scholarly journals Computer simulation of block polymerization of 1,6-Hexanediol Diacrylate

2021 ◽  
Vol 2131 (2) ◽  
pp. 022006
Author(s):  
E D Shakiryanov
Keyword(s):  
Experimental Data ◽  
Computer Simulation ◽  
Three Dimensional ◽  
Reaction System ◽  
Adequate Description ◽  
Volume Model ◽  
Ideal Mixing ◽  
The Monte Carlo Method ◽  
Free Volume Model ◽  
Growth Reaction

Abstract In this paper, a computer model of the block three-dimensional free-radical polymerization of 1,6-Hexanediol Diacrylate (HDDA) is proposed. The model of the reaction system is based on an ideal mixing reactor. The reaction process is modeled by the Monte Carlo method. Accounting for the diffusion inhibition of the reaction is described using the free volume model. An adequate description of the experimental data of the calculated conversion rate curve is obtained. The nature of the change in the rate constant of the growth reaction with increasing conversion is shown.

Computer simulation of phase transitions of the Heisenberg antiferromagnetic model

2019 ◽  
pp. 25-31
Author(s):  
M.K. Ramazanov ◽  
A.K. Murtazaev
Keyword(s):  
Computer Simulation ◽  
Phase Transitions ◽  
Nearest Neighbor ◽  
Three Dimensional ◽  
Exchange Interactions ◽  
Nearest Neighbors ◽  
Neighbor Interaction ◽  
A Value ◽  
The Monte Carlo Method ◽  
Antiferromagnetic Model

Based on the replica algorithm by the Monte Carlo method, a computer simulation of the three-dimensional antiferromagnetic Heisenberg model is performed, taking into account the interactions of the first and second nearest neighbors. The phase transitions of this model are studied. The investigations were carried out for the ratios of the exchange interactions of the first and second nearest neighbors $r = J_2 / J_1$ in the range $0.0 \leq r \leq 1.0$. The phase diagram of the critical temperature dependence on a value of the next-nearest neighbor interaction is plotted.

Study of Ice Failure and Deformation Processes

2014 ◽  
Author(s):  
Anatolii V. Aleksandrov ◽  
Viktor V. Platonov ◽  
Roman A. Matantsev
Keyword(s):  
Experimental Data ◽  
Computer Simulation ◽  
Numerical Models ◽  
Three Dimensional ◽  
Image Correlation ◽  
Strength Analysis ◽  
Element Analysis ◽  
Deformation And Failure ◽  
Test Methodology ◽  
Ice Failure

Intensive development of computer simulation technique for ice deformation and failure processes is an important problem in respect to both ice propulsion definition and strength analysis for ice vessel and ice-resistant structures. However, evaluation of applied algorithms effectiveness requires developing a procedure for verification of numerical models. This paper presents results of experiment-calculated studies for strains in a bounded region on a specimen surface containing a point grid. Grid movement during the tests was recorded with the help of a system of three-dimensional computer vision and digital image correlation for noncontacting shape and deformation measurements. An experimental facility, test methodology, observed results and test results processing method are explained. Experimental data on freshwater field ice under uniaxial compression and bending are given. Ice mechanical characteristics were evaluated based on inverse solution and finding ice strain characteristics as initial data for the finite element analysis. The calculated results were analyzed and compared with experimental data. Application of the proposed methodology will extend essentially a verification base for computer simulation of ice failure under contact with a structure and create prerequisites for forming a new direction in the area of ice numerical simulation.

Three-dimensional asymmetric maximum weight lifting prediction considering dynamic joint strength

2021 ◽  
pp. 095441192098703
Author(s):  
Rahid Zaman ◽  
Yujiang Xiang ◽  
Jazmin Cruz ◽  
James Yang
Keyword(s):  
Experimental Data ◽  
Degrees Of Freedom ◽  
Inverse Dynamics ◽  
Three Dimensional ◽  
Optimization Method ◽  
Weight Lifting ◽  
Joint Torque ◽  
Maximum Weight ◽  
Angular Velocities ◽  
Asymmetric Lifting

In this study, the three-dimensional (3D) asymmetric maximum weight lifting is predicted using an inverse-dynamics-based optimization method considering dynamic joint torque limits. The dynamic joint torque limits are functions of joint angles and angular velocities, and imposed on the hip, knee, ankle, wrist, elbow, shoulder, and lumbar spine joints. The 3D model has 40 degrees of freedom (DOFs) including 34 physical revolute joints and 6 global joints. A multi-objective optimization (MOO) problem is solved by simultaneously maximizing box weight and minimizing the sum of joint torque squares. A total of 12 male subjects were recruited to conduct maximum weight box lifting using squat-lifting strategy. Finally, the predicted lifting motion, ground reaction forces, and maximum lifting weight are validated with the experimental data. The prediction results agree well with the experimental data and the model’s predictive capability is demonstrated. This is the first study that uses MOO to predict maximum lifting weight and 3D asymmetric lifting motion while considering dynamic joint torque limits. The proposed method has the potential to prevent individuals’ risk of injury for lifting.

scholarly journals Three-Dimensional Structures of Carbohydrates and Where to Find Them

2020 ◽  
Vol 21 (20) ◽  
pp. 7702 ◽  
Author(s):  
Sofya I. Scherbinina ◽  
Philip V. Toukach
Keyword(s):  
Experimental Data ◽  
Molecular Modeling ◽  
Computational Methods ◽  
Three Dimensional ◽  
Structural Diversity ◽  
Structural Data ◽  
Structural Features ◽  
Data Validation ◽  
Data Generation ◽  
Efficient Treatment

Analysis and systematization of accumulated data on carbohydrate structural diversity is a subject of great interest for structural glycobiology. Despite being a challenging task, development of computational methods for efficient treatment and management of spatial (3D) structural features of carbohydrates breaks new ground in modern glycoscience. This review is dedicated to approaches of chemo- and glyco-informatics towards 3D structural data generation, deposition and processing in regard to carbohydrates and their derivatives. Databases, molecular modeling and experimental data validation services, and structure visualization facilities developed for last five years are reviewed.

scholarly journals Effect of an Improved Yasutomi Pressure-Viscosity Relationship on the Elastohydrodynamic Line Contact Problem

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
Vincenzo Petrone ◽  
Adolfo Senatore ◽  
Vincenzo D'Agostino
Keyword(s):  
High Pressure ◽  
Film Thickness ◽  
Free Volume ◽  
Experimental Studies ◽  
Line Contact ◽  
Volume Model ◽  
Free Volume Model ◽  
Pressure Area ◽  
New Formulation ◽  
Lubricant Viscosity

This paper presents the application of an improved Yasutomi correlation for lubricant viscosity at high pressure in a Newtonian elastohydrodynamic line contact simulation. According to recent experimental studies using high pressure viscometers, the Yasutomi pressure-viscosity relationship derived from the free-volume model closely represents the real lubricant piezoviscous behavior for the high pressure typically encountered in elastohydrodynamic applications. However, the original Yasutomi correlation suffers from the appearance of a zero in the function describing the pressure dependence of the relative free volume thermal expansivity. In order to overcome this drawback, a new formulation of the Yasutomi relation was recently developed by Bair et al. This new function removes these concerns and provides improved precision without the need for an equation of state. Numerical simulations have been performed using the improved Yasutomi model to predict the lubricant pressure-viscosity, the pressure distribution, and the film thickness behavior in a Newtonian EHL simulation of a squalane-lubricated line contact. This work also shows that this model yields a higher viscosity at the low-pressure area, which results in a larger central film thickness compared with the previous piezoviscous relations.

Development and Validation of a Three-Dimensional Multiphase Flow CFD Analysis for Journal Bearings in Steam and Heavy Duty Gas Turbines

2012 ◽  
Author(s):  
Stephan Uhkoetter ◽  
Stefan aus der Wiesche ◽  
Michael Kursch ◽  
Christian Beck
Keyword(s):  
Experimental Data ◽  
Multiphase Flow ◽  
Gas Turbines ◽  
High Speed ◽  
Three Dimensional ◽  
Air Entrainment ◽  
Journal Bearings ◽  
Heavy Duty ◽  
Present Contribution ◽  
Two Phase

The traditional method for hydrodynamic journal bearing analysis usually applies the lubrication theory based on the Reynolds equation and suitable empirical modifications to cover turbulence, heat transfer, and cavitation. In cases of complex bearing geometries for steam and heavy-duty gas turbines this approach has its obvious restrictions in regard to detail flow recirculation, mixing, mass balance, and filling level phenomena. These limitations could be circumvented by applying a computational fluid dynamics (CFD) approach resting closer to the fundamental physical laws. The present contribution reports about the state of the art of such a fully three-dimensional multiphase-flow CFD approach including cavitation and air entrainment for high-speed turbo-machinery journal bearings. It has been developed and validated using experimental data. Due to the high ambient shear rates in bearings, the multiphase-flow model for journal bearings requires substantial modifications in comparison to common two-phase flow simulations. Based on experimental data, it is found, that particular cavitation phenomena are essential for the understanding of steam and heavy-duty type gas turbine journal bearings.

The cathodic reduction of PbO in the passive layer on lead in aqueous sulphuric acid

1984 ◽  
Vol 62 (3) ◽  
pp. 596-600 ◽  
Author(s):  
R. G. Barradas ◽  
D. S. Nadezhdin
Keyword(s):  
Experimental Data ◽  
Three Dimensional ◽  
Reference Electrode ◽  
Linear Sweep Voltammetry ◽  
Passive Layer ◽  
Cathodic Reduction ◽  
Linear Sweep ◽  
Current Time ◽  
Lead Monoxide ◽  
Two Peaks

The cathodic reduction of the lead monoxide layer formed on lead in 30% aqueous H2SO4 under anodic oxidation at 0.6 V (vs. Hg/HgSO4 reference electrode) was investigated by linear sweep voltammetry, potential step and admittance measurements. The experimental data were analyzed respectively in terms of thin-layer electrochemistry, electrocrystallisation, and changes of resistance of the PbO layer under reduction. The results seem to be best interpreted from the theory of three-dimensional electrocrystallisation as PbO is reduced to Pb. At sub-zero temperatures the PbO peak observed on our voltammograms and potentiostatic current time transients reveals the splitting of the curves into two peaks, which may be a result of reduction of the same material but of different phases, namely, orthorhombic and tetragonal PbO.

Three-dimensional predator–prey interactions: a computer simulation of bird flocks and aircraft

1986 ◽  
Vol 64 (11) ◽  
pp. 2624-2633 ◽  
Author(s):  
Peter F. Major ◽  
Lawrence M. Dill ◽  
David M. Eaves
Keyword(s):  
Computer Simulation ◽  
Prey Species ◽  
Three Dimensional ◽  
Aircraft Engine ◽  
Aquatic Environments ◽  
Aircraft Engines ◽  
Predator Prey ◽  
Simulation Techniques ◽  
Computer Simulation Techniques ◽  
Individual Prey

Three-dimensional interactions between grouped aerial predators (frontal discs of aircraft engines), either linearly arrayed or clustered, and flocks of small birds were studied using interactive computer simulation techniques. Each predator modelled was orders of magnitude larger than an individual prey, but the prey flock was larger than each predator. Expected numbers of individual prey captured from flocks were determined for various predator speeds and trajectories, flock–predator initial distances and angles, and flock sizes, shapes, densities, trajectories, and speeds. Generally, larger predators and clustered predators caught more prey. The simulation techniques employed in this study may also prove useful in studies of predator–prey interactions between schools or swarms of small aquatic prey species and their much larger vertebrate predators, such as mysticete cetaceans.The study also provides a method to study problems associated with turbine aircraft engine damage caused by the ingestion of small flocking birds, as well as net sampling of organisms in open aquatic environments.

The Petrogenetic Model, an Extension of Bowen's Petrogenetic Grid

1962 ◽  
Vol 99 (6) ◽  
pp. 558-569 ◽  
Author(s):  
Peter J. Wyllie
Keyword(s):  
Experimental Data ◽  
Constant Pressure ◽  
Three Dimensional ◽  
Pore Fluid ◽  
Fluid Composition ◽  
Solid Reaction ◽  
Petrogenetic Model ◽  
Wide Range ◽  
Opposite Face ◽  
Reaction Surfaces

AbstractBowen's petrogenetic grid is a PT projection containing univariant curves for decarbonation, dehydration, and solid-solid reactions, with vapour pressure (Pf) equal to total pressure (Ps). Analysis of experimental data in the system MgO–CO2–H2O leads to an expansion of this grid. Three of the important variables in metamorphism when Pf = Ps are P, T, and variation of the pore fluid composition between H2O and CO2. These can be illustrated in a three-dimensional petrogenetic model; one face is a PT plane for reactions occurring with pure H2O, and the opposite face is a similar plane for reactions with pure CO2; these are separated by an axis for pore fluid composition varying between H2O and CO2. Superposition of the PT faces of the model provides the petrogenetic grid. The reactions within the model are represented by divariant surfaces, which may meet along univariant lines. For dissociation reactions, the surfaces curve towards lower temperatures as the proportion of non-reacting volatile increases, and solid-solid reaction surfaces are parallel to the vapour composition axis and perpendicular to the PT axes. The relative temperatures of reactions and the lines of intersections of the surfaces can be illustrated in isobaric sections. Isobaric sections are used to illustrate reactions proceeding at constant pressure with (1) pore fluid composition remaining constant during the reaction, with temperature increasing (2) pore fluid composition changing during the reaction, with temperature increasing, and (3) pore fluid changing composition at constant temperature. The petrogenetic model provides a convenient framework for a wide range of experimental data.

Sign in / Sign up

Export Citation Format

Share Document