• Geomechanics and Engineering
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• v.27 no.6
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• pp.573-582
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• 2021

From the effect of bound water, this study aims to seek the potential reasons for difference of mechanical experiment results of subgrades soils. To attain the comparatively test condition of bound water, dry forming (DF) and wet forming (WF) were used in the specimen forming process before testing, series of laboratory tests, i.e., CBR tests, direct shear tests and compaction tests. The measured optimal moisture contents, maximum dry densities, CBR, cohesion c, and internal friction angle 𝜑 were given contrastive analysis. Then to detect the adsorptive bound water in the subgrade soils, the thermal gravimetric and differential scanning calorimetry (TG-DSC) test were employed under different heating rates. The free water, loosely bound water and tightly bound water in soils were qualitatively and quantitatively analyzed. It was found that due to the different dehydration mechanics, the lost bound water in DF and WF process show their own characteristics. This may lead to the different mechanical properties of tested soils. The clayey particles have a great influence on the bound water adsorbed ability of subgrade soils. The more the clay content, the greater the difference of mechanical properties tested between the two forming methods. Moreover, in highway construction of southern China, the wet forming method is recommended for its higher authenticity in simulating the subgrade filed humidity.

• Geomechanics and Engineering
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• v.30 no.5
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• pp.471-478
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• 2022

Creep of soils has a significant impact on mechanical properties. The one-dimensional consolidation creep test, thermal analysis test, scanning electron microscope (SEM) test, and mercury compression test were performed on Guilin red clay to study the changes in bound water and microstructure during the creep process of Guilin red clay. According to the results of the tests, only free and weakly bound water is discharged during the creep of Guilin red clay. When the consolidation pressure p is in the 12.5-400.0 kPa range, it is primarily the discharge of free water; when the consolidation pressure p is in the 800.0-1600.0 kPa range, the weakly bound water is converted to free water and discharged. After consolidation creep, the microstructure of soil changes from granular overhead contact structure to flat sheet-like stacking structure, with a decrease in the number of large and medium pores, an increase in the number of small and micro pores, and a decrease in the fractal dimension of pores. The creep process of red clay is the discharge of weakly bound water as well as the compression of large pores into small pores and the transition of soil particles from loose to dense.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.261-268
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• 2000

In this study the bearing capacity of the eccentrically loaded shallow footing is estimated by means of the upper bound method of limit analysis. In the case of applying the upper bound, the results depend on the failure mechanism. So the failure surface is correctly studied through the model test using sand. New method is proposed to estimate the bearing capacity of the eccentrically loaded shallow footing by means of the upper bound method to apply the failure mechanism based on the model test. The propriety of new method is verified by the results of various methods. And the influences of the variables eccentricity, embedment depth, variations of contact width factor by model test using sand are also studied in this paper

• Korean Journal of Computational Design and Engineering
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• v.15 no.1
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• pp.24-32
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• 2010

This paper introduces a B-spline based branch & bound algorithm for global optimization. The branch & bound is a well-known algorithm paradigm for global optimization, of which key components are the subdivision scheme and the bound calculation scheme. For this, we consider the B-spline hypervolume to approximate an objective function defined in a design space. This model enables us to subdivide the design space, and to compute the upper & lower bound of each subspace where the bound calculation is based on the LHS sampling points. We also describe a search tree to represent the searching process for optimal solution, and explain iteration steps and some conditions necessary to carry out the algorithm. Finally, the performance of the proposed algorithm is examined on some test problems which would cover most difficulties faced in global optimization area. It shows that the proposed algorithm is complete algorithm not using heuristics, provides an approximate global solution within prescribed tolerances, and has the good possibility for large scale NP-hard optimization.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.9 s.252
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• pp.1049-1061
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• 2006

In the study, the flow stress of material and friction condition were determined by using the cylinder compression test and numerical method. We proposed the flow stress equation including the initial yield strength to predict it from the upper bound method. The upper bound technique uses the velocity field which includes two unknowns to effectively express bulging. Also, inverse engineering technique uses the object function to minimize area enclosed by load-stroke curve. The friction factor is determined from the radius of curvature of the barrel by cylinder compression test. Flow stress and initial yield strength predicted from the above techniques are verified through the finite element simulation.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.4
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• pp.1-9
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• 2010

In this paper, we consider a two-machine re-entrant permutation flowshop scheduling problem with the objective of minimizing total flowtime, and suggest branch and bound algorithms for the scheduling problem. In this scheduling problem, each job must be processed twice on each machine, that is, each job should be processed on the two machines in the order of machine 1, machine 2 and then machine 1 and machine 2. In this research, based on the results of existing researches for re-entrant permutation flowshop scheduling problems, various dominance properties, lower bound and heuristic algorithm are suggested for the problem, and those are used to develop branch and bound algorithms. In the computational experiments for evaluation of the performance of the algorithms, the suggested branch and bound algorithms are tested on randomly generated test problems and results are reported.

• Geomechanics and Engineering
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• v.11 no.4
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• pp.587-605
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• 2016

This study aimed to develop upper and lower bounds to predict the tunnel support pressure under the pile tip during the circular tunnel excavation. Most previous studies on the upper and lower bound methods were carried out for the single ground structures, e.g., retaining wall, foundation, ground anchor and tunnel, in the homogeneous ground conditions, since the pile-soil-tunnel interaction problem is very complicated and sophisticated to solve using those bound methods. Therefore, in the lower bound approach two appropriate stress fields were proposed for single pile and tunnel respectively, and then they were superimposed. In addition, based on the superimposition several failure mechanisms were proposed for the upper bound solution. Finally, these upper bound mechanisms were examined by shear strain data from the laboratory model test and numerical analysis using finite element method.

• Communications for Statistical Applications and Methods
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• v.6 no.2
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• pp.443-456
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• 1999

The estimation of mean lifetimes in presence of interval censoring with mixed replacement procedure are examined when the distribution s of lifetimes are exponential. it is assumed that due to physical restrictions and/or economic constraints the number of failures is investigated only at several inspection times during the lifetime test; thus there is interval censoring. Comparisons of mixed replacement designs are made with those with and without replacement The maximum likelihood estimator is found in an implicit form. The Cramer-Rao lower bound which is the asymptotic variance of the estimator is derived. The test conditions for minimizing the Cramer-Rao lower bound and minimizing the test costs within a desired width of the Cramer-Rao bound have been studied.

• Korean Journal of Veterinary Research
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• v.30 no.2
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• pp.187-192
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• 1990

The Presence and quantity of protein A in Staphylococcus hyicus subsp hyicus isolates from pigs were determined by indirect hemagglutination test and enzyme-linked immunosorbent assay(ELISA). Cell-bound and extracellular protein A was demonstrated in 87.7% and 36.0% of 489 isolates, respectively, by indirect hemagglutination test. When contents of the protein A were estimated by ELISA method, all of the isolates that were positive to protein A in indirect hemagglutination test produced extracellular protein A of less than 1ng/ml. Most of the isolates produced cell-bound protein A of less than 1ng/ml, whereas 28 isolates produced 1 to 35ng/ml and 11 isolates produced 25 to 108ng/ml.

• Journal of Conservation Science
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• v.25 no.3
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• pp.273-282
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• 2009

As a result of investigating research papers concerning the metal bound rim decoration on four pieces of 'Bowl, white porcelain with impressed floral design and sliver bound rim' and one piece of 'Bowl, white porcelain with sliver bound rim' from among the Jingdezhen white porcelain, which are Sinan remains that are kept in a National museum of Korea. It was found that the material of the bound rim was not silver but tin, and lacquer was used as glue. Based on such a scientific analysis, this study conducted a reproduction test of the manufacturing technique and the bonding method of the metal bound rim attached to the upper tip of the china ware. As a way of reproducing the bound rim, the study was able to discover the best method in terms of the avoidance of loss of materials and the workability out of various cutting methods for tin plates, and it also discovered that the use of lacquer in mixture with soil showed a better workability than the use only of a lacquer ingredient in a test of the bonding method of a metal bound rim using lacquer. Also, in the test of a drying method, a bonding method after drying within a short time at a relatively high temperature was found to be more effective than the drying method after humidifying at a normal temperature, which is used in traditional lacquer ware preservation treatment.