Improved model for atomic displacement calculation

Atomic displacement is one of the key factors that influence the behaviors of material properties during and after irradiation. Many models, including the international standard metric Norgett-Robinson-Torrens model (NRT), have been developed to calculate the number of Displacement per Atom (DPA) using the energy of Primary Knocked-on Atom (PKA) as a major parameter. However, extensive experiments and simulations indicate that the NRT-DPA model seriously overestimates (about 3 times) the actual DPA. Nordlund recently developed the Athermal Recombination-Corrected DPA (ARC-DPA) model, which shows that the Molecular Dynamics (MD) simulations can be directly used to compute DPA by fitting the simulated data for each isotope. The present work proposes a simpler expression for the efficiency function to calculate the DPA without requiring fitting parameters as needed in the ARC-DPA model. Our DPA calculation results utilizing the improved efficiency function are validated against the experimental data for the Fe, Ni, Cu, and Ag. The applications in fast breeder nuclear reactors show good agreement with the ARC-DPA metric for 56Fe.

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A Streamline Curvature Method for Calculating S1 Stream Surface Flow

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.3239564 ◽

1984 ◽

Vol 106 (2) ◽

pp. 306-312

Author(s):

S. K. Mao ◽

D. T. Li

Keyword(s):

Surface Flow ◽

Approximation Technique ◽

Flow Section ◽

Boolean Expression ◽

Simple Method ◽

Stream Surface ◽

Streamline Curvature ◽

Calculation Results ◽

Good Agreement ◽

Streamline Curvature Method

A streamline curvature method for calculating S1 surface flow in turbines is presented. The authors propose a simple method in which a domain of calculation can be changed into an orderly rectangle without making coordinate transformations. Calculation results obtained on subsonic and transonic turbine cascades have been compared with those of experiment and another theory. Good agreement has been found. When calculating blade-to-blade flow velocity at subsonic speed, a function approximation technique can be used in lieu of iteration method in order to reduce calculation time. If the calculated flow section is of a mixed (subsonic-supersonic) flow type, a Boolean expression obtained from the truth table of flow states is proposed to judge the integrated character of the mixed flow section. Similarly, another Boolean expression is used to determine whether there exists a “choking” of the relevant section. Periodical conditions are satisfied by iterating the first-order derivative of stagnation streamline, which is formed simultaneously. It can be proved that the stagnation streamline formed in this way is unique.

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Study on Roll Wear Model for Hot Strip Mill

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.535-537.697 ◽

2012 ◽

Vol 535-537 ◽

pp. 697-700

Author(s):

Zhong Feng Guo ◽

Jun Hong Hu ◽

Xue Yan Sun

Keyword(s):

Work Roll ◽

Hot Strip Mill ◽

Rolling Schedule ◽

Wear Model ◽

C Language ◽

Hot Strip ◽

Roll Wear ◽

Calculation Results ◽

Strip Length ◽

Good Agreement

Roll wear model for Hot Strip Mill (HSM) was researched and the factors affect roll wear are analyzed. The simulation program was compiled by program visual C++ language and work roll wear was calculated according to the rolling schedule. Calculation results shows that roll wear like box shape. Strip width affects roll wear clearly. The strip length is one of the important issues which affect roll wear. Work roll wear of F7 top roll middle get to 280μm after a rolling schedule. Roll wear curve calculated by program were good agreement with the wear curve got by high-precision grinder. The results show that the roll wear model has high accuracy.

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In-Plane Force Effect of Reinforced Concrete Beam with Elastic Supports

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.287-290.1896 ◽

2011 ◽

Vol 287-290 ◽

pp. 1896-1901

Author(s):

Zhi Kun Guo ◽

Wan Xiang Chen ◽

Qi Fan Wang ◽

Yu Huang ◽

Chao Pu Li ◽

...

Keyword(s):

Reinforced Concrete ◽

Concrete Beam ◽

Reinforced Concrete Beam ◽

Reinforced Concrete Beams ◽

Nonlinear Characteristics ◽

Elastic Supports ◽

Calculation Results ◽

Basic Equations ◽

First Time ◽

Good Agreement

The bearing capacities of one-way reinforced concrete beams with elastic supports are investigated in this paper. According to the nonlinear characteristics of the beams, the basic equations based on plastic theory of concrete are derived by considering the in-plane force effects that aroused by the constraints of supports when the beams deforming. It is indicated that the calculation results are in good agreement with experimental datum, and the influences of different supports on the bearing capacities of the beams are quantitatively given for the first time.

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The Thermodynamics Calculation of Mg-Zn Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.546-549.447 ◽

2007 ◽

Vol 546-549 ◽

pp. 447-450

Author(s):

Tian Mo Liu ◽

Hong Yi Zhou ◽

Fu Sheng Pan

Keyword(s):

Excess Entropy ◽

Formation Enthalpy ◽

Miedema Model ◽

Activity Curve ◽

Calculation Results ◽

Experimental Values ◽

Zn Alloy ◽

Zn Alloys ◽

Good Agreement

In the present work Miedema model has been developed, and the formation enthalpy of Mg-Zn alloys and the activity curve of Zn in Mg-Zn alloy at 1000K have been calculated according to the Miedema model. The calculation results showed that the formation enthalpy of Mg-Zn was small, and the excess entropy attributes a lot to the result. When excess enthopy was considered, the calculation results were found to be in good agreement with the experimental values.

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Novel Pyrazolo[3,4-c]pyridine Antagonists with Nanomolar affinity for A1 / A3 Adenosine Receptors: Binding Kinetics and Exploration of their Binding Profile Using Mutagenesis Experiments, MD simulations and TI/MD calculations

10.26434/chemrxiv-2021-j18mg ◽

2021 ◽

Author(s):

Margarita Stampelou ◽

Anna Suchankova ◽

Eva Tzortzini ◽

Lakshiv Dhingra ◽

Kerry Barkan ◽

...

Keyword(s):

Drug Design ◽

Transmembrane Helix ◽

Rank Correlation ◽

Membrane System ◽

Md Simulations ◽

Dissociation Rate ◽

The Novel ◽

Free Energies ◽

Electronegative Group ◽

Good Agreement

Drugs targeting the four adenosine receptor (AR) subtypes can provide “soft" treatment of various significant diseases. Even for the two experimentally resolved AR subtypes the description of the orthosteric binding area and structure-activity relationships of ligands remains a demanding task due to the high similar amino acids sequence but also the broadness and flexibility of the ARs binding area. The identification of new pharmacophoric moieties and nanomolar leads and the exploration of their binding area with mutagenesis and state-of-the-art computational methods useful also for drug design purposes remains a challenging aim for all ARs. Here, we identified several low nanomolar ligands and potent competitive antagonists against A1R / A3R, containing the novel pyrazolo[3,4-c]pyridine pharmacophore for ARs, from a screen of an in-house library of only 52 compounds, originally designed for anti-proliferative activity. We identified L2-L10, A15, A17 with 3-aryl, 7-anilino and a electronegative group at 5-position as low micromolar to low nanomolar A1R / A3R antagonists. A17 has for A1R Kd = 5.62 nM and a residence time (RT) 41.33 min and for A3R Kd = 13.5 nM, RT = 47.23 min. The kinetic data showed that compared to the not potent or mediocre congeners the active compounds have similar association, for example at A1R Kon = 13.97 x106 M-1 (A17) vs Kon = 3.36 x106 M-1 (A26) but much lower dissociation rate Koff = 0.024 min-1 (A17) vs 0.134 min-1 (A26). Using molecular dynamics (MD) simulations and mutagenesis experiments we investigated the binding site of A17 showing that it can interact with an array of residues in transmembrane helix 5 (TM5), TM6, TM7 of A1R or A3R including residues E5.30, E5.28, T7.35 in A1R instead of Q5.28, V5.30 , L7.35 in A3R. A striking observation for drug design purposes is that for L2506.51A the binding affinity of A17 significantly increased at A1R. A17 provides a lead representative of a promising series and by means of the Thermodynamics Integration coupled with MD simulations (TI/MD) method, first applied here on whole GPCR- membrane system and showing a very good agreement between calculated and experimental relative binding free energies for A1R and A3R (spearman rank correlation p = 0.82 and 0.84, respectively), and kinetic experiments can lead to ligands with improved profile against ARs.

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KINEMATIC WAVE EQUATIONS FOR MOVABLE RIVERBEDS

Meteorologiya i Gidrologiya ◽

10.52002/0130-2906-2021-6-43-54 ◽

2021 ◽

pp. 43-54

Author(s):

A. N. Krutov ◽

◽

S. Ya. Shkol’nikov ◽

Keyword(s):

Mathematical Model ◽

Numerical Method ◽

Wave Equations ◽

Simple Wave ◽

Kinematic Wave ◽

Calculation Results ◽

Self Similar ◽

Molecular Dynamics Modellization and Simulation of Water Diffusion through Plant Cutin

Zeitschrift für Naturforschung C ◽

10.1515/znc-1999-1107 ◽

1999 ◽

Vol 54 (11) ◽

pp. 896-902 ◽

Cited By ~ 5

Author(s):

Antonio Matas ◽

Antonio Heredia

Keyword(s):

Experimental Data ◽

Molecular Dynamics ◽

Structural Information ◽

Md Simulations ◽

Water Molecules ◽

Plant Cuticle ◽

X Ray Diffraction ◽

Cross Link ◽

X Ray ◽

Good Agreement

Abstract A theoretical molecular modelling study has been conducted for cutin, the biopolyester that forms the main structural component of the plant cuticle. Molecular dynamics (MD) simulations, extended over several ten picoseconds, suggests that cutin is a moderately flexible netting with motional constraints mainly located at the cross-link sites of functional ester groups. This study also gives structural information essentially in accordance with previously reported experimental data, obtained from X -ray diffraction and nuclear magnetic resonance experiments. MD calculations were also performed to simulate the diffusion of water molecules through the cutin biopolymer. The theoretical analysis gives evidence that water permeation proceedes by a “hopping mechanism”. Coefficients for the diffusion of the water molecules in cutin were obtained from their mean-square displacements yielding values in good agreement with experimental data.

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Precipitation Behavior of a Maraging Stainless Steel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.567.92 ◽

2012 ◽

Vol 567 ◽

pp. 92-95 ◽

Cited By ~ 2

Author(s):

Yue Jiang ◽

Ying Ying Ai ◽

Qi Ting Wang

Keyword(s):

Stainless Steel ◽

Treatment Process ◽

Aging Treatment ◽

Heat Treatment Process ◽

New Materials ◽

Precipitation Behavior ◽

Thermo Calc Software ◽

Calculation Results ◽

Maraging Stainless Steel ◽

Good Agreement

The changes of precipitation phases and matrix structures in Fe-13Cr-7Ni-4Mo-4Co-2W maraging stainless steel at different temperature were studied by using the Thermo-Calc software. The research was on the microstructures and precipitation behaviors of the maraging stainless steel, the performance is investigated through solution and aging treatment by TEMand SADP. The calculation results were in good agreement with the experiments, which demonstrated that when maraging stainless steel was treated in high temperature, the Laves-Fe2Mo precipitates became totally dissolved as the temperature was above 1050°C, and about 8% of R phase was found during aging. The calculation provides a guiding significant to the establishment of reasonable heat treatment process and the development of new materials.

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Simulation on Coal Devolatilization Combined a Multi-Step Kinetic Model with Chemkin Software

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.608-609.1375 ◽

2012 ◽

Vol 608-609 ◽

pp. 1375-1382

Author(s):

Rui Zhang ◽

Qin Hui Wang ◽

Zhong Yang Luo ◽

Meng Xiang Fang

Keyword(s):

Experimental Data ◽

Kinetic Model ◽

Intermediate Product ◽

Coal Combustion ◽

Model Complexity ◽

Coal Pyrolysis ◽

Simple Application ◽

Calculation Results ◽

Simulation Results ◽

Good Agreement

As the first step in coal combustion and gasification, coal devolatilization has significant effect on reaction process. Previous coal devolatilization models have some disadvantages, such as poor flexibility, model complexity, and requirement of characterization parameters. Recently, Sommariva et al. have proposed a multi-step kinetic model of coal devolatilization. This model avoids the disadvantages mentioned above and can predict elemental composition of tar and char. In this paper, the mechanism of this model has been revised for simple application to Chemkin. Revision method is that some reactions are split into more reactions by using one pseudo-intermediate-product to replace several final products. Simulation results show that calculation results from revised mechanism compare quite well with that from original mechanism and have good agreement with experimental data. The revised mechanism is accurate and can be applied to Chemkin very easily, which gives it wide application to simulation of coal pyrolysis, gasification and combustion.

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RFID Loop Tags for Merchandise Identification Onboard Ships

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1036.969 ◽

2014 ◽

Vol 1036 ◽

pp. 969-974

Author(s):

Daniela Deacu

Keyword(s):

Radio Frequency Identification ◽

Block Diagram ◽

Simulated Data ◽

Open Loop ◽

Closed Loops ◽

Passive Tags ◽

Received Power ◽

Resonance Frequencies ◽

Frequency Identification ◽

Good Agreement

Radio frequency identification (RFID) is one of the most actual techniques employed to control the circuit of merchandises, as an alternative to the classical barecode. RFID tags should be cheap and easy to reproduct on a multitude of dielectric supports. There are several types of RFID systems, depending on whether tag and/or reader are active or passive. For cost reasons, merchandise identification should use active reader and passive tag, as the latter might be manufactured on a cheap FR4 support or printed directly on paper, by using a conductive ink. Passive tags can be shaped as straight dipoles, meandered dipoles, or loops. When a small area is required, loops are more appropriated. Codes are made different one from another by using on the same tag antennas with different resonance frequencies. Another advantage of loops is that they can be placed one inside other, so the occupied area is even smaller compared to other multi-resonant tags. Firstly, a single loop is analyzed, in order to model the resonant behaviour, correlated to the loop geometry and size. Open and closed loops are studied; the lowest resonance frequency for a given loop length is achieved for the open loop. In that case, the loop is resonating as a dipole. Next, a tag with three concentric loops is investigated. Separately, a small loop is used on the tag, in order to couple the received power in a resistor. When the tag is close to the reader, the latter is triggered if power is absorbed simultaneously on the three expected frequencies. The proposed tag was simulated and manufactured. Results show a good agreement between measured and simulated data. Finally, a block diagram for the reader was proposed.

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