models to evaluate the stability of the dual-mode regime when laser characteristics are varied: mode gains and losses, non-radiative recombination rates, intraband relaxation time, capture time in QD, transfer of excitation between QD via the wetting layer. . . As a major result, a possible steady-sate dualmode regime is predicted for specially designed QD semiconductor lasers thereby acting as a CW microwave or terahertz-beating source whereas it does not occur for QW lasers.
Gromova, L V; Gruzdkov, A A
1999-06-01
In order to throw light on the mechanisms responsible for the enzyme-dependent absorption of disaccharides membrane hydrolysis of maltose and trehalose and the absorption of glucose (free and that derived from disaccharides) were studied in isolated loops (20 cm) of the rat small intestine in chronic experiments. The rates of glucose absorption were 0.26-0.81 micromol x min(-1) x cm(-1) when the loop was perfused with a 12.5 to 75.0 mmol/l free glucose solution, which is only insignificantly higher than the rates observed during perfusion with equivalent maltose solutions. The coupling coefficient (the ratio of glucose absorption rate to the rate of disaccharide hydrolysis) decreased from 0.90 to 0.60 with the increasing maltose concentrations in the infusate from 6.25 to 37.5 mmol/l, but remained unchanged (approximately 0.95) within the same range of trehalose concentrations. The permeability of the pre-epithelial barrier was equivalent to that of unstirred water layer of less than 40 microm thickness. Fluid absorption was within the range of 0.73-2.55 microl x min(-1) x cm(-1), and it showed a correlation with the rates of glucose absorption. The results agree with a model developed on the assumption that free glucose and that released from disaccharides share the same membrane transporters. It could be concluded that a close coupling of disaccharide hydrolysis with derived glucose absorption in chronic experiments is achieved mainly due to a high activity of glucose transporters, which are presumably not associated with membrane disaccharidases. The transcellular active transport is a predominant mechanism of disaccharide-derived glucose absorption under conditions close to physiological.
Hood, L. L.
1983-01-01
A modeling analysis is carried out of six experimental phase space density profiles for nearly equatorially mirroring protons using methods based on the approach of Thomsen et al. (1977). The form of the time-averaged radial diffusion coefficient D(L) that gives an optimal fit to the experimental profiles is determined under the assumption that simple satellite plus Ring E absorption of inwardly diffusing particles and steady-state radial diffusion are the dominant physical processes affecting the proton data in the L range that is modeled. An extension of the single-satellite model employed by Thomsen et al. to a model that includes multisatellite and ring absorption is described, and the procedures adopted for estimating characteristic satellite and ring absorption times are defined. The results obtained in applying three representative solid-body absorption models to evaluate D(L) in the range where L is between 4 and 16 are reported, and a study is made of the sensitivity of the preferred amplitude and L dependence for D(L) to the assumed model parameters. The inferred form of D(L) is then compared with that which would be predicted if various proposed physical mechanisms for driving magnetospheric radial diffusion are operative at Saturn.
The transverse-momentum distribution in the central region in a phenomenological dual model
Bebel, D
1974-01-01
A phenomenological dual amplitude for double pomeron exchange is evaluated for the transverse-momentum distribution at x=0. It shows an exp(-bp/sub perpendicular to /) dependence for low p/sub perpendicular to / values and a subsequent flattening-off for larger p/sub perpendicular to /. The results are compared with ISR data. Some analogies to the statistical bootstrap model are discussed. (14 refs).
DUAL RANDOM MODEL OF INCREASING LIFE INSURANCE FOR MULTIPLE-LIFE STATUS
Institute of Scientific and Technical Information of China (English)
ZhangYi; HeWenjiong
2002-01-01
In this paper the dual random model of increasing life insurance for multiple-life status is discussed. The rnth moment of the present value of benefits are calculated and the respective expressions of the moments under joint life status or last- survivor status are presented.Fur-thermore,the limiting distribution of average cost of a portfolio of increasing life insurance for multiple-life status is studied.
Energy Technology Data Exchange (ETDEWEB)
Gregory Flach; Mary Harris; Susan Hubbard; Camelia Knapp; Mike Kowalsky; Maggie Millings; John Shafer; Mike Waddell
2006-06-01
Our research project is motivated by the observations that conventional characterization approaches capture only a fraction of heterogeneity affecting field-scale transport, and that conventional modeling approaches, which use this sparse data, typically do not successfully predict long term plume behavior with sufficient accuracy to guide remedial strategies. Our working hypotheses are that improved prediction of contaminant transport can be achieved using a dual-domain transport approach and field-scale characterization approaches.
On a Class of Dual Risk Model with Dependence based on the FGM Copula
Directory of Open Access Journals (Sweden)
Hua Dong
2010-12-01
Full Text Available In this paper, we consider an extension to a dual model under a barrier strategy, in which the innovation sizes depend on the innovation time via the FGM copula. We first derive a renewal equation for the expected total discounted dividends until ruin. Some differential equations and closed-form expressions are given for exponential innovation sizes. Then the optimal dividend barrier and the Laplace transform of the time to ruin are considered. Finally, a numerical example is given.
Models of Five Absorption Line Systems Along the Line of Sight Toward PG0117+213
Masiero, J R; Ding, J; Churchill, C W; Kacprzak, G G
2005-01-01
We present our investigation into the physical conditions of the gas in five intervening quasar absorption line systems along the line of sight toward the quasar PG 0117+213, with redshifts of z=0.57, z=0.72, z=1.04, z=1.32 and z=1.34. Photoionization modeling of HST, Keck I, and Palomar data, using the code Cloudy, is employed to derive densities and metallicities of the multiple phases of gas required to fit the absorption profile for each system. We discuss the implications of these models for galaxy evolution, including the interpretation of ``CIV deficiency'' and damped Lyman alpha absorbers (DLAs), and the relationships between galaxy morphology, galaxy luminosity, and absorption signature.
Pulse shape control in a dual cavity laser: numerical modeling
Yashkir, Yuri
2006-04-01
We present a numerical model of the laser system for generating a special shape of the pulse: a steep peak at the beginning followed by a long pulse tail. Laser pulses of this nature are required for various applications (laser material processing, optical breakdown spectroscopy, etc.). The laser system consists of two "overlapped" cavities with different round-trip times. The laser crystal, the Q-switching element, the back mirror, and the output coupler are shared. A shorter pulse is generated in a short cavity. A small fraction of this pulse is injected into the long cavity as a seed. It triggers generation of the longer pulse. The output emission from this hybrid laser produces a required pulse shape. Parameters of the laser pulse (ratios of durations and energies of short- and long- pulse components) can be controlled through cavity length and the output coupler reflection. Modelling of the laser system is based on a set of coupled rate equations for dynamic variables of the system: the inverse population in an active laser media and photon densities in coupled cavities. Numerical experiments were provided with typical parameters of a Nd:YAG laser to study the system behaviour for different combinations of parameters.
Dynamic modeling of dual-arm cooperating manipulators based on Udwadia–Kalaba equation
Directory of Open Access Journals (Sweden)
Jia Liu
2016-07-01
Full Text Available Dual-arm cooperating manipulators subject to a certain constraint brought about by the desired trajectory and geometric constraint show high nonlinearity and coupling in their dynamic characteristic. Therefore, it is hard to build dynamical equation with traditional Lagrange equation. The Udwadia–Kalaba equation presents a new idea of dynamic modeling of multi-body systems. However, the dynamic modeling of the unconstrained systems still depends on the traditional Lagrange equation and is quite tedious for dual-arm cooperating manipulators. A generalized dynamical equation of multi-link planar manipulators is thus presented and proven to make modeling conveniently. The constraint relationship is established from a new perspective, and the dynamical equation of dual-arm cooperating manipulator subject to the desired trajectory is acquired with the Udwadia–Kalaba equation. The simple approach overcomes the disadvantage of obtaining dynamical equation from traditional Lagrange equation by Lagrange multiplier. The simulation results of varying law of the joint angles and the motion path of the bar prove that the dynamical equation established by this method conforms to reality.
Delay, Frederick; Porel, Gilles; Chatelier, Marion
2013-07-01
We present a modeling exercise of solute transport and biodegradation in a coarse porous medium widely colonized by a biofilm phase. Tracer tests in large laboratory columns using both conservative (fluorescein) and biodegradable (nitrate) solutes are simulated by means of a dual flowing continuum approach. The latter clearly distinguishes concentrations in a flowing porous phase from concentrations conveyed in the biofilm. With this conceptual setting, it becomes possible to simulate the sharp front of concentrations at early times and the flat tail of low concentrations at late times observed on the experimental breakthrough curves. Thanks to the separation of flow in two phases at different velocities, dispersion coefficients in both flowing phases keep reasonable values with some physical meaning. This is not the case with simpler models based on a single continuum (eventually concealing dead-ends), for which inferred dispersivity may reach the unphysical value of twice the size of the columns. We also show that the behavior of the dual flowing continuum is mainly controlled by the relative fractions of flow passing in each phase and the rate of mass transfer between phases. These parameters also condition the efficiency of nitrate degradation, the degradation rate in a well-seeded medium being a weakly sensitive parameter. Even though the concept of dual flowing continuum appears promising for simulating transport in complex porous media, its inversion onto experimental data really benefits from attempts with simpler models providing a rough pre-evaluation of parameters such as porosity and mean fluid velocity in the system.
Modelling of Dual-Junction Solar Cells including Tunnel Junction
Directory of Open Access Journals (Sweden)
Abdelaziz Amine
2013-01-01
Full Text Available Monolithically stacked multijunction solar cells based on III–V semiconductors materials are the state-of-art of approach for high efficiency photovoltaic energy conversion, in particular for space applications. The individual subcells of the multi-junction structure are interconnected via tunnel diodes which must be optically transparent and connect the component cells with a minimum electrical resistance. The quality of these diodes determines the output performance of the solar cell. The purpose of this work is to contribute to the investigation of the tunnel electrical resistance of such a multi-junction cell through the analysis of the current-voltage (J-V characteristics under illumination. Our approach is based on an equivalent circuit model of a diode for each subcell. We examine the effect of tunnel resistance on the performance of a multi-junction cell using minimization of the least squares technique.
Consensus hologram QSAR modeling for the prediction of human intestinal absorption.
Moda, Tiago L; Andricopulo, Adriano D
2012-04-15
Consistent in silico models for ADME properties are useful tools in early drug discovery. Here, we report the hologram QSAR modeling of human intestinal absorption using a dataset of 638 compounds with experimental data associated. The final validated models are consistent and robust for the consensus prediction of this important pharmacokinetic property and are suitable for virtual screening applications. Copyright © 2012 Elsevier Ltd. All rights reserved.
Directory of Open Access Journals (Sweden)
P. Suveetha Dhanaselvam
2014-10-01
Full Text Available In this paper, electric field distribution of the junctionless dual material surrounding gate MOSFETs (JLDMSG is developed. Junctionless is a device that has similar characteristics like junction based devices, but junctionless has a positive flatband voltage with zero electric field. In Surrounding gate MOSFETs gate material surrounds the channel in all direction , therefore it can overcome the short channel effects effectively than other devices. In this paper, surface potential and electric field distribution is modelled. The proposed surface potential model is compared with the existing central potential model. It is observed that the short channel effects (SCE is reduced and the performance is better than the existing method.
Modelling of the dual frequency capacitive sheath in the intermediate pressure range
Energy Technology Data Exchange (ETDEWEB)
Boyle, P C [Plasma Research Laboratory, National Centre for Plasma Science and Technology and School of Physical Sciences, Dublin City University, Dublin 9 (Ireland); Robiche, J [Laboratoire de Physique et Technologie des Plasmas, Ecole Polytechnique, Palaiseau 91 128 Cedex (France); Turner, M M [Plasma Research Laboratory, National Centre for Plasma Science and Technology and School of Physical Sciences, Dublin City University, Dublin 9 (Ireland)
2004-05-21
The nonlinearity of the plasma sheath in dual frequency capacitively coupled reactors is investigated for frequencies well above the ion plasma frequency. This work focuses on the behaviour of the voltage and the sheath width with respect to the driving current source and the collisionality regime. For typical plasma processing applications, the gas pressure ranges from a few milliTorrs to hundreds of milliTorrs, and the ion dynamics span different collisional regimes. To describe these different ion dynamics, we have used a collisionless model and a variable mobility model. The sheath widths and the voltages obtained from these two models have then been compared.
The dividend function in the jump-diffusion dual model with barrier dividend strategy
Institute of Scientific and Technical Information of China (English)
LI Bo; WU Rong
2008-01-01
A dual model of the perturbed classical compound Poisson risk model is considered under a constant dividend barrier.A new method is used in deriving the boundary condition of the equation for the expectation function by studying the local time of a related process.We obtain the expression for the expected discount dividend function in terms of those in the corresponding perturbed compound Poisson risk model without barriers.A special case in which the gain size is phase-type distributed is illustrated.We also consider the existence of the optimal dividend level.
Weak Dual Pairs and Jetlet Methods for Ideal Incompressible Fluid Models in n ≥ 2 Dimensions
Cotter, C. J.; Eldering, J.; Holm, D. D.; Jacobs, H. O.; Meier, D. M.
2016-12-01
We review the role of dual pairs in mechanics and use them to derive particle-like solutions to regularized incompressible fluid systems. In our case we have a dual pair resulting from the action of diffeomorphisms on point particles (essentially by moving the points). We then augment our dual pair by considering the action of diffeomorphisms on Taylor series, also known as jets. The augmented weak dual pairs induce a hierarchy of particle-like solutions and conservation laws with particles carrying a copy of a jet group. We call these augmented particles jetlets. The jet groups serve as finite-dimensional models of the diffeomorphism group itself, and so the jetlet particles serve as a finite-dimensional model of the self-similarity exhibited by ideal incompressible fluids. The conservation law associated to jetlet solutions is shown to be a shadow of Kelvin's circulation theorem. Finally, we study the dynamics of infinite time particle mergers. We prove that two merging particles at the zeroth level in the hierarchy yield dynamics which asymptotically approach that of a single particle in the first level in the hierarchy. This merging behavior is then verified numerically as well as the exchange of angular momentum which must occur during a near collision of two particles. The resulting particle-like solutions suggest a new class of meshless methods which work in dimensions n ≥ 2 and which exhibit a shadow of Kelvin's circulation theorem. More broadly, this provides one of the first finite-dimensional models of self-similarity in ideal fluids.
Religion, fertility and genes: a dual inheritance model
Rowthorn, Robert
2011-01-01
Religious people nowadays have more children on average than their secular counterparts. This paper uses a simple model to explore the evolutionary implications of this difference. It assumes that fertility is determined entirely by culture, whereas subjective predisposition towards religion is influenced by genetic endowment. People who carry a certain ‘religiosity’ gene are more likely than average to become or remain religious. The paper considers the effect of religious defections and exogamy on the religious and genetic composition of society. Defections reduce the ultimate share of the population with religious allegiance and slow down the spread of the religiosity gene. However, provided the fertility differential persists, and people with a religious allegiance mate mainly with people like themselves, the religiosity gene will eventually predominate despite a high rate of defection. This is an example of ‘cultural hitch-hiking’, whereby a gene spreads because it is able to hitch a ride with a high-fitness cultural practice. The theoretical arguments are supported by numerical simulations. PMID:21227968
Probabilistic conditional reasoning: Disentangling form and content with the dual-source model.
Singmann, Henrik; Klauer, Karl Christoph; Beller, Sieghard
2016-08-01
The present research examines descriptive models of probabilistic conditional reasoning, that is of reasoning from uncertain conditionals with contents about which reasoners have rich background knowledge. According to our dual-source model, two types of information shape such reasoning: knowledge-based information elicited by the contents of the material and content-independent information derived from the form of inferences. Two experiments implemented manipulations that selectively influenced the model parameters for the knowledge-based information, the relative weight given to form-based versus knowledge-based information, and the parameters for the form-based information, validating the psychological interpretation of these parameters. We apply the model to classical suppression effects dissecting them into effects on background knowledge and effects on form-based processes (Exp. 3) and we use it to reanalyse previous studies manipulating reasoning instructions. In a model-comparison exercise, based on data of seven studies, the dual-source model outperformed three Bayesian competitor models. Overall, our results support the view that people make use of background knowledge in line with current Bayesian models, but they also suggest that the form of the conditional argument, irrespective of its content, plays a substantive, yet smaller, role.
Time-dependent excitation and ionization modelling of absorption-line variability due to GRB080310
DEFF Research Database (Denmark)
Vreeswijk, P.M.; De Cia, A.; Jakobsson, P.
2013-01-01
We model the time-variable absorption of Feii, Feiii, Siii, Cii and Crii detected in Ultraviolet and Visual Echelle Spectrograph (UVES) spectra of gamma-ray burst (GRB) 080310, with the afterglow radiation exciting and ionizing the interstellar medium in the host galaxy at a redshift of z = 2.427...
DEFF Research Database (Denmark)
Nørskov, Natalja; Hedemann, Mette Skou; Theil, Peter Kappel
2013-01-01
The concentration and absorption of the nine phenolic acids of wheat were measured in a model experiment with catheterized pigs fed whole grain wheat and wheat aleurone diets. Six pigs in a repeated crossover design were fitted with catheters in the portal vein and mesenteric artery to study the ...
Experimental and modeling studies on the absorption of NO in aqueous ferrous EDTA solutions
Gambardella, F; Alberts, MS; Winkelman, JGM; Heeres, EJ; Alberts, Michel S.; Heeres, H.J.
2005-01-01
This work describes an experimental and modeling study on an industrial relevant process (i.e., the absorption of NO in aqueous Fell(EDTA) solutions) to accurately determine the equilibrium constant of the reaction in the temperature range of 299-329 K. The experiments were carried out in a stirred
Strong absorption model and radial parameters of medium-weight nuclei
Kuterbekov, K A
2002-01-01
The results of analysis of the angular distributions of differential cross sections for elastic scattering in the medium-weight nuclei in the framework strong absorption model are given. There are presented the A-relations of interaction radius, the data of radial parameters of even isotopes with mass number A=64-124 are obtained. (author)
Particle-in-a-Box Model of Exciton Absorption and Electroabsorption in Conjugated Polymers
DEFF Research Database (Denmark)
Pedersen, Thomas Garm
2001-01-01
The recently proposed particle-in-a-box model of one-dimensional excitons in conjugated polymers is applied in calculations of optical absorption and electroabsorption spectra. It is demonstrated that for polymers of long conjugation length a superposition of single exciton resonances produces...
Self-dual soliton solutions in a Chern-Simons-CP(1) model with a nonstandard kinetic term
Casana, Rodolfo; Sourrouille, Lucas
2014-07-01
A generalization of the Chern-Simons-CP(1) model is considered by introducing a nonstandard kinetic term. For a particular case, of this nonstandard kinetic term, we show that the model support self-dual Bogomol'nyi equations. The Bogomol'nyi-Prasad-Sommerfield (BPS) energy has a bound proportional to the sum of the magnetic flux and the CP(1) topological charge. The self-dual equations are solved analytically and verified numerically.
递增年金的双随机模型%DUAL RANDOM MODEL OF INCREASING ANNUITY
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The dual random models about the life insurance and social pension insurance have received considerable attention in the recent articles on actuarial theory and applications. This paper discusses a general kind of increasing annuity based on its force of interest accumulation function as a general random process. The dual random model of the present value of the benefits of the increasing annuity has been set, and their moments have been calculated under certain conditions.
Tests of a Dual-systems Model of Speech Category Learning.
Maddox, W Todd; Chandrasekaran, Bharath
2014-10-01
In the visual domain, more than two decades of work posits the existence of dual category learning systems. The reflective system uses working memory to develop and test rules for classifying in an explicit fashion. The reflexive system operates by implicitly associating perception with actions that lead to reinforcement. Dual-systems models posit that in learning natural categories, learners initially use the reflective system and with practice, transfer control to the reflexive system. The role of reflective and reflexive systems in second language (L2) speech learning has not been systematically examined. Here monolingual, native speakers of American English were trained to categorize Mandarin tones produced by multiple talkers. Our computational modeling approach demonstrates that learners use reflective and reflexive strategies during tone category learning. Successful learners use talker-dependent, reflective analysis early in training and reflexive strategies by the end of training. Our results demonstrate that dual-learning systems are operative in L2 speech learning. Critically, learner strategies directly relate to individual differences in category learning success.
DualTrust: A Distributed Trust Model for Swarm-Based Autonomic Computing Systems
Energy Technology Data Exchange (ETDEWEB)
Maiden, Wendy M.; Dionysiou, Ioanna; Frincke, Deborah A.; Fink, Glenn A.; Bakken, David E.
2011-02-01
For autonomic computing systems that utilize mobile agents and ant colony algorithms for their sensor layer, trust management is important for the acceptance of the mobile agent sensors and to protect the system from malicious behavior by insiders and entities that have penetrated network defenses. This paper examines the trust relationships, evidence, and decisions in a representative system and finds that by monitoring the trustworthiness of the autonomic managers rather than the swarming sensors, the trust management problem becomes much more scalable and still serves to protect the swarm. We then propose the DualTrust conceptual trust model. By addressing the autonomic manager’s bi-directional primary relationships in the ACS architecture, DualTrust is able to monitor the trustworthiness of the autonomic managers, protect the sensor swarm in a scalable manner, and provide global trust awareness for the orchestrating autonomic manager.
The dual loop model: its relation to language and other modalities
Directory of Open Access Journals (Sweden)
Michel eRijntjes
2012-07-01
Full Text Available The current neurobiological consensus of a general dual-loop system scaffolding human and primate brains gives evidence that the dorsal and ventral connections subserve similar functions, independent of the modality and species. However, most current commentators agree that, although bees dance and chimpanzees grunt, these systems of communication differ qualitatively from human language. So why is language in humans unique?We discuss anatomical differences between humans and other animals, the meaning of lesion studies in patients, the role of inner speech, and compare functional imaging studies in language with other modalities in respect to the dual loop model. These aspects might be helpful for understanding what kind of biological system the language faculty is, and how it relates to other systems in our own species and others.
Modeling of discharges in a capacitively coupled dual frequency plasma reactor
Directory of Open Access Journals (Sweden)
Bojarov Aleksandar
2009-01-01
Full Text Available In this paper we have modeled a dual frequency coupled plasma reactor (DF-CCP by using a 1d3v PIC/MCC code. The obtained results apart from their theoretical relevance have practical applications especially for development of plasma reactors and for nanoelectronics. Dual frequency plasmas are used for etching of dielectric interconnect layers with high aspect ratios (contact holes. In the DF-CCP, the density of the plasma is controlled by the high frequency, while the ion energy depends mainly on the potential drop in the sheath, which is controlled by the low frequency. The results of our simulations show the dependence of the energy of the ions arriving at the inner electrode on the voltage of the low frequency generator and how the voltage of the high frequency generator affects the ion flux on the electrode.
Stability and Thermodynamic Restrictions for a Dual-Phase-Lag Thermal Model
Fabrizio, Mauro; Lazzari, Barbara; Tibullo, Vincenzo
2017-06-01
In this paper, the seeming inconsistency highlighted by Fabrizio and Lazzari (Stability and second law of thermodynamics in dual-phase-lag heat conduction, Int. J. Heat Mass Transfer 74 (2014), 484-489) and Quintanilla and Racke (A note on stability of dual-phase-lag heat conduction, Int. J. Heat Mass Transfer 49 (2007), 1209-1213) for a thermoelastic material, between the thermodynamic restrictions and the stability conditions is studied. Actually, we show as these results are due to the use of different formulations of the thermodynamic principles, which are not always equivalent. So that, we prove by the model considered in the paper that these two formulations do not lead to the same restrictions on the constitutive equations. This analysis allowed us to restore the compatibility by an appropriate and wide representation of the Second Law.
Modeling and Power Flow Analysis for Herringbone Gears Power Dual-Branching Transmission System
Yang, Xiaofang; Zhu, Yanxiang; Fang, Zongde; Gu, Jiangong
Based on power dual-branching transmission system of herringbone gears, the mechanical structural model was established. This study represented the simplified algorithm to obtain its power flow situations through formulating the deformation compatibility condition for the linear relationship between the torque and transverse deformation of tooth surface and the torque equilibrium condition. Besides, the effects on the power flow of system were calculated under all kinds of the installation error and processing error of gear pairs. Finally, the power flow situations of dual branches were solved via Programming. A numerical example that illustrated the developed theory was provided. The research results can be applied to analyze the actual application of herringbone gears power split-path transmission system.
Sabaeian, Mohammad; Rezaei, Hamidreza; Ghalambor-Dezfouli, Abdolmohammad
2017-02-01
Pulsed laser beam excitations are more commonly used in thermal lens spectroscopy (TLS) than continuous-wave (CW) ones, because CW excitations limit the measurement to linear absorption processes [J. Opt. A5, 256 (2003)]. In this work, we present a new and full analytical model for a single-pulsed laser excitation dual-beam mode-mismatched TLS for low absorption solid-state and liquid samples. Our model has been based on a new solution of time-dependent heat equation for a finite-radius cylindrical sample exposed to a single-pulsed excitation laser beam. For low absorbent samples, unlike previous models, all aberration terms associated in the thermal lens were taken into account in Fresnel integration. Besides, the model provides a full analytical mathematical expression for the temperature rise, normalized signal intensity, and Z-scan photothermal lens signal. The model was confirmed with experimental data of distilled deionized water with excellent agreement. Therefore, the model allows us to extract thermo-optical properties of samples in an analytical and more accurate way.
Modeling of a Von Platen-Munters diffusion absorption refrigeration cycle
Agostini, Bruno; Agostini, Francesco; Habert, Mathieu
2016-09-01
This article presents a thermodynamical model of a Von-Platen diffusion absorption refrigeration cycle for power electronics applications. It is first validated by comparison with data available in the literature for the classical water-ammonia-helium cycle for commercial absorption fridges. Then new operating conditions corresponding to specific ABB applications, namely high ambient temperature and new organic fluids combinations compatible with aluminium are simulated and discussed. The target application is to cool power electronics converters in harsh environments with high ambient temperature by providing refrigeration without compressor, for passive components losses of about 500 W, with a compact and low cost solution.
Pietrzak, Monika; Szabelski, Mariusz; Kasparek, Adam; Wieczorek, Zbigniew
2017-02-01
The present study was designed to estimate the ability of hypericin to interact with a model mutagen - acridine orange. The hetero-association of hypericin and acridine orange was investigated with absorption and fluorescence spectroscopy methods in aqueous solution of DMSO. The data indicate that hypericin forms complexes with acridine orange and that the association constants are relatively high and depend on DMSO concentration. The absorption spectra of the hypericin - acridine orange complexes were examined as well. Owing to its ability to interact with flat aromatic compounds, hypericin may potentially be used as an interceptor molecule.
Compound Hertzian Chain Model for Copper-Carbon Nanocomposites' Absorption Spectrum
Kokabi, Alireza; Saeedi, Saman; Moftakharzadeh, Ali; Vesaghi, Mohammad Ali; Fardmanesh, Mehdi
2011-01-01
The infrared range optical absorption mechanism of Carbon-Copper composite thin layer coated on the Diamond-Like Carbon (DLC) buffer layer has been investigated. By consideration of weak interactions between copper nanoparticles in their network, optical absorption is modeled using their coherent dipole behavior induced by the electromagnetic radiation. The copper nanoparticles in the bulk of carbon are assumed as a chain of plasmonic dipoles, which have coupling resonance. Considering nearest neighbor interactions for this metallic nanoparticles, surface plasmon resonance frequency ({\\omega}\
Excited state absorption in glasses activated with rare earth ions: Experiment and modeling
Piatkowski, Dawid; Mackowski, Sebastian
2012-10-01
We present semiempirical approach based on the Judd-Ofelt theory and apply it for modeling the spectral properties of fluoride glasses activated with the rare earth (RE) ions. This method provide a powerful tool for simulating both ground state absorption (GSA) and excited state absorption (ESA) spectra of RE ions, e.g. Nd3+, Ho3+, Er3+ and Tm3+ in the ZBLAN glass matrix. The results of theoretical calculations correspond to the experimentally measured data. We also demonstrate that the spectra obtained using the presented approach are applicable in the analysis of up-conversion excitation schemes in these optoelectronically relevant materials.
Indian Academy of Sciences (India)
Dhairya A Dholakia; G K Solanki; S G Patel; M K Agarwal
2001-06-01
The optical energy gaps of WS2 single crystal were determined from the analysis of the absorption spectrum near the fundamental absorption edge at room temperature using light parallel to -axis incident normally on the basal plane. On the basis of two- and three-dimensional models it was found that both direct and indirect band transitions took place in WS2 and the indirect transition was of the allowed type. The optical energy gaps corresponding to both transitions were determined and the phonon energies associated with the indirect transitions estimated. The implications of the results have been discussed.
A dual-scale turbulence model for gas-liquid bubbly flows☆
Institute of Scientific and Technical Information of China (English)
Xiaoping Guan; Zhaoqi Li; Lijun Wang⁎; Xi Li; Youwei Cheng
2015-01-01
A dual-scale turbulence model is applied to simulate cocurrent upward gas–liquid bubbly flows and validated with available experimental data. In the model, liquid phase turbulence is split into shear-induced and bubble-induced turbulence. Single-phase standard k-εmodel is used to compute shear-induced turbulence and another transport equation is added to model bubble-induced turbulence. In the latter transport equation, energy loss due to interface drag is the production term, and the characteristic length of bubble-induced turbulence, simply the bubble diameter in this work, is introduced to model the dissipation term. The simulated results agree well with experimental data of the test cases and it is demonstrated that the proposed dual-scale turbulence model outperforms other models. Analysis of the predicted turbulence shows that the main part of turbulent kinetic en-ergy is the bubble-induced one while the shear-induced turbulent viscosity predominates within turbulent vis-cosity, especially at the pipe center. The underlying reason is the apparently different scales for the two kinds of turbulence production mechanisms:the shear-induced turbulence is on the scale of the whole pipe while the bubble-induced turbulence is on the scale of bubble diameter. Therefore, the model reflects the multi-scale phe-nomenon involved in gas–liquid bubbly flows.
DEFF Research Database (Denmark)
Sadegh, Negar; Stenby, Erling Halfdan; Thomsen, Kaj
2015-01-01
of pure MDEA vapor pressure, vapor-liquid equilibrium (VLE) (total pressure and CO2 partial pressure), freezing point depression (SLE), excess enthalpy, heat capacity and heat of absorption were used to adjust model parameters. The model was then used to predict the NMR spectroscopic data. The developed...
Paziresh, M.; Kingston, A. M.; Latham, S. J.; Fullagar, W. K.; Myers, G. M.
2016-06-01
Dual-energy computed tomography and the Alvarez and Macovski [Phys. Med. Biol. 21, 733 (1976)] transmitted intensity (AMTI) model were used in this study to estimate the maps of density (ρ) and atomic number (Z) of mineralogical samples. In this method, the attenuation coefficients are represented [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976)] in the form of the two most important interactions of X-rays with atoms that is, photoelectric absorption (PE) and Compton scattering (CS). This enables material discrimination as PE and CS are, respectively, dependent on the atomic number (Z) and density (ρ) of materials [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976)]. Dual-energy imaging is able to identify sample materials even if the materials have similar attenuation coefficients at single-energy spectrum. We use the full model rather than applying one of several applied simplified forms [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976); Siddiqui et al., SPE Annual Technical Conference and Exhibition (Society of Petroleum Engineers, 2004); Derzhi, U.S. patent application 13/527,660 (2012); Heismann et al., J. Appl. Phys. 94, 2073-2079 (2003); Park and Kim, J. Korean Phys. Soc. 59, 2709 (2011); Abudurexiti et al., Radiol. Phys. Technol. 3, 127-135 (2010); and Kaewkhao et al., J. Quant. Spectrosc. Radiat. Transfer 109, 1260-1265 (2008)]. This paper describes the tomographic reconstruction of ρ and Z maps of mineralogical samples using the AMTI model. The full model requires precise knowledge of the X-ray energy spectra and calibration of PE and CS constants and exponents of atomic number and energy that were estimated based on fits to simulations and calibration measurements. The estimated ρ and Z images of the samples used in this paper yield average relative errors of 2.62% and 1.19% and maximum relative errors of 2.64% and 7.85%, respectively. Furthermore, we demonstrate that the method accounts for the beam hardening effect in density (ρ) and
Kesisoglou, Filippos; Mitra, Amitava
2015-09-01
Physiologically based absorption models can be an important tool in understanding product performance and hence implementation of Quality by Design (QbD) in drug product development. In this report, we show several case studies to demonstrate the potential application of absorption modeling in rational design of drug product under the QbD paradigm. The examples include application of absorption modeling—(1) prior to first-in-human studies to guide development of a formulation with minimal sensitivity to higher gastric pH and hence reduced interaction when co-administered with PPIs and/or H2RAs, (2) design of a controlled release formulation with optimal release rate to meet trough plasma concentrations and enable QD dosing, (3) understanding the impact of API particle size distribution on tablet bioavailability and guide formulation design in late-stage development, (4) assess impact of API phase change on product performance to guide specification setting, and (5) investigate the effect of dissolution rate changes on formulation bioperformance and enable appropriate specification setting. These case studies are meant to highlight the utility of physiologically based absorption modeling in gaining a thorough understanding of the product performance and the critical factors impacting performance to drive design of a robust drug product that would deliver the optimal benefit to the patients.
Energy Technology Data Exchange (ETDEWEB)
Abbas, Nikhar; Tom, Nathan
2017-09-01
Wave energy converter (WEC) control strategies have been primarily focused on maximizing power absorption. The use of model predictive control strategies allows for a finite-horizon, multiterm objective function to be solved. This work utilizes a multiterm objective function to maximize power absorption while minimizing the structural loads on the WEC system. Furthermore, a Kalman filter and autoregressive model were used to estimate and forecast the wave exciting force and predict the future dynamics of the WEC. The WEC's power-take-off time-averaged power and structural loads under a perfect forecast assumption in irregular waves were compared against results obtained from the Kalman filter and autoregressive model to evaluate model predictive control performance.
Full counting statistics in the self-dual interacting resonant level model.
Carr, Sam T; Bagrets, Dmitry A; Schmitteckert, Peter
2011-11-11
We present a general technique to obtain the zero temperature cumulant generating function of the full counting statistics of charge transfer in interacting impurity models out of equilibrium from time-dependent simulations on a lattice. We demonstrate the technique with application to the self-dual interacting resonant level model, where very good agreement between numerical simulations using the density matrix renormalization group and those obtained analytically from the thermodynamic Bethe ansatz is found. We show from the exact form of counting statistics that the quasiparticles involved in transport carry charge 2e in the low bias regime and e/2 in the high bias regime.
Ding, Dawei; Luo, Xiaoshu; Liu, Yuliang
2007-01-01
This paper focuses on the delay induced Hopf bifurcation in a dual model of Internet congestion control algorithms which can be modeled as a time-delay system described by a one-order delay differential equation (DDE). By choosing communication delay as the bifurcation parameter, we demonstrate that the system loses its stability and a Hopf bifurcation occurs when communication delay passes through a critical value. Moreover, the bifurcating periodic solution of system is calculated by means of perturbation methods. Discussion of stability of the periodic solutions involves the computation of Floquet exponents by considering the corresponding Poincare -Lindstedt series expansion. Finally, numerical simulations for verify the theoretical analysis are provided.
Richardson, George B; Hardesty, Patrick
2012-01-01
Researchers have recently applied evolutionary life history theory to the understanding of behaviors often conceived of as prosocial or antisocial. In addition, researchers have applied cognitive science to the understanding of substance use and used dual process models, where explicit cognitive processes are modeled as relatively distinct from implicit cognitive processes, to explain and predict substance use behaviors. In this paper we synthesized these two theoretical perspectives to produce an adaptive and cognitive framework for explaining substance use. We contend that this framework provides new insights into the nature of substance use that may be valuable for both clinicians and researchers.
Directory of Open Access Journals (Sweden)
George B. Richardson
2012-10-01
Full Text Available Researchers have recently applied evolutionary life history theory to the understanding of behaviors often conceived of as prosocial or antisocial. In addition, researchers have applied cognitive science to the understanding of substance use and used dual process models, where explicit cognitive processes are modeled as relatively distinct from implicit cognitive processes, to explain and predict substance use behaviors. In this paper we synthesized these two theoretical perspectives to produce an adaptive and cognitive framework for explaining substance use. We contend that this framework provides new insights into the nature of substance use that may be valuable for both clinicians and researchers.
Convex relaxation for a 3D spatiotemporal segmentation model using the primal-dual method
Institute of Scientific and Technical Information of China (English)
Shi-yan WANG; Hui-min YU
2012-01-01
A method based on 3D videos is proposed for multi-target segmentation and tracking with a moving viewing system.A spatiotemporal energy functional is built up to perform motion segmentation and estimation simultaneously.To overcome the limitation of the local minimum problem with the level set method,a convex relaxation method is applied to the 3D spatiotemporal segmentation model.The relaxed convex model is independent of the initial condition.A primal-dual algorithm is used to improve computational efficiency.Several indoor experiments show the validity of the proposed method.
Investigating whether it is optimal to make replenishments simultaneously in dual source model
DEFF Research Database (Denmark)
Abginehchi, Soheil; Larsen, Christian
be relaxed. We study a dual source system with non-identical suppliers and model the problem as a semi-Markov decision model, allowing the decision maker the choice whether he will simultaneously issue two orders to both suppliers or he will issue the orders to suppliers at two different times.......In multiple sourcing, when supplier lead times are stochastic it makes sense to split any replenishment order into several smaller orders to pool lead time risks. In literature it is always assumed these orders are issued simultaneously to the suppliers. Here we let this simultaneousness assumption...
Multicanonical analysis of the plaquette-only gonihedric Ising model and its dual
Mueller, Marco; Johnston, Desmond A.; Janke, Wolfhard
2014-11-01
The three-dimensional purely plaquette gonihedric Ising model and its dual are investigated to resolve inconsistencies in the literature for the values of the inverse transition temperature of the very strong temperature-driven first-order phase transition that is apparent in the system. Multicanonical simulations of this model allow us to measure system configurations that are suppressed by more than 60 orders of magnitude compared to probable states. With the resulting high-precision data, we find excellent agreement with our recently proposed nonstandard finite-size scaling laws for models with a macroscopic degeneracy of the low-temperature phase by challenging the prefactors numerically. We find an overall consistent inverse transition temperature of β∞=0.551334(8) from the simulations of the original model both with periodic and fixed boundary conditions, and the dual model with periodic boundary conditions. For the original model with periodic boundary conditions, we obtain the first reliable estimate of the interface tension σ=0.12037(18), using the statistics of suppressed configurations.
Multicanonical analysis of the plaquette-only gonihedric Ising model and its dual
Directory of Open Access Journals (Sweden)
Marco Mueller
2014-11-01
Full Text Available The three-dimensional purely plaquette gonihedric Ising model and its dual are investigated to resolve inconsistencies in the literature for the values of the inverse transition temperature of the very strong temperature-driven first-order phase transition that is apparent in the system. Multicanonical simulations of this model allow us to measure system configurations that are suppressed by more than 60 orders of magnitude compared to probable states. With the resulting high-precision data, we find excellent agreement with our recently proposed nonstandard finite-size scaling laws for models with a macroscopic degeneracy of the low-temperature phase by challenging the prefactors numerically. We find an overall consistent inverse transition temperature of β∞=0.551334(8 from the simulations of the original model both with periodic and fixed boundary conditions, and the dual model with periodic boundary conditions. For the original model with periodic boundary conditions, we obtain the first reliable estimate of the interface tension σ=0.12037(18, using the statistics of suppressed configurations.
Multicanonical analysis of the plaquette-only gonihedric Ising model and its dual
Energy Technology Data Exchange (ETDEWEB)
Mueller, Marco, E-mail: Marco.Mueller@itp.uni-leipzig.de [Institut für Theoretische Physik, Universität Leipzig, Postfach 100 920, D-04009 Leipzig (Germany); Johnston, Desmond A., E-mail: D.A.Johnston@hw.ac.uk [Department of Mathematics and the Maxwell Institute for Mathematical Sciences, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS, Scotland (United Kingdom); Janke, Wolfhard, E-mail: Wolfhard.Janke@itp.uni-leipzig.de [Institut für Theoretische Physik, Universität Leipzig, Postfach 100 920, D-04009 Leipzig (Germany)
2014-11-15
The three-dimensional purely plaquette gonihedric Ising model and its dual are investigated to resolve inconsistencies in the literature for the values of the inverse transition temperature of the very strong temperature-driven first-order phase transition that is apparent in the system. Multicanonical simulations of this model allow us to measure system configurations that are suppressed by more than 60 orders of magnitude compared to probable states. With the resulting high-precision data, we find excellent agreement with our recently proposed nonstandard finite-size scaling laws for models with a macroscopic degeneracy of the low-temperature phase by challenging the prefactors numerically. We find an overall consistent inverse transition temperature of β{sup ∞}=0.551334(8) from the simulations of the original model both with periodic and fixed boundary conditions, and the dual model with periodic boundary conditions. For the original model with periodic boundary conditions, we obtain the first reliable estimate of the interface tension σ=0.12037(18), using the statistics of suppressed configurations.
Microwave Absorption and Response Modeling of Nanocomposites Embedded SiC Nanoparticles
Institute of Scientific and Technical Information of China (English)
LU Ran; FANG Xiao-Yong; KANG Yu-Qing; YUAN Jie; CAO Mao-Sheng
2009-01-01
@@ We study the mechanism of microwave response properties of SiCp/paraffin nanocomposites and propose a mi-crowave absorption model of nanocomposites based on the conservation law of energy and the theory of electro-magnetic scattering. Using the model we calculate the reflectivity of SiCp/paraffin nanocomposites ranging from 2 CHz to 18 GHz. The calculated results are very consistent with the experimental data in the frequency range investigated.
Enhancement Factors in Ozone Absorption Based on the Surface Renewal Model and its Application
Institute of Scientific and Technical Information of China (English)
程江; 杨卓如; 陈焕钦; C.H.Kuo; M.E.Zappi
2000-01-01
Based on the Danckwerts surface renewal model, a simple explicit expression of the enhancement factor in ozone absorption with a first order ozone self-decomposition and parallel second order ozonation reactions has been derived. The results are compared with our previous work based on the film theory. The 2,4-dichlorophenol destruction rate by ozonation is predicted using the enhancement factor model in this paper.
Molecular modeling of C 60:cobaltocene and nickelocene complexes, comparison with IR absorption
Byszewski, P.; Antonova, K.; Kowalska, E.; Radomska, J.; Baran, J.
2000-06-01
C 60 was reacted with cobaltocene and nickelocene. The samples of the composition C 60(Cocp 2) 3 and C 60Nicp 2 were obtained in the reaction. Their thermal stability was measured by Thermogravimetry and Differential Scanning Calorimetry and the vibrational spectrum was investigated by infrared absorption. Hydrocarbon groups may be evacuated from the reaction products by annealing, while metal atoms remain dispersed between fullerenes. The experiments are compared with the molecular modeling results obtained by applying the PM3 model.
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
On the basis of analysis on the temperature monitoring methods for high voltage devices, a new type of fiber optic sensor structure with reference channel is given. And the operation principle of fiber optic sensor is analysed at large based on the absorption of semiconductor chip. The mathematical model of both devices and the whole system are also given. It is proved by the experiment that this mathematical model is reliable.
An Image Fusion Method Based on NSCT and Dual-channel PCNN Model
Directory of Open Access Journals (Sweden)
Nianyi Wang
2014-02-01
Full Text Available NSCT is one of useful multiscale geometric analysis tools, which takes full advantage of geometric regularity of image intrinsic structures. The dual-channel PCNN is a simplified PCNN model, which can process multiple images by a single PCNN. This saves time in the process of image fusion and cuts down computational complexity. In this paper, we present a new image fusion scheme based on NSCT and dual-channel PCNN. Firstly, the fusion rules of subband coefficients of NSCT are discussed. For the fusion rule of low frequency coefficients, the maximum selection rule (MSR is used. Then, for the fusion rule of high frequency coefficients, spatial frequency (SF of each high frequency subband is considered as the gradient features of images to motivate dual-channel PCNN networks and generate pulse of neurons. At last, fused image is obtained by using the inverse NSCT transform. In order to show that the proposed method can deal with image fusion, we used two pairs of images as our experimental subjects. The proposed method is compared with other five methods. The performance of various methods is mathematically evaluated by using four image quality evaluation criteria. Experimental comparisons conducted on different fusion methods prove the effectiveness of the proposed fusion method
The Chinese Urban-rural Dual Economic Structure Model and Analysis
Institute of Scientific and Technical Information of China (English)
Xiuchuan; XU; Shengping; SHI; Qinghua; HUANG
2014-01-01
Based on the characteristics of urban-rural dual economic structure in China,we build a dynamic endogenous urban-rural dual economic model closely linked to China’s reality,and carry out mathematical economics analysis of optimized conditions for urban and rural sectors. The main results show that:(i) The labor growth rate of urban-rural sectors must be greater than the time discount rate,or else there would be a vicious cycle of diminishing returns in the sectors;(ii) The accumulation rate of physical capital and human capital of urban-rural sectors,and the rate of technological progress,need to be greater than the corresponding depreciation rate plus the time discount rate,otherwise there would be a vicious cycle of diminishing returns in the sectors;(iii) The low accumulation rate in the rural sector,and the occurrence of labor outflow,human capital loss and lack of investment,will expand income gap between urban and rural areas,which is a reason for solidification of urban-rural dual economic structure.
Energy Technology Data Exchange (ETDEWEB)
Ho, Clifford Kuofei
2004-06-01
Chemical transport through human skin can play a significant role in human exposure to toxic chemicals in the workplace, as well as to chemical/biological warfare agents in the battlefield. The viability of transdermal drug delivery also relies on chemical transport processes through the skin. Models of percutaneous absorption are needed for risk-based exposure assessments and drug-delivery analyses, but previous mechanistic models have been largely deterministic. A probabilistic, transient, three-phase model of percutaneous absorption of chemicals has been developed to assess the relative importance of uncertain parameters and processes that may be important to risk-based assessments. Penetration routes through the skin that were modeled include the following: (1) intercellular diffusion through the multiphase stratum corneum; (2) aqueous-phase diffusion through sweat ducts; and (3) oil-phase diffusion through hair follicles. Uncertainty distributions were developed for the model parameters, and a Monte Carlo analysis was performed to simulate probability distributions of mass fluxes through each of the routes. Sensitivity analyses using stepwise linear regression were also performed to identify model parameters that were most important to the simulated mass fluxes at different times. This probabilistic analysis of percutaneous absorption (PAPA) method has been developed to improve risk-based exposure assessments and transdermal drug-delivery analyses, where parameters and processes can be highly uncertain.
Rapcsak, Steven Z.; Henry, Maya L.; Teague, Sommer L.; Carnahan, Susan D.; Beeson, Pélagie M.
2007-01-01
Coltheart and colleagues (Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001; Castles, Bates, & Coltheart, 2006) have demonstrated that an equation derived from dual-route theory accurately predicts reading performance in young normal readers and in children with reading impairment due to developmental dyslexia or stroke. In this paper we present evidence that the dual-route equation and a related multiple regression model also accurately predict both reading and spelling performance in adult neurological patients with acquired alexia and agraphia. These findings provide empirical support for dual-route theories of written language processing. PMID:17482218
Modelling and measurement of wear particle flow in a dual oil filter system for condition monitoring
DEFF Research Database (Denmark)
Henneberg, Morten; Eriksen, René Lynge; Fich, Jens
2016-01-01
Wear debris is an indicator of the health of machinery, and the availability of accurate methods for characterising debris is important. In this work, a dual filter model for a gear oil system is used in conjunction with operational data to indicate three different system operating states. The qu...... particle generation is made possible by model parameter estimation and identification of an unintended lack of filter change. The model may also be used to optimise system and filtration performance, and to enable continuous condition monitoring.......Wear debris is an indicator of the health of machinery, and the availability of accurate methods for characterising debris is important. In this work, a dual filter model for a gear oil system is used in conjunction with operational data to indicate three different system operating states....... The quantity of wear particles in gear oil is analysed with respect to system running conditions. It is shown that the model fits the data in terms of startup “particle burst” phenomenon, quasi-stationary conditions during operation, and clean-up filtration when placed out of operation. In order to establish...
Mottin, Stephane; Panasenko, Grigory; Ganesh, S Sivaji
2010-12-31
In biophotonics, the light absorption in a tissue is usually modeled by the Helmholtz equation with two constant parameters, the scattering coefficient and the absorption coefficient. This classic approximation of "haemoglobin diluted everywhere" (constant absorption coefficient) corresponds to the classical homogenization approach. The paper discusses the limitations of this approach. The scattering coefficient is supposed to be constant (equal to one) while the absorption coefficient is equal to zero everywhere except for a periodic set of thin parallel strips simulating the blood vessels, where it is a large parameter ω. The problem contains two other parameters which are small: ε, the ratio of the distance between the axes of vessels to the characteristic macroscopic size, and δ, the ratio of the thickness of thin vessels and the period. We construct asymptotic expansion in two cases: ε --> 0, ω --> ∞, δ --> 0, ωδ --> ∞, ε2ωδ --> 0 and ε --> 0, ω --> ∞, δ --> 0, ε2ωδ --> ∞, and and prove that in the first case the classical homogenization (averaging) of the differential equation is true while in the second case it is wrong. This result may be applied in the biomedical optics, for instance, in the modeling of the skin and cosmetics.
Gao, Duyang; Zhang, Pengfei; Liu, Chengbo; Chen, Chi; Gao, Guanhui; Wu, Yayun; Sheng, Zonghai; Song, Liang; Cai, Lintao
2015-10-01
A chelator-free doping method is developed for constructing a Ni-integrated CuS nanostructure as a novel PA/MRI contrast agent. It exhibits tunable near-infrared absorption. Moreover, the hybrid nanostructure has demonstrated a dramatically enhanced T1 relaxivity compared with Ni ions. Due to these unique properties, chelator-free nanoparticles have been successfully applied for in vivo PA/MRI dual-modal imaging.A chelator-free doping method is developed for constructing a Ni-integrated CuS nanostructure as a novel PA/MRI contrast agent. It exhibits tunable near-infrared absorption. Moreover, the hybrid nanostructure has demonstrated a dramatically enhanced T1 relaxivity compared with Ni ions. Due to these unique properties, chelator-free nanoparticles have been successfully applied for in vivo PA/MRI dual-modal imaging. Electronic supplementary information (ESI) available: Details of the experimental procedure and Fig. S1 to S5. See DOI: 10.1039/c5nr05237h
An analytical solution for the model of drug distribution and absorption in small intestine
Mingyu, Xu
1990-11-01
According to the physiological and anatomical characteristics of small intestine, neglecting the effect of its motility on the distribution and absorption of drug and nutrient, Y. Miyamoto et al.[1] proposed a model of two-dimensional laminar flow in a circular porous tube with permeable wall and calculated the concentration profile of drug by numerical analysis. In this paper, we give a steady state analytical solution of the above model including deactivation term. The obtained results are in agreement with the results of their numerical analysis. Moreover the analytical solution presented in this paper reveals the relation among the physiological parameters of the model and describes the basic absorption rule of drug and nutrient through the intestinal wall and hence provides a theoretical basis for determining the permeability and reflection coefficient through in situ experiments.
Comparison between two models of absorption of matter waves by a thin time-dependent barrier
Barbier, Maximilien; Beau, Mathieu; Goussev, Arseni
2015-11-01
We report a quantitative, analytical, and numerical comparison between two models of the interaction of a nonrelativistic quantum particle with a thin time-dependent absorbing barrier. The first model represents the barrier by a set of time-dependent discontinuous matching conditions, which are closely related to Kottler boundary conditions used in stationary-wave optics as a mathematical basis for Kirchhoff diffraction theory. The second model mimics the absorbing barrier with an off-diagonal δ potential with a time-dependent amplitude. We show that the two models of absorption agree in their predictions in a semiclassical regime, the regime readily accessible in modern experiments with ultracold atoms.
A dual-porosity model for simulating solute transport in oil shale
Glover, K.C.
1987-01-01
A model is described for simulating three-dimensional groundwater flow and solute transport in oil shale and associated geohydrologic units. The model treats oil shale as a dual-porosity medium by simulating flow and transport within fractures using the finite-element method. Diffusion of solute between fractures and the essentially static water of the shale matrix is simulated by including an analytical solution that acts as a source-sink term to the differential equation of solute transport. While knowledge of fracture orientation and spacing is needed to effectively use the model, it is not necessary to map the locations of individual fractures. The computer program listed in the report incorporates many of the features of previous dual-porosity models while retaining a practical approach to solving field problems. As a result the theory of solute transport is not extended in any appreciable way. The emphasis is on bringing together various aspects of solute transport theory in a manner that is particularly suited to the unusual groundwater flow and solute transport characteristics of oil shale systems. (Author 's abstract)
Active open boundary forcing using dual relaxation time-scales in downscaled ocean models
Herzfeld, M.; Gillibrand, P. A.
2015-05-01
Regional models actively forced with data from larger scale models at their open boundaries often contain motion at different time-scales (e.g. tidal and low frequency). These motions are not always individually well specified in the forcing data, and one may require a more active boundary forcing while the other exert less influence on the model interior. If a single relaxation time-scale is used to relax toward these data in the boundary equation, then this may be difficult. The method of fractional steps is used to introduce dual relaxation time-scales in an open boundary local flux adjustment scheme. This allows tidal and low frequency oscillations to be relaxed independently, resulting in a better overall solution than if a single relaxation parameter is optimized for tidal (short relaxation) or low frequency (long relaxation) boundary forcing. The dual method is compared to the single relaxation method for an idealized test case where a tidal signal is superimposed on a steady state low frequency solution, and a real application where the low frequency boundary forcing component is derived from a global circulation model for a region extending over the whole Great Barrier Reef, and a tidal signal subsequently superimposed.
A dual pathway model of daily stressor effects on rheumatoid arthritis.
Affleck, G; Urrows, S; Tennen, H; Higgins, P; Pav, D; Aloisi, R
1997-01-01
This study evaluated the initial promise of a dual-pathway conceptual model linking daily event stressors to rheumatoid arthritis (RA) disease activity through changes in immune system activation and mood. Fifty individuals, who were studied on five occasions two weeks apart, reported daily event stressors on the Daily Life Experience Checklist, daily mood on an abbreviated version of the Profile of Mood States-B, and daily joint pain on the Rapid Assessment of Disease Activity in Rheumatology. Serial clinical examinations comprised ratings of joint tenderness and swelling, and blood drawn during exams was analyzed for sedimentation rate (an indicator of systemic inflammation) and soluble interleukin-2 receptors (a marker of immune system activation known to correlate with RA disease activity). Across-person analyses failed to establish links from daily event stressors to either disease activity or composites of joint pain and joint inflammation when associations were adjusted for the effect of neuroticism on self-report measures. Pooled within-person analyses, however, were generally consistent with the relations predicted by the dual-pathway model. Increases in daily event stressors during the week preceding each clinical exam were associated with increased joint pain (regardless of changes in mood). At the same time, increased daily stressors were indirectly associated with decreased joint inflammation through reduction in levels of soluble interleukin-2 receptors. The dual-pathway model, which may be limited to short-term psychological and psychoimmunologic processes, underscores the importance of distinguishing potentially opposing effects of stress on pain versus inflammation in individuals with rheumatoid arthritis.
Directory of Open Access Journals (Sweden)
T N Hagawane
2016-01-01
Results: It was noted that the respiratory rate, and tumour necrosis factor-α (TNF-α levels were significantly higher at 4 h in the dual hit group as compared to LPS, OA and control groups. Interleukin-6 (IL-6 levels were significantly higher in the dual hit group as compared to LPS at 8 and 24 h, OA at 8 h and control (at all time intervals group. IL-1β levels were significantly higher in LPS and dual hit groups at all time intervals, but not in OA and control groups. The injury induced in dual hit group was earlier and more sustained as compared to LPS and OA alone. Interpretation & conclusions: The lung pathology and changes in respiration functions produced by the dual hit model were closer to the diagnostic criteria of ALI/ARDS in terms of clinical manifestations and pulmonary injury and the injury persisted longer as compared to LPS and OA single hit model. Therefore, the ARDS model produced by the dual hit method was closer to the diagnostic criteria of ARDS in terms of clinical manifestations and pulmonary injury.
Energy Technology Data Exchange (ETDEWEB)
Gerde, P. [National Inst. for Working Life, Solna (Sweden); Muggenburg, B.A.; Thornton-Manning, J.R. [and others
1995-12-01
Most chemically induced lung cancer originates in the epithelial cells in the airways. Common conceptions are that chemicals deposited on the airway surface are rapidly absorbed through mucous membranes, limited primarily by the rate of blood perfusion in the mucosa. It is also commonly thought that for chemicals to induce toxicity at the site of entry, they must be either rapidly reactive, readily metabolizable, or especially toxic to the tissues at the site of entry. For highly lipophilic toxicants, there is a third option. Our mathematical model predicts that as lipophilicity increases, chemicals partition more readily into the cellular lipid membranes and diffuse more slowly through the tissues. Therefore, absorption of very lipophilic compounds will be almost entirely limited by the rate of diffusion through the epithelium rather than by perfusion of the capillary bed in the subepithelium. We have reported on a preliminary model for absorption through mucous membranes of any substance with a lipid/aqueous partition coefficient larger than one. The purpose of this work was to experimentally validate the model in Beagle dogs. This validated model on toxicant absorption in the airway mucosa will improve risk assessment of inhaled
Institute of Scientific and Technical Information of China (English)
Wang Xuanyin; Xiao Baoping; Pan Feng
2003-01-01
A dual-CCD simulating human eyes and neck (DSHEN) vision system is put forward. Its structure and principle are introduced. The DSHEN vision system can perform some movements simulating human eyes and neck by means of four rotating joints, and realize precise object recognizing and distance measuring in all orientations. The mathematic model of the DSHEN vision system is built, and its movement equation is solved. The coordinate error and measure precision affected by the movement parameters are analyzed by means of intersection measuring method. So a theoretic foundation for further research on automatic object recognizing and precise target tracking is provided.
SIX SIGMA OPTIMIZATION IN SHEET METAL FORMING BASED ON DUAL RESPONSE SURFACE MODEL
Institute of Scientific and Technical Information of China (English)
LI Yuqiang; CUI Zhenshan; ZHANG Dongjuan; RUAN Xueyu; CHEN Jun
2006-01-01
Iterations in optimization and numerical simulation for the sheet metal forming process may lead to extensive computation. In addition, uncertainties in materials or processing parameters may have great influence on the design quality. A six sigma optimization method is proposed, by combining the dual response surface method (DRSM) and six sigma philosophy, to save computation cost and improve reliability and robustness of parts. Using this method, statistical technology,including the design of experiment and analysis of variance, approximate model and six sigma philosophy are integrated together to achieve improved quality. Two sheet metal forming processes are provided as examples to illustrate the proposed method.
DEFF Research Database (Denmark)
Portero, Ana; Remuñán-López, Carmen; Nielsen, Hanne Mørck
2002-01-01
To investigate the potential of chitosan (CS) to enhance buccal peptide and protein absorption, the TR146 cell culture model, a model of the buccal epithelium, was used.......To investigate the potential of chitosan (CS) to enhance buccal peptide and protein absorption, the TR146 cell culture model, a model of the buccal epithelium, was used....
Highly nonlinear wave solutions in a dual to the chiral model
Rajeev, S G
2016-01-01
We consider a two-dimensional scalar field theory with a nilpotent current algebra, which is dual to the Principal Chiral Model. The quantum theory is renormalizable and not asymptotically free: the theory is strongly coupled at short distances (encountering a Landau pole). We suggest it can serve as a toy model for $\\lambda\\phi^{4}$ theory in four dimensions, just as the principal chiral model is a useful toy model for Yang-Mills theory. We find some classical wave solutions that survive the strong coupling limit and quantize them by the collective variable method. They describe excitations with an unusual dispersion relation $\\omega\\propto|k|^{\\frac{2}{3}}$ . Perhaps they are the "preons" at strong coupling, whose bound states form massless particles over long distances.
Highly nonlinear wave solutions in a dual to the chiral model
Rajeev, S. G.; Ranken, Evan
2016-05-01
We consider a two-dimensional scalar field theory with a nilpotent current algebra, which is dual to the Principal Chiral Model. The quantum theory is renormalizable and not asymptotically free; the theory is strongly coupled at short distances (encountering a Landau pole). We suggest it can serve as a toy model for λ ϕ4 theory in four dimensions, just as the principal chiral model is a useful toy model for Yang-Mills theory. We find some classical wave solutions that survive the strong coupling limit and quantize them by the collective variable method. They describe excitations with an unusual dispersion relation ω ∝|k |2/3 . Perhaps they are the "preons" at strong coupling, the bound states of which form massless particles over long distances.
Wilczynska, Michael R; King, Julian A; Murphy, Michael T; Bainbridge, Matthew B; Flambaum, Victor V
2015-01-01
We present an analysis of 23 absorption systems along the lines of sight towards 18 quasars in the redshift range of $0.4 \\leq z_{abs} \\leq 2.3$ observed on the Very Large Telescope (VLT) using the Ultraviolet and Visual Echelle Spectrograph (UVES). Considering both statistical and systematic error contributions we find a robust estimate of the weighted mean deviation of the fine-structure constant from its current, laboratory value of $\\Delta\\alpha/\\alpha=\\left(0.22\\pm0.23\\right)\\times10^{-5}$, consistent with the dipole variation reported in Webb et al. and King et al. This paper also examines modelling methodologies and systematic effects. In particular we focus on the consequences of fitting quasar absorption systems with too few absorbing components and of selectively fitting only the stronger components in an absorption complex. We show that using insufficient continuum regions around an absorption complex causes a significant increase in the scatter of a sample of $\\Delta\\alpha/\\alpha$ measurements, th...
Modeling of ammonia absorption chillers integration in energy systems of process plants
Energy Technology Data Exchange (ETDEWEB)
Bruno, J.C.; Castells, F. [Universitat Rovira i Virgili, Tarragona (Spain). Dept. d' Enginyeria Quimica; Miquel, J. [Universitat Politecnica de Catalunya (Spain). Dept. de Mecanica de Fluids
1999-12-01
A mathematical programming approach is proposed to study the integration of absorption chillers in combined heat and power plants. The aim of this work is to determine the economic viability of the introduction of ammonia absorption chillers in energy systems instead of using the more conventional compression cycles. This procedure selects the best refrigeration alternative taking into account both absorption and compression cycles. To select the most suitable refrigeration cycle for a given refrigeration load, it is not only necessary to model the performance of each cycle, but also to take into account the interactions between the energy system and the considered cycles, optimizing the performance of the global plant. This approach has been implemented in the computer program XV, and tested in an energy plant in the petrochemical complex of Tarragona (Catalunya, Spain). The refrigeration demands to be met are at 0 and -20{sup o}C. The results highlighted the benefit obtained with the simultaneous presence of ammonia absorption cycles and a cogeneration based energy plant. (author)
Bazeia, D; Nascimento, J R S; Ribeiro, R F; Wotzasek, C
2001-01-01
We study the equivalence between a nonlinear self-dual model (NSD) with the Born-Infeld-Chern-Simons (BICS) models using an iterative gauge embedding procedure that produces the duality mapping, including the case where the NSD model is minimally coupled to dynamical, U(1) charged fermionic matter. The duality mapping introduces a current-current interaction term while at the same time the minimal coupling of the original nonlinear self-dual model is replaced by a non-minimal magnetic like coupling in the BICS side.
Helal, Yaser H.; Neese, Christopher F.; De Lucia, Frank C.; Ewing, Paul R.; Agarwal, Ankur; Craver, Barry; Stout, Phillip J.; Armacost, Michael D.
2015-06-01
Plasmas used in the semiconductor manufacturing industry are of a similar nature to the environments often created for submillimeter spectroscopic study of astrophysical species. At the low operating pressures of these plasmas, submillimeter absorption spectroscopy is a method capable of measuring the abundances and temperatures of molecules, radicals, and ions without disturbing any of the properties of the plasma. These measurements provide details and insight into the interactions and reactions occurring within the plasma and their implications for semiconductor manufacturing processes. A continuous wave, 500 to 750 GHz, absorption spectrometer was designed and used to make measurements of species in semiconductor processing plasmas. Comparisons with expectations from theoretical plasma models provide a basis for validating and improving these models, which is a complex and difficult science itself. Furthermore, these comparisons are an evaluation for the use of submillimeter spectroscopy as a diagnostic tool in manufacturing processes.
Modeling dual-scale epidemic dynamics on complex networks with reaction diffusion processes
Institute of Scientific and Technical Information of China (English)
Xiao-gang JIN; Yong MIN
2014-01-01
The frequent outbreak of severe foodborne diseases (e.g., haemolytic uraemic syndrome and Listeriosis) in 2011 warns of a potential threat that world trade could spread fatal pathogens (e.g., enterohemorrhagic Escherichia coli). The epidemic potential from trade involves both intra-proliferation and inter-diffusion. Here, we present a worldwide vegetable trade network and a stochastic computational model to simulate global trade-mediated epidemics by considering the weighted nodes and edges of the network and the dual-scale dynamics of epidemics. We address two basic issues of network structural impact in global epi-demic patterns:(1) in contrast to the prediction of heterogeneous network models, the broad variability of node degree and edge weights of the vegetable trade network do not determine the threshold of global epidemics;(2) a‘penetration effect’, by which community structures do not restrict propagation at the global scale, quickly facilitates bridging the edges between communities, and leads to synchronized diffusion throughout the entire network. We have also defined an appropriate metric that combines dual-scale behavior and enables quantification of the critical role of bridging edges in disease diffusion from widespread trading. The unusual structure mechanisms of the trade network model may be useful in producing strategies for adaptive immunity and reducing international trade frictions.
Dynamic Model and Fault Feature Research of Dual-Rotor System with Bearing Pedestal Looseness
Directory of Open Access Journals (Sweden)
Nanfei Wang
2016-01-01
Full Text Available The paper presents a finite element model of dual-rotor system with pedestal looseness stemming from loosened bolts. Dynamic model including bearing pedestal looseness is established based on the dual-rotor test rig. Three-degree-of-freedom (DOF planar rigid motion of loose bearing pedestal is fully considered and collision recovery coefficient is also introduced in the model. Based on the Timoshenko beam elements, using the finite element method, rigid body kinematics, and the Newmark-β algorithm for numerical simulation, dynamic characteristics of the inner and outer rotors and the bearing pedestal plane rigid body motion under bearing pedestal looseness condition are studied. Meanwhile, the looseness experiments under two different speed combinations are carried out, and the experimental results are basically the same. The simulation results are compared with the experimental results, indicating that vibration displacement waveforms of loosened rotor have “clipping” phenomenon. When the bearing pedestal looseness fault occurs, the inner and outer rotors vibration spectrum not only contains the difference and sum frequency of the two rotors’ fundamental frequency but also contains 2X and 3X component of rotor with loosened support, and so forth; low frequency spectrum is more, containing dividing component, and so forth; the rotor displacement spectrums also contain fewer combination frequency components, and so forth; when one side of the inner rotor bearing pedestal is loosened, the inner rotor axis trajectory is drawn into similar-ellipse shape.
Dual conical conducting filament model in resistance switching TiO2 thin films.
Kim, Kyung Min; Park, Tae Hyung; Hwang, Cheol Seong
2015-01-19
The resetting behaviors of Pt/TiO2/Pt resistive switching (RS) cell in unipolar RS operations were studied in detail through an experiment and by modeling. The experiment showed that the apparently highly arbitrary resetting current-voltage (I-V) curves could be grouped into three types: normal, delayed, and abnormal behaviors. A dual conical conducting filament (CF) model was conceived, and their electrothermal behaviors were analytically described from the heat-balance and charge-transport equations. The almost spontaneous resetting behavior of the normal reset could be easily understood from the mutually constructive interference effect between the Joule heating and temperature-dependent resistance effect along the CF. The delayed reset could be explained by the time-dependent increase in the reset voltage during the rest process, which was most probably induced in the more conical-shaped CF. The abnormal reset could be understood from the temporal transfer of oxygen ions near the kink positions of the two different-diameter portions of the more cylindrical CFs, which temporally decreases the overall resistance immediately prior for the actual reset to occur. The accuracy of the dual conical CF model was further confirmed by adopting a more thorough electrothermal simulation package, COMSOL.
More evidence for a dual-process model of conditional reasoning.
Markovits, Henry; Forgues, Hugues Lortie; Brunet, Marie-Laurence
2012-07-01
Many studies have shown that the deductive inferences that people make have global properties that reflect the statistical information implicit in the premises. This suggests that such reasoning can be explained by a single, underlying probabilistic model. In contrast, the dual process model of conditional reasoning (Verschueren, Schaeken, & d'Ydewalle, 2005b) proposes that people can use either a logical, counterexample-based strategy or a probabilistic one. In two studies, we presented reasoners with sequences of affirmation-of-the-consequent inferences that differed with respect to the statistical properties of the premises, either explicitly or implicitly. As predicted by the dual-process model, an analysis of individual response patterns showed the presence of two distinct strategies, with use of the counterexample strategy being associated with higher levels of abstract-reasoning competence. Use of the counterexample strategy was facilitated by the explicit presentation of counterexample information. In a further study, we then examined explicitly probabilistic inferences. This study showed that although most reasoners made statistically appropriate inferences, the ability to make more-accurate inferences was associated with higher levels of abstract reasoning competence. These results show that deductive inferential reasoning cannot be explained by a single, unitary process and that any analysis of reasoning must consider individual differences in strategy use.
Dual energy CT at the synchrotron: A piglet model for neurovascular research
Energy Technology Data Exchange (ETDEWEB)
Schueltke, Elisabeth, E-mail: e.schultke@usask.ca [University of Saskatchewan, Saskatoon, SK (Canada); Kelly, Michael E. [University of Saskatchewan, Saskatoon, SK (Canada); Nemoz, Christian [European Synchrotron Radiation Facility (ESRF), 6 rue Horowitz, 38043 Grenoble (France); Fiedler, Stefan [European Molecular Biology Laboratory (EMBL), Nottkestrasse 85, 22603 Hamburg (Germany); Ogieglo, Lissa [University of Saskatchewan, Saskatoon, SK (Canada); Crawford, Paul [Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Herfordshire AL9 7TA (United Kingdom); Paterson, Jessica; Beavis, Cole [University of Saskatchewan, Saskatoon, SK (Canada); Esteve, Francois [CR INSERM U836-Team 6/ESRF, 6 rue Horowitz, 38043 Grenoble (France); Brochard, Thierry; Renier, Michel; Requardt, Herwig; Dallery, Dominique; Le Duc, Geraldine [European Synchrotron Radiation Facility (ESRF), 6 rue Horowitz, 38043 Grenoble (France); Meguro, Kotoo [University of Saskatchewan, Saskatoon, SK (Canada)
2011-08-15
Background: Although the quality of imaging techniques available for neurovascular angiography in the hospital environment has significantly improved over the last decades, the equipment used for clinical work is not always suited for neurovascular research in animal models. We have previously investigated the suitability of synchrotron-based K-edge digital subtraction angiography (KEDSA) after intravenous injection of iodinated contrast agent for neurovascular angiography in radiography mode in both rabbit and pig models. We now have used the KEDSA technique for the acquisition of three-dimensional images and dual energy CT. Materials and methods: All experiments were conducted at the biomedical beamline ID 17 of the European Synchrotron Radiation Facility (ESRF). A solid state germanium (Ge) detector was used for the acquisition of image pairs at 33.0 and 33.3 keV. Three-dimensional images were reconstructed from an image series containing 60 single images taken throughout a full rotation of 360{sup o}. CT images were reconstructed from two half-acquisitions with 720 projections each. Results: The small detector field of view was a limiting factor in our experiments. Nevertheless, we were able to show that dual energy CT using the KEDSA technique available at ID 17 is suitable for neurovascular research in animal models.
Dual luminophor pressure-sensitive paint: III. Application to automotive model testing
Gouterman, Martin; Callis, James; Dalton, Larry; Khalil, Gamal; Mébarki, Youssef; Cooper, Kevin R.; Grenier, Michel
2004-10-01
Porphyrins play key roles in natural energy conversion systems, including photosynthesis and oxygen transport. Because of their chemical stability, unique optical properties and synthetic versatility, porphyrins are well suited as chemical sensors. One successful application is the use of platinum porphyrin (PtP) in pressure-sensitive paint (PSP). Oxygen in the film quenches luminescence, and oxygen pressure was initially monitored by measuring the ratio of I(wind-off)/I(wind-on). But this ratio is compromised if there is model motion and if the paint layer is inhomogeneous. Furthermore it requires careful monitoring and placement of light sources. Moreover, this method is seriously affected by temperature. The errors caused by model motion and temperature sensitivity are eliminated or greatly reduced using dual luminophor paint. This paper illustrates a successful application of a dual luminophor PSP in auto model testing. The PSP is made from an oxygen sensitive luminophor, Pt tetra(pentafluorophenyl)-porpholactone, which provides Isen, and Mg tetra(pentafluorophenyl)porphine, which provides temperature-sensitive paint (TSP) as the pressure-independent reference. The ratio PSP/TSP in the FIB polymer produced ideal PSP measurements with a very low-temperature dependence of -0.1% °C-1.
Measurement and modelling of enhanced absorption Hanle effect resonances in {sup 85}Rb
Energy Technology Data Exchange (ETDEWEB)
Vilardi, Andrea; Tabarelli, Davide; Botti, Laura; Bertoldi, Andrea; Ricci, Leonardo [Dipartimento di Fisica, Universita di Trento, I-38100 Trento-Povo (Italy)], E-mail: andrea.bertoldi@institutoptique.fr
2009-03-14
We report on a detailed measurement of the enhanced absorption Hanle effect resonances in {sup 85}Rb. The effect was analysed with an experimental setup allowing for the control of each magnetic field component within 1 mG. The characterization deals with the dependence of resonances, observed under different magnetic field conditions, on the frequency, intensity and polarization of the exciting radiation field. An analytic model that precisely describes the resonance behaviour is discussed.
The Phenion (R) Full-Thickness Skin Model for Percutaneous Absorption Testing
2010-01-01
In recent years many efforts have been made to replace dermal toxicity testing of chemicals in the animal by in vitro assays. As a member of a German research consortium, we have previously contributed to the validation of an in vitro test protocol for percutaneous absorption studies on the basis of reconstructed human epidermis and both human and pig skin ex vivo. Aiming to assess the barrier properties of a newly developed reconstructed skin model, this protocol has now been transferred to ...
Dynamic Model and Performance of Absorption Heat Pump in Shut-down Process
Institute of Scientific and Technical Information of China (English)
WANG Lei; LU Zhen
2002-01-01
The dynamic model of LiBr absorption heat pump in shut-down process is established. The simulation results show good agreement with the experiments. The dynamic performance of high-pressure generator, low-pressure generator and heat exchanger are analyzed in detail. The proper shut-down mode of the heat pump is presented,which, in consideration of solution parameters, has a great effect on the possibility of crystallization of some components.
Microscopic modeling of País grape seed extract absorption in the small intestine.
Morales, Cristian; Roeckel, Marlene; Fernández, Katherina
2014-02-01
The concentration profiles and the absorbed fraction (F) of the País grape seed extract in the human small intestine were obtained using a microscopic model simulation that accounts for the extracts' dissolution and absorption. To apply this model, the physical and chemical parameters of the grape seed extract solubility (C s), density (ρ), global mass transfer coefficient between the intestinal and blood content (k) (effective permeability), and diffusion coefficient (D) were experimentally evaluated. The diffusion coefficient (D = 3.45 × 10(-6) ± 5 × 10(-8) cm(2)/s) was approximately on the same order of magnitude as the coefficients of the relevant constituents. These results were chemically validated to discover that only the compounds with low molecular weights diffused across the membrane (mainly the (+)-catechin and (-)-epicatechin compounds). The model demonstrated that for the País grape seed extract, the dissolution process would proceed at a faster rate than the convective process. In addition, the absorbed fraction was elevated (F = 85.3%). The global mass transfer coefficient (k = 1.53 × 10(-4) ± 5 × 10(-6) cm/s) was a critical parameter in the absorption process, and minor changes drastically modified the prediction of the extract absorption. The simulation and experimental results show that the grape seed extract possesses the qualities of a potential phytodrug.
Modeling size-dependent photosynthesis: light absorption and the allometric rule.
Finkel, Z V; Irwin, A J
2000-06-07
Microalgal photosynthesis can be predicted using empirical allometric or mechanistic bio-optic models. These two descriptions are usually considered independently. We compare the size scaling of photosynthesis predicted by these two models. Size scaling exponents for phytoplankton often deviate from the allometric 3/4 rule. This may be because the allometric model does not account for the size dependence of light absorption and its effect on the size scaling of photosynthesis. In contrast to the allometric model and experimental data, the bio-optic model predicts photosynthesis should be independent of cell size when intracellular pigment concentrations are low or inversely related to cell diameter. A composite of the allometric and bio-optic models is described and compared to laboratory data of light-limited nutrient-saturated diatom photosynthesis. The allo-bio-optic model provides a mechanistic explanation for the anomalous size scaling found in laboratory and field studies of microalgal photosynthesis and growth.
Quantification of colloidal and aqueous element transfer in soils: The dual-phase mass balance model
Bern, Carleton R.; Thompson, Aaron; Chadwick, Oliver A.
2015-01-01
Mass balance models have become standard tools for characterizing element gains and losses and volumetric change during weathering and soil development. However, they rely on the assumption of complete immobility for an index element such as Ti or Zr. Here we describe a dual-phase mass balance model that eliminates the need for an assumption of immobility and in the process quantifies the contribution of aqueous versus colloidal element transfer. In the model, the high field strength elements Ti and Zr are assumed to be mobile only as suspended solids (colloids) and can therefore be used to distinguish elemental redistribution via colloids from redistribution via dissolved aqueous solutes. Calculations are based upon element concentrations in soil, parent material, and colloids dispersed from soil in the laboratory. We illustrate the utility of this model using a catena in South Africa. Traditional mass balance models systematically distort elemental gains and losses and changes in soil volume in this catena due to significant redistribution of Zr-bearing colloids. Applying the dual-phase model accounts for this colloidal redistribution and we find that the process accounts for a substantial portion of the major element (e.g., Al, Fe and Si) loss from eluvial soil. In addition, we find that in illuvial soils along this catena, gains of colloidal material significantly offset aqueous elemental loss. In other settings, processes such as accumulation of exogenous dust can mimic the geochemical effects of colloid redistribution and we suggest strategies for distinguishing between the two. The movement of clays and colloidal material is a major process in weathering and pedogenesis; the mass balance model presented here is a tool for quantifying effects of that process over time scales of soil development.
Hydroclimatology of Dual-Peak Annual Cholera Incidence: Insights from a Spatially Explicit Model
Bertuzzo, E.; Mari, L.; Righetto, L.; Gatto, M.; Casagrandi, R.; Rodriguez-Iturbe, I.; Rinaldo, A.
2012-12-01
Cholera incidence in some regions of the Indian subcontinent may exhibit two annual peaks although the main environmental drivers that have been linked to the disease (e.g. sea surface temperature, zooplankton abundance, river discharge) peak once per year during the summer. An empirical hydroclimatological explanation relating cholera transmission to river flows and to the disease spatial spreading has been recently proposed. We specifically support and substantiate mechanistically such hypothesis by means of a spatially explicit model of cholera transmission. Our framework directly accounts for the role of the river network in transporting and redistributing cholera bacteria among human communities as well as for spatial and temporal annual fluctuations of precipitation and river flows. To single out the single out the hydroclimatologic controls on the prevalence patterns in a non-specific geographical context, we first apply the model to Optimal Channel Networks as a general model of hydrological networks. Moreover, we impose a uniform distribution of population. The model is forced by seasonal environmental drivers, namely precipitation, temperature and chlorophyll concentration in the coastal environment, a proxy for Vibrio cholerae concentration. Our results show that these drivers may suffice to generate dual-peak cholera prevalence patterns for proper combinations of timescales involved in pathogen transport, hydrologic variability and disease unfolding. The model explains the possible occurrence of spatial patterns of cholera incidence characterized by a spring peak confined to coastal areas and a fall peak involving inland regions. We then proceed applying the model to the specific settings of Bay of Bengal accounting for the actual river networks (derived from digital terrain map manipulations), the proper distribution of population (estimated from downscaling of census data based on remotely sensed features) and precipitation patterns. Overall our
Oral absorption of ginsenoside Rb1 using in vitro and in vivo models.
Han, Min; Sha, Xianyi; Wu, Yunjuan; Fang, Xiaoling
2006-04-01
This research attempts to clarify the cause for poor oral absorption of ginsenoside Rb1 (Rb1), one main ingredient of the well known Panax notoginseng saponins (PNS) for curing hemorrhage. Caco-2 cell monolayers were used as an in vitro model to reveal the transport mechanism of Rb1 across the intestinal mucosa. Moreover, the serum concentration-time profiles of Rb1 after tail venous (IV), portal venous (PV), intraduodenal (ID) and peroral (PO) administration to rats were compared to evaluate the first-pass effects of stomach, intestine and liver. In vitro experiments showed that uptake by Caco-2 cell monolayers was temperature dependent, but was not influenced by cyclosporine A and ketoconazole. The change in the apical pH showed no obvious effects on the uptake of Rb1. The uptake and transport were non-saturable, and flux from the apical compartment to the basolateral compartment (A-B) increased linearly with increasing concentration, which indicated a passive transport. Meanwhile, an apparent permeability coefficient of (5.90 +/- 1.02) x 10(-8) cm/s (C0 = 1 mg/mL) predicted an incomplete absorption. The investigation on the pharmacokinetic behavior of Rb1 after different routes of administration to rats showed a significant difference between PO (F(PO) was 0.64%), ID (F(ID) was 2.46%) and PV (F(PV) was 59.49%) administration, and the first-pass effect of the intestine is more significant than that of the stomach and liver in the absorption process. In summary, elimination in the stomach, large intestine and liver contributed to the poor absorption of Rb1, but the low membrane permeability might be a more important factor dominating the extent of absorption.
Data Analytics Based Dual-Optimized Adaptive Model Predictive Control for the Power Plant Boiler
Directory of Open Access Journals (Sweden)
Zhenhao Tang
2017-01-01
Full Text Available To control the furnace temperature of a power plant boiler precisely, a dual-optimized adaptive model predictive control (DoAMPC method is designed based on the data analytics. In the proposed DoAMPC, an accurate predictive model is constructed adaptively by the hybrid algorithm of the least squares support vector machine and differential evolution method. Then, an optimization problem is constructed based on the predictive model and many constraint conditions. To control the boiler furnace temperature, the differential evolution method is utilized to decide the control variables by solving the optimization problem. The proposed method can adapt to the time-varying situation by updating the sample data. The experimental results based on practical data illustrate that the DoAMPC can control the boiler furnace temperature with errors of less than 1.5% which can meet the requirements of the real production process.
Li, Guochang; Chen, George; Li, Shengtao
2016-08-01
Charge transport properties in nanodielectrics present different tendencies for different loading concentrations. The exact mechanisms that are responsible for charge transport in nanodielectrics are not detailed, especially for high loading concentration. A charge transport model in nanodielectrics has been proposed based on quantum tunneling mechanism and dual-level traps. In the model, the thermally assisted hopping (TAH) process for the shallow traps and the tunnelling process for the deep traps are considered. For different loading concentrations, the dominant charge transport mechanisms are different. The quantum tunneling mechanism plays a major role in determining the charge conduction in nanodielectrics with high loading concentrations. While for low loading concentrations, the thermal hopping mechanism will dominate the charge conduction process. The model can explain the observed conductivity property in nanodielectrics with different loading concentrations.
El-Rayes, Mohamed A.; Ulaby, Fawwaz T.
1987-01-01
The microwave dielectric behavior of vegetation materials is examined as a function of water content, microwave frequency, and temperature. Dielectric spectra for various types of vegetation, such as leaves, stalks, and trunks at various moisture conditions, were measured using a coaxial probe technique. The basic features and operation of the coaxial probe system are described. Examples of dielectric measurements for the vegetation materials are presented, and the relation between temperature and the dielectric constant is studied. The development of a dual-dispersion model that accounts for the dielectric properties of water in both free and bound conditions is described. The applicability of the model is evaluated by comparing it with the dielectric data; good correlation is observed between the model and the data over a wide range of moisture conditions and over the 0.2-20 GHz range.
Complexity analysis of dual-channel game model with different managers' business objectives
Li, Ting; Ma, Junhai
2015-01-01
This paper considers dual-channel game model with bounded rationality, using the theory of bifurcations of dynamical system. The business objectives of retailers are assumed to be different, which is closer to reality than previous studies. We study the local stable region of Nash equilibrium point and find that business objectives can expand the stable region and play an important role in price strategy. One interesting finding is that a fiercer competition tends to stabilize the Nash equilibrium. Simulation shows the complex behavior of two dimensional dynamic system, we find period doubling bifurcation and chaos phenomenon. We measure performances of the model in different period by using the index of average profit. The results show that unstable behavior in economic system is often an unfavorable outcome. So this paper discusses the application of adaptive adjustment mechanism when the model exhibits chaotic behavior and then allows the retailers to eliminate the negative effects.
Directory of Open Access Journals (Sweden)
Jixiang Zhou
2014-01-01
Full Text Available We investigate a joint pricing and purchasing problem for the dual-channel newsvendor model with the assumption that only the mean and variance of the demand are known. The newsvendor in our model simultaneously distributes a single product through traditional retail and Internet. A robust optimization approach that maximizes the worst-case profit is adapted under the aforementioned conditions to model demand uncertainty and linear clearing functions that characterize the relationship between demand and prices. We obtain a close-form expression for the robust optimal policy. Illustrative simulations and numerical experiments show the effects of several parameters on the optimal policy and on newsvendor performance. Finally, we determine that the gap between newsvendor performance under demand certainty and uncertainty is minimal, which shows that the robust approach can significantly improve performance.
Dual coding with STDP in a spiking recurrent neural network model of the hippocampus.
Directory of Open Access Journals (Sweden)
Daniel Bush
Full Text Available The firing rate of single neurons in the mammalian hippocampus has been demonstrated to encode for a range of spatial and non-spatial stimuli. It has also been demonstrated that phase of firing, with respect to the theta oscillation that dominates the hippocampal EEG during stereotype learning behaviour, correlates with an animal's spatial location. These findings have led to the hypothesis that the hippocampus operates using a dual (rate and temporal coding system. To investigate the phenomenon of dual coding in the hippocampus, we examine a spiking recurrent network model with theta coded neural dynamics and an STDP rule that mediates rate-coded Hebbian learning when pre- and post-synaptic firing is stochastic. We demonstrate that this plasticity rule can generate both symmetric and asymmetric connections between neurons that fire at concurrent or successive theta phase, respectively, and subsequently produce both pattern completion and sequence prediction from partial cues. This unifies previously disparate auto- and hetero-associative network models of hippocampal function and provides them with a firmer basis in modern neurobiology. Furthermore, the encoding and reactivation of activity in mutually exciting Hebbian cell assemblies demonstrated here is believed to represent a fundamental mechanism of cognitive processing in the brain.
Saab, Rim; Tausch, Nicole; Spears, Russell; Cheung, Wing-Yee
2015-09-01
We examined predictors of collective action among bystander group members in solidarity with a disadvantaged group by extending the dual pathway model of collective action, which proposes one efficacy-based and one emotion-based path to collective action (Van Zomeren, Spears, Fischer, & Leach, 2004). Based on two proposed functions of social identity performance (Klein, Spears, & Reicher, 2007), we distinguished between the efficacy of collective action at consolidating the identity of a protest movement and its efficacy at achieving social change (political efficacy). We expected identity consolidation efficacy to positively predict collective action tendencies directly and indirectly via political efficacy. We also expected collective action tendencies to be positively predicted by moral outrage and by sympathy in response to disadvantaged outgroup's suffering. These hypotheses were supported in two surveys examining intentions to protest for Palestine in Britain (Study 1), and intentions to attend the June 4th vigil in Hong Kong to commemorate the Tiananmen massacre among a sample of Hong Kong citizens (Study 2). The contributions of these findings to research on the dual pathway model of collective action and the different functions of collective action are discussed.
Model Algorithm Research on Cooling Path Control of Hot-rolled Dual-phase Steel
Institute of Scientific and Technical Information of China (English)
Xiao-qing XU; Xiao-dong HAO; Shi-guang ZHOU; Chang-sheng LIU; Qi-fu ZHANG
2016-01-01
With the development of advanced high strength steel,especially for dual-phase steel,the model algorithm for cooling control after hot rolling has to achieve the targeted coiling temperature control at the location of downcoiler whilst maintaining the cooling path control based on strip microstructure along the whole cooling section.A cooling path control algorithm was proposed for the laminar cooling process as a solution to practical difficulties associated with the realization of the thermal cycle during cooling process.The heat conduction equation coupled with the carbon diffusion equation with moving boundary was employed in order to simulate temperature change and phase transfor-mation kinetics,making it possible to observe the temperature field and the phase fraction of the strip in real time. On this basis,an optimization method was utilized for valve settings to ensure the minimum deviations between the predicted and actual cooling path of the strip,taking into account the constraints of the cooling equipment′s specific capacity,cooling line length,etc.Results showed that the model algorithm was able to achieve the online cooling path control for dual-phase steel.
An analytical model for cumulative infiltration into a dual-permeability media
Peyrard, Xavier; Lassabatere, Laurent; Angulo-Jaramillo, Rafael; Simunek, Jiri
2010-05-01
Modeling of water infiltration into the vadose zone is important for better understanding of movement of water-transported contaminants. There is a great need to take into account the soil heterogeneity and, in particular, the presence of macropores or cracks that could generate preferential flow. Several mathematical models have been proposed to describe unsaturated flow through heterogeneous soils. The dual-permeability model assumes that flow is governed by Richards equation in both porous regions (matrix and fractures). Water can be exchanged between the two regions following a first-order rate law. A previous study showed that the influence of the hydraulic conductivity of the matrix/macropore interface had a little influence on cumulative infiltration at the soil surface. As a result, one could consider the surface infiltration for a specific case of no water exchange between the fracture and matrix regions (a case of zero interfacial hydraulic conductivity). In such a case, water infiltration can be considered to be the sum of the cumulative infiltrations into the matrix and the fractures. On the basis of analytical models for each sub domain (matrix and fractures), an analytical model is proposed for the entire dual-porosity system. A sensitivity analysis is performed to characterize the influence of several factors, such as the saturated hydraulic conductivity ratio, the water pressure scale parameter ratio, and the saturated volumetric water content scale ratio, on the total cumulative infiltration. Such an analysis greatly helps in quantifying the impact of macroporosity and fractures on water infiltration, which can be of great interest for hydrological models.
Mitri, F G
2016-01-01
A necessary condition for the validity of the linear viscoelastic model for a (passive) polymeric cylinder with an ultrasonic hysteresis-type absorption submerged in a non-viscous fluid requires that the absorption efficiency is positive (Qabs > 0) satisfying the law of the conservation of energy. This condition imposes restrictions on the values attributed to the normalized absorption coefficients for the compressional and shear-wave wavenumbers for each partial-wave mode n. The forbidden values produce negative axial radiation force, absorption and extinction efficiencies, as well as an enhancement of the scattering efficiency, not in agreement with the conservation of energy law. Numerical results for the radiation force, extinction, absorption and scattering efficiencies are performed for three viscoelastic (VE) polymer cylinders immersed in a non-viscous host liquid (i.e. water) with particular emphasis on the shear-wave absorption coefficient of the cylinder, the dimensionless size parameter and the par...
Semi-mechanistic modelling of ammonia absorption in an acid spray wet scrubber based on mass balance
A model to describe reactive absorption of ammonia (NH3) in an acid spray scrubber was developed as a function of the combined overall mass transfer coefficient K. An experimental study of NH3 absorption using 1% dilute sulphuric acid was carried out under different operating conditions. An empiric...
Modeling of Liquid Film along Absorber Cylinders in an Absorption Chiller
Suzuki, Hiroshi; Yamanaka, Tomofumi; Nagamoto, Wataru; Sugiyama, Takahide
A two-dimensional liquid film model of LiBr solution falling along absorber cylinders has been studied to obtain boundary conditions for computing vapor flow in the absorber-evaporator of an absorption chiller. The model was established based on the assumptions that LiBr concentration and temperature profiles in the liquid film obey the third order polynomial expressions. It was indicated that mass flux and absorbed heat on the liquid surface can be calculated with simple numerical computations on the present analytical model. The overall heat transfer coefficient and total absorbed mass per second calculated with the present liquid film model was compared with experimental data for validation. The results calculated with the present model showed good agreement with the experimental data. Then, it was concluded the present model was useful enough for determining surface conditions on the LiBr liquid film around absorber cylinders.
Modeling of the Interminiband Absorption Coefficient in InGaN Quantum Dot Superlattices
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Giovanni Giannoccaro
2016-01-01
Full Text Available In this paper, a model to estimate minibands and theinterminiband absorption coefficient for a wurtzite (WZ indium gallium nitride (InGaN self-assembled quantum dot superlattice (QDSL is developed. It considers a simplified cuboid shape for quantum dots (QDs. The semi-analytical investigation starts from evaluation through the three-dimensional (3D finite element method (FEM simulations of crystal mechanical deformation derived from heterostructure lattice mismatch under spontaneous and piezoelectric polarization effects. From these results, mean values in QDs and barrier regions of charge carriers’ electric potentials and effective masses for the conduction band (CB and three valence sub-bands for each direction are evaluated. For the minibands’ investigation, the single-particle time-independent Schrödinger equation in effective mass approximation is decoupled in three directions and resolved using the one-dimensional (1D Kronig–Penney model. The built-in electric field is also considered along the polar axis direction, obtaining Wannier–Stark ladders. Then, theinterminiband absorption coefficient in thermal equilibrium for transverse electric (TE and magnetic (TM incident light polarization is calculated using Fermi’s golden rule implementation based on a numerical integration into the first Brillouin zone. For more detailed results, an absorption coefficient component related to superlattice free excitons is also introduced. Finally, some simulation results, observations and comments are given.
A simplified nonlinear model of the Marangoni instability in gas absorption
Skurygin, E. F.; Poroyko, T. A.
2016-04-01
The process of gas absorption into initially motionless liquid layer is investigated. The convective instability caused by the temperature dependence of the surface tension. The critical time of transition of the process to unstable convective regime, as well as the intensity of mass transfer in a surface convection are estimated numerically. The mathematical model includes the equations of convective diffusion, thermal conduction and fluid motion. The problem was solved numerically in the two-dimensional formulation. In the coordinate along the interface the concentration of the absorbed substance is represented by three terms of the trigonometric Fourier series. A difference approximation of equations with an exponentially changing grid in the direction normal to the interface is used. The simulations results agree with the well-known experimental data on the absorption of carbon dioxide in water.
Treeby, Bradley E; Cox, B T
2010-05-01
The efficient simulation of wave propagation through lossy media in which the absorption follows a frequency power law has many important applications in biomedical ultrasonics. Previous wave equations which use time-domain fractional operators require the storage of the complete pressure field at previous time steps (such operators are convolution based). This makes them unsuitable for many three-dimensional problems of interest. Here, a wave equation that utilizes two lossy derivative operators based on the fractional Laplacian is derived. These operators account separately for the required power law absorption and dispersion and can be efficiently incorporated into Fourier based pseudospectral and k-space methods without the increase in memory required by their time-domain fractional counterparts. A framework for encoding the developed wave equation using three coupled first-order constitutive equations is discussed, and the model is demonstrated through several one-, two-, and three-dimensional simulations.
Modeling And Experimental Analysis Of Generator In Vapour Absorption Refrigeration System
Directory of Open Access Journals (Sweden)
Christy V Vazhappilly
2013-09-01
Full Text Available A breadboard prototype of an absorption system for refrigeration using heat from the exhaust-gases is to be designed, built and tested. In the commercial vapour absorption refrigeration system a heating coil generator system has been employed to vaporize the ammonia efrigerant. In the present work, the heating coil generator system has been replaced by the frame plate type heat exchanger. The exhaust gases from the IC engine have been utilized to vaporize the ammonia refrigerant. The available heat in the exhaust gases has to be estimated based on actual I.C-Engine driving cycles. The frame plate type heat exchanger has to be modeled and flow analysis inside the heat exchanger has to be analyzed. In addition, the recoverable energy of the exhaust gases is to be analyzed for representative Internal Combustion Engine.
Simulation model of a single-stage lithium bromide-water absorption cooling unit
Miao, D.
1978-01-01
A computer model of a LiBr-H2O single-stage absorption machine was developed. The model, utilizing a given set of design data such as water-flow rates and inlet or outlet temperatures of these flow rates but without knowing the interior characteristics of the machine (heat transfer rates and surface areas), can be used to predict or simulate off-design performance. Results from 130 off-design cases for a given commercial machine agree with the published data within 2 percent.
The role of nicotine in smoking: a dual-reinforcement model.
Caggiula, Anthony R; Donny, Eric C; Palmatier, Matthew I; Liu, Xiu; Chaudhri, Nadia; Sved, Alan F
2009-01-01
Models of intravenous nicotine self-administration in laboratory animals are being used to investigate the behavioral and neurobiological consequences of nicotine reinforcement, and to aid in the development of novel pharmacotherapies for smoking cessation. Central to these models is the principle of primary reinforcement, which posits that response-contingent presentation of a primary reinforcer, nicotine, engenders robust operant behavior, whereas response-independent drug delivery does not. This dictum of nicotine as a primary reinforcer has been widely used to explain why people smoke tobacco-smoking results in the rapid delivery of nicotine to the brain, setting up a cascade of neurobiological processes that strengthen subsequent smoking behavior. However, there is mounting evidence that the primary reinforcement model of nicotine self-administration fails to fully explain existing data from both the animal self-administration and human smoking literatures. We have recently proposed a "dual reinforcement" model to more fully capture the relationship between nicotine and self-administration, including smoking. Briefly, the "dual reinforcement" model posits that nicotine acts as both a primary reinforcer and a reinforcement enhancer. The latter action of nicotine had originally been uncovered by showing that a reinforcing VS, which accompanies nicotine delivery, synergizes with nicotine in the acquisition and maintenance of self-administration, and that this synergism can be reproduced by combining operant responding for the reinforcing stimulus with non-contingent (response-independent) nicotine. Thus, self-administration (and smoking) is sustained by three actions: (1) nicotine, acting as a primary reinforcer, can sustain behavior that leads to its delivery; (2) nicotine, acting as a primary reinforcer, can establish neutral environmental stimuli as conditioned reinforcers through Pavlovian associations; and (3) nicotine, acting as a reinforcement enhancer
New normative standards of conditional reasoning and the dual-source model.
Singmann, Henrik; Klauer, Karl Christoph; Over, David
2014-01-01
There has been a major shift in research on human reasoning toward Bayesian and probabilistic approaches, which has been called a new paradigm. The new paradigm sees most everyday and scientific reasoning as taking place in a context of uncertainty, and inference is from uncertain beliefs and not from arbitrary assumptions. In this manuscript we present an empirical test of normative standards in the new paradigm using a novel probabilized conditional reasoning task. Our results indicated that for everyday conditional with at least a weak causal connection between antecedent and consequent only the conditional probability of the consequent given antecedent contributes unique variance to predicting the probability of conditional, but not the probability of the conjunction, nor the probability of the material conditional. Regarding normative accounts of reasoning, we found significant evidence that participants' responses were confidence preserving (i.e., p-valid in the sense of Adams, 1998) for MP inferences, but not for MT inferences. Additionally, only for MP inferences and to a lesser degree for DA inferences did the rate of responses inside the coherence intervals defined by mental probability logic (Pfeifer and Kleiter, 2005, 2010) exceed chance levels. In contrast to the normative accounts, the dual-source model (Klauer et al., 2010) is a descriptive model. It posits that participants integrate their background knowledge (i.e., the type of information primary to the normative approaches) and their subjective probability that a conclusion is seen as warranted based on its logical form. Model fits showed that the dual-source model, which employed participants' responses to a deductive task with abstract contents to estimate the form-based component, provided as good an account of the data as a model that solely used data from the probabilized conditional reasoning task.
New Normative Standards of Conditional Reasoning and the Dual-Source Model
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Henrik eSingmann
2014-04-01
Full Text Available There has been a major shift in research on human reasoning towards Bayesian and probabilistic approaches, which has been called a new paradigm. The new paradigm sees most everyday and scientific reasoning as taking place in a context of uncertainty, and inference is from uncertain beliefs and not from arbitrary assumptions. In this manuscript we present an empirical test of normative standards in the new paradigm using a novel probabilized conditional reasoning task. Our results indicated that for everyday conditional with at least a weak causal connection between antecedent and consequent only the conditional probability of the consequent given antecedent contributes unique variance to predicting the probability of conditional, but not the probability of the conjunction, nor the probability of the material conditional. Regarding normative accounts of reasoning, we found significant evidence that participants' responses were confidence preserving (i.e., p-valid in the sense of Adams, 1998 for MP inferences, but not for MT inferences. Additionally, only for MP inferences and to a lesser degree for DA inferences did the rate of responses inside the coherence intervals defined by mental probability logic (Pfeifer & Kleiter, 2005, 2010 exceed chance levels. In contrast to the normative accounts, the dual-source model (Klauer, Beller, & Hütter, 2010 is a descriptive model. It posits that participants integrate their background knowledge (i.e., the type of information primary to the normative approaches and their subjective probability that a conclusion is seen as warranted based on its logical form. Model fits showed that the dual-source model, which employed participants' responses to a deductive task with abstract contents to estimate the form-based component, provided as good an account of the data as a model that solely used data from the probabilized conditional reasoning task.
DDA Modeling for the Mid-IR Absorption of Irregularly Shaped Crystalline Forsterite Grains
Lindsay, Sean; Wooden, D. H.; Kelley, M. S.; Harker, D. E.; Woodward, C. E.; Murphy, J.
2010-10-01
An analysis of the Spitzer IRS spectra of the Deep Impact ejecta of comet 9P/Tempel 1 (Wooden et al. 2010, 42nd DPS Meeting) in conjunction with the dynamics of the ejecta grains (Kelley et al. 2010, 42nd DPS Meeting) strongly suggests that ecliptic comets have comae dominated by large (> 10 - 20 micron in radii) porous grains with Mg-rich crystal inclusions. In fact, Kelley et al. (2010) conclude that many ecliptic comets may be dominated by such grains with a high crystalline fraction, approximately 40% by mass, despite their generally weak silicate emission feature. To date, no model for the optical properties in the mid-IR of multi-mineralic large porous grains with silicate crystal inclusions, has been performed. We have initiated a program to compute the absorption and scattering efficiencies for these grains. Presented here are the 3 - 40 micron absorption efficiencies for models of sub-micron sized crystalline forsterite grains of irregular shape. We use the Discrete Dipole Approximation (DDA) to create discrete targets of forsterite that can be included in large porous aggregates. Computations are performed on the NAS Pleiades supercomputer. Our calculated absorption efficiencies for individual grains of forsterite are in agreement with laboratory measurements (Tamanai et al. 2006; Koike et al. 2003) and the continuous distribution of ellipsoids (CDE) method by Harker et al. (2007). We find for discrete grains that grain shape has a strong effect on the peak location of a crystalline resonance and that mimicking the physical properties of forsterite is important. Also presented are the absorption efficiencies for simple multi-component aggregates and for collections of forsterite crystals of different size and shape to replicate laboratory samples. This research is supported by the NASA GSRP Program.
Amundsen, David. S.; Tremblin, Pascal; Manners, James; Baraffe, Isabelle; Mayne, Nathan J.
2016-01-01
The correlated-k method is frequently used to speed up radiation calculations in both one-dimensional and three-dimensional atmosphere models. An inherent difficulty with this method is how to treat overlapping absorption, i.e. absorption by more than one gas in a given spectral region. We have evaluated the applicability of three different methods in hot Jupiter and brown dwarf atmosphere models, all of which have been previously applied within models in the literature: (i) Random overlap, b...
Caricati, Luca; Guberti, Monica; Borgognoni, Patrizia; Prandi, Carmen; Spaggiari, Ivana; Vezzani, Emanuela; Iemmi, Marina
2015-01-01
Nurse-physician collaboration involves healthcare operators from different professions working together. The dual identity model predicts that nurse-physician interprofessional collaboration could improve if these operators feel they belong to both their professional category and care unit. This study tested this prediction by analyzing the effect of professional and team commitments on interprofessional collaboration between nurses and physicians in a hospital based in Northern Italy. A cross-section questionnaire survey was administered to 270 nurses and 95 physicians. Results indicate that interprofessional collaboration is positively affected by team commitment, while professional commitment had no effect. In accordance with the dual identity model, results indicate that interprofessional collaboration is higher when: (i) both professional and team commitment is high, and (ii) when team commitment is high and professional commitment is low. These results support dual identity model predictions and suggest that interprofessional collaboration can be increased by bolstering both team and professional commitment of nurses and physicians.
Submodels of model of nonlinear diffusion in the inhomogeneous medium involving absorption
Energy Technology Data Exchange (ETDEWEB)
Chirkunov, Yu. A., E-mail: chr101@mail.ru [Novosibirsk State Technical University, Marks Avenue 20, Novosibirsk 630073 (Russian Federation)
2015-10-15
We study the five-parameter model, describing the process of nonlinear diffusion in an inhomogeneous medium in the presence of absorption, for which the differential equation of the model admits a continuous Lie group of transformations, acting on the set of its solutions. We found six submodels of the original model of nonlinear diffusion, with different symmetry properties. Of these six submodels, the five submodels with transient absorption, for which the absorption coefficient depends on time according to a power law, represent the greatest interest with a mathematical point of view and with the point of view of physical applications. For each of these nonlinear submodels, we obtained formulas for producing new solutions that contain arbitrary constants, and we found all invariant submodels. All essentially distinct invariant solutions describing these invariant submodels are found in an explicit form or are reduced to finding the solution of nonlinear integral equations. The presence of the arbitrary constants in the integral equations that determine these solutions provide new opportunities for analytical and numerical study of boundary value problems for the received submodels and, thus, for the original model of nonlinear diffusion. For the received invariant submodels, we studied diffusion processes for which at the initial moment of the time at a fixed point is specified as a concentration and its gradient or as a concentration and its velocity. Solving of boundary value problems describing these processes is reduced to the solving of nonlinear integral equations. We established the existence and uniqueness of solutions of these boundary value problems under some additional conditions. The obtained results can be used to study the diffusion of substances, diffusion of conduction electrons and other particles, diffusion of physical fields and propagation of heat in inhomogeneous medium, and also to study a turbulence (Leith model, differential
Oberauer, Klauss; Lange, Elke B.
2009-01-01
The article presents a mathematical model of short-term recognition based on dual-process models and the three-component theory of working memory [Oberauer, K. (2002). Access to information in working memory: Exploring the focus of attention. "Journal of Experimental Psychology: Learning, Memory, and Cognition, 28", 411-421]. Familiarity arises…
Ma, Junhai; Li, Ting; Ren, Wenbo
2017-06-01
This paper examines the optimal decisions of dual-channel game model considering the inputs of retailing service. We analyze how adjustment speed of service inputs affect the system complexity and market performance, and explore the stability of the equilibrium points by parameter basin diagrams. And chaos control is realized by variable feedback method. The numerical simulation shows that complex behavior would trigger the system to become unstable, such as double period bifurcation and chaos. We measure the performances of the model in different periods by analyzing the variation of average profit index. The theoretical results show that the percentage share of the demand and cross-service coefficients have important influence on the stability of the system and its feasible basin of attraction.
Predator-prey model for the self-organisation of stochastic oscillators in dual populations
Moradi, Sara; Gürcan, Özgür
2015-01-01
A predator-prey model of dual populations with stochastic oscillators is presented. A linear cross-coupling between the two populations is introduced following the coupling between the motions of a Wilberforce pendulum in two dimensions: one in the longitudinal and the other in torsional plain. Within each population a Kuramoto type competition between the phases is assumed. Thus, the synchronisation state of the whole system is controlled by these two types of competitions. The results of the numerical simulations show that by adding the linear cross-coupling interactions predator-prey oscillations between the two populations appear which results in self-regulation of the system by a transfer of synchrony between the two populations. The model represents several important features of the dynamical interplay between the drift wave and zonal flow turbulence in magnetically confined plasmas, and a novel interpretation of the coupled dynamics of drift wave-zonal flow turbulence using synchronisation of stochasti...
A stochastic inventory management model for a dual sourcing supply chain with disruptions
Iakovou, Eleftherios; Vlachos, Dimitrios; Xanthopoulos, Anastasios
2010-03-01
As companies continue to globalise their operations and outsource significant portion of their value chain activities, they often end up relying heavily on order replenishments from distant suppliers. The explosion in long-distance sourcing is exposing supply chains and shareholder value at ever increasing operational and disruption risks. It is well established, both in academia and in real-world business environments, that resource flexibility is an effective method for hedging against supply chain disruption risks. In this contextual framework, we propose a single period stochastic inventory decision-making model that could be employed for capturing the trade-off between inventory policies and disruption risks for an unreliable dual sourcing supply network for both the capacitated and uncapacitated cases. Through the developed model, we obtain some important managerial insights and evaluate the merit of contingency strategies in managing uncertain supply chains.
Phase diagram of the two-dimensional O(3) model from dual lattice simulations
Bruckmann, Falk; Kloiber, Thomas; Sulejmanpasic, Tin
2016-01-01
We have simulated the asymptotically free two-dimensional O(3) model at nonzero chemical potential using the model's dual representation. We first demonstrate how the latter solves the sign (complex action) problem. The system displays a crossover at nonzero temperature, while at zero temperature it undergoes a quantum phase transition when mu reaches the particle mass (generated dynamically similar to QCD). The density follows a square root behavior universal for repulsive bosons in one spatial dimension. We have also measured the spin stiffness, known to be sensitive to the spatial correlation length, using different scaling trajectories to zero temperature and infinite size. It points to a dynamical critical exponent z=2. Comparisons to thermodynamic Bethe ansaetze are shown as well.
Semi-numerical solution for a fractal telegraphic dual-porosity fluid flow model
Herrera-Hernández, E C; Luis, D P; Hernández, D; Camacho-Velázquez, R G
2016-01-01
In this work, we present a semi-numerical solution of a fractal telegraphic dual-porosity fluid flow model. It combines Laplace transform and finite difference schemes. The Laplace transform handles the time variable whereas the finite difference method deals with the spatial coordinate. This semi-numerical scheme is not restricted by space discretization and allows the computation of a solution at any time without compromising numerical stability or the mass conservation principle. Our formulation results in a non-analytically-solvable second-order differential equation whose numerical treatment outcomes in a tri-diagonal linear algebraic system. Moreover, we describe comparisons between semi-numerical and semi-analytical solutions for particular cases. Results agree well with those from semi-analytic solutions. Furthermore, we expose a parametric analysis from the coupled model in order to show the effects of relevant parameters on pressure profiles and flow rates for the case where neither analytic nor sem...
Energy Technology Data Exchange (ETDEWEB)
Nguyen, Ba Nghiep; Henager, Charles H.; Kurtz, Richard J.; Ferraris, M.; Katoh, Yutai
2016-09-30
Finite element (FE) continuum damage mechanics (CDM) models have been developed to simulate and model dual-phase joints and cracked joints for improved analysis of SiC materials in nuclear environments. This report extends the analysis from the last reporting cycle by including preliminary thermomechanical analyses of cracked joints and implementation of dual-phase damage models.
Modeling of normal incidence absorption in p-type GaAs/AlGaAs quantum well infrared detectors
Brown, Gail J.; Szmulowicz, Frank
1995-04-01
The absorption of infrared radiation at normal incidence in p-type GaAs/AlGaAs quantum wells, unlike in n-type, is fundamentally allowed. We have measured and theoretically modeled the bound-to-continuum absorption in these p-type materials. The infrared absorption coefficient was calculated are based on the electronic structure, wave functions and optical matrix elements obtained from an 8 X 8 envelope-function approximation (EFA) calculation. The 8 X 8 EFA Hamiltonian incorporates the coupling between the heavy, light, spin-orbit, and conduction bands. In calculating the continuum states for bound-to- continuum intersubband absorption, we do not enclose the well in an artificial box with infinite walls. A comparison of the theoretical absorption and measured photoresponse results verified the accuracy of our model and provided a basis for optimizing the design of p-type quantum wells for infrared detection.
Theoretical modeling of a self-referenced dual mode SPR sensor utilizing indium tin oxide film
Srivastava, Sachin K.; Verma, Roli; Gupta, Banshi D.
2016-06-01
A prism based dual mode SPR sensor was theoretically modeled to work as a self-referenced sensor in spectral interrogation scheme. Self-referenced sensing was achieved by sandwiching an indium tin oxide thin film in between the prism base and the metal layer. The proposed sensor possesses two plasmon modes similar to long and short range SPRs (LR- and SR-SPRs) and we have analogically used LRSPR and SRSPR for them. However, these modes do not possess usual long range character due to the losses introduced by the imaginary part of indium tin oxide (ITO) dielectric function. One of the two plasmon modes responds to change in analyte refractive index while the other remains fixed. The influence of various design parameters on the performance of the sensor was evaluated. The performance of the proposed sensor was compared, via control simulations, with established dual mode geometries utilizing silicon dioxide (SiO2), Teflon AF-1600 and Cytop. The design parameters of the established geometries were optimized to obtain self-referenced sensing operation. Trade-offs between the resonance spectral width, minimum reflectivity, shift in resonance wavelength and angle of incidence were examined for optimal design. The present study will be useful in the fabrication of self-referenced sensors where the ambient conditions are not quite stable.
Bag model of hadrons, dual QCD thermodynamics and Quark-Gluon Plasma
Chandola, H C; Dehnen, H
2015-01-01
Using the grand canonical ensemble formulation of a multi-particle statistical system, the thermodynamical description of the dual QCD has been presented in terms of the bag model of hadrons and analyzed for the quark-gluon plasma phase of hadronic matter. The dual QCD bag construction has been shown to lead to the radial pressure on the bag surface in terms of the vector glueball masses of the magnetically condensed QCD vacuum. Constructing the grand canonical partition function to deal with the quark-gluon plasma phase of the non-strange hadrons, the energy density and the plasma pressure have been derived and used to understand the dynamics of the associated phase transition. The critical temperature for QGP-hadron phase transition has been derived and numerically estimated by using various thermodynamic considerations. A comparison of the values of the critical temperatures for QGP-hadron phase transition with those obtained for the deconfinement-phase transition, has been shown to lead to the relaxation ...
CT/FMT dual-model imaging of breast cancer based on peptide-lipid nanoparticles
Xu, Guoqiang; Lin, Qiaoya; Lian, Lichao; Qian, Yuan; Lu, Lisen; Zhang, Zhihong
2016-03-01
Breast cancer is one of the most harmful cancers in human. Its early diagnosis is expected to improve the patients' survival rate. X-ray computed tomography (CT) has been widely used in tumor detection for obtaining three-dimentional information. Fluorescence Molecular Tomography (FMT) imaging combined with near-infrared fluorescent dyes provides a powerful tool for the acquisition of molecular biodistribution information in deep tissues. Thus, the combination of CT and FMT imaging modalities allows us to better differentiate diseased tissues from normal tissues. Here we developed a tumor-targeting nanoparticle for dual-modality imaging based on a biocompatible HDL-mimicking peptide-phospholipid scaffold (HPPS) nanocarrier. By incorporation of CT contrast agents (iodinated oil) and far-infrared fluorescent dyes (DiR-BOA) into the hydrophobic core of HPPS, we obtained the FMT and CT signals simultaneously. Increased accumulation of the nanoparticles in the tumor lesions was achieved through the effect of the tumor-targeting peptide on the surface of nanoparticle. It resulted in excellent contrast between lesions and normal tissues. Together, the abilities to sensitively separate the lesions from adjacent normal tissues with the aid of a FMT/CT dual-model imaging approach make the targeting nanoparticles a useful tool for the diagnostics of breast cancer.
Treatment of Murine Tumor Models of Breast Adenocarcinoma by Continuous Dual-Frequency Ultrasound
Directory of Open Access Journals (Sweden)
Amir Hoshang Barati
2009-03-01
Full Text Available Introduction: Acoustic transient cavitation is the primary mechanism of sonochemical reaction and has potential use for tumor treatment. In this study, the in vivo anti-tumor effect of simultaneous dual-frequency ultrasound at low-level intensity (ISATA < 6 W/cm2 was investigated in a spontaneous murine model of breast adenocarcinoma in Balb/c mice. Materials and Methods: Forty tumor bearing mice were divided into four groups (10 in each group. The treated groups received 15 or 30 minutes of combined dual-frequency ultrasound in continuous mode (1 MHzcon + 150 kHzcon respectively. The control and the sham groups contained the untreated mice. The tumor growth delay parameters including tumor volume, relative tumor volume, T5 and T2 (the needed time for each tumor to reach 5 and 2 times the initial tumor volume, respectively, survival period and percent of tumor growth inhibition ratio were measured on different days after treatment. Results: The results showed that the 30 min treatment was effective in tumor growth delay and percent of tumor growth inhibitory ratio compared to the sham and the control groups. The tumor volume growth and relative volume of tumors in the same treated group showed an anti-tumor effect relative to the sham and the control groups. There was a significant difference in tumor volume growth between this 30 min treatment group and the sham group 12 days after treatment (p-value
Non-Abelian duality from vortex moduli: a dual model of color-confinement
Eto, M; Konishi, K; Marmorini, G; Nitta, M; Ohashi, K; Vinci, W; Yokoi, N
2006-01-01
It is argued that the dual transformation of non-Abelian monopoles occurring in a system with gauge symmetry breaking G \\longrightarrow H is to be defined by setting the low-energy H system in Higgs phase, so that the dual system is in confinement phase. The transformation law of the monopoles follows from that of monopole-vortex mixed configurations in the system (with a large hierarchy of energy scales, v_1 \\gg v_2) G {\\stackrel {v_1} {\\longrightarrow}} H {\\stackrel {v_2} {\\longrightarrow}} \\emptyset, under an unbroken, exact color-flavor diagonal symmetry H_{C+F} \\sim {\\tilde H}. The transformation property among the regular monopoles characterized by \\pi_2(G/H), follows from that among the non-Abelian vortices with flux quantized according to \\pi_1(H), via the isomorphism \\pi_1(G) \\sim {\\pi_1(H) \\over \\pi_2(G/H)}. Our idea is tested against the concrete models -- softly-broken {\\cal N}=2 supersymmetric SU(N), SO(N) and USp(2N) theories, with appropriate number of flavors. The results obtained in the semic...
A dual-process model of early substance use: tests in two diverse populations of adolescents.
Wills, Thomas A; Bantum, Erin O'Carroll; Pokhrel, Pallav; Maddock, Jay E; Ainette, Michael G; Morehouse, Ellen; Fenster, Bonnie
2013-05-01
We tested a dual-process model based on behavioral and emotional regulation constructs, which posits that good self-control and poor regulation make independent contributions and have different types of pathways to outcomes. The utility of the model for predicting substance use was tested in two diverse populations of younger adolescents. A survey was administered in classrooms to middle-school students in Westchester County, New York (N = 601) and Honolulu, Hawaii (N = 881). The New York sample was 8% African American, 5% Asian American, 47% Caucasian, 31% Hispanic, and 9% other ethnicity. The Hawaii sample was 21% Asian American, 8% Caucasian, 26% Native Hawaiian/Pacific Islander, 34% Filipino, and 10% other ethnicity. Structural equation modeling analyses tested pathways from the four regulation variables through six hypothesized mediators to a criterion construct of substance use (tobacco, alcohol, and marijuana). Results were replicated across samples and were consistent with prediction. Unique contributions were found for good self-control and poor regulation, including both behavioral and emotional aspects. Good self-control had an inverse effect on substance use primarily through relations to higher levels of protective factors (e.g., academic competence). Poor regulation independently had a risk-promoting effect on substance use through relations to higher levels of risk factors (e.g., negative life events). Two field studies showed the dual-process model is robust across different populations. Substance prevention programs should consider approaches for enhancing good self-control as well as procedures for reducing poor regulation and minimizing its impact. Extensions to health behaviors including dietary intake and physical activity are discussed. PsycINFO Database Record (c) 2013 APA, all rights reserved.
Self-dual soliton solutions in a Chern-Simons-CP(1) model with a nonstandard kinetic term
Casana, Rodolfo
2013-01-01
A generalization of the Chern-Simons-CP(1) model is considered by introducing a nonstandard kinetic term. For a particular case, of this nonstandard kinetic term, we show that the model support self-dual Bogomol'nyi equations. The BPS energy has a bound proportional to the sum of the magnetic flux and the CP(1) topological charge. The magnetic flux is a finite quantity proportional to the potential coupling constant and to the effective radius of the topological defect. The self-dual equations are solved analytically and verified numerically.
Voitsekhovskaya, Olga K; Kashirskii, Danila E; Egorov, Oleg V; Shefer, Olga V
2016-05-10
The absorption spectra of exhaust gases (H2O, CO, CO2, NO, NO2, and SO2) and aerosol (soot and Al2O3) particles were modeled at different temperatures for the first time and suitable spectral ranges were determined for conducting laser remote sensing of the combustion products of jet engines. The calculations were conducted on the basis of experimental concentrations of the substances and the sizes of the aerosol particles. The temperature and geometric parameters of jet engine exhausts were also taken from the literature. The absorption spectra were obtained via the line-by-line method, making use of the spectral line parameters from the authors' own high-temperature databases (for NO2 and SO2 gases) and the HITEMP 2010 database, and taking into account atmospheric transmission. Finally, the theoretical absorption spectra of the exhaust gases were plotted at temperatures of 400, 700, and 1000 K, and the impact of aerosol particles on the total exhaust spectra was estimated in spectral ranges suitable for remote sensing applications.
European Regional Climate Zone Modeling of a Commercial Absorption Heat Pump Hot Water Heater
Energy Technology Data Exchange (ETDEWEB)
Sharma, Vishaldeep [ORNL; Shen, Bo [ORNL; Keinath, Chris [Stone Mountain Technologies, Inc., Johnson City; Garrabrant, Michael A. [Stone Mountain Technologies, Inc., Johnson City; Geoghegan, Patrick J [ORNL
2017-01-01
High efficiency gas-burning hot water heating takes advantage of a condensing heat exchanger to deliver improved combustion efficiency over a standard non-condensing configuration. The water heating is always lower than the gas heating value. In contrast, Gas Absorption Heat Pump (GAHP) hot water heating combines the efficiency of gas burning with the performance increase from a heat pump to offer significant gas energy savings. An ammonia-water system also has the advantage of zero Ozone Depletion Potential and low Global Warming Potential. In comparison with air source electric heat pumps, the absorption system can maintain higher coefficients of performance in colder climates. In this work, a GAHP commercial water heating system was compared to a condensing gas storage system for a range of locations and climate zones across Europe. The thermodynamic performance map of a single effect ammonia-water absorption system was used in a building energy modeling software that could also incorporate the changing ambient air temperature and water mains temperature for a specific location, as well as a full-service restaurant water draw pattern.
Modeling and calculation of light absorption in silicon/metal nanocomposites
Energy Technology Data Exchange (ETDEWEB)
Santacruz, Luis Andres; Solarte, Efrain [Departamento de Fisica, Universidad del Valle, Cali (Colombia); Garcia, Hernando, E-mail: landress18@gmail.com [Department of Physics, Southern Illinois University, Edwardsville (United States)
2011-01-01
Silicon thin films over a glass substrate has been considerate an economical and viable alternative for the photovoltaic industry. Implementation of this technology will contribute to preserve a clean environment helping to reach a sustainable future. Nevertheless, by their own nature, Silicon thin films present small light absorption, and its electrical energy conversion mechanisms, besides their non ideal character, are not completely understood. The inclusions of metal nanoparticles in semiconductors can modify and improve the light absorption properties of these materials by surface plasmon interaction. It is well known that metal nanoparticles, deposited on the surface of Si-Solar cells, improve considerable the efficiency of the cell and it has been shown that there is a strong correlation between the surface plasmon excitation frequency and that of the exciting light. To study the light interactions on such material, we have developed a theoretical model that takes into account the incorporation of metallic nano-particles over Silicon thin films. We have obtained an analytical expression for the effective permittivity of the Semiconductor/Nano-particle system, {epsilon}{sub eff} using this result we have analyzed the light absorption process in the case of Silicon with two types of metallic inclusions.
Dual pairs of gauged linear sigma models and derived equivalences of Calabi-Yau threefolds
Gerhardus, Andreas; Jockers, Hans
2017-04-01
In this work we study the phase structure of skew symplectic sigma models, which are a certain class of two-dimensional N =(2 , 2) non-Abelian gauged linear sigma models. At low energies some of them flow to non-linear sigma models with Calabi-Yau target spaces, which emerge from non-Abelian strong coupling dynamics. The observed phase structure results in a non-trivial duality proposal among skew symplectic sigma models and connects non-complete intersection Calabi-Yau threefolds-that are non-birational among another-in a common quantum Kähler moduli space. As a consequence we find non-trivial identifications of spectra of topological B-branes, which from a modern algebraic geometry perspective imply derived equivalences among Calabi-Yau varieties. To further support our proposals, we calculate the two sphere partition function of skew symplectic sigma models to determine geometric invariants, which confirm the anticipated Calabi-Yau threefold phases. We show that the two sphere partition functions of a pair of dual skew symplectic sigma models agree in a non-trivial fashion. To carry out these calculations, we develop a systematic approach to study higher-dimensional Mellin-Barnes type integrals. In particular, these techniques admit the evaluation of two sphere partition functions for gauged linear sigma models with higher rank gauge groups, but are applicable in other contexts as well.
Cai, Qing; Lee, Jaeyoung; Eluru, Naveen; Abdel-Aty, Mohamed
2016-08-01
This study attempts to explore the viability of dual-state models (i.e., zero-inflated and hurdle models) for traffic analysis zones (TAZs) based pedestrian and bicycle crash frequency analysis. Additionally, spatial spillover effects are explored in the models by employing exogenous variables from neighboring zones. The dual-state models such as zero-inflated negative binomial and hurdle negative binomial models (with and without spatial effects) are compared with the conventional single-state model (i.e., negative binomial). The model comparison for pedestrian and bicycle crashes revealed that the models that considered observed spatial effects perform better than the models that did not consider the observed spatial effects. Across the models with spatial spillover effects, the dual-state models especially zero-inflated negative binomial model offered better performance compared to single-state models. Moreover, the model results clearly highlighted the importance of various traffic, roadway, and sociodemographic characteristics of the TAZ as well as neighboring TAZs on pedestrian and bicycle crash frequency.
Difference in oral absorption of ginsenoside Rg1 between in vitro and in vivo models
Institute of Scientific and Technical Information of China (English)
Min HAN; Xiao-ling FANG
2006-01-01
Aim:To clarify the cause of poor oral absorption of ginsenoside Rg1 (Rg1) ,the active ingredient in Panax notoginseng saponins (PNS) used for treating hemorrhage.Methods:Caco-2 cell monolayers were used as an in vitro model to study the transport mechanism of Rg1 across the intestinal mucosa.Moreover,the serum concentration-time profiles after peroral (po) ,intraduodenal (id) ,portal venous (pv) and tail venous (iv) administration of Rg1 in rats were compared to evaluate the first-pass effects in the stomach.intestine,and liver.Results:Uptake of Rg1 by Caco-2 cell monolayers was temperature-dependent,but was not influenced by cyclosporin A.The change in the apical pH produced no obvious effect on the uptake of Rg1.The uptake and transport of Rg1 was non-saturable;whereas the flux from the apical compartment to the basolateral compartment (A-B) increased in a linear manner with the increase in concentration,indicating passive transport.An apparent permeability coefficient of (2.59±0.17)×10-7 cm/s (C0=1mg/mL) predicted incomplete absorption.A significant difference was observed between the po (Fpo was 3.29% at a dose of 1500 mg/kg) ,id (Fid was 6.60% at a dose of 1200 mg/kg) and pv (Fpv was 50.56%) administration methods,and the barrier function of the intestine was more significant than those of the stomach and liver in the absorption process.Conclusion:Elimination in the stomach.large intestine and liver contributed to the low oral bioavailability of Rg,but low membrane permeability might be a more important factor in determining the extent of absorption.
Energy Technology Data Exchange (ETDEWEB)
Chatterjee, I.; Hagmann, M.J.; Gandhi, O.P.
1980-01-01
The electromagnetic energy deposited in a semi-infinite slab model consisting of skin, fat, and muscle layers is calculated for both plane-wave and near-field exposures. The plane-wave spectrum (PWS) approach is used to calculate the energy deposited in the model by fields present due to leakage from equipment using electromagnetic energy. This analysis applies to near-field exposures where coupling of the target to the leakage source can be neglected. Calculations were made for 2,450 MHz, at which frequency the layered slab adequately models flat regions of the human body. Resonant absorption due to layering is examined as a function of the skin and fat thicknesses for plane-wave exposure and as a function of the physical extent of the near-field distribution. Calculations show that for fields that are nearly constant over at least a free-space wavelength, the energy deposition (for skin, fat, and muscle combination that gives resonant absorption) is equal to or less than that resulting from plane-wave exposure, but is appreciably greater than that obtained for a homogeneous muscle slab model.
EVALUATION OF THE STRUCTURAL FUNDS ABSORPTION RATE BY MEANS OF THE HERMIN MODEL
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Opritescu Elena Madalina
2012-07-01
Full Text Available The main objective of this article is to highlight the main method that could quantify the impact of the structural funds on the Gross Domestic Product. I also presented the regional disparities situation and the European funds absorption rate. The HERMIN model has been designed considering the evolution of macro-variables throughout transition and pre-accession process, as well as out of the need to analyze the gradual alignment of Romaniaâ€™s economic policies to those of EU. The fact that, initially, the HERMIN model was designed for the European Unionâ€™s less developed economies represented the cornerstone in choosing it, as it was the case for Romania, too. However, the quantitative evaluation must always be accompanied by a qualitative evaluation, in order to comprise factors which cannot be measured by the econometrical modeling. For this purpose, when the results of econometrical model based evaluation are used, it is important to be aware of the fact that models simplify reality, no matter the impressive mathematical calculations they employ. Also, we must not omit the fact that Romaniaâ€™s major development needs and the current economic context imperatively demand a high as possible level of structural funds absorption, as well as their efficient use, meant to generate a significant impact at a national, regional and local level. One of the main instruments employed to sustain economic growth, while also reducing disparities between regions is represented by the structural funds. These funds, consisting in financial contributions of the member states, according to their level of development, are redistributed in compliance with an extremely complex regulating and procedural frame, to those EU states of regions which are fallen behind from a social and economical development perspective Nevertheless, when absorption capacity of a member state is evaluated, the used percentage from the allocated funds is not the only
Modeling depth-variant and domain-specific sorption and biodegradation in dual-permeability media
Ray, Chittaranjan; Vogel, Tomas; Dusek, Jaromir
2004-05-01
A dual-permeability model (S_1D_DUAL) was developed to simulate the transport of land-applied pesticides in macroporous media. In this model, one flow domain was represented by the bulk matrix and the other by the preferential flow domain (PFD) where water and chemicals move at faster rates. The model assumed the validity of Darcian flow and the advective-dispersive solute transport in each of the two domains with inter-domain transfer of water and solutes due to pressure and concentration gradients. It was conceptualized that sorption and biodegradation rates vary with soil depth as well as in each of the two flow domains. In addition to equilibrium sorption, kinetic sorption was simulated in the PFD. Simulations were conducted to evaluate the combined effects of preferential flow, depth- and domain-variant sorption, and degradation on leaching of two pesticides: one with strong sorption potential (trifluralin) and the other with weak sorption potential (atrazine). Simulation results for a test case showed that water flux in the PFD was three times more than in the matrix for selected storm events. When equilibrium sorption was considered, the simulated profile of trifluralin in each domain was similar; however, the atrazine profile was deeper in the PFD than in the bulk matrix under episodic storm events. With an assumption of negligible sorption in the PFD, both the atrazine and the trifluralin profiles moved twice deeper into the PFD. The simulated concentrations of the chemicals were several orders higher in the PFD than in the matrix, even at deeper depths. The volume fraction of the macropores and the sorption and biodegradation properties of the chemicals could also affect the amount of pesticides leaving the root zone. For an intense storm event, slow sorption reaction rates in the PFD produced higher breakthrough concentrations of atrazine at the bottom of the simulated soil profile, thus posing the risk for breakthrough of chemicals from the root zone.
Monte Carlo modeling of the dual-mode regime in quantum-well and quantum-dot semiconductor lasers.
Chusseau, Laurent; Philippe, Fabrice; Disanto, Filippo
2014-03-10
Monte Carlo markovian models of a dual-mode semiconductor laser with quantum well (QW) or quantum dot (QD) active regions are proposed. Accounting for carriers and photons as particles that may exchange energy in the course of time allows an ab initio description of laser dynamics such as the mode competition and intrinsic laser noise. We used these models to evaluate the stability of the dual-mode regime when laser characteristics are varied: mode gains and losses, non-radiative recombination rates, intraband relaxation time, capture time in QD, transfer of excitation between QD via the wetting layer... As a major result, a possible steady-state dual-mode regime is predicted for specially designed QD semiconductor lasers thereby acting as a CW microwave or terahertz-beating source whereas it does not occur for QW lasers.
Chen, Jui-Sheng; Hsu, Shao-Yiu; Li, Ming-Hsu; Liu, Chen-Wuing
2016-12-01
Transport behavior through a permeable reactive barrier (PRB)-aquifer system is complicated because of the different physical and chemical properties of the PRB and the aquifer. Dual-domain solute transport models are efficient tools for better understanding the various processes and mechanisms of reactive solute transport through a PRB-aquifer system. This study develops a dual-domain analytical model to assess the physical and chemical processes of two-dimensional reactive solute transport through a PRB-aquifer system. The dispersion processes of a dual-domain system on the solute transport are investigated. The results show that the dispersion parameters in a dual-domain system synchronously govern the dynamic shape of the contaminant plume. The low longitudinal and transverse dispersion coefficients of a dual-domain system may restrict the spreading of the plume and elevate the plume's concentration level. The derived analytical solution is applied to explore how the different reactive transport processes affect the performance of a PRB-aquifer system. The results show that the first-order decay rate constant of the PRB has a critical effect on the performance of the PRB-aquifer system, whereas the effects of the physical dispersion properties on PRB performance are less significant.
Research Article. Improved Dual Frequency PPP Model Using GPS and BeiDou Observations
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Afifi A.
2017-02-01
Full Text Available This paper introduces a new dual-frequency precise point positioning (PPP model, which combines GPS and BeiDou observations. Combining GPS and BeiDou observations in a PPP model offers more visible satellites to the user, which is expected to enhance the satellite geometry and the overall PPP solution in comparison with GPSonly PPP solution. However, combining different GNSS constellations introduces additional biases, which require rigorous modelling, including GNSS time offset and hardware delays. In this research, ionosphere-free linear combination PPP model is developed. The additional biases, which result from combining the GPS and BeiDou observables, are lumped into a new unknown parameter identified as the inter-system bias. Natural Resources Canada’s GPSPace PPP software is modified to enable a combined GPS/BeiDou PPP solution and to handle the newly introduced biases. A total of four data sets at four IGS stations are processed to verify the developed PPP model. Precise satellite orbit and clock products from the IGS-MGEX network are used to correct both of the GPS and BeiDou measurements. It is shown that a sub-decimeter positioning accuracy level and 25% reduction in the solution convergence time can be achieved with combining GPS and Bei-Dou observables in a PPP model, in comparison with the GPS-only PPP solution.
Research Article. Improved Dual Frequency PPP Model Using GPS and BeiDou Observations
Afifi, A.; El-Rabbany, A.
2017-02-01
This paper introduces a new dual-frequency precise point positioning (PPP) model, which combines GPS and BeiDou observations. Combining GPS and BeiDou observations in a PPP model offers more visible satellites to the user, which is expected to enhance the satellite geometry and the overall PPP solution in comparison with GPSonly PPP solution. However, combining different GNSS constellations introduces additional biases, which require rigorous modelling, including GNSS time offset and hardware delays. In this research, ionosphere-free linear combination PPP model is developed. The additional biases, which result from combining the GPS and BeiDou observables, are lumped into a new unknown parameter identified as the inter-system bias. Natural Resources Canada's GPSPace PPP software is modified to enable a combined GPS/BeiDou PPP solution and to handle the newly introduced biases. A total of four data sets at four IGS stations are processed to verify the developed PPP model. Precise satellite orbit and clock products from the IGS-MGEX network are used to correct both of the GPS and BeiDou measurements. It is shown that a sub-decimeter positioning accuracy level and 25% reduction in the solution convergence time can be achieved with combining GPS and Bei-Dou observables in a PPP model, in comparison with the GPS-only PPP solution.
The dual quark condensate in local and nonlocal NJL models: An order parameter for deconfinement?
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Federico Marquez
2015-07-01
Full Text Available We study the behavior of the dual quark condensate Σ1 in the Nambu–Jona-Lasinio (NJL model and its nonlocal variant. In quantum chromodynamics Σ1 can be related to the breaking of the center symmetry and is therefore an (approximate order parameter of confinement. The deconfinement transition is then signaled by a strong rise of Σ1 as a function of temperature. However, a similar behavior is also seen in the NJL model, which is known to have no confinement. Indeed, it was shown that in this model the rise of Σ1 is triggered by the chiral phase transition. In order to shed more light on this issue, we calculate Σ1 for several variants of the NJL model, some of which have been suggested to be confining. Switching between “confining” and “non-confining” models and parametrizations we find no qualitative difference in the behavior of Σ1, namely, it always rises in the region of the chiral phase transition. We conclude that without having established a relation to the center symmetry in a given model, Σ1 should not blindly be regarded as an order parameter of confinement.
Directory of Open Access Journals (Sweden)
J. Y. Tang
2014-01-01
Full Text Available Representation of gaseous diffusion in variably saturated near-surface soils is becoming more common in land biogeochemical models, yet the formulations and numerical solution algorithms applied vary widely. We present three different but equivalent formulations of the dual-phase (gaseous and aqueous tracer diffusion transport problem that is relevant to a wide class of volatile tracers in land biogeochemical models. Of these three formulations (i.e., the gas-primary, aqueous-primary, and bulk tracer based formulations, we contend the gas-primary formulation is the most convenient for modeling tracer dynamics in biogeochemical models. We then provide finite volume approximation to the gas-primary equation and evaluate its accuracy against three analytical models: one for steady-state soil CO2 dynamics, one for steady-state soil CO2 dynamics, and one for transient tracer diffusion from a constant point source into two different sequentially aligned medias. All evaluations demonstrated good accuracy of the numerical approximation. We expect our result will standardize an efficient mechanistic numerical method for solving relatively simple, multi-phase, one-dimensional diffusion problems in land models.
Monte Carlo Modeling of Dual and Triple Photon Energy Absorptiometry Technique
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Alireza Kamali-Asl
2007-12-01
Full Text Available Introduction: Osteoporosis is a bone disease in which there is a reduction in the amount of bone mineral content leading to an increase in the risk of bone fractures. The affected individuals not only have to go through lots of pain and suffering but this disease also results in high economic costs to the society due to a large number of fractures. A timely and accurate diagnosis of this disease makes it possible to start a treatment and thus preventing bone fractures as a result of osteoporosis. Radiographic methods are particularly well suited for in vivo determination of bone mineral density (BMD due to the relatively high x-ray absorption properties of bone mineral compared to other tissues. Materials and Methods: Monte Carlo simulation has been conducted to explore the possibilities of triple photon energy absorptiometry (TPA in the measurement of bone mineral content. The purpose of this technique is to correctly measure the bone mineral density in the presence of fatty and soft tissues. The same simulations have been done for a dual photon energy absorptiometry (DPA system and an extended DPA system. Results: Using DPA with three components improves the accuracy of the obtained result while the simulation results show that TPA system is not accurate enough to be considered as an adequate method for the measurement of bone mineral density. Discussion: The reason for the improvement in the accuracy is the consideration of fatty tissue in TPA method while having attenuation coefficient as a function of energy makes TPA an inadequate method. Conclusion: Using TPA method is not a perfect solution to overcome the problem of non uniformity in the distribution of fatty tissue.
Multiple Absorption-Line Spectroscopy of the Intergalactic Medium. I. Model
Yao, Yangsen; Danforth, Charles W; Keeney, Brian A; Stocke, John T
2011-01-01
We present a physically-based absorption-line model for the spectroscopic study of the intergalactic medium (IGM). This model adopts results from Cloudy simulations and theoretical calculations by Gnat and Sternberg (2007) to examine the resulting observational signatures of the absorbing gas with the following ionization scenarios: collisional ionization equilibrium (CIE), photoionization equilibrium, hybrid (photo- plus collisional ionization), and non-equilibrium cooling. As a demonstration, we apply this model to new observations made with the Cosmic Origins Spectrograph aboard the Hubble Space Telescope of the IGM absorbers at z~0.1877 along the 1ES 1553+113 sight line. We identify Ly alpha, C III, O VI, and N V absorption lines with two distinct velocity components (blue at z_b=0.18757; red at z_r=0.18772) separated by Delta(cz)/(1+z)~38 km/s. Joint analyses of these lines indicate that none of the examined ionization scenarios can be applied with confidence to the blue velocity component, although phot...
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Salem M. Osta-Omar
2016-11-01
Full Text Available The objective of this paper is to develop a mathematical model for thermodynamic analysis of an absorption refrigeration system equipped with an adiabatic absorber using a lithium-bromide/water (LiBr/water pair as the working fluid. The working temperature of the generator, adiabatic absorber, condenser, evaporator, the cooling capacity of the system, and the ratio of the solution mass flow rate at the circulation pump to that at the solution pump are used as input data. The model evaluates the thermodynamic properties of all state points, the heat transfer in each component, the various mass flow rates, and the coefficient of performance (COP of the cycle. The results are used to investigate the effect of key parameters on the overall performance of the system. For instance, increasing the generator temperatures and decreasing the adiabatic absorber temperatures can increase the COP of the cycle. The results of this mathematical model can be used for designing and sizing new LiBr/water absorption refrigeration systems equipped with an adiabatic absorber or for optimizing existing aforementioned systems.
Topics in dual models and extended solutions. [Bethe-Salpeter equation
Energy Technology Data Exchange (ETDEWEB)
Roth, R.S.
1977-06-01
Two main topics are explored. The first deals with the infinities arising from the one loop planar string diagram of the standard dual model. It is shown that for the number of dimensions d = 25 or 26, these infinities lead to a renormalization of the slope of the Regge trajectories, in addition to a renormalization of the coupling constant. The second topic deals with the propagator for a confined particle (monopole) in a field theory. When summed to all orders, this propagator is altogether free of singularities in the finite momentum plane, and an attempt is made to illustrate this. One examines the Bethe-Salpeter equation and shows that ladder diagrams are not sufficient to obtain this result. However, in a nonrelativistic approximation confinement is obtained and all poles disappear.
The dual process model of ideology and prejudice: a longitudinal test during a global recession.
Sibley, Chris G; Duckitt, John
2013-01-01
This study tested the pathways between personality, social worldviews, and ideology, predicted by the Dual Process Model (DPM) of ideology and prejudice. These paths were tested using a full cross-lagged panel design administered to a New Zealand community sample in early 2008 (before the effects of the global financial crisis reached New Zealand) and again in 2009 (when the crisis was near its peak; n = 247). As hypothesized, low openness to experience predicted residualized change in dangerous worldview, which in turn predicted right-wing authoritarianism (RWA). Low agreeableness predicted competitive worldview, which in turn predicted social dominance orientation (SDO). RWA and SDO also exerted unexpected reciprocal effects on worldviews. This study provides the most comprehensive longitudinal test of the DPM to date, and was conducted during a period of systemic instability when the causal effects predicted by the DPM should be, and were, readily apparent.
Effect of temperature gradient on heavy quark anti-quark potential using gravity dual model
Ganesh, S
2016-01-01
The Quark-gluon plasma (QGP) is an expanding fireball, with finite dimensions. Given the finite dimensions, the temperature would be highest at the center, and close to the critical temperature, $T_c$, at the boundary, giving rise to a temperature gradient inside the QGP. A heavy quark anti-quark pair immersed in the QGP medium would see this temperature gradient. The effect of the temperature gradient on the quark anti-quark potential is analyzed using a gravity dual model. The resulting modification to the potential due to the temperature gradient is seen to have a $L^{-2}$ correction term. This could be a possible fallout of the breaking of conformal invariance at finite temperature.
Liu, Huimin; Cheung, Fanny M
2015-03-01
The purpose of the present study is to examine the crossover effects from one partner's work-family interface (work-family conflict [WFC] and work-family enrichment [WFE]) to the other partner's four outcomes (psychological strain, life satisfaction, marital satisfaction and job satisfaction) in a sample of Chinese dual-earner couples. Married couples (N = 361) completed a battery of questionnaires, including the work-family interface scale, the psychological strain scale, the life, marital, as well as job satisfaction scale. Results from the actor-partner interdependence model (APIM) analyses showed that wives' WFE was negatively associated with husbands' psychological strain, and positively associated with husbands' life, marital and job satisfaction. Furthermore, husbands' WFC was negatively related to wives' marital satisfaction, whereas husbands' WFE was positively related to wives' marital satisfaction. Theoretical and practical implications were discussed, and future research directions were provided.
Characterization of a Dual CDC7/CDK9 Inhibitor in Multiple Myeloma Cellular Models
Energy Technology Data Exchange (ETDEWEB)
Natoni, Alessandro [Centre for Chromosome Biology, School of Natural Sciences National University of Ireland Galway, Galway (Ireland); Coyne, Mark R. E. [Centre for Chromosome Biology, School of Natural Sciences National University of Ireland Galway, Galway (Ireland); Department of Medicine, National University of Ireland Galway, Galway (Ireland); Department of Haematology, Galway University Hospital, Galway (Ireland); Jacobsen, Alan; Rainey, Michael D.; O’Brien, Gemma; Healy, Sandra [Centre for Chromosome Biology, School of Natural Sciences National University of Ireland Galway, Galway (Ireland); Montagnoli, Alessia; Moll, Jürgen [Nerviano Medical Sciences S.r.l., Via Pasteur 10, Nerviano 20014 (Italy); O’Dwyer, Michael, E-mail: michael.odwyer@nuigalway.ie [Department of Medicine, National University of Ireland Galway, Galway (Ireland); Department of Haematology, Galway University Hospital, Galway (Ireland); Santocanale, Corrado, E-mail: michael.odwyer@nuigalway.ie [Centre for Chromosome Biology, School of Natural Sciences National University of Ireland Galway, Galway (Ireland)
2013-07-24
Two key features of myeloma cells are the deregulation of the cell cycle and the dependency on the expression of the BCL2 family of anti-apoptotic proteins. The cell division cycle 7 (CDC7) is an essential S-phase kinase and emerging CDC7 inhibitors are effective in a variety of preclinical cancer models. These compounds also inhibit CDK9 which is relevant for MCL-1 expression. The activity and mechanism of action of the dual CDC7/CDK9 inhibitor PHA-767491 was assessed in a panel of multiple myeloma cell lines, in primary samples from patients, in the presence of stromal cells and in combination with drugs used in current chemotherapeutic regimens. We report that in all conditions myeloma cells undergo cell death upon PHA-767491 treatment and we report an overall additive effect with melphalan, bortezomib and doxorubicin, thus supporting further assessment of targeting CDC7 and CDK9 in multiple myeloma.
Precommitted Investment Strategy versus Time-Consistent Investment Strategy for a Dual Risk Model
Directory of Open Access Journals (Sweden)
Lidong Zhang
2014-01-01
Full Text Available We are concerned with optimal investment strategy for a dual risk model. We assume that the company can invest into a risk-free asset and a risky asset. Short-selling and borrowing money are allowed. Due to lack of iterated-expectation property, the Bellman Optimization Principle does not hold. Thus we investigate the precommitted strategy and time-consistent strategy, respectively. We take three steps to derive the precommitted investment strategy. Furthermore, the time-consistent investment strategy is also obtained by solving the extended Hamilton-Jacobi-Bellman equations. We compare the precommitted strategy with time-consistent strategy and find that these different strategies have different advantages: the former can make value function maximized at the original time t=0 and the latter strategy is time-consistent for the whole time horizon. Finally, numerical analysis is presented for our results.
Institute of Scientific and Technical Information of China (English)
LIU Xiang-Mei; SONG Yuan-Hong; WANG You-Nian
2009-01-01
A self-consistent fluid model, which incorporates density and flux balances of electrons, ions, neutrals and nanopar ticles, electron energy balance, and Poiaaon 's equation, is employed to investigate the capacitively coupled silane discharge modulated by dual-frequency electric sources. In this discharge process, nanoparticles are formed by a successive chemical reactions of anion with silane. The density distributions of the precursors in the dust particle formation are put forward, and the charging, transport and growth of nanoparticles are simulated. In this work, we focus our main attention on the influences of the high-frequency and low-frequency voltage on nanoparticle densities, nanoparticle charge distributions in both the bulk plasma and sheath region.
Thermodynamic modelling and optimization of a dual pressure reheat combined power cycle
Indian Academy of Sciences (India)
T Srinivas
2010-10-01
Heat recovery steam generator (HRSG) plays a key role on performance of combined cycle (CC). In this work, attention was focused on a dual pressure reheat (DPRH) HRSG to maximize the heat recovery and hence performance of CC. Deaerator, an essential open feed water heater in steam bottoming cycle was located to enhance the efﬁciency and remove the dissolved gasses in feedwater. Each of the heating section in HRSG is solved from the local ﬂue gas condition with an aim of getting minimum possible temperature difference. For high performance, better conditions for compressor, HRSG sections, steam reheater and deaerator are developed. The CC system is optimized at a gas turbine inlet temperature of 1400°C due to the present available technology of modern gas turbine blade cooling systems. The exergetic losses in CC system are compared with each other. The present DPRH HRSG model has been compared and validated with the plant and published data.
Compound analysis of gallstones using dual energy computed tomography-Results in a phantom model
Energy Technology Data Exchange (ETDEWEB)
Bauer, Ralf W., E-mail: ralfwbauer@aol.co [Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University Frankfurt, Theodor-Stern-Kai 7, 60596 Frankfurt (Germany); Schulz, Julian R., E-mail: julian.schulz@t-online.d [Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University Frankfurt, Theodor-Stern-Kai 7, 60596 Frankfurt (Germany); Zedler, Barbara, E-mail: zedler@em.uni-frankfurt.d [Department of Forensic Medicine, Clinic of the Goethe University Frankfurt, Kennedyallee 104, 60596 Frankfurt (Germany); Graf, Thomas G., E-mail: thomas.gt.graf@siemens.co [Siemens AG Healthcare Sector, Computed Tomography, Physics and Applications, Siemensstrasse 1, 91313 Forchheim (Germany); Vogl, Thomas J., E-mail: t.vogl@em.uni-frankfurt.d [Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University Frankfurt, Theodor-Stern-Kai 7, 60596 Frankfurt (Germany)
2010-07-15
Purpose: The potential of dual energy computed tomography (DECT) for the analysis of gallstone compounds was investigated. The main goal was to find parameters, that can reliably define high percentage (>70%) cholesterol stones without calcium components. Materials and methods: 35 gallstones were analyzed with DECT using a phantom model. Stone samples were put into specimen containers filled with formalin. Containers were put into a water-filled cylindrical acrylic glass phantom. DECT scans were performed using a tube voltage/current of 140 kV/83 mAs (tube A) and 80 kV/340 mAs (tube B). ROI-measurements to determine CT attenuation of each sector of the stones that had different appearance on the CT images were performed. Finally, semi-quantitative infrared spectroscopy (FTIR) of these sectors was performed for chemical analysis. Results: ROI-measurements were performed in 45 different sectors in 35 gallstones. Sectors containing >70% of cholesterol and no calcium component (n = 20) on FTIR could be identified with 95% sensitivity and 100% specificity on DECT. These sectors showed typical attenuation of -8 {+-} 4 HU at 80 kV and +22 {+-} 3 HU at 140 kV. Even the presence of a small calcium component (<10%) hindered the reliable identification of cholesterol components as such. Conclusion: Dual energy CT allows for reliable identification of gallstones containing a high percentage of cholesterol and no calcium component in this pre-clinical phantom model. Results from in vivo or anthropomorphic phantom trials will have to confirm these results. This may enable the identification of patients eligible for non-surgical treatment options in the future.
van Duijvenvoorde, A C K; Achterberg, M; Braams, B R; Peters, S; Crone, E A
2016-01-01
The current study aimed to test a dual-systems model of adolescent brain development by studying changes in intrinsic functional connectivity within and across networks typically associated with cognitive-control and affective-motivational processes. To this end, resting-state and task-related fMRI data were collected of 269 participants (ages 8-25). Resting-state analyses focused on seeds derived from task-related neural activation in the same participants: the dorsal lateral prefrontal cortex (dlPFC) from a cognitive rule-learning paradigm and the nucleus accumbens (NAcc) from a reward-paradigm. Whole-brain seed-based resting-state analyses showed an age-related increase in dlPFC connectivity with the caudate and thalamus, and an age-related decrease in connectivity with the (pre)motor cortex. nAcc connectivity showed a strengthening of connectivity with the dorsal anterior cingulate cortex (ACC) and subcortical structures such as the hippocampus, and a specific age-related decrease in connectivity with the ventral medial PFC (vmPFC). Behavioral measures from both functional paradigms correlated with resting-state connectivity strength with their respective seed. That is, age-related change in learning performance was mediated by connectivity between the dlPFC and thalamus, and age-related change in winning pleasure was mediated by connectivity between the nAcc and vmPFC. These patterns indicate (i) strengthening of connectivity between regions that support control and learning, (ii) more independent functioning of regions that support motor and control networks, and (iii) more independent functioning of regions that support motivation and valuation networks with age. These results are interpreted vis-à-vis a dual-systems model of adolescent brain development.
Dual Processes in Decision Making and Developmental Neuroscience: A Fuzzy-Trace Model.
Reyna, Valerie F; Brainerd, Charles J
2011-09-01
From Piaget to the present, traditional and dual-process theories have predicted improvement in reasoning from childhood to adulthood, and improvement has been observed. However, developmental reversals-that reasoning biases emerge with development -have also been observed in a growing list of paradigms. We explain how fuzzy-trace theory predicts both improvement and developmental reversals in reasoning and decision making. Drawing on research on logical and quantitative reasoning, as well as on risky decision making in the laboratory and in life, we illustrate how the same small set of theoretical principles apply to typical neurodevelopment, encompassing childhood, adolescence, and adulthood, and to neurological conditions such as autism and Alzheimer's disease. For example, framing effects-that risk preferences shift when the same decisions are phrases in terms of gains versus losses-emerge in early adolescence as gist-based intuition develops. In autistic individuals, who rely less on gist-based intuition and more on verbatim-based analysis, framing biases are attenuated (i.e., they outperform typically developing control subjects). In adults, simple manipulations based on fuzzy-trace theory can make framing effects appear and disappear depending on whether gist-based intuition or verbatim-based analysis is induced. These theoretical principles are summarized and integrated in a new mathematical model that specifies how dual modes of reasoning combine to produce predictable variability in performance. In particular, we show how the most popular and extensively studied model of decision making-prospect theory-can be derived from fuzzy-trace theory by combining analytical (verbatim-based) and intuitive (gist-based) processes.
Energy Technology Data Exchange (ETDEWEB)
Hernández S, A., E-mail: h.s.alfonso@gmail.com, E-mail: meduardo2001@hotmail.com; Cano, M. E., E-mail: h.s.alfonso@gmail.com, E-mail: meduardo2001@hotmail.com [Centro Universitario de la Ciénega, Universidad de Guadalajara, Ocotlán, Jalisco (Mexico); Torres-Arenas, J., E-mail: torresare@gmail.com [Division de Ciencias e Ingenierías, Universidad de Guanajuato, León, Guanajuato (Mexico)
2014-11-07
Currently the absorption of electromagnetic radiation by magnetic nanoparticles is studied for biomedical applications of cancer thermotherapy. Several experiments are conduced following the framework of the Rosensweig model, in order to estimate their specific absorption rate. Nevertheless, this linear approximation involves strong simplifications which constrain their accuracy and validity range. The main aim of this work is to incorporate the deviation of the sphericity assumption in particles shapes, to improve the determination of their specific absorption rate. The correction to the effective particles volume is computed as a measure of the apparent amount of magnetic material, interacting with the external AC magnetic field. Preliminary results using the physical properties of Fe3O4 nanoparticles, exhibit an important correction in their estimated specific absorption rate, as a function of the apparent mean particles radius. Indeed, we have observed using a small deviation (6% of the apparent radius), up to 40% of the predicted specific absorption rate by the Rosensweig linear approximation.
A dual-phantom system for validation of velocity measurements in stenosis models under steady flow.
Blake, James R; Easson, William J; Hoskins, Peter R
2009-09-01
A dual-phantom system is developed for validation of velocity measurements in stenosis models. Pairs of phantoms with identical geometry and flow conditions are manufactured, one for ultrasound and one for particle image velocimetry (PIV). The PIV model is made from silicone rubber, and a new PIV fluid is made that matches the refractive index of 1.41 of silicone. Dynamic scaling was performed to correct for the increased viscosity of the PIV fluid compared with that of the ultrasound blood mimic. The degree of stenosis in the models pairs agreed to less than 1%. The velocities in the laminar flow region up to the peak velocity location agreed to within 15%, and the difference could be explained by errors in ultrasound velocity estimation. At low flow rates and in mild stenoses, good agreement was observed in the distal flow fields, excepting the maximum velocities. At high flow rates, there was considerable difference in velocities in the poststenosis flow field (maximum centreline differences of 30%), which would seem to represent real differences in hydrodynamic behavior between the two models. Sources of error included: variation of viscosity because of temperature (random error, which could account for differences of up to 7%); ultrasound velocity estimation errors (systematic errors); and geometry effects in each model, particularly because of imperfect connectors and corners (systematic errors, potentially affecting the inlet length and flow stability). The current system is best placed to investigate measurement errors in the laminar flow region rather than the poststenosis turbulent flow region.
Comprehensive behavioral model of dual-gate high voltage JFET and pinch resistor
Banáš, Stanislav; Paňko, Václav; Dobeš, Josef; Hanyš, Petr; Divín, Jan
2016-09-01
Many analog technologies operate in large voltage range and therefore include at least one or more high voltage devices built from low doped layers. Such devices exhibit effects not covered by standard compact models, namely pinching (depletion) effects, in high voltage FETs often called quasisaturation. For example, the conventional compact JFET model is insufficient and oversimplified. Its scalability is controlled by the area factor, which only multiplies currents and capacitances but does not take into account existing 3-D effects. Also the optional second independent gate is missing. Therefore, the customized four terminal (4T) model written in Verilog-A (FitzPatrick and Miller, 2007; Sagdeo, 2007) was developed. It converges very well, its simulation speed is comparable with conventional compact models, and contains all required phenomena, including parasitic effects as, for example, impact ionization. This model has universal usage for many types of devices in various high voltage technologies such as stand-alone voltage dependent resistor, pinch resistor, drift area of power FET, part of special high side or start-up devices, and dual-gate JFET.
ISMabs: A COMPREHENSIVE X-RAY ABSORPTION MODEL FOR THE INTERSTELLAR MEDIUM
Energy Technology Data Exchange (ETDEWEB)
Gatuzz, E.; Mendoza, C. [Centro de Física, Instituto Venezolano de Investigaciones Científicas (IVIC), P.O. Box 20632, Caracas 1020A (Venezuela, Bolivarian Republic of); García, J. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, 02138 (United States); Kallman, T. R. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Gorczyca, T. W., E-mail: egatuzz@ivic.gob.ve, E-mail: claudio@ivic.gob.ve, E-mail: javier@head.cfa.harvard.edu, E-mail: timothy.r.kallman@nasa.gov, E-mail: thomas.gorczyca@wmich.edu [Department of Physics, Western Michigan University, Kalamazoo, MI 49008 (United States)
2015-02-10
We present an X-ray absorption model for the interstellar medium, to be referred to as ISMabs, that takes into account both neutral and ionized species of cosmically abundant elements, and includes the most accurate atomic data available. Using high-resolution spectra from eight X-ray binaries obtained with the Chandra High Energy Transmission Grating Spectrometer, we proceed to benchmark the atomic data in the model particularly in the neon K-edge region. Compared with previous photoabsorption models, which solely rely on neutral species, the inclusion of ions leads to improved spectral fits. Fit parameters comprise the column densities of abundant contributors that allow direct estimates of the ionization states. ISMabs is provided in the appropriate format to be implemented in widely used X-ray spectral fitting packages such as XSPEC, ISIS, and SHERPA.
X-Ray Modeling of the Intrinsic Absorption in NGC 4151
Denes Couto, Jullianna; Kraemer, Steven; Turner, T. Jane; Crenshaw, D. Michael
2017-01-01
We have investigated the relationship between the long term X-ray spectral variability in the Seyfert 1.5 galaxy NGC 4151 and its intrinsic absorption, by comparing our 2014 simultaneous ultraviolet/X-Ray observations taken with Hubble STIS Echelle and Chandra HETGS with archival observations from Chandra, XMM-Newton and Suzaku. The observations were divided into "high" and "low" states, with the low states showing strong and unabsorbed extended emission at energies below 2 keV. Our X-ray model consists of a broken powerlaw, neutral reflection and the two dominant absorption components identified by Kraemer et al (2005), X-High and D+Ea, which are present in all epochs. The model fittings suggest that the absorbers are very stable, with the principal changes in the intrinsic absorption resulting from variations in the ionization state of the gas in response to the variable strength of the ionizing continuum. However, the low states show evidence of larger column densities in one or both of the absorbers. Among plausible explanations for the column increase, we discuss the possibility of an expanding/contracting X-ray corona. X-High is consistent with being part of a magnetohydrodynamic (MHD) wind, while D+Ea is possibly radiatively driven, which suggests that at a sufficiently large radial distance there could be a break point between MHD-dominated and radiatively driven outflows. Preliminary results on the analysis of the AGN mass outflow rates and kinematics of the ionized gas in the extended emission region of NGC 4151 will also be presented.
Ireland, J J; Roberts, R M; Palmer, G H; Bauman, D E; Bazer, F W
2008-10-01
Research on domestic animals (cattle, swine, sheep, goats, poultry, horses, and aquatic species) at land grant institutions is integral to improving the global competitiveness of US animal agriculture and to resolving complex animal and human diseases. However, dwindling federal and state budgets, years of stagnant funding from USDA for the Competitive State Research, Education, and Extension Service National Research Initiative (CSREES-NRI) Competitive Grants Program, significant reductions in farm animal species and in numbers at land grant institutions, and declining enrollment for graduate studies in animal science are diminishing the resources necessary to conduct research on domestic species. Consequently, recruitment of scientists who use such models to conduct research relevant to animal agriculture and biomedicine at land grant institutions is in jeopardy. Concerned stakeholders have addressed this critical problem by conducting workshops, holding a series of meetings with USDA and National Institutes of Health (NIH) officials, and developing a white paper to propose solutions to obstacles impeding the use of domestic species as dual-purpose animal models for high-priority problems common to agriculture and biomedicine. In addition to shortfalls in research support and human resources, overwhelming use of mouse models in biomedicine, lack of advocacy from university administrators, long-standing cultural barriers between agriculture and human medicine, inadequate grantsmanship by animal scientists, and a scarcity of key reagents and resources are major roadblocks to progress. Solutions will require a large financial enhancement of USDA's Competitive Grants Program, educational programs geared toward explaining how research using agricultural animals benefits both animal agriculture and human health, and the development of a new mind-set in land grant institutions that fosters greater cooperation among basic and applied researchers. Recruitment of
Dual-porosity model of solute diffusion in biological tissue modified by electroporation.
Mahnič-Kalamiza, Samo; Miklavčič, Damijan; Vorobiev, Eugène
2014-07-01
In many electroporation applications mass transport in biological tissue is of primary concern. This paper presents a theoretical advancement in the field and gives some examples of model use in electroporation applications. The study focuses on post-treatment solute diffusion. We use a dual-porosity approach to describe solute diffusion in electroporated biological tissue. The cellular membrane presents a hindrance to solute transport into the extracellular space and is modeled as electroporation-dependent porosity, assigned to the intracellular space (the finite rate of mass transfer within an individual cell is not accounted for, for reasons that we elaborate on). The second porosity is that of the extracellular space, through which solute vacates a block of tissue. The model can be used to study extraction out of or introduction of solutes into tissue, and we give three examples of application, a full account of model construction, validation with experiments, and a parametrical analysis. To facilitate easy implementation and experimentation by the reader, the complete derivation of the analytical solution for a simplified example is presented. Validation is done by comparing model results to experimentally-obtained data; we modeled kinetics of sucrose extraction by diffusion from sugar beet tissue in laboratory-scale experiments. The parametrical analysis demonstrates the importance of selected physicochemical and geometrical properties of the system, illustrating possible outcomes of applying the model to different electroporation applications. The proposed model is a new platform that supports rapid extension by state-of-the-art models of electroporation phenomena, developed as latest achievements in the field of electroporation.
Huang, Susie Shih-Yin; Strathe, Anders Bjerring; Hung, Silas S O; Boston, Raymond C; Fadel, James G
2012-03-01
The biological function of selenium (Se) is determined by its form and concentration. Selenium is an essential micronutrient for all vertebrates, however, at environmental levels, it is a potent toxin. In the San Francisco Bay-Delta, Se pollution threatens top predatory fish, including white sturgeon. A multi-compartmental Bayesian hierarchical model was developed to estimate the fractional rates of absorption, disposition, and elimination of selenocompounds, in white sturgeon, from tissue measurements obtained in a previous study (Huang et al., 2012). This modeling methodology allows for a population based approach to estimate kinetic physiological parameters in white sturgeon. Briefly, thirty juvenile white sturgeon (five per treatment) were orally intubated with a control (no selenium) or a single dose of Se (500 μg Se/kg body weight) in the form of one inorganic (Selenite) or four organic selenocompounds: selenocystine (SeCys), l-selenomethionine (SeMet), Se-methylseleno-l-cysteine (MSeCys), or selenoyeast (SeYeast). Blood and urine Se were measured at intervals throughout the 48h post intubation period and eight tissues were sampled at 48 h. The model is composed of four state variables, conceptually the gut (Q1), blood (Q2), and tissue (Q3); and urine (Q0), all in units of μg Se. Six kinetics parameters were estimated: the fractional rates [1/h] of absorption, tissue disposition, tissue release, and urinary elimination (k12, k23, k32, and k20), the proportion of the absorbed dose eliminated through the urine (f20), and the distribution blood volume (V; percent body weight, BW). The parameter k12 was higher in sturgeon given the organic Se forms, in the descending order of MSeCys > SeMet > SeCys > Selenite > SeYeast. The parameters k23 and k32 followed similar patterns, and f20 was lowest in fish given MSeCys. Selenium form did not affect k20 or V. The parameter differences observed can be attributed to the different mechanisms of transmucosal transport
Design, Modelling and Fabrication of a 40-330 Hz Dual-Mass MEMS Gyroscope on Thick-SOI Technology
Rajaraman, V.; Sabageh, I.; French, P.; Pansraud, G.; Cretu, E.
2011-01-01
This work reports the design, modelling, fabrication and preliminary functionality testing of a dual-mass MEMS vibratory gyroscope for application in medical instrumentation, among others. The two-framed gyro has drive and sense mode resonance frequencies of 2500Hz and 2830Hz, with its bandwidth tun
Ghetti, Simona; Angelini, Laura
2008-01-01
Two experiments examined the development of recollection (recalling qualitative details about an event) and familiarity (recognizing the event) using the dual-process signal detection model. In Experiment 1 (n = 117; ages 6, 8, 10, 14, and 18 years), recollection improved from childhood to adolescence after semantic encoding but not after…
Hedonic tone and activation in the mood-creativity link: towards a dual pathway to creativity model
de Dreu, C.K.W.; Baas, M.; Nijstad, B.A.
2008-01-01
To understand when and why mood states influence creativity, the authors developed and tested a dual pathway to creativity model; creative fluency (number of ideas or insights) and originality (novelty) are functions of cognitive flexibility, persistence, or some combination thereof. Invoking work o
De Dreu, Carsten K. W.; Baas, Matthijs; Nijstad, Bernard A.
2008-01-01
To understand when and why mood states influence creativity, the authors developed and tested a dual pathway to creativity model; creative fluency (number of ideas or insights) and originality (novelty) are functions of cognitive flexibility, persistence, or some combination thereof. Invoking work o
Chen, Lung Hung; Kee, Ying Hwa; Tsai, Ying-Mei
2009-01-01
The dual model of perfectionism (Slade and Owens, Behav Modificat 22(3):372-390, 1998) is adopted to examine the influence of adaptive and maladaptive perfectionism on adolescent athlete burnout in Taiwan. Participants were 188 high school adolescent student-athletes (M = 16.48, SD = 0.59). They were administered the Multidimensional Inventory of…
Murphy, Audrey Figueroa
2014-01-01
The effects of "transitional-bilingual" and "dual-language" educational models on proficiency in students' home language (Spanish) were examined in a study of English language learners in the first and second grades in a large urban elementary school. In each grade, students were taught with either a transitional-bilingual…
Purkarthofer, Judith; Mossakowski, Jan
2011-01-01
Traditional bilingual education programmes in regional linguistic minority contexts face major challenges within the recent paradigm of linguistic diversity against a background of increasing migration, mobility and trans-locality. Based on three case studies, the authors of this paper focus on how particular dual-medium models are applied in…
Lv, Jitao; Luo, Lei; Zhang, Jing; Christie, Peter; Zhang, Shuzhen
2012-03-01
Adsorption of mercury (Hg) on lignin was studied at a range of pH values using a combination of batch adsorption experiments, a surface complexation model (SCM) and synchrotron X-ray absorption spectroscopy (XAS). Surface complexation modeling indicates that three types of acid sites on lignin surfaces, namely aliphatic carboxylic-, aromatic carboxylic- and phenolic-type surface groups, contributed to Hg(II) adsorption. The bond distance and coordination number of Hg(II) adsorption samples at pH 3.0, 4.0 and 5.5 were obtained from extended X-ray absorption fine structure (EXAFS) spectroscopy analysis. The results of SCM and XAS combined reveal that the predominant adsorption species of Hg(II) on lignin changes from HgCl(2)(0) to monodentate complex -C-O-HgCl and then bidentate complex -C-O-Hg-O-C- with increasing pH value from 2.0 to 6.0. The good agreement between SCM and XAS results provides new insight into understanding the mechanisms of Hg(II) adsorption on lignin.
2015-05-15
1 COMPARING TWO NUMERICAL MODELS IN SIMULATING HYDRODYNAMICS AND SEDIMENT TRANSPORT AT A DUAL INLET SYSTEM, WEST-CENTRAL FLORIDA PING WANG1...numerical modeling systems, CMS and DELFT3D, in simulating the hydrodynamic and sediment transport processes. The model results are compared with...Introduction Simulating complex fields of wave, current, sediment transport , and morphology change in the vicinity of tidal inlets is a
Mathematical Modeling of Dual Layer Shell Type Recuperation System for Biogas Dehumidification
Gendelis, S.; Timuhins, A.; Laizans, A.; Bandeniece, L.
2015-12-01
The main aim of the current paper is to create a mathematical model for dual layer shell type recuperation system, which allows reducing the heat losses from the biomass digester and water amount in the biogas without any additional mechanical or chemical components. The idea of this system is to reduce the temperature of the outflowing gas by creating two-layered counter-flow heat exchanger around the walls of biogas digester, thus increasing a thermal resistance and the gas temperature, resulting in a condensation on a colder surface. Complex mathematical model, including surface condensation, is developed for this type of biogas dehumidifier and the parameter study is carried out for a wide range of parameters. The model is reduced to 1D case to make numerical calculations faster. It is shown that latent heat of condensation is very important for the total heat balance and the condensation rate is highly dependent on insulation between layers and outside temperature. Modelling results allow finding optimal geometrical parameters for the known gas flow and predicting the condensation rate for different system setups and seasons.
Testing a Dual Process Model of Gender-Based Violence: A Laboratory Examination.
Berke, Danielle S; Zeichner, Amos
2016-01-01
The dire impact of gender-based violence on society compels development of models comprehensive enough to capture the diversity of its forms. Research has established hostile sexism (HS) as a robust predictor of gender-based violence. However, to date, research has yet to link men's benevolent sexism (BS) to physical aggression toward women, despite correlations between BS and HS and between BS and victim blaming. One model, the opposing process model of benevolent sexism (Sibley & Perry, 2010), suggests that, for men, BS acts indirectly through HS to predict acceptance of hierarchy-enhancing social policy as an expression of a preference for in-group dominance (i. e., social dominance orientation [SDO]). The extent to which this model applies to gender-based violence remains untested. Therefore, in this study, 168 undergraduate men in a U. S. university participated in a competitive reaction time task, during which they had the option to shock an ostensible female opponent as a measure of gender-based violence. Results of multiple-mediation path analyses indicated dual pathways potentiating gender-based violence and highlight SDO as a particularly potent mechanism of this violence. Findings are discussed in terms of group dynamics and norm-based violence prevention.
Analytical Modeling of Dual Material Gate SOI MOSFET with Asymmetric Halo
Institute of Scientific and Technical Information of China (English)
LI Zun-chao; JIANG Yao-lin; ZHANG Li-li
2006-01-01
A dual material gate silicon-on-insulator MOSFET with asymmetrical halo is presented to improve short channel effect and carrier transport efficiency for the first time. The front gate consists of two metal gates with different work functions by making them contacting laterally, and the channel is more heavily doped near the source than in the rest. Using a three-region polynomial potential distribution and a universal boundary condition, a two-dimensional analytical model for the fully depleted silicon-on-insulator MOSFET is developed based on the explicit solution of two-dimensional Poisson's equation. The model includes the calculation of potential distribution along the channel and subthreshold current. The performance improvement of the novel silicon-on-insulator MOSFET is examined and compared with the traditional silicon-on-insulator MOSFET using the analytical model and two-dimensional device simulator MEDICI. It is found that the novel silicon-on-insulator MOSFET could not only suppress short channel effect, but also increase carrier transport efficiency noticeably. The derived analytical model agrees well with MEDICI.
Identifying western yellow-billed cuckoo breeding habitat with a dual modelling approach
Johnson, Matthew J.; Hatten, James R.; Holmes, Jennifer A.; Shafroth, Patrick B.
2017-01-01
The western population of the yellow-billed cuckoo (Coccyzus americanus) was recently listed as threatened under the federal Endangered Species Act. Yellow-billed cuckoo conservation efforts require the identification of features and area requirements associated with high quality, riparian forest habitat at spatial scales that range from nest microhabitat to landscape, as well as lower-suitability areas that can be enhanced or restored. Spatially explicit models inform conservation efforts by increasing ecological understanding of a target species, especially at landscape scales. Previous yellow-billed cuckoo modelling efforts derived plant-community maps from aerial photography, an expensive and oftentimes inconsistent approach. Satellite models can remotely map vegetation features (e.g., vegetation density, heterogeneity in vegetation density or structure) across large areas with near perfect repeatability, but they usually cannot identify plant communities. We used aerial photos and satellite imagery, and a hierarchical spatial scale approach, to identify yellow-billed cuckoo breeding habitat along the Lower Colorado River and its tributaries. Aerial-photo and satellite models identified several key features associated with yellow-billed cuckoo breeding locations: (1) a 4.5 ha core area of dense cottonwood-willow vegetation, (2) a large native, heterogeneously dense forest (72 ha) around the core area, and (3) moderately rough topography. The odds of yellow-billed cuckoo occurrence decreased rapidly as the amount of tamarisk cover increased or when cottonwood-willow vegetation was limited. We achieved model accuracies of 75–80% in the project area the following year after updating the imagery and location data. The two model types had very similar probability maps, largely predicting the same areas as high quality habitat. While each model provided unique information, a dual-modelling approach provided a more complete picture of yellow-billed cuckoo habitat
Flow and transport in the drift shadow in a dual-continuum model
Energy Technology Data Exchange (ETDEWEB)
Houseworth, J.E.; Finsterle, S.; Bodvarsson, G.S.
2002-09-01
The current concept for high-level radioactive waste disposal at Yucca Mountain is for the waste to be placed in underground tunnels (or drifts) in the middle of a thick unsaturated zone. Flow modeling and field testing have shown that not all flow encountering a drift will seep into the drift. The underlying reason for the diversion of unsaturated flow around a drift is that capillary forces in the fractures and matrix prevent water entry into the drift unless the capillary pressure in the rock decreases sufficiently to allow for gravity forces to overcome the capillary barrier. As a result of the capillary barrier effect, flow tends to be diverted around the drift, affecting the flow pattern beneath the drift. For some distance beneath the drift, water saturation and flux are reduced. This drift shadow zone is much more pronounced in the fractures than in the matrix due to dominance of gravity over capillary forces in the fractures. Moving downward, away from the drift, the shadow zone asymptotically re-equilibrates to the undisturbed flow conditions due to capillary forces. The behavior of radionuclide transport in this zone of reduced flow is investigated here because this will affect the amount of time required for radionuclides to penetrate the unsaturated zone. The delay of radio nuclide movement in the geosphere is one aspect of the potential repository system that could limit public exposure to radioactive waste. The behavior of flow and transport are calculated using a two-dimensional, drift-scale dual permeability model extending to nine drift diameters below the potential waste emplacement drift. The flow model is first compared with an analytical model for a single-continuum. Then the dual-continuum flow model is investigated with respect to drift-scale and mountain-scale property sets. Transport calculations are performed for a wide range of flow conditions and for different aqueous radionuclides and colloids. Findings indicate that transport times
Eckersall, A. J.; Vaughan, S.; Wynn, G. A.
2017-10-01
All observations of Galactic X-ray binaries are affected by absorption from gas and dust in the interstellar medium (ISM) which imprints narrow (line) and broad (photoelectric edges) features on the continuum emission spectrum of the binary. Any spectral model used to fit data from a Galactic X-ray binary must therefore take account of these features; when the absorption is strong (as for most Galactic sources) it becomes important to accurately model the ISM absorption in order to obtain unbiased estimates of the parameters of the (emission) spectrum of the binary system. In this paper, we present analysis of some of the best spectroscopic data from the XMM-Newton RGS instrument using the most up-to-date photoabsorption model of the gaseous ISM ISMabs. We calculate column densities for H, O, Ne and Fe for seven transient black hole X-ray binary systems. We find that the hydrogen column densities in particular can vary greatly from those presented elsewhere in the literature. We assess the impact of using inaccurate column densities and older X-ray absorption models on spectral analysis using simulated data. We find that poor treatment of absorption can lead to large biases in inferred disc properties and that an independent analysis of absorption parameters can be used to alleviate such issues.
Directory of Open Access Journals (Sweden)
R. Wagner
2011-09-01
Full Text Available We present computational results on the shape dependency of the extinction and absorption cross sections of dustlike aerosol particles that were modeled as randomly oriented spheroids. Shape dependent variations in the extinction cross sections are largest in the size regime that is governed by the interference structure. Elongated spheroids best fitted measured extinction spectra of re-dispersed Saharan dust samples. For dust particles smaller than 1.5 μm in diameter and low absorption potential, shape effects on the absorption cross sections are very small.
Directory of Open Access Journals (Sweden)
Li Hua-Rong
2014-01-01
Full Text Available Two improved multigrain models (MGMs for preparing homopolypropylene and long chain branched polypropylene via propylene polymerization using silica-supported metallocene or dual function metallocene as catalysts are presented in this paper. The presented models are used to predict the intraparticle flow fields involved in the polymerizations. The simulation results show that the flow field distributions involve dare basically identical. The results also show that both the two polymerization processes have an initiation stage and the controlling step for them is reaction-diffusion-reaction with the polymerization proceeding. Furthermore, the simulation results show that the intra particle mass transfer resistance has significant effect on the polymerization but the heat transfer resistance can be ignored.
CO2 Absorption in a Lab-Scale Fixed Solid Bed Reactor: Modelling and Experimental Tests
Directory of Open Access Journals (Sweden)
Roberto Gabbrielli
2004-09-01
Full Text Available The CO2 absorption in a lab-scale fixed solid bed reactor filled with different solid sorbents has been studied under different operative conditions regarding temperature (20-200°C and input gas composition (N2, O2, CO2, H2O at 1bar pressure. The gas leaving the reactor has been analysed to measure the CO2 and O2 concentrations and, consequently, to evaluate the overall CO2 removal efficiency. In order to study the influence of solid sorbent type (i.e. CaO, coal bottom ash, limestone and blast furnace slag and of mass and heat transfer processes on CO2 removal efficiency, a one-dimensional time dependent mathematical model of the reactor, which may be considered a Plug Flow Reactor, has been developed. The quality of the model has been confirmed using the experimental results.
Mouadili, A; Boudouti, E H El; Soltani, A; Talbi, A; Djafari-Rouhani, B; Akjouj, A; Haddadi, K
2014-12-17
We give an analytical and experimental demonstration of a classical analogue of the electromagnetic induced absorption (EIA) in a simple photonic device consisting of two stubs of lengths d1 and d2 grafted at the same site along a waveguide. By detuning the lengths of the two stubs (i.e. δ = d(2) - d(1)) we show that: (i) the amplitudes of the electromagnetic waves in the two stubs can be written following the two resonators model where each stub plays the role of a radiative resonator with low Q factor. The destructive interference between the waves in the two stubs may give rise to a sharp resonance peak with high Q factor in the transmission as well as in the absorption. (ii) The transmission coefficient around the resonance induced by the stubs can be written following a Fano-like form. In particular, we give an explicit expression of the position, width and Fano parameter of the resonances as a function of δ. (iii) By taking into account the loss in the waveguides, we show that at the transmission resonance, the transmission (reflection) increases (decreases) as a function of δ. Whereas the absorption goes through a maximum around 0.5 for a threshold value δth which depends on the attenuation in the system and then falls to zero. (iv) We give a comparison between the phase of the determinant of the scattering matrix, the so-called Friedel phase and the phase of the transmission amplitude. (v) The effect of the boundary conditions at the end of the resonators on the EIA resonance is also discussed. The analytical results are obtained by means of the Green's function method, whereas the experiments are carried out using coaxial cables in the radio-frequency regime. These results should have important consequences for designing integrated devices such as narrow-frequency optical or microwave filters and high-speed switches.
Trend-Residual Dual Modeling for Detection of Outliers in Low-Cost GPS Trajectories.
Chen, Xiaojian; Cui, Tingting; Fu, Jianhong; Peng, Jianwei; Shan, Jie
2016-12-01
Low-cost GPS (receiver) has become a ubiquitous and integral part of our daily life. Despite noticeable advantages such as being cheap, small, light, and easy to use, its limited positioning accuracy devalues and hampers its wide applications for reliable mapping and analysis. Two conventional techniques to remove outliers in a GPS trajectory are thresholding and Kalman-based methods, which are difficult in selecting appropriate thresholds and modeling the trajectories. Moreover, they are insensitive to medium and small outliers, especially for low-sample-rate trajectories. This paper proposes a model-based GPS trajectory cleaner. Rather than examining speed and acceleration or assuming a pre-determined trajectory model, we first use cubic smooth spline to adaptively model the trend of the trajectory. The residuals, i.e., the differences between the trend and GPS measurements, are then further modeled by time series method. Outliers are detected by scoring the residuals at every GPS trajectory point. Comparing to the conventional procedures, the trend-residual dual modeling approach has the following features: (a) it is able to model trajectories and detect outliers adaptively; (b) only one critical value for outlier scores needs to be set; (c) it is able to robustly detect unapparent outliers; and (d) it is effective in cleaning outliers for GPS trajectories with low sample rates. Tests are carried out on three real-world GPS trajectories datasets. The evaluation demonstrates an average of 9.27 times better performance in outlier detection for GPS trajectories than thresholding and Kalman-based techniques.
Trend-Residual Dual Modeling for Detection of Outliers in Low-Cost GPS Trajectories
Directory of Open Access Journals (Sweden)
Xiaojian Chen
2016-12-01
Full Text Available Low-cost GPS (receiver has become a ubiquitous and integral part of our daily life. Despite noticeable advantages such as being cheap, small, light, and easy to use, its limited positioning accuracy devalues and hampers its wide applications for reliable mapping and analysis. Two conventional techniques to remove outliers in a GPS trajectory are thresholding and Kalman-based methods, which are difficult in selecting appropriate thresholds and modeling the trajectories. Moreover, they are insensitive to medium and small outliers, especially for low-sample-rate trajectories. This paper proposes a model-based GPS trajectory cleaner. Rather than examining speed and acceleration or assuming a pre-determined trajectory model, we first use cubic smooth spline to adaptively model the trend of the trajectory. The residuals, i.e., the differences between the trend and GPS measurements, are then further modeled by time series method. Outliers are detected by scoring the residuals at every GPS trajectory point. Comparing to the conventional procedures, the trend-residual dual modeling approach has the following features: (a it is able to model trajectories and detect outliers adaptively; (b only one critical value for outlier scores needs to be set; (c it is able to robustly detect unapparent outliers; and (d it is effective in cleaning outliers for GPS trajectories with low sample rates. Tests are carried out on three real-world GPS trajectories datasets. The evaluation demonstrates an average of 9.27 times better performance in outlier detection for GPS trajectories than thresholding and Kalman-based techniques.
Dual-Extrusion 3D Printing of Anatomical Models for Education.
Smith, Michelle L; Jones, James F X
2017-09-14
Two material 3D printing is becoming increasingly popular, inexpensive and accessible. In this paper, freely available printable files and dual extrusion fused deposition modelling were combined to create a number of functional anatomical models. To represent muscle and bone FilaFlex(3D) flexible filament and polylactic acid (PLA) filament were extruded respectively via a single 0.4 mm nozzle using a Big Builder printer. For each filament, cubes (5 mm(3) ) were printed and analyzed for X, Y, and Z accuracy. The PLA printed cubes resulted in errors averaging just 1.2% across all directions but for FilaFlex(3D) printed cubes the errors were statistically significantly greater (average of 3.2%). As an exemplar, a focus was placed on the muscles, bones and cartilage of upper airway and neck. The resulting single prints combined flexible and hard structures. A single print model of the vocal cords was constructed which permitted movement of the arytenoids on the cricoid cartilage and served to illustrate the action of intrinsic laryngeal muscles. As University libraries become increasingly engaged in offering inexpensive 3D printing services it may soon become common place for both student and educator to access websites, download free models or 3D body parts and only pay the costs of print consumables. Novel models can be manufactured as dissectible, functional multi-layered units and offer rich possibilities for sectional and/or reduced anatomy. This approach can liberate the anatomist from constraints of inflexible hard models or plastinated specimens and engage in the design of class specific models of the future. Anat Sci Educ. © 2017 American Association of Anatomists. © 2017 American Association of Anatomists.
Menezes, R; Ribeiro, R F; Wotzasek, C
2002-01-01
We study the dual equivalence between the nonlinear generalization of the self-dual ($NSD_{B\\wedge F}$) and the topologically massive $B\\wedge F$ models with particular emphasis on the nonlinear electrodynamics proposed by Born and Infeld. This is done through a dynamical gauge embedding of the nonlinear self-dual model yielding to a gauge invariant and dynamically equivalent theory. We clearly show that nonpolinomial $NSD_{B\\wedge F}$ models can be mapped, through a properly defined duality transformation, into $TM_{B\\wedge F}$ actions. The general result obtained is then particularized for a number of examples, including the Born-Infeld-BF (BIBF) model that has experienced a revival in the recent literature.
Simulation and modeling CO2 absorption in biogas with DEA promoted K2CO3 solution in packed column
Nurkhamidah, Siti; Altway, Ali; Airlangga, Bramantyo; Emilia, Dwi Putri
2017-05-01
Absorption of carbon dioxide (CO2) using potassium carbonate (K2CO3) is one of biogas purification method. However, K2CO3 have slow mass transfer in liquid phase. So it is necessary to eliminate the disadvantage of CO2 absorption using K2CO3 by adding promotor (activator). Diethanol amine (DEA) is one of promotor which can increase its reaction rate. Simulation and modeling research of the CO2 absorption from biogas with DEA promoted K2CO3 solution has not been conducted. Thus, the main goal of this research is create model and simulation for the CO2 absorption from biogas with DEA promoted K2CO3 solution, then observe the influence of promoter concentration. DEA concentration varies between 1-5 %wt. From the simulation, we concluded that the CO2 removal rise with the increasing of promoter concentration. The highest CO2 removal is 54.5318 % at 5 % wt DEA concentration.
SU-C-BRE-03: Dual Compartment Mathematical Modeling of Glioblastoma Multiforme (GBM)
Energy Technology Data Exchange (ETDEWEB)
Yu, V; Nguyen, D; Kupelian, P; Kaprealian, T; Selch, M; Low, D; Pajonk, F; Sheng, K [UCLA, Los Angeles, CA (United States)
2014-06-15
Purpose: To explore the aggressive recurrence and radioresistence of GBM with a dual compartment tumor survival mathematical model based on intrinsic tumor heterogeneity, cancer stem cells (CSC) and differentiated cancer cells (DCC). Methods: The repopulation and differentiation responses to radiotherapy of a solid tumor were simulated using an Ordinary Differential Equation (ODE). To obtain the tumor radiobiological parameters, we assumed that a tumor consists of two subpopulations, each with its distinctive linear quadratic parameters. The dual compartment cell survival model was constructed as SF(D)=F × exp(-α{sub 1} D-β{sub 1}D{sup 2}) + (1-F) × exp(-α{sub 2}D-β{sub 2}D{sup 2}) for a single fraction of treatment, with F as the fraction of CSC, and α and β describing the radiological properties of each population. Robust least square fitting was performed on clonogenic survival data from one GBM (U373MG) and one NSCLC (H460) cell line. The fit parameters were then used in the ODE model to predict treatment outcome of various treatment schemes. Results: The fit parameters from GBM cell survival data were (F, α{sub 1}, β{sub 1}, α{sub 2}, β{sub 2})=(0.0396, 0.0801, 0.0006, 0.1363, 0.0279), exhibiting two populations with distinctive radiological properties, CSC more radioresistant than DCC. The GBM cell line exhibited significantly poorer tumor control than its single compartment model prediction and NSCLC, which responded well to hypofrationation. The increased radioresistance was due to rapid regrowth of the DCC compartment triggered by its depletion while maintaining a viable CSC population. The rapid regrowth can be reduced by treating dose fractions ≤ 2 Gy with a prolonged treatment period. Conclusion: The interaction between a radioresistant CSC compartment and DCC compartment can explain the poor clinical outcome of GBM after radiotherapy despite dose escalation and hypofractionation attempts. Lower dose fractions result in better treatment
Classifying Chinese children with dyslexia by dual-route and triangle models of Chinese reading.
Wang, Li-Chih; Yang, Hsien-Ming
2014-11-01
This present study focuses on classifying developmental dyslexia by combining two famous models, the dual-route model and the triangle model of Chinese reading, re-examining validity of the subtypes, and observing the error types of word recognition for each subtype. Sixty-sixth graders with dyslexia in Chinese and 45 sixth graders who were matched by age and IQ with the dyslexic group were involved in the present study. Twelve (20%) sixth graders from the dyslexic group were classified as having phonological dyslexia, 11 (18.3%) were classified as surface dyslexia, 12 (20%) were classified as deep dyslexia, and five (8.3%) of them were classified as displaying more than one kind of deficit. Besides, still more than half (31; 51.7%) of the dyslexic group did not belong to any subtypes here. These subtypes had a good validity based on comparison of their phonological awareness, orthography, and semantics. Finally, for their error types of word recognition, both children with multiple-deficit dyslexia and children with non-subtype dyslexia showed a proportional pattern of six kinds of errors. Children with phonological dyslexia showed more phonetic errors and analogy errors, children with surface dyslexia showed more visual errors and analogy errors, and children with deep dyslexia showed more semantic errors and selective errors.
Topological Symmetry, Spin Liquids and CFT Duals of Polyakov Model with Massless Fermions
Energy Technology Data Exchange (ETDEWEB)
Unsal, Mithat
2008-04-30
We prove the absence of a mass gap and confinement in the Polyakov model with massless complex fermions in any representation of the gauge group. A U(1){sub *} topological shift symmetry protects the masslessness of one dual photon. This symmetry emerges in the IR as a consequence of the Callias index theorem and abelian duality. For matter in the fundamental representation, the infrared limits of this class of theories interpolate between weakly and strongly coupled conformal field theory (CFT) depending on the number of flavors, and provide an infinite class of CFTs in d = 3 dimensions. The long distance physics of the model is same as certain stable spin liquids. Altering the topology of the adjoint Higgs field by turning it into a compact scalar does not change the long distance dynamics in perturbation theory, however, non-perturbative effects lead to a mass gap for the gauge fluctuations. This provides conceptual clarity to many subtle issues about compact QED{sub 3} discussed in the context of quantum magnets, spin liquids and phase fluctuation models in cuprate superconductors. These constructions also provide new insights into zero temperature gauge theory dynamics on R{sup 2,1} and R{sup 2,1} x S{sup 1}. The confined versus deconfined long distance dynamics is characterized by a discrete versus continuous topological symmetry.
Directory of Open Access Journals (Sweden)
Rim Amri
2014-06-01
Full Text Available The main goal of this study is to evaluate the potential of the FAO-56 dual technique for the estimation of regional evapotranspiration (ET and its constituent components (crop transpiration and soil evaporation, for two classes of vegetation (olives trees and cereals in the semi-arid region of the Kairouan plain in central Tunisia. The proposed approach combines the FAO-56 technique with remote sensing (optical and microwave, not only for vegetation characterization, as proposed in other studies but also for the estimation of soil evaporation, through the use of satellite moisture products. Since it is difficult to use ground flux measurements to validate remotely sensed data at regional scales, comparisons were made with the land surface model ISBA-A-gs which is a physical SVAT (Soil–Vegetation–Atmosphere Transfer model, an operational tool developed by Météo-France. It is thus shown that good results can be obtained with this relatively simple approach, based on the FAO-56 technique combined with remote sensing, to retrieve temporal variations of ET. The approach proposed for the daily mapping of evapotranspiration at 1 km resolution is approved in two steps, for the period between 1991 and 2007. In an initial step, the ISBA-A-gs soil moisture outputs are compared with ERS/WSC products. Then, the output of the FAO-56 technique is compared with the output generated by the SVAT ISBA-A-gs model.
Auracher, Hein; Wohlfeil, Arnold; Ziegler, Felix
2008-03-01
For one horizontal tube in an absorber the Nusselt solution for film thickness and velocity distribution was applied, assuming steady state in heat transfer and a semi-infinite body’s concentration profile with unsteady state mass transfer. The model was applied to the absorption of steam into aqueous lithium bromide in absorption chillers. The results are compared to published experimental values and show fair agreement.
Institute of Scientific and Technical Information of China (English)
WANG Hong-qi; SHU Yan; QI Yong-qiang; ZHANG Jun
2005-01-01
A series of simulation experiments of nitrogen transportation, absorption and transformation were conducted, and the different cropping patterns of winter wheat and wastewater irrigation plans were taken into consideration. Based on the experiments, an integrated model of crop growth, roots distribution, water and nitrogen absorption by roots, water and nitrogen movement and transformation in soilcrop system by two-dimension was developed. Parameters and boundary conditions were identified and an effective computing method for optimizing watering and wastewater irrigating plans was provided.
Radial diffusion in the Uranian radiatian belts - Inferences from satellite absorption loss models
Hood, L. L.
1989-01-01
Low-energy charged particle (LECP) phase space density profiles available from the Voyager/1986 Uranus encounter are analyzed, using solutions of the time-averaged radial diffusion equation for charged particle transport in a dipolar planetary magnetic field. Profiles for lower-energy protons and electrons are first analyzed to infer radial diffusion rate as a function of L, assuming that satellite absorption is the dominant loss process and local sources for these particles are negligible. Satellite macrosignatures present in the experimentally derived profiles are approximately reproduced in several cases, lending credence to the loss model and indicating that magnetospheric distributed losses are not as rapid as satellite absorption near the minimum satellite L shells for the particles. Diffusion rates and L dependences are found to be similar to those previously inferred in the inner Jovian magnetosphere (Thomsen et al., 1977) and for the inner Saturnian magnetosphere (Hood, 1985). Profiles for higher energy electrons and protons are also analyzed using solutions that allow for the existence of significant particle sources as well as sinks. Possible implications for radial diffusion mechanisms in the Uranian radiation belts are discussed.
Testing Disk-Wind Models with Quasar CIV 1549Å Associated Absorption Lines
DEFF Research Database (Denmark)
Vestergaard, Marianne
2012-01-01
Narrow associated C IV 1549Å absorption lines (NALs) with a rest equivalent width EW =3 Å detected in z ˜ 2 radio-loud and radio-quiet quasars, (a) exhibit evidence of an origin in radiatively accelerated gas, and (b) may be closely related to broad absorption line (BAL) outflows. These NALs...... and the few BALs detected in this quasar sample obey key predictions of models of radiatively driven disk-winds in which (1) the local disk luminosity launches the wind, (2) the central UV radiation drives it outwards, and (3) the wind acceleration (i.e., terminal velocity) depends on the strength of the X......-ray to UV emission ratio, i.e., aOX. The latter means that quasars with flat aOX (like radio-louds) should not have strong, high-velocity (BAL-like) outflows. These results are of interest not only to studies of disk wind scenarios and quasar structure, but also to studies of quasar feedback: NALs...
Testing Disk-Wind Models with Quasar CIV 1549Å Associated Absorption Lines
DEFF Research Database (Denmark)
Vestergaard, Marianne
2012-01-01
Narrow associated C IV 1549Å absorption lines (NALs) with a rest equivalent width EW =3 Å detected in z ˜ 2 radio-loud and radio-quiet quasars, (a) exhibit evidence of an origin in radiatively accelerated gas, and (b) may be closely related to broad absorption line (BAL) outflows. These NALs...... and the few BALs detected in this quasar sample obey key predictions of models of radiatively driven disk-winds in which (1) the local disk luminosity launches the wind, (2) the central UV radiation drives it outwards, and (3) the wind acceleration (i.e., terminal velocity) depends on the strength of the X......-ray to UV emission ratio, i.e., aOX. The latter means that quasars with flat aOX (like radio-louds) should not have strong, high-velocity (BAL-like) outflows. These results are of interest not only to studies of disk wind scenarios and quasar structure, but also to studies of quasar feedback: NALs...
Radial diffusion in the Uranian radiatian belts - Inferences from satellite absorption loss models
Hood, L. L.
1989-01-01
Low-energy charged particle (LECP) phase space density profiles available from the Voyager/1986 Uranus encounter are analyzed, using solutions of the time-averaged radial diffusion equation for charged particle transport in a dipolar planetary magnetic field. Profiles for lower-energy protons and electrons are first analyzed to infer radial diffusion rate as a function of L, assuming that satellite absorption is the dominant loss process and local sources for these particles are negligible. Satellite macrosignatures present in the experimentally derived profiles are approximately reproduced in several cases, lending credence to the loss model and indicating that magnetospheric distributed losses are not as rapid as satellite absorption near the minimum satellite L shells for the particles. Diffusion rates and L dependences are found to be similar to those previously inferred in the inner Jovian magnetosphere (Thomsen et al., 1977) and for the inner Saturnian magnetosphere (Hood, 1985). Profiles for higher energy electrons and protons are also analyzed using solutions that allow for the existence of significant particle sources as well as sinks. Possible implications for radial diffusion mechanisms in the Uranian radiation belts are discussed.
Energy Technology Data Exchange (ETDEWEB)
Shafirstein, Gal [Department of Otolaryngology, College of Medicine, University of Arkansas for Medical Sciences, 4301 W. Markham, 543, Little Rock, AR 72205 (United States); Moros, Eduardo G, E-mail: shafirsteingal@uams.edu [Division of Radiation Physics and Informatics, Department of Radiation Oncology, College of Medicine, University of Arkansas for Medical Sciences, 4301 W. Markham, 771, Little Rock, AR 72205 (United States)
2011-03-07
The aim of this work was to investigate the potential effect of sweat gland ducts (SGD) on specific absorption rate (SAR) and temperature distributions during mm-wave irradiation. High resolution electromagnetic and bio-heat transfer models of human skin with SGD were developed using a commercially available simulation software package (SEMCAD X(TM)). The skin model consisted of a 30 {mu}m stratum corneum, 350 {mu}m epidermis and papillary dermis (EPD) and 1000 {mu}m dermis. Five SGD of 60 {mu}m radius and 300 {mu}m height were embedded linearly with 370 {mu}m separation. A WR-10 waveguide positioned 20 {mu}m from the skin surface and delivering 94 GHz electromagnetic radiation was included in the model. Saline conductivity was assigned inside SGD. SAR and temperatures were computed with and without SGD. Despite their small scale, SAR was significantly higher within SGD than in the EPD without SGD. Without SGD, SAR and temperature maxima were in the dermis near EPD. With SGD, SAR maximum was inside SGD while temperature maximum moved to the EPD/stratum-corneum junction. Since the EPD participates actively in perception, the effect of SGD should be taken into account in nociceptive studies involving mm-waves. This research represents a significant step towards higher spatial resolution numerical modelling of the skin and shows that microstructures can play a significant role in mm-wave absorption and induced temperature distributions.
Shafirstein, Gal; Moros, Eduardo G.
2011-03-01
The aim of this work was to investigate the potential effect of sweat gland ducts (SGD) on specific absorption rate (SAR) and temperature distributions during mm-wave irradiation. High resolution electromagnetic and bio-heat transfer models of human skin with SGD were developed using a commercially available simulation software package (SEMCAD X™). The skin model consisted of a 30 µm stratum corneum, 350 µm epidermis and papillary dermis (EPD) and 1000 µm dermis. Five SGD of 60 µm radius and 300 µm height were embedded linearly with 370 µm separation. A WR-10 waveguide positioned 20 µm from the skin surface and delivering 94 GHz electromagnetic radiation was included in the model. Saline conductivity was assigned inside SGD. SAR and temperatures were computed with and without SGD. Despite their small scale, SAR was significantly higher within SGD than in the EPD without SGD. Without SGD, SAR and temperature maxima were in the dermis near EPD. With SGD, SAR maximum was inside SGD while temperature maximum moved to the EPD/stratum-corneum junction. Since the EPD participates actively in perception, the effect of SGD should be taken into account in nociceptive studies involving mm-waves. This research represents a significant step towards higher spatial resolution numerical modelling of the skin and shows that microstructures can play a significant role in mm-wave absorption and induced temperature distributions.
Implementation science: a role for parallel dual processing models of reasoning?
Directory of Open Access Journals (Sweden)
Phillips Paddy A
2006-05-01
Full Text Available Abstract Background A better theoretical base for understanding professional behaviour change is needed to support evidence-based changes in medical practice. Traditionally strategies to encourage changes in clinical practices have been guided empirically, without explicit consideration of underlying theoretical rationales for such strategies. This paper considers a theoretical framework for reasoning from within psychology for identifying individual differences in cognitive processing between doctors that could moderate the decision to incorporate new evidence into their clinical decision-making. Discussion Parallel dual processing models of reasoning posit two cognitive modes of information processing that are in constant operation as humans reason. One mode has been described as experiential, fast and heuristic; the other as rational, conscious and rule based. Within such models, the uptake of new research evidence can be represented by the latter mode; it is reflective, explicit and intentional. On the other hand, well practiced clinical judgments can be positioned in the experiential mode, being automatic, reflexive and swift. Research suggests that individual differences between people in both cognitive capacity (e.g., intelligence and cognitive processing (e.g., thinking styles influence how both reasoning modes interact. This being so, it is proposed that these same differences between doctors may moderate the uptake of new research evidence. Such dispositional characteristics have largely been ignored in research investigating effective strategies in implementing research evidence. Whilst medical decision-making occurs in a complex social environment with multiple influences and decision makers, it remains true that an individual doctor's judgment still retains a key position in terms of diagnostic and treatment decisions for individual patients. This paper argues therefore, that individual differences between doctors in terms of
Modeling the absorption spectra of Er3+ and Yb3+ in a phosphate glass
Gruber, John B.; Sardar, Dhiraj K.; Zandi, Bahram; Hutchinson, J. Andrew; Trussell, C. Ward
2003-10-01
Absorption spectra of Er3+ and Yb3+ ions, codopants in a phosphate glass, are reported at 8 K and at wavelengths between 350 and 1600 nm. Detailed structure appearing in the spectra, associated with individual multiplet states, 2S+1LJ, of Er3+(4f11) and Yb3+(4f13) is interpreted using a ligand-field coordination sphere model to characterize the microscopic environment surrounding the rare earth ions in multiple sites. Inhomogeneous broadening of the spectra is likely due to different configurations of PO4 tetrahedra clustered about a caged rare earth ion in the amorphous host. Similarity between the Er3+ spectrum in the glass and in the spectrum of single-crystal LiErP4O12, where Er3+ occupies sites of C2 symmetry, suggests that an averaged site symmetry of C2 is a reasonable approximation for Er3+ and Yb3+ ions in the phosphate glass. Calculated splitting of multiplet states by the ligand-field cluster model are compared with energy levels derived from the observed absorption peaks and well-defined shoulders. Inhomogeneous broadening of the spectra limit the precision in establishing the energy of the multiplet splittings, but the analysis is useful for modeling studies of the Er:Yb:phosphate glass as an eye-safe laser (1.53 μm). The splitting of the Yb3+(4f13)2FJ states is determined using parameters obtained from the Er3+ set by means of the three-parameter theory. No adjustments were made to the Yb3+ parameters that predict multiplet splittings in reasonable agreement with experimental data.
Directory of Open Access Journals (Sweden)
Risheng Ding
Full Text Available The dual-source Shuttleworth-Wallace model has been widely used to estimate and partition crop evapotranspiration (λET. Canopy stomatal conductance (Gsc, an essential parameter of the model, is often calculated by scaling up leaf stomatal conductance, considering the canopy as one single leaf in a so-called "big-leaf" model. However, Gsc can be overestimated or underestimated depending on leaf area index level in the big-leaf model, due to a non-linear stomatal response to light. A dual-leaf model, scaling up Gsc from leaf to canopy, was developed in this study. The non-linear stomata-light relationship was incorporated by dividing the canopy into sunlit and shaded fractions and calculating each fraction separately according to absorbed irradiances. The model includes: (1 the absorbed irradiance, determined by separately integrating the sunlit and shaded leaves with consideration of both beam and diffuse radiation; (2 leaf area for the sunlit and shaded fractions; and (3 a leaf conductance model that accounts for the response of stomata to PAR, vapor pressure deficit and available soil water. In contrast to the significant errors of Gsc in the big-leaf model, the predicted Gsc using the dual-leaf model had a high degree of data-model agreement; the slope of the linear regression between daytime predictions and measurements was 1.01 (R2 = 0.98, with RMSE of 0.6120 mm s-1 for four clear-sky days in different growth stages. The estimates of half-hourly λET using the dual-source dual-leaf model (DSDL agreed well with measurements and the error was within 5% during two growing seasons of maize with differing hydrometeorological and management strategies. Moreover, the estimates of soil evaporation using the DSDL model closely matched actual measurements. Our results indicate that the DSDL model can produce more accurate estimation of Gsc and λET, compared to the big-leaf model, and thus is an effective alternative approach for estimating and
Zhao, Jingkai; Xia, Yinfeng; Li, Meifang; Li, Sujing; Li, Wei; Zhang, Shihan
2016-08-16
The chemical absorption-biological reduction (CABR) integrated process is regarded as a promising technology for NOx removal from flue gas. To advance the scale-up of the CABR process, a mathematic model based on mass transfer with reaction in the gas, liquid, and biofilm was developed to simulate and predict the NOx removal by the CABR system in a biotrickling filter. The developed model was validated by the experimental results and subsequently was used to predict the system performance under different operating conditions, such as NO and O2 concentration and gas and liquid flow rate. NO distribution in the gas phase along the biotrickling filter was also modeled and predicted. On the basis of the modeling results, the liquid flow rate and total iron concentration were optimized to achieve >90% NO removal efficiency. Furthermore, sensitivity analysis of the model revealed that the performance of the CABR process was controlled by the bioreduction activity of Fe(III)EDTA. This work will provide the guideline for the design and operation of the CABR process in the industrial application.
Made-to-measure galaxy modelling utilising absorption line strength data
Long, Richard
2016-01-01
We enhance the Syer & Tremaine made-to-measure (M2M) particle method of stellar dynamical modelling to model simultaneously both kinematic data and absorption line strength data thus creating a `chemo-M2M' modelling scheme. We apply the enhanced method to four galaxies (NGC 1248, NGC 3838, NGC 4452, NGC 4551) observed using the SAURON integral-field spectrograph as part of the ATLAS3D programme. We are able to reproduce successfully the 2D line strength data achieving mean chi^2 per bin values of ~1 with >95\\% of particles having converged weights. Because M2M uses a 3D particle system, we are also able to examine the underlying 3D line strength distributions. The extent to which these distributions are plausible representations of real galaxies requires further consideration. Overall we consider the modelling exercise to be a promising first step in developing a `chemo-M2M' modelling system and in understanding some of the issues to be addressed. Whilst the made-to-measure techniques developed have been ...
Wang, Wei; Ma, Wanbiao; Lai, Xiulan
2017-01-01
From a biological perspective, a diffusive virus infection dynamic model with nonlinear functional response, absorption effect and chemotaxis is proposed. In the model, the diffusion of virus consists of two parts, the random diffusion and the chemotactic movement. The chemotaxis flux of virus depends not only on their own density, but also on the density of infected cells, and the density gradient of infected cells. The well posedness of the proposed model is deeply investigated. For the proposed model, the linear stabilities of the infection-free steady state E0 and the infection steady state E* are extensively performed. We show that the threshold dynamics can be expressed by the basic reproduction number R0 of the model without chemotaxis. That is, the infection-free steady state E0 is globally asymptotically stable if R0 virus is uniformly persistent if R0 > 1. In addition, we use the cross iteration method and the Schauder's fixed point theorem to prove the existence of travelling wave solutions connecting the infection-free steady state E0 and the infection steady state E* by constructing a pair of upper-lower solutions. At last, numerical simulations are presented to confirm theoretical findings.
Jenni, A.; Gimmi, T.; Alt-Epping, P.; Mäder, U.; Cloet, V.
2017-06-01
Interactions between concrete and clays are driven by the strong chemical gradients in pore water and involve mineral reactions in both materials. In the context of a radioactive waste repository, these reactions may influence safety-relevant clay properties such as swelling pressure, permeability or radionuclide retention. Interfaces between ordinary Portland cement and Opalinus Clay show weaker, but more extensive chemical disturbance compared to a contact between low-pH cement and Opalinus Clay. As a consequence of chemical reactions porosity changes occur at cement-clay interfaces. These changes are stronger and may lead to complete pore clogging in the case of low-pH cements. The prediction of pore clogging by reactive transport simulations is very sensitive to the magnitude of diffusive solute fluxes, cement clinker chemistry, and phase reaction kinetics. For instance, the consideration of anion-depleted porosity in clays substantially influences overall diffusion and pore clogging at interfaces. A new concept of dual porosity modelling approximating Donnan equilibrium is developed and applied to an ordinary Portland cement - Opalinus Clay interface. The model predictions are compared with data from the cement-clay interaction (CI) field experiment in the Mt Terri underground rock laboratory (Switzerland), which represent 5 y of interaction. The main observations such as the decalcification of the cement at the interface, the Mg enrichment in the clay detached from the interface, and the S enrichment in the cement detached from the interface, are qualitatively predicted by the new model approach. The model results reveal multiple coupled processes that create the observed features. The quantitative agreement of modelled and measured data can be improved if uncertainties of key input parameters (tortuosities, reaction kinetics, especially of clay minerals) can be reduced.
Modeling Shock Train Leading Edge Detection in Dual-Mode Scramjets
Ladeinde, Foluso; Lou, Zhipeng; Li, Wenhai
2016-11-01
The objective of this study is to accurately model the detection of shock train leading edge (STLE) in dual-mode scramjet (DMSJ) engines intended for hypersonic flight in air-breathing propulsion systems. The associated vehicles have applications in military warfare and intelligence, and there is commercial interest as well. Shock trains are of interest because they play a significant role in the inability of a DMSJ engine to develop the required propulsive force. The experimental approach to STLE detection has received some attention; as have numerical calculations. However, virtually all of the numerical work focus on mechanically- (i.e., pressure-) generated shock trains, which are much easier to model relative to the phenomenon in the real system where the shock trains are generated by combustion. A focus on combustion, as in the present studies, enables the investigation of the effects of equivalence ratio, which, together with the Mach number, constitutes an important parameter determining mode transition. The various numerical approaches implemented in our work will be reported, with result comparisons to experimental data. The development of an STLE detection procedure in an a priori manner will also be discussed.
Model based design of an intercooled dual stage sliding vane rotary compressor system
Cipollone, Roberto; Bianchi, Giuseppe; Di Battista, Davide; Contaldi, Giulio; Murgia, Stefano
2015-08-01
Energy saving is currently one of the most important driving factors for innovation all over the world. With reference to global electricity consumptions, electrical energy for compressed air production accounts for 4-5%. Among the rotary compressor technologies, Sliding Vane Rotary Compressors (SVRC) are characterized by noteworthy specific energy consumptions and demonstrated an unforeseen energy saving potential thanks to some intrinsic features specifically related to this kind of machines. The paper presents a further reduction strategy to lower energy consumptions in compressed air systems using SVRCs that relies on the combination of the recent use of a pressure swirled oil injection technology and a dual stage intercooling. The synergy between technologies already mature approaches to the lowest energy consumption and candidates SVRCs as superior machines in the energy context. The saving potential compared to the technology at the state of the art was evaluated thanks to a comprehensive mathematical modeling of the two compressor sections and the intercooling heat exchanger and fan. Results showed a reduction of the electrical power required to drive the compressor system up to 9.5%. The overall approach represents a model-based design for a new machine which is under development.
Modeling and dynamic properties of dual-chamber solid and liquid mixture vibration isolator
Li, F. S.; Chen, Q.; Zhou, J. H.
2016-07-01
The dual-chamber solid and liquid mixture (SALiM) vibration isolator, mainly proposed for vibration isolation of heavy machines with low frequency, consists of four principle parts: SALiM working media including elastic elements and incompressible oil, multi-layers bellows container, rigid reservoir and the oil tube connecting the two vessels. The isolation system under study is governed by a two-degrees-of-freedom (2-DOF) nonlinear equation including quadratic damping. Simplifying the nonlinear damping into viscous damping, the equivalent stiffness and damping model is derived from the equation for the response amplitude. Theoretical analysis and numerical simulation reveal that the isolator's stiffness and damping have multiple properties with different parameters, among which the effects of exciting frequency, vibrating amplitude, quadratic damping coefficient and equivalent stiffness of the two chambers on the isolator's dynamics are discussed in depth. Based on the boundary characteristics of stiffness and damping and the main causes for stiffness hardening effect, improvement strategies are proposed to obtain better dynamic properties. At last, experiments were implemented and the test results were generally consistent with the theoretical ones, which verified the reliability of the nonlinear dynamic model.
Predator-prey model for the self-organization of stochastic oscillators in dual populations
Moradi, Sara; Anderson, Johan; Gürcan, Ozgur D.
A predator-prey model of dual populations with stochastic oscillators is presented. A linear cross-coupling between the two populations is introduced that follows the coupling between the motions of a Wilberforce pendulum in two dimensions: one in the longitudinal and the other in torsional plain. Within each population a Kuramoto type competition between the phases is assumed. Thus, the synchronization state of the whole system is controlled by these two types of competitions. The results of the numerical simulations show that by adding the linear cross-coupling interactions predator-prey oscillations between the two populations appear which results in self-regulation of the system by a transfer of synchrony between the two populations. The model represents several important features of the dynamical interplay between the drift wave and zonal flow turbulence in magnetically confined plasmas, and a novel interpretation of the coupled dynamics of drift wave-zonal flow turbulence using synchronization of stochastic oscillator is discussed. Sara Moradi has benefited from a mobility grant funded by the Belgian Federal Science Policy Office and the MSCA of the European Commission (FP7-PEOPLE-COFUND-2008 nº 246540).
Modeling the Material Flow and Heat Transfer in Reverse Dual-Rotation Friction Stir Welding
Shi, L.; Wu, C. S.; Liu, H. J.
2014-08-01
Reverse dual-rotation friction stir welding (RDR-FSW) is a novel modification of conventional friction stir welding (FSW) process. During the RDR-FSW process, the tool pin and the assisted shoulder are separated and rotate with opposite direction independently, so that there are two material flows with reverse direction. The material flow and heat transfer in RDR-FSW have significant effects on the microstructure and properties of the weld joint. A 3D model is developed to quantitatively analyze the effects of the separated tool pin and the assisted shoulder which rotate in reverse direction on the material flow and heat transfer during RDR-FSW process. Numerical simulation is conducted to predict the temperature profile, material flow field, streamlines, strain rate, and viscosity distributions near the tool. The calculated results show that as the rotation speed of the tool pin increases, the temperature near the tool gets higher, the zone with higher temperature expands, and approximately symmetric temperature distribution is obtained near the tool. Along the workpiece thickness direction, the calculated material flow velocity and its layer thickness near the tool get lowered because the effect of the shoulder is weakened as the distance away from the top surface increases. The model is validated by comparing the predicted values of peak temperature at some typical locations with the experimentally measured ones.
Directory of Open Access Journals (Sweden)
Junhai Ma
2016-01-01
Full Text Available In order to explore how the manufacturers make decisions when two manufacturers compete for local advertising investment, we examine two noncooperative models (Stackelberg and Nash game and propose a cost sharing contract to investigate channel competition of dual-channel supply chain. The dominant power between manufacturer and retailer and the effect of channel competition strategy on price are mainly discussed. In addition, dynamic system concepts are integrated into Stackelberg game model based on bounded rational mechanism. We analyze the local stability and find that the stability level of the dual-channel supply chains depends crucially on the price adjustment speed, the level of demand uncertainty, and the risk preference. The outcome shows that, under the master-slave game model, the profits of manufacturers are greater than that under decentralized decision-making mode, and the profits of retailers under master-slave game model are less than that under decentralized decision-making mode. The profits of manufacturers and retailers in the stable region are greater than that in unstable region. Finally, the delay feedback control method is utilized and effectively controls the chaotic behavior of dual-channel supply chain model. The results have theoretical and practical significance for the game models in terms of advertising and price competition.
Yellowhair, Julius; Ho, Clifford K.; Ortega, Jesus D.; Christian, Joshua M.; Andraka, Charles E.
2015-09-01
Concentrating solar power receivers are comprised of panels of tubes arranged in a cylindrical or cubical shape on top of a tower. The tubes contain heat-transfer fluid that absorbs energy from the concentrated sunlight incident on the tubes. To increase the solar absorptance, black paint or a solar selective coating is applied to the surface of the tubes. However, these coatings degrade over time and must be reapplied, which reduces the system performance and increases costs. This paper presents an evaluation of novel receiver shapes and geometries that create a light-trapping effect, thereby increasing the effective solar absorptance and efficiency of the solar receiver. Several prototype shapes were fabricated from Inconel 718 and tested in Sandia's solar furnace at an irradiance of ~30 W/cm2. Photographic methods were used to capture the irradiance distribution on the receiver surfaces. The irradiance profiles were compared to results from raytracing models. The effective solar absorptance was also evaluated using the ray-tracing models. Results showed that relative to a flat plate, the new geometries could increase the effective solar absorptance from 86% to 92% for an intrinsic material absorptance of 86%, and from 60% to 73% for an intrinsic material absorptance of 60%.
A modeling and simulation study of siderophore mediated antagonism in dual-species biofilms
Directory of Open Access Journals (Sweden)
Collinson Shannon
2009-12-01
Full Text Available Abstract Background Several bacterial species possess chelation mechanisms that allow them to scavenge iron from the environment under conditions of limitation. To this end they produce siderophores that bind the iron and make it available to the cells later on, while rendering it unavailable to other organisms. The phenomenon of siderophore mediated antagonism has been studied to some extent for suspended populations where it was found that the chelation ability provides a growth advantage over species that do not have this possibility. However, most bacteria live in biofilm communities. In particular Pseudomonas fluorescens and Pseudomonas putida, the species that have been used in most experimental studies of the phenomenon, are known to be prolific biofilm formers, but only very few experimental studies of iron chelation have been published to date for the biofilm setting. We address this question in the present study. Methods Based on a previously introduced model of iron chelation and an existing model of biofilm growth we formulate a model for iron chelation and competition in dual species biofilms. This leads to a highly nonlinear system of partial differential equations which is studied in computer simulation experiments. Conclusions (i Siderophore production can give a growth advantage also in the biofilm setting, (ii diffusion facilitates and emphasizes this growth advantage, (iii the magnitude of the growth advantage can also depend on the initial inoculation of the substratum, (iv a new mass transfer boundary condition was derived that allows to a priori control the expect the expected average thickness of the biofilm in terms of the model parameters.
Dual-Source Linear Energy Prediction (LINE-P) Model in the Context of WSNs.
Ahmed, Faisal; Tamberg, Gert; Le Moullec, Yannick; Annus, Paul
2017-07-20
Energy harvesting technologies such as miniature power solar panels and micro wind turbines are increasingly used to help power wireless sensor network nodes. However, a major drawback of energy harvesting is its varying and intermittent characteristic, which can negatively affect the quality of service. This calls for careful design and operation of the nodes, possibly by means of, e.g., dynamic duty cycling and/or dynamic frequency and voltage scaling. In this context, various energy prediction models have been proposed in the literature; however, they are typically compute-intensive or only suitable for a single type of energy source. In this paper, we propose Linear Energy Prediction "LINE-P", a lightweight, yet relatively accurate model based on approximation and sampling theory; LINE-P is suitable for dual-source energy harvesting. Simulations and comparisons against existing similar models have been conducted with low and medium resolutions (i.e., 60 and 22 min intervals/24 h) for the solar energy source (low variations) and with high resolutions (15 min intervals/24 h) for the wind energy source. The results show that the accuracy of the solar-based and wind-based predictions is up to approximately 98% and 96%, respectively, while requiring a lower complexity and memory than the other models. For the cases where LINE-P's accuracy is lower than that of other approaches, it still has the advantage of lower computing requirements, making it more suitable for embedded implementation, e.g., in wireless sensor network coordinator nodes or gateways.
What makes us think? A three-stage dual-process model of analytic engagement.
Pennycook, Gordon; Fugelsang, Jonathan A; Koehler, Derek J
2015-08-01
The distinction between intuitive and analytic thinking is common in psychology. However, while often being quite clear on the characteristics of the two processes ('Type 1' processes are fast, autonomous, intuitive, etc. and 'Type 2' processes are slow, deliberative, analytic, etc.), dual-process theorists have been heavily criticized for being unclear on the factors that determine when an individual will think analytically or rely on their intuition. We address this issue by introducing a three-stage model that elucidates the bottom-up factors that cause individuals to engage Type 2 processing. According to the model, multiple Type 1 processes may be cued by a stimulus (Stage 1), leading to the potential for conflict detection (Stage 2). If successful, conflict detection leads to Type 2 processing (Stage 3), which may take the form of rationalization (i.e., the Type 1 output is verified post hoc) or decoupling (i.e., the Type 1 output is falsified). We tested key aspects of the model using a novel base-rate task where stereotypes and base-rate probabilities cued the same (non-conflict problems) or different (conflict problems) responses about group membership. Our results support two key predictions derived from the model: (1) conflict detection and decoupling are dissociable sources of Type 2 processing and (2) conflict detection sometimes fails. We argue that considering the potential stages of reasoning allows us to distinguish early (conflict detection) and late (decoupling) sources of analytic thought. Errors may occur at both stages and, as a consequence, bias arises from both conflict monitoring and decoupling failures.
COMPARISON OF EXPERIMENTAL RESULTS TO CFD MODELS FOR BLENDING IN A TANK USING DUAL OPPOSING JETS
Energy Technology Data Exchange (ETDEWEB)
Leishear, R.
2011-08-07
Research has been completed in a pilot scale, eight foot diameter tank to investigate blending, using a pump with dual opposing jets. The jets re-circulate fluids in the tank to promote blending when fluids are added to the tank. Different jet diameters and different horizontal and vertical orientations of the jets were investigated. In all, eighty five tests were performed both in a tank without internal obstructions and a tank with vertical obstructions similar to a tube bank in a heat exchanger. These obstructions provided scale models of several miles of two inch diameter, serpentine, vertical cooling coils below the liquid surface for a full scale, 1.3 million gallon, liquid radioactive waste storage tank. Two types of tests were performed. One type of test used a tracer fluid, which was homogeneously blended into solution. Data were statistically evaluated to determine blending times for solutions of different density and viscosity, and the blending times were successfully compared to computational fluid dynamics (CFD) models. The other type of test blended solutions of different viscosity. For example, in one test a half tank of water was added to a half tank of a more viscous, concentrated salt solution. In this case, the fluid mechanics of the blending process was noted to significantly change due to stratification of fluids. CFD models for stratification were not investigated. This paper is the fourth in a series of papers resulting from this research (Leishear, et.al. [1- 4]), and this paper documents final test results, statistical analysis of the data, a comparison of experimental results to CFD models, and scale-up of the results to a full scale tank.
Multi-objective optimisation of a vehicle energy absorption structure based on surrogate model
Institute of Scientific and Technical Information of China (English)
谢素超; 周辉
2014-01-01
In order to optimize the crashworthy characteristic of energy-absorbing structures, the surrogate models of specific energy absorption (SEA) and ratio of SEA to initial peak force (REAF) with respect to the design parameters were respectively constructed based on surrogate model optimization methods (polynomial response surface method (PRSM) and Kriging method (KM)). Firstly, the sample data were prepared through the design of experiment (DOE). Then, the test data models were set up based on the theory of surrogate model, and the data samples were trained to obtain the response relationship between the SEA & REAF and design parameters. At last, the structure optimal parameters were obtained by visual analysis and genetic algorithm (GA). The results indicate that the KM, where the local interpolation method is used in Gauss correlation function, has the highest fitting accuracy and the structure optimal parameters are obtained as: the SEA of 29.8558 kJ/kg (corresponding toa=70 mm andt= 3.5 mm) and REAF of 0.2896 (corresponding toa=70 mm andt=1.9615 mm). The basis function of the quartic PRSM with higher order than that of the quadratic PRSM, and the mutual influence of the design variables are considered, so the fitting accuracy of the quartic PRSM is higher than that of the quadratic PRSM.
Larkeche, O.; Meniai, A.-H.; Cachot, T.
2012-06-01
The present study concerns the cycle performance modelling of a particular configuration of an absorption refrigeration machine based on phase separation as well as development of a strategy for computer aided design of absorbents. The model uses predictive methods based on the group contribution concept for the computation of the thermodynamic phase equilibria involved such as liquid-liquid and vapour-liquid as well as enthalpy-concentration diagrams. The proposed absorbents computer-aided design strategy is based on the exploration of a number of structural group combinations obtained from a selected set of functional groups, according to the chemistry laws. The model was tested on four different absorbent-refrigerant pairs reported in the literature, namely (benzyl ethyl amine-glycerol), (water-hexanoic acid), (water-2-hexanone) and (water-ethyl propionate) as well as on pairs where the absorbent compound is generated by the proposed absorbent design strategy and the refrigerant is water. The results show that quite good values of the coefficient of performance (COP) can be obtained, indicating that this cycle configuration is promising and energetically efficient, mainly due to hardware savings, i.e. absence of condenser. However, other working fluid combinations have to be tested using the proposed model.
Directory of Open Access Journals (Sweden)
Bogdan Woźniak
2005-12-01
Full Text Available Model spectra of mass-specific absorption coefficients a*OM(λ were established for 26 naturally occurring organic substances or their possible mixtures, capable of forming particulate organic matter (POM in the sea. An algorithm was constructed, and the set of spectra of a*OM(λ was used to determine the spectra of the imaginary part of the complex refractive index n'p(λ characteristic of different physical types and chemical classes of POM commonly occurring in sea water. The variability in the spectra and absolute values of n'p for the various model classes and types of POM was shown to range over many orders of magnitude. This implies that modelling the optical properties of sea water requires a multi-component approach that takes account of the numerous living and non-living fractions of POM, each of which has a different value of n'p.
Gaudreault, François; Drolet, Pierre; Fallaha, Michel; Varin, France
2012-12-01
Because of its slow systemic absorption and flip-flop kinetics, ropivacaine's pharmacokinetics after a peripheral nerve block has never been thoroughly characterized. The purpose of this study was to develop a population pharmacokinetic model for ropivacaine after loco-regional administration and to identify patient characteristics that may influence the drug's absorption and disposition. Frequent plasma samples were taken up to 93 h after a 100 mg dose given as femoral block for postoperative analgesia in 15 orthopedic patients. Ropivacaine plasma concentration-time data were analyzed using a nonlinear mixed effects modeling method. A one-compartment model with parallel inverse Gaussian and time-dependent inputs best described ropivacaine plasma concentration-time curves. Ropivacaine systemic absorption was characterized by a rapid phase (mean absorption time of 25 ± 4.8 min) followed by a much slower phase (half-life of 3.9 ± 0.65 h). Interindividual variability (IIV) for these parameters, 58 and 9 %, indicated that the initial absorption phase was more variable. The apparent volume of distribution (V/F = 77.2 ± 11.5 L, IIV = 26 %) was influenced by body weight (Δ 1.49 % per kg change) whereas the absorption rate constant (slower phase) of ropivacaine was affected by age (Δ 2.25 % per year change). No covariate effects were identified for the apparent clearance of the drug (CL/F =10.8 ± 1.0 L/h, 34 IIV = 34 %). These findings support our hypothesis that modeling a complex systemic absorption directly from plasma concentration-time curves exhibiting flip-flop kinetics is possible. Only the age-effect was considered as relevant for possible dosing adjustments.
Blöcher, Johanna; Kuraz, Michal
2017-04-01
In this contribution we propose implementations of the dual permeability model with different inter-domain exchange descriptions and metaheuristic optimization algorithms for parameter identification and mesh optimization. We compare variants of the coupling term with different numbers of parameters to test if a reduction of parameters is feasible. This can reduce parameter uncertainty in inverse modeling, but also allow for different conceptual models of the domain and matrix coupling. The different variants of the dual permeability model are implemented in the open-source objective library DRUtES written in FORTRAN 2003/2008 in 1D and 2D. For parameter identification we use adaptations of the particle swarm optimization (PSO) and Teaching-learning-based optimization (TLBO), which are population-based metaheuristics with different learning strategies. These are high-level stochastic-based search algorithms that don't require gradient information or a convex search space. Despite increasing computing power and parallel processing, an overly fine mesh is not feasible for parameter identification. This creates the need to find a mesh that optimizes both accuracy and simulation time. We use a bi-objective PSO algorithm to generate a Pareto front of optimal meshes to account for both objectives. The dual permeability model and the optimization algorithms were tested on virtual data and field TDR sensor readings. The TDR sensor readings showed a very steep increase during rapid rainfall events and a subsequent steep decrease. This was theorized to be an effect of artificial macroporous envelopes surrounding TDR sensors creating an anomalous region with distinct local soil hydraulic properties. One of our objectives is to test how well the dual permeability model can describe this infiltration behavior and what coupling term would be most suitable.
Fotaki, Nikoletta; Klein, Sandra
2013-11-04
Proton pump inhibitors (PPIs) are potent gastric acid suppressing agents and are among the most widely sold drugs in the world. However, even though these antisecretory agents are regarded as safe, they can alter the pharmacokinetics of coadministered drugs. Due to the suppression of gastric acid secretion, they can significantly alter the intragastric pH conditions and are thus likely to affect the bioavailability of coadministered drugs requiring an acidic gastric environment for dissolution and subsequent absorption. Among these drugs can be found itraconazole, a poorly soluble triazole-type antifungal compound. Based on observations reported in the literature, gastric pH alterations due to the coadministration of PPIs or acidic beverages can significantly decrease (PPI) or increase (e.g., Coca-Cola) the bioavailability of this compound. In the present work we estimated the fraction of itraconazole that can be absorbed (fabs) from Sporanox capsules or an itraconazole-HBenBCD complex formulation after oral administration with and without coadministration of a PPI or an acidic (carbonated) beverage. For this purpose, the sensitivity of the two formulations toward the impact of various gastric variations (pH, volume, and emptying rate) as they can result from such administration conditions was studied using solubility and dissolution experiments and a physiologically based absorption model. Simulating coadministration of the two formulations with a PPI resulted in a significant (∼ 10-fold) decrease in itraconazole fabs, indicating the pH to be essential for in vivo dissolution and subsequent absorption. The fabs of itraconazole after coadministration of an acidic beverage (Coca-Cola) was far lower than the fabs obtained for itraconazole alone and did not support the observations reported in the literature. These results clearly indicate that in contrast to PPIs, which seem to affect itraconazole bioavailability mainly via intragastric pH changes, coadministered
Rehman, Khalil Ur; Malik, M. Y.; Salahuddin, T.; Naseer, M.
2016-07-01
Present work is made to study the effects of double stratified medium on the mixed convection boundary layer flow of Eyring-Powell fluid induced by an inclined stretching cylinder. Flow analysis is conceded in the presence of heat generation/absorption. Temperature and concentration are supposed to be higher than ambient fluid across the surface of cylinder. The arising flow conducting system of partial differential equations is primarily transformed into coupled non-linear ordinary differential equations with the aid of suitable transformations. Numerical solutions of resulting intricate non-linear boundary value problem are computed successfully by utilizing fifth order Runge-Kutta algorithm with shooting technique. The effect logs of physical flow controlling parameters on velocity, temperature and concentration profiles are examined graphically. Further, numerical findings are obtained for two distinct cases namely, zero (plate) and non-zero (cylinder) values of curvature parameter and the behaviour are presented through graphs for skin-friction coefficient, Nusselt number and Sherwood number. The current analysis is validated by developing comparison with previously published work, which sets a benchmark of quality of numerical approach.
Wang, Jun-jun; Liao, Xiao-huan; Ye, Min; Chen, Yong
2010-09-01
To study the effect of liquiritin (Liq) on the transport of strychnine (Str) in Caco-2 cell monolayer model, the transport parameters of Str, such as apparent permeability coefficient (P app (B-->A) and P app (A-->B)) and cumulative transport amount (TRcum), were determined and comparatively analyzed when Str was used solely and co-used with Liq. The effect of drug concentrations, conveying times, P-glycoprotein (P-gp) inhibitor verapamil and conveying liquor pH values on the transport of Str were also investigated. The results indicated that the absorption of Str in Caco-2 cell monolayer model was well and the passive transference was the main intestinal absorption mechanism of Str in the Caco-2 monolayer model, along with the excretion action mediated by P-gp. Liq enhanced the absorption of Str. Meanwhile, conveying liquor pH value had significant influence on the excretion transport of Str.
Directory of Open Access Journals (Sweden)
Alessandro Settimi
2014-01-01
Full Text Available The present paper conducts a scientific review on ionospheric absorption, extrapolating the research prospects of a complex eikonal model for one-layer ionosphere. As regards the scientific review, here a quasi-longitudinal (QL approximation for nondeviative absorption is deduced which is more refined than the corresponding equation reported by Davies (1990. As regards the research prospects, a complex eikonal model for one-layer ionosphere is analyzed in depth here, already discussed by Settimi et al. (2013. A simple formula is deduced for a simplified problem. A flat, layered ionospheric medium is considered, without any horizontal gradient. The authors prove that the QL nondeviative amplitude absorption according to the complex eikonal model is more accurate than Rawer’s theory (1976 in the range of middle critical frequencies.
Le Pichon, Claire E; Meilandt, William J; Dominguez, Sara; Solanoy, Hilda; Lin, Han; Ngu, Hai; Gogineni, Alvin; Sengupta Ghosh, Arundhati; Jiang, Zhiyu; Lee, Seung-Hye; Maloney, Janice; Gandham, Vineela D; Pozniak, Christine D; Wang, Bei; Lee, Sebum; Siu, Michael; Patel, Snahel; Modrusan, Zora; Liu, Xingrong; Rudhard, York; Baca, Miriam; Gustafson, Amy; Kaminker, Josh; Carano, Richard A D; Huang, Eric J; Foreman, Oded; Weimer, Robby; Scearce-Levie, Kimberly; Lewcock, Joseph W
2017-08-16
Hallmarks of chronic neurodegenerative disease include progressive synaptic loss and neuronal cell death, yet the cellular pathways that underlie these processes remain largely undefined. We provide evidence that dual leucine zipper kinase (DLK) is an essential regulator of the progressive neurodegeneration that occurs in amyotrophic lateral sclerosis and Alzheimer's disease. We demonstrate that DLK/c-Jun N-terminal kinase signaling was increased in mouse models and human patients with these disorders and that genetic deletion of DLK protected against axon degeneration, neuronal loss, and functional decline in vivo. Furthermore, pharmacological inhibition of DLK activity was sufficient to attenuate the neuronal stress response and to provide functional benefit even in the presence of ongoing disease. These findings demonstrate that pathological activation of DLK is a conserved mechanism that regulates neurodegeneration and suggest that DLK inhibition may be a potential approach to treat multiple neurodegenerative diseases. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.
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Shikhar Gupta
2014-01-01
Full Text Available In this study, we have employed in silico methodology combining double pharmacophore based screening, molecular docking, and ADME/T filtering to identify dual binding site acetylcholinesterase inhibitors that can preferentially inhibit acetylcholinesterase and simultaneously inhibit the butyrylcholinesterase also but in the lesser extent than acetylcholinesterase. 3D-pharmacophore models of AChE and BuChE enzyme inhibitors have been developed from xanthostigmine derivatives through HypoGen and validated using test set, Fischer’s randomization technique. The best acetylcholinesterase and butyrylcholinesterase inhibitors pharmacophore hypotheses Hypo1_A and Hypo1_B, with high correlation coefficient of 0.96 and 0.94, respectively, were used as 3D query for screening the Zinc database. The screened hits were then subjected to the ADME/T and molecular docking study to prioritise the compounds. Finally, 18 compounds were identified as potential leads against AChE enzyme, showing good predicted activities and promising ADME/T properties.
Modeling the effectiveness of U(VI) biomineralization in dual-porosity porous media
Rotter, B. E.; Barry, D. A.; Gerhard, J. I.; Small, J. S.
2011-05-01
SummaryUranium contamination is a serious environmental concern worldwide. Recent attention has focused on the in situ immobilization of uranium by stimulation of dissimilatory metal-reducing bacteria (DMRB). The objective of this work was to investigate the effectiveness of this approach in heterogeneous and structured porous media, since such media may significantly affect the geochemical and microbial processes taking place in contaminated sites, impacting remediation efficiency during biostimulation. A biogeochemical reactive transport model was developed for uranium remediation by immobile-region-resident DMRB in two-region porous media. Simulations were used to investigate the parameter sensitivities of the system over wide-ranging geochemical, microbial and groundwater transport conditions. The results suggest that optimal biomineralization is generally likely to occur when the regional mass transfer timescale is less than one-thirtieth the value of the volumetric flux timescale, and/or the organic carbon fermentation timescale is less than one-thirtieth the value of the advective timescale, and/or the mobile region porosity ranges between equal to and four times the immobile region porosity. Simulations including U(VI) surface complexation to Fe oxides additionally suggest that, while systems exhibiting U(VI) surface complexation may be successfully remediated, they are likely to display different degrees of remediation efficiency over varying microbial efficiency, mobile-immobile mass transfer, and porosity ratios. Such information may aid experimental and field designs, allowing for optimized remediation in dual-porosity (two-region) biostimulated DMRB U(VI) remediation schemes.
Energy Technology Data Exchange (ETDEWEB)
Zhou, Jing [Universiyt of Utah; Huang, Hai [Idaho National Lab. (INL), Idaho Falls, ID (United States); Deo, Milind
2015-10-01
The interaction between hydraulic fractures (HF) and natural fractures (NF) will lead to complex fracture networks due to the branching and merging of natural and hydraulic fractures in unconventional reservoirs. In this paper, a newly developed hydraulic fracturing simulator based on discrete element method is used to predict the generation of complex fracture network in the presence of pre-existing natural fractures. By coupling geomechanics and reservoir flow within a dual lattice system, this simulator can effectively capture the poro-elastic effects and fluid leakoff into the formation. When HFs are intercepting single or multiple NFs, complex mechanisms such as direct crossing, arresting, dilating and branching can be simulated. Based on the model, the effects of injected fluid rate and viscosity, the orientation and permeability of NFs and stress anisotropy on the HF-NF interaction process are investigated. Combined impacts from multiple parameters are also examined in the paper. The numerical results show that large values of stress anisotropy, intercepting angle, injection rate and viscosity will impede the opening of NFs.
Estimation of dual phase lag model parameters using the evolutionary algorithms
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B. Mochnacki
2011-07-01
Full Text Available Generalization of Fourier law, in particular the introduction of two ‘delay times’ (relaxation time q and thermalization time T leads to thenew form of energy equation called the dual-phase-lag model (DPLM. This equation should be applied in a case of microscale heat transfermodeling. In particular, DPLM constitutes a good approximation of thermal processes which are characterized by extremely short duration(e.g. ultrafast laser pulse, extreme temperature gradients and geometrical features of domain considered (e.g. thin metal film. The aim ofconsiderations presented in this paper is the identification of two above mentioned positive constants q, T. They correspond to the relaxationtime, which is the mean time for electrons to change their energy states and the thermalization time, which is the mean time required forc(TTl G(TT electrons and lattice to reach equilibrium. In this paper the DPlLMlequation ise appllied for analysis of thermal processes proceeding in a thint metal film subjected to a laser beam. At the stage of computations connected with the identification problem solution the evolutionaryalgorithms are used. To solve the problem the additional information concerning the transient temperature distribution on a metal film surface is assumed to be known.
Dual-Model Reverse CKF Algorithm in Cooperative Navigation for USV
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Bo Xu
2014-01-01
Full Text Available As one of the most promising research directions, cooperative location with high precision and low-cost IMU is becoming an emerging research topic in many positioning fields. Low-cost MEMS/DVL is a preferred solution for dead-reckoning in multi-USV cooperative network. However, large misalignment angles and large gyro drift coexist in low-cost MEMS that leads to the poor observability. Based on cubature Kalman filter (CKF algorithm that has access to high accuracy and relative small computation, dual-model filtering scheme is proposed. It divides the whole process into two subsections that cut off the coupling relations and improve the observability of MEMS errors: it first estimates large misalignment angle and then estimates the gyro drift. Furthermore, to improve the convergence speed of large misalignment angle estimated in the first subsection, “time reversion” concept is introduced. It uses a short period time to forward and backward several times to improve convergence speed effectively. Finally, simulation analysis and experimental verification is conducted. Simulation and experimental results show that the algorithm can effectively improve the cooperative navigation performance.