• Bulletin of the Korean Chemical Society
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• v.24 no.6
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• pp.771-776
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• 2003

The structural and dynamic properties of small n-alkane clusters embedded in a mesoscopic solvent are investigated. The solvent interactions are taken into account through a multi-particle collision operator that conserves mass, momentum and energy and the solvent dynamics is updated at discrete time intervals. The cluster molecules interact among themselves and with the solvent molecules through intermolecular forces. The properties of n-heptane and n-decane clusters interacting with the mesoscopic solvent molecules through repulsive Lennard-Jones interactions are studied as a function of the number of the mesoscopic solvent molecules. Modifications of both the cluster and solvent structure as a result of cluster-solvent interactions are considered. The cluster-solvent interactions also affect the dynamics of the small n-alkane clusters.

• 한국초전도학회:학술대회논문집
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• v.14
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• pp.19-19
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• 2004

• Journal of the Korean Society for Heat Treatment
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• v.12 no.4
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• pp.320-326
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• 1999

In rapidly solidified $Al_{92-x}Nd_8$(Cu,Ag)x ($0{\leq}X{\leq}10at%$) alloys, amorphous single phases were obtained in the ranges of $Oat%{\leq}X{\leq}4at%$ for Al-Nd-Cu system and $Oat%{\leq}X{\leq}6at%$ for Al-Nd-Ag system, respectively. Mesoscopic structures consisted of amorphous and crystalline phases were formed above solute ranges. It was founded that the mesoscopic structures were also formed near 1st exothermic peak on DSC curve by aging in amorphous single phase alloys. For example, amorphous $Al_{92-x}Nd_8$(Cu,Ag)x (X=2.4at%) alloys containing nanoscale Al particles and compounds, i.e., mesoscopic structure, exhibited higher tensile fracture strength(${\sigma}_f$) than those of amorphous single phase alloys with the same composition. The ${\sigma}_f$ showed a maximum value in the $V_f$ ranges of 10~15%. The reason is presumed that the nanoscale precipitates which have higher mechanical strength compared with the amorphous phase with the same composition act as an effective resistance to shear deformation of the amorphous matrix.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2004.11a
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• pp.53-59
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• 2004

Rough surfaces are taking into account to estimate the contact fatigue life. A computational methodology and the theoretical basis in this case is presented in this paper. Displacement solution technique by Cho and Love is applied to calculate the stress history beneath the surface subjected to loading. Mesoscopic multiaxial fatigue criterion is then applied to predict fatigue life. This fatigue criterion yields satisfactory results for non-proportional loading and can satisfactorily describe the physical mechanisms of crack initiation as well. As a result of analysis the relation between the life and the roughness as well as the most probable depth of the crack nucleation is discussed.

• Bulletin of the Korean Chemical Society
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• v.25 no.12
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• pp.1893-1897
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• 2004

Hydrodynamic simulations of mesoscopic solvent have been performed by multi-particle collision algorithm in a real dimensional system without and with the random shifting of the grid. A systematic conversion of the dimensionless units to a real dimensional system was confirmed by jump rates of solvent particles. Speed distributions of solvent particles obtained from the simulations agreed very well with the Maxwell-Boltzmann distributions. Solvent viscosities obtained from the simulations and from the conversion of units are exactly the same which confirmed the correct conversion of the units once again. The calculation of the friction coefficient of a massive Brownian particle in a mesoscopic solvent as a function of Brownian particle diameter was examined as an example.

• Coupled systems mechanics
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• v.8 no.4
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• pp.289-298
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• 2019

Reinforced concrete can be considered as a heterogeneous material consisting of coarse aggregate, mortar mix and reinforcing bars. This paper presents a two-dimensional mesoscopic analysis of reinforced concrete beams using a simple two-phase mesoscopic model for concrete. The two phases of concrete, coarse aggregate and mortar mix are bonded together with reinforcement bars so that inter force transfer will occur through the material surfaces. Monte Carlo's method is used to generate the random aggregate structure using the constitutive model at mesoscale. The generated models have meshed such that there is no material discontinuity within the elements. The proposed model simulates the load-deflection behavior, crack pattern and ultimate load of reinforced concrete beams reasonably well.

• Structural Engineering and Mechanics
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• v.37 no.2
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• pp.215-231
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• 2011

As a brittle and heterogeneous material, concrete behaves differently under different stress conditions and its bulk strength is loading rate dependent. To a large extent, the varying behavioural properties of concrete can be explained by the mechanical failure processes at a mesoscopic level. The development of a computational mesoscale model in a general finite element environment, as presented in the preceding companion paper (Part 1), makes it possible to investigate into the underlying mechanisms governing the bulk-scale behaviour of concrete under a variety of loading conditions and to characterise the variation in quantitative terms. In this paper, we first present a series of parametric studies on the behaviour of concrete material under quasi-static compression and tension conditions. The loading-face friction effect, the possible influences of the non-homogeneity within the mortar and ITZ phases, and the effect of randomness of coarse aggregates are examined. The mesoscale model is then applied to analyze the dynamic behaviour of concrete under high rate loading conditions. The potential contribution of the mesoscopic heterogeneity towards the generally recognized rate enhancement of the material compressive strength is discussed.

• Interaction and multiscale mechanics
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• v.3 no.1
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• pp.23-37
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• 2010

Concrete is a heterogeneous material consisting of coarse aggregate, mortar matrix and interfacial zones at the meso level. Though studies have been done to interpret the fracture process in concrete using meso level models, not much work has been done for simulating the macroscopic behaviour of reinforced concrete structures using the meso level models. This paper presents a procedure for the mesoscopic analysis of reinforced concrete beams using a modified micro truss model. The micro truss model is derived based on the framework method and uses the lattice meshes for representing the coarse aggregate (CA), mortar matrix, interfacial zones and reinforcement bars. A simple procedure for generating a random aggregate structure is developed using the constitutive model at meso level. The study reveals the potential of the mesoscopic numerical simulation using a modified micro truss model to predict the nonlinear response of reinforced concrete structures. The modified micro truss model correctly predicts the load-deflection behaviour, crack pattern and ultimate load of reinforced concrete beams failing under different failure modes.

• Journal of the Korea Society for Simulation
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• v.10 no.3
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• pp.47-58
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• 2001

Evaluation of Freeway Congestion Management Using Mesoscopic Traffic Simulator A mesoscopic simulation study to measure the effects of trip generation caused by rampant expansion of residential area around the Kyungbu corridor has been conducted. Some alternatives, which seem to be judgememtally plausible and technically feasible to mitigate such congestion, have been carefully examined and evaluated by the simulation model called INTEGRATION. Alternatives are mostly network improvements. Banpo IC dedicated ramp construction (A1), Seocho IC TSM based weaving elimination (A2), dedicated local and express separation over Seocho-Yangjae segment (A3), Heonleung IC (A4) and Daewang If installations (A5), Pangyo IC improvement (A6), Baikhyun IC (A7) and Dongbaek IC installations (A8) along with Shingal-Pangyo segment capacity addition (A9). The most capital intensive ones are A9, A5, and A4 in that order. A1, A6, A7, and A8 are short in distance but they are also capital intensive and need some construction periods. The least capital driven alternatives are h2 and A3, the h2 is easier to do, but A3 needs traffic diversion scheme during construction. The A1, A7, and A8 have been identified cost effective in terms of speed increase and travel time saving. Along with these results, some limitations and future research agenda regarding simulation have also been presented.

• ETRI Journal
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• v.16 no.2
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• pp.1-13
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• 1994

We have identified two new features related to the coherent transport in the mesoscopic loop structure of aluminum wire, including the autocorrelation of the conductance fluctuations beyond $B_c$ and fine structure in the low-field magnetoresistance curve in the superconducting transition regime, which, to the best of our knowledge, have not been reported in the literature. Since the electrons in Al have a phase coherence length larger than $1\;{\mu}m$ at or below T = 3K, which is comparable to the dimensions of the structure, the wave nature of the electronic transport has been clearly observed: the universal conductance fluctuations, the Aharonov-Bohm oscillations, and the Altshuler-Aronov-Spivak oscillations. Due to the transition of Al to a superconducting state at T = 1.3 K, the coherent phenomena of Cooper pairs, i.e., the Little-Parks oscillations, have also been observed.