P-V-T behaviour of hard body fluids. Theory and experiment

1986 ◽  
Vol 51 (11) ◽  
pp. 2301-2432 ◽  
Author(s):  
Tomáš Boublík ◽  
Ivo Nezbeda
Keyword(s):  
Virial Coefficients ◽  
Numerical Data ◽  
Body Fluids ◽  
Simulation Results ◽  
The Individual ◽  
Compressibility Factors ◽  
Theory And Experiment

All available numerical data on virial coefficients along with simulation results for the compressibility factors of hard body fluids and their mixtures have been compiled. Practically all relevant theories for these fluids (lattice theories, specific methods for discontinuous potentials, integral and integro-differential theories, expansion and resummation techniques, as well as perturbation and conformal theories) are reviewed and their results are compared with the data. The individual methods are critically assessed and their advantages and limits are discussed.

Off-line classification of Polish vowel spectra using artificial neural networks

2004 ◽  
Vol 34 (1) ◽  
pp. 37-52
Author(s):  
Wiktor Jassem ◽  
Waldemar Grygiel
Keyword(s):  
Neural Networks ◽  
Numerical Data ◽  
Word List ◽  
Original Data ◽  
Data Matrix ◽  
Probabilistic Neural Networks ◽  
Independent Variable ◽  
The Individual ◽  
Vowel Phoneme

The mid-frequencies and bandwidths of formants 1–5 were measured at targets, at plus 0.01 s and at minus 0.01 s off the targets of vowels in a 100-word list read by five male and five female speakers, for a total of 3390 10-variable spectrum specifications. Each of the six Polish vowel phonemes was represented approximately the same number of times. The 3390* 10 original-data matrix was processed by probabilistic neural networks to produce a classification of the spectra with respect to (a) vowel phoneme, (b) identity of the speaker, and (c) speaker gender. For (a) and (b), networks with added input information from another independent variable were also used, as well as matrices of the numerical data appropriately normalized. Mean scores for classification with respect to phonemes in a multi-speaker design in the testing sets were around 95%, and mean speaker-dependent scores for the phonemes varied between 86% and 100%, with two speakers scoring 100% correct. The individual voices were identified between 95% and 96% of the time, and classifications of the spectra for speaker gender were practically 100% correct.

On the Utility of Crystal Plasticity Modeling to Uncover the Individual Roles of Microdeformation Mechanisms on the Work Hardening Response of Fe-23Mn-0.5C TWIP Steel in the Presence of Hydrogen

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
B. Bal ◽  
M. Koyama ◽  
D. Canadinc ◽  
G. Gerstein ◽  
H. J. Maier ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Embrittlement ◽  
Twip Steel ◽  
Strain Response ◽  
Deformation Response ◽  
Self Consistent ◽  
Twip Steels ◽  
Simulation Results ◽  
The Individual ◽  
Experimental Findings

This paper presents a combined experimental and theoretical analysis focusing on the individual roles of microdeformation mechanisms that are simultaneously active during the deformation of twinning-induced plasticity (TWIP) steels in the presence of hydrogen. Deformation responses of hydrogen-free and hydrogen-charged TWIP steels were examined with the aid of thorough electron microscopy. Specifically, hydrogen charging promoted twinning over slip–twin interactions and reduced ductility. Based on the experimental findings, a mechanism-based microscale fracture model was proposed, and incorporated into a visco-plastic self-consistent (VPSC) model to account for the stress–strain response in the presence of hydrogen. In addition, slip-twin and slip–grain boundary interactions in TWIP steels were also incorporated into VPSC, in order to capture the deformation response of the material in the presence of hydrogen. The simulation results not only verify the success of the proposed hydrogen embrittlement (HE) mechanism for TWIP steels, but also open a venue for the utility of these superior materials in the presence of hydrogen.

Expressions for the effective diffusivity in materials with interphase boundaries

2004 ◽  
Vol 819 ◽  
Author(s):  
Irina V. Belova ◽  
Graeme E. Murch
Keyword(s):  
Polycrystalline Material ◽  
Effective Diffusivity ◽  
Poor Agreement ◽  
Two Phase ◽  
Interphase Boundaries ◽  
Long Time ◽  
Simulation Results ◽  
The Individual ◽  
Individual Grains ◽  
Good Agreement

AbstractWe address the problem of calculating the long-time-limit effective diffusivity in stable two- phase polycrystalline material. A phenomenological model is used where the high diffusivity interphase boundaries are treated as connected “coatings” of the individual grains. Derivation of expressions for the effective diffusivity with segregation is made along Maxwell lines. Monte Carlo simulation using lattice-based random walks is used to test the validity of the expressions. It is shown that for the case analysed the derived expressions for the effective diffusivity are in very good agreement with simulation results. The equivalent of the Hart equation is also derived. It is shown to be in poor agreement with simulation results.

scholarly journals Extracting Interface Correlations from the Pair Distribution Function of Composite Materials

2021 ◽  
Author(s):  
Harry Geddes ◽  
Henry D. Hutchinson ◽  
Alex R Ha ◽  
Nicholas P. Funnell ◽  
Andrew Goodwin
Keyword(s):  
Distribution Function ◽  
Pair Distribution Function ◽  
Functional Materials ◽  
Model System ◽  
Complex Mixtures ◽  
Proof Of Concept ◽  
X Ray ◽  
The Individual ◽  
Theory And Experiment ◽  
Matrix Factorisation

<div> <div> <div> <p>Using a non-negative matrix factorisation (NMF) approach, we show how the pair distribution function (PDF) of complex mixtures can be deconvolved into the contributions from the individual phase components and also the interface between phases. Our focus is on the model system Fe||Fe3O4. We establish proof-of-concept using idealised PDF data generated from established theory-driven models of the Fe||Fe3O4 interface. Using X-ray PDF measurements for corroded Fe samples, and employing our newly-developed NMF analysis, we extract the experimental interface PDF (‘iPDF’) for this same system. We find excellent agreement between theory and experiment. The implications of our results in the broader context of interface characterisation for complex functional materials are discussed. </p> </div> </div> </div>

scholarly journals Study on droplet nucleation position and jumping on structured hydrophobic surface using the lattice Boltzmann method

2021 ◽  
pp. 149-149
Author(s):  
Gaojie Liang ◽  
Lijun Liu ◽  
Haiqian Zhao ◽  
Cong Li ◽  
Nandi Zhang
Keyword(s):  
Lattice Boltzmann Method ◽  
Significant Influence ◽  
Lattice Boltzmann ◽  
Hydrophobic Surface ◽  
Numerical Results ◽  
Nucleation Mode ◽  
Droplet Nucleation ◽  
Simulation Results ◽  
The Individual ◽  
Boltzmann Method

In this study, droplet nucleation and jumping on the conical microstructure surface is simulated using the Lattice Boltzmann Method (LBM). The nucleation and jumping laws of the droplet on the surface are summarized. The numerical results suggest that the height and the gap of the conical microstructure exhibit a significant influence on the nucleation position of the droplet. When the ratio of height to the gap of the microstructure(H/D) is small, the droplet tends to nucleate at the bottom of the structure. Otherwise, the droplet tends to nucleate towards the side of the structure. The droplet grown in the side nucleation mode possesses better hydrophobicity than that of the droplet grown in the bottom nucleation mode and the droplet jumping becomes easier. Apart from the coalescence of the droplets jumping out of the surface, jumping of individual droplets may also occur under certain conditions. The ratio of the clearance to the width of the conical microstructure(D/F) depends on the jumping mode of the droplet. The simulation results indicate that when the D/F ratio is greater than 1.2, the coalescence jump of droplets is likely to occur. On the contrary, the individual jump of droplets is easy to occur.

scholarly journals Multicell Power Supplies for Improved Energy Efficiency in the Information and Communications Technology Infrastructures

2021 ◽  
Author(s):  
Michael Chrysostomou ◽  
Nicholas Christofides ◽  
Stelios Ioannou ◽  
Alexis Polycarpou
Keyword(s):  
Energy Demand ◽  
Information And Communications Technology ◽  
Power Supplies ◽  
Communications Technology ◽  
Cell Structures ◽  
Full Power ◽  
Overall Efficiency ◽  
Simulation Results ◽  
The Individual ◽  
Theoretical Results

The rapid growth of the Information and Communications Technology (ICT) sector requires additional infrastructure, such as more micro-datacenters and telecom stations, to support the higher internet speeds and low latency requirements of 5G net-works. The increased power requirements of the new ICT technologies necessitate the proposal of new power supplies in an attempt to retain the increase in energy demand and running costs. This work provides an in-depth theoretical analysis on the losses of the individual stages of commercially available PSU and proposes a new multicell PSU, Buck-PFC converter, which offers a higher overall efficiency at varying load levels. The theoretical results are verified using simulation results, via PSIM Thermal Module, and using experimental data. The results indicate that multi-cell structures can improve the overall PSU ef-ficiency by 1.2% at 50% rated power and more than 2.1% at full power. Finally, taking into consideration the economic implica-tions of this study, it is shown that the proposed multicell structure may increase the PSU costs by 10.78% but the payback pe-riod is in the order of just 3.3 years.

scholarly journals Motoneuron output regulated by ionic channels: a modeling study of motoneuron frequency-current relationships during fictive locomotion

2018 ◽  
Vol 120 (4) ◽  
pp. 1840-1858 ◽  
Author(s):  
Yue Dai ◽  
Yi Cheng ◽  
Brent Fedirchuk ◽  
Larry M. Jordan ◽  
Junhao Chu
Keyword(s):  
Input Resistance ◽  
Ionic Channels ◽  
Motor Output ◽  
Membrane Properties ◽  
Fictive Locomotion ◽  
State Dependent ◽  
Simulation Results ◽  
The Individual ◽  
Ionic Basis ◽  
Frequency Current

Cat lumbar motoneurons display changes in membrane properties during fictive locomotion. These changes include reduction of input resistance and afterhyperpolarization, hyperpolarization of voltage threshold, and voltage-dependent excitation of the motoneurons. The state-dependent alteration of membrane properties leads to dramatic changes in frequency-current (F-I) relationship. The mechanism underlying these changes remains unknown. Using a motoneuron model combined with electrophysiological data, we investigated the channel mechanisms underlying the regulation of motoneuronal excitability and motor output. Simulation results showed that upregulation of transient sodium, persistent sodium, or Cav1.3 calcium conductances or downregulation of calcium-activated potassium or KCNQ/Kv7 potassium conductances could increase motoneuronal excitability and motor output through hyperpolarizing (left shifting) the F-I relationships or increasing the F-I slopes, whereas downregulation of input resistance or upregulation of potassium-mediated leak conductance produced the opposite effects. The excitatory phase of locomotor drive potentials (LDPs) also substantially hyperpolarized the F-I relationships and increased the F-I slopes, whereas the inhibitory phase of the LDPs had opposite effects to a similar extent. The simulation results also showed that none of the individual channel modulations could produce all the changes in the F-I relationships. The effects of modulation of Cav1.3 and KCNQ/Kv7 on F-I relationships were supported by slice experiments with the Cav1.3 agonist Bay K8644 and the KCNQ/Kv7 antagonist XE-991. The conclusion is that the varying changes in F-I relationships during fictive locomotion could be regulated by multichannel modulations. This study provides insight into the ionic basis for control of motor output in walking. NEW & NOTEWORTHY Mammalian spinal motoneurons have their excitability adapted to facilitate recruitment and firing during locomotion. Cat lumbar motoneurons display dramatic changes in membrane properties during fictive locomotion. These changes lead to a varying alteration of frequency-current relationship. The mechanisms underlying the changes remain unknown. In particular, little is known about the ionic basis for regulation of motoneuronal excitability and thus control of the motor output for walking by the spinal motor system.

On the determination of intermolecular energies by inductive analysis

1942 ◽  
Vol 38 (2) ◽  
pp. 224-230
Author(s):  
William J. C. Orr
Keyword(s):  
Virial Coefficients ◽  
Intermolecular Potential ◽  
Rare Gases ◽  
Second Virial Coefficients ◽  
Classical Expression ◽  
The Individual ◽  
Image Position ◽  
Range Of Values ◽  
Inductive Analysis

For a direct comparison of the individual attractive and repulsive terms of an intermolecular potential determined by the inductive analysis of themodynamic data with the same terms calculated by quantal methods it is desirable to carry out the analyses, in the first approximation, with an intermolecular potential of the form ø(R) = Pe−aR − A1/R6 − A2/R8. For mathematical convenience, in place of the above expression, two potential functions,andare considered, the first being taken to be adequate in the range of values of R between 0 and R0 (the minimum of the potential function) and the second, in the range from R0 to ∞. By dividing the problem in this way it is possible to find substitutions which permit the integration of the classical expression for the second virial coefficients (and other appropriate thermodynamic data) directly in terms of fairly simple series in | ψ0 |, R0, a and r. Finally it is pointed out that for such simple atoms or molecules as the rare gases, oxygen, nitrogen and methane r may be taken as 0·15 throughout, which considerably simplifies the application of the method to the experimental data.

Tensile behavior of single crystalline GaN nanotube bundles: An atomistic-level study

2014 ◽  
Vol 28 (20) ◽  
pp. 1450135 ◽  
Author(s):  
Zhiguo Wang ◽  
G. Q. Yin ◽  
Liming Jing ◽  
Jianjian Shi ◽  
Zhijie Li
Keyword(s):  
Molecular Dynamics ◽  
Critical Stress ◽  
Tensile Behavior ◽  
Single Crystalline ◽  
Brittle To Ductile Transition ◽  
Nanotube Bundles ◽  
Higher Temperature ◽  
Simulation Results ◽  
The Individual ◽  
Weber Potential

The tensile behavior of single crystalline GaN nanotube bundles was studied using classical molecular dynamics. Stillinger–Weber potential was used to describe the atom–atom interactions. The GaN bundles consisted of several individual GaN nanotubes with {100} side planes. The simulation results show that the nanotube bundles show a brittle to ductile transition (BDT) by changing the temperatures. The fracture of GaN nanotube bundles is ruled by a thermal activated process, higher temperature will lead to the decrease of the critical stress. At high temperatures the individual nanotube in the bundles interact with each other, which induces the increase of the critical stress of bundles.

Control of Multichaotic Systems Using the Extended OGY Method

2015 ◽  
Vol 25 (08) ◽  
pp. 1550096 ◽  
Author(s):  
Ensieh Nobakhti ◽  
Ali Khaki-Sedigh ◽  
Nastaran Vasegh
Keyword(s):  
Dynamical Systems ◽  
Decentralized Control ◽  
Chaotic Maps ◽  
Control Design ◽  
Complex Dynamical Systems ◽  
Design Scheme ◽  
Simulation Results ◽  
The Individual ◽  
Systems Simulation

This paper considers the problem of controlling coupled chaotic maps. Coupled chaotic maps or multichaotic subsystems are complex dynamical systems that consist of several chaotic sub-systems with interactions. The OGY methodology is extended to deal with the control of such systems. It is shown that the decentralized control design scheme in which the individual controllers share no information is not generally able to control multichaotic systems. Simulation results are used to support the main conclusions of the paper.

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