• Journal of the Korean Society for Precision Engineering
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• v.15 no.5
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• pp.167-175
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• 1998

A mathematical formulation is presented to model anisotropy from the deformation textures developed in a forming process. In this work, a micro-mechanical-based polycrystalline analysis is implemented into a consistent finite element method for the anisotropic, viscoplastic deformation of polycrystalline metals. As suggested by Taylor, the deformation of each grain in an aggregate is assumed to be same as the macroscopic deformation of an aggregate or a macro-continuum point. Algorithms are developed to represent the plastic anisotropy, such as the anisotropic yield surface and R-value, from the predicted deformation texture. As applications, the evolution of texture in rolling, upsetting and drawing/extrusion processes are simulated and the corresponding changes of mechanical properties such as yield surface and R-value are predicted.

• Transactions of Materials Processing
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• v.16 no.4 s.94
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• pp.234-238
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• 2007

Magnesium alloy sheets in room temperature have unusual mechanical properties such as high in-plane anisotropy/asymmetry of yield stress and hardening behavior. In this paper, the continuum plasticity models considering the plastic behavior of AZ31B Mg alloy sheet were derived. A new hardening law based on modified two-surface model was developed to consider the general stress-strain response of metals including Bauschinger effect, transient behavior and the unusual asymmetry. Three deformation modes observed during the continuous tension/compression tests were mathematically formulated with simplified relations between the state of deformation and their histories. To include the anisotropy and asymmetry of the initial yield stress, the Drucker-Prager's pressure dependent yield surface was modified by adding anisotropic constants.

• Geomechanics and Engineering
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• v.11 no.5
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• pp.725-738
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• 2016

A theoretical study of the behavior of structured soils is presented herein. By introducing the effect of soil structure and loading history into the Cam Clay model, a new model was formulated. The concept of differing void ratios was modified to combine structural parameters and the over consolidation ratio, and an evolution law was proposed. Upon introducing the concept of the subloading yield surface, a new two-yield surface model was obtained. The predicted results were compared to the experimental data, demonstrating that the new model provided satisfactory qualitative modeling of many important features of structured soils.

• Korean Journal of Organic Agriculture
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• v.20 no.1
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• pp.81-89
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• 2012

This study was investigated to evaluate the effects of fertilizer application of surface and broadcast for rice culture on the soil chemical, physical, and microbial properties as well as growth and yield of rice. The application was made with 'Dongjin 1' rice at Jeollanam-do Agricultural Research & Extension Services from 2008 to 2010. Soil organic matter and cation concentrations were increased by surface and broadcast applications, respectively. Plots treated by surface application tended to be higher seasonal N-mineralization rate in the organic fertilizer and seasonal soil organic matter than those of broadcast application. Soil physical properties seemed to be improved by the broadcast application, and soil microbial properties were increased by the surface application. Surface application increased 5% of rice yield compared to that of broadcast.

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.3
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• pp.91-100
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• 1999

Tow constitutive models for weathered granite soil, Yasufuku's constitutive model with a single yield surface and Lade's constitutive model with two intersectiong yield surface compared in terms of their capabilities to accurately capture the observed behavior of compacted weathered grainite soil for various stress-paths. Both the single surface and the double surface models capture the experimentally observed behavior at a variety of stress-paths with good accuracy. The double surface model may model the observed compacted weathered granite soil behavior with better accuracy for proportational loading with increasing stress, but the single surface model may model dilatancy property with better accuracy for p-constant loading with increasing stress ratio.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.2
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• pp.268-272
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• 2015

The current study was carried out to determine the influence of different resting surfaces and stall types on milk yield and animal health. Study was carried out in Bursa that is one of the most important cities of Turkey in terms of dairy production. Effects of resting surfaces and stall types on milk yield were found to be important. Also influence of different resting surfaces and stall types on lactation length was examined and found that rubber mats were different from the two other options. Relationships between different resting surfaces or stall types and health problems were examined and connection between stall type and repeat breeding (RB), dystocia, retained placenta and a connection between resting surface types and RB and clinical mastitis were found to be important. Considering their economic reflections, it can be said that results are quite important to the Turkish dairy industry.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.4
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• pp.387-398
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• 1997

This experiment was to investigate the surface coverage, sward height and dry matter yield of 63 perennial ryegrass cultivars with control cultivar, orchardgrass(Potomac) at different cutting dates(May 25, July 5, August 20 and October 5), in order to select the adaptable cultivars of perennial ryegrass in the middle region of Korea. Four perennial ryegrass cultivars, E.V. Meadea, Aberystwyth S101, Raidor and Real, didn't survive afler sowing. Surface coverage of perennial ryegrass cultivars cut in August 20 was lower than others. Sward height of perennial ryegrass cultivars at each cutting dates was lower than that of orchardgrass. There were no significant differences in sward heights of each cutting date. Dry matter yield of perennial ryegrass cultivars cut in August 20 was lower than others. Total dry matter yield of Oakpark 6% Viktoria, Petra, G. Manawa, and Kangaroo Valley was fell in the range of 11.76 and 10.37t/ha while that of orchardgrass was 12.09t/ha. On the basis of total annual dry matter yield, the adaptability of perennial ryegrass cultivars was classfied as following.

• Macromolecular Research
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• v.11 no.5
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• pp.387-392
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• 2003

The ablation effects of Ar-plasma treatment and alkali-decomposition behavior in NaOH solution of polyethylene terephthalate (PET) film were investigated. The modifications were evaluated by analysis of atomic force microscopy topographical changes, and by the measurement of decomposition yield in conjunction with heats of formation and electron densities of acyl carbon calculated by Parameterization Method 3 method. It has shown that the alkali-decomposition is hampered by plasma treatment and its decomposition yield is closely related with plasma treatment conditions such as exposure time to plasma. Plasma-treated PET films exhibited lower decomposition yield, compared to that of virgin PET. Increasing plasma exposure time contributes positively to decrease the decomposition yield. It has also shown that the topography of PET surface was affected by the base-promoted hydrolysis as well as Ar-plasma treatments. These behaviors are attributed to the decreased nucleophilicity of acyl carbon damaged by the ablation of Ar-plasma.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.563-569
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• 2013

This experiment was carried out to investigate the effect of liquid-pig-manure application method (Tr.1: surface appl. LPM 150%, Tr.2: surface appl. LPM 50% + LPM 50%, Tr.3: chemical fertilizer, Tr.4: soil injection LPM 150%, Tr.5: soil injection LPM 50% + surface appl. 50%, Tr.6: no fertilizer) and the economic efficiency of yield on forage crops cultivaion. In barley cultivation experiment, Tr.5 was found to be best, showing the yield of 1,462 kg $10a^{-1}$, and followed by Tr.2(1,226 kg $10a^{-1}$), Tr.3(1,226 kg $10a^{-1}$), Tr.4(1,225 kg $10a^{-1}$) and Tr.1(1,209 kg $10a^{-1}$) in order. In maize cultivation experiment, Tr.4 was found to be best, showing the yield of 2,142 kg/10a, and followed by Tr.1(2,125 kg $10a^{-1}$), Tr.3(2,024 kg $10a^{-1}$), Tr.5(2,011 kg $10a^{-1}$) and Tr.2(1,925 kg 1$10a^{-1}$) in order. The income was showing 1,274,000 ~ 1,591,000 Won $10a^{-1}$ in barley, whereas 766,000-794,000 Won 1$10a^{-1}$ in maize. There was more economical efficiency in barley cultivation than maize cultivation. Rather than the LPM surface application, LPM soil injection was more effective.

• Journal of The Korean Society of Grassland and Forage Science
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• v.10 no.2
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• pp.65-69
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• 1990

An experiment was carried out ot determine the effects of seeding rates and seedbed preparations on the establishment and yield of surface-sown pasture species. Establishment of orchardgrass was significantly increased by the lowest seeding rate of 20 kg/ha as compared to 30 and 40 kg/ha, but no differences were found between the seeding rates of ladino clover. Both raking and burning significantly improved the establishment of pasture species in comparison with non-treatment. There was a significant difference between the raking and burning for the establishment of orchardgrass, but no significant difference was found between the two treatments for that of ladino clover. Increasing seeding rate of pasture species did not enhance the yield of surface-sown pasture, but both the raking and non-treatment significantly increased the yield of pasture species. The results suggest that both the raking and burning can improve the establishment but increasing seeding rate over 20 kg/ha and burning may not increase the yield.