• Nuclear Engineering and Technology
• /
• v.53 no.11
• /
• pp.3816-3823
• /
• 2021

The mechanical features evaluated theoretically using Makishima-Mackenzie's model for glasses xBaO-(50-x) PbO-50P₂O₅ where x = 0, 5, 10, 15, 20, 30, 40, and 50 mol%. Wherefore, the elastic characteristics; Young's, bulk, shear, and longitudinal modulus calculated. The obtained result showed an increase in the calculated values of elastic moduli with the replacement of the PbO by BaO contents. Moreover, the Poisson ratio, micro-hardness, and the softening temperature calculated for the investigated glasses. Besides, gamma and neutron shielding ability evaluated for the barium doped lead phosphate glasses. Monte Caro code (MCNP-5) and the Phy-X/PSD program applied to estimate the mass attenuation coefficient of the studied glasses. The decrease in the PbO ratio has a negative effect on the MAC. The highest MAC decreased from 65.896 cm²/g to 32.711 cm²/g at 0.015 MeV for BPP0 and BPP7, respectively. The calculated values of EBF and EABF showed that replacement of PbO with BaO contents in the studied BPP glasses helps to reduce the number of photons accumulated inside the studied BPP glasses.

• Journal of the Korean Society of Food Culture
• /
• v.35 no.6
• /
• pp.582-589
• /
• 2020

This study was carried out to determine the optimum temperature of the jicama pickle solution by evaluating physicochemical and sensory characteristics at various temperatures. The soaking solution of the jicama pickle was prepared at different temperatures (95, 75, 50, and 25℃). During storage, the titratable acidity, Brix, and the salinity of the jicama pickles increased, and these values increased with increasing temperature of the soaking solution. The higher the temperature of the soaking solution, the lower the L and b values. In all samples, the hardness increased rapidly until the 5th day of storage, and then gradually decreased. During storage, the jicama pickles showed a high tendency to harden at soaking solution temperatures of 75 and 95℃. Sensory evaluation indicated that the taste, flavor, crispness, and overall preference of the jicama pickle were higher at a soaking solution temperature of 75℃ and above. The higher the temperature of the soaking solution, the higher the acceptability. Based on these results, we conclude that soaking solution temperature of 75°¦95℃ in the manufacture of jicama pickles had a positive effect on the reduction in tissue softening and the sensory properties of the jicama pickle.

• Korean Journal of Metals and Materials
• /
• v.47 no.11
• /
• pp.687-693
• /
• 2009

Experiments have demonstrated that a moderate amount of Be added to $Zr_{57.5}Cu_{38.3}Al_{4.2}$ amorphous alloy enhances the plasticity of the alloy. In particular, $Zr_{54}Cu_{36}Al_{4}Be_{6}$ alloy exhibited 19% of strain to fracture along with a strength exceeding 2 GPa. Energy dispersive x-ray spectroscopy conducted on the $Zr_{54}Cu_{36}Al_{4}Be_{6}$ alloy exhibited the presence of compositional modulation, indicating that nm-scale phase separation had occurred at local regions. In this study, the role played by the nm-scale phase separation on the plasticity was investigated in terms of structural disordering, structural softening and shear localization in order to better understand the structural origin of the enhanced plasticity shown by the developed alloy.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.21 no.8
• /
• pp.93-98
• /
• 2022

Adiabatic blanking is a method to improve productivity through an autocatalytic cycle that occurs repeatedly through plastic deformation and thermal softening caused by impact energy. In this study, an axisymmetric analysis model comprising a punch, die, holder, and specimen was developed to confirm the temperature and deformation characteristics caused by an impact load. Through this, the impact energy, diameter of the punch, gap between the punch and die, and the effect of the fillet were analyzed. Because this process occurs in a very short time, adiabatic analysis can be performed using the explicit time-integration method. The analysis, confirmed that it is necessary to design a structure capable of increasing the local temperature and plastic deformation by controlling the impact energy, working area, gap, and the fillet.

• Steel and Composite Structures
• /
• v.47 no.3
• /
• pp.423-436
• /
• 2023

In this research, we tested 10 simply supported concrete-encased composite columns under monotonic eccentric loads and investigated their shear behaviour. The specimens tested were two reinforced concrete specimens, three steel-reinforced concrete (SRC) specimens with an H-shaped steel section (also called a beam section), and five SRC specimens with a cruciform-shaped steel section (also called a column section). The experimental variables included the transverse steel shape's depth and the longitudinal steel flange's width. Experimental observations indicated the following. (1) The ultimate load-carrying capacity was controlled by web compression failure, defined as a situation where the concrete within the diagonal strut's upper end was crushed. (2) The composite effect was strong before the crushing of the concrete outside the steel shape. (3) We adjusted the softened strut-and-tie SRC (SST-SRC) model to yield more accurate strength predictions than those obtained using the strength superposition method. (4) The MSST-SRC model can more reasonably predict shear strength at an initial concrete softening load point. The rationality of the MSST-SRC model was inferred by experimentally observing shear behaviour, including concrete crushing and the point of sharp variation in the shear strain.

• Geomechanics and Engineering
• /
• v.34 no.1
• /
• pp.69-86
• /
• 2023

To overcome the dilemma of the [BQ] method's inability to predict mountain tunnel support loads, this study is based on the Hoek-Brown criterion and previous results to obtain the connection equations from GSI scores to each parameter of the Hoek-Brown criterion and the link between the [BQ] scores and the GSI system. The equations were embedded in the Hoek-Brown criterion of FLAC6.0 software to obtain tunnel construction forecasts without destroying the in-situ stratigraphy. The feasibility of the secondary development of the Hoek-Brown criterion was verified through comparative analysis with field engineering measurements. If GSI > 45 with a confining pressure of less than 10 MPa, GSI has little effect on the critical softening factor while we should pay attention to the parameter of confining pressure when GSI < 45. The design values for each parameter are closer to the FLAC3D simulation results and the secondary development of the Hoek-Brown criterion meets the design objectives. If the Class V surrounding rock is thinned with shotcrete or the secondary lining is installed earlier, the secondary lining may act as the main load-bearing structure. The study may provide ideas for rapid prediction of mountainous tunnels in China.

• Journal of the Korean Society of Food Culture
• /
• v.25 no.1
• /
• pp.82-90
• /
• 2010

In this study, the rheological properties of doughs blended with 5% to 20% fermented rice bran (FRB) were investigated using farinographs, amylographs, extensographs, and SEM. In the farinograph analysis, the water absorption decreased and the replacement ratio of FRB increased over the time of development of the dough. The stability time of the dough was shortened, and the degree of softening decreased with added volume of FRB. The amylograph analysis showed that the temperature at the beginning of gelatinization showed a tendency to increase with increasing replacement ratio of FRB, but the gelatinization temperature showed no significant difference between the FRB-added groups and control group. The extensograph analysis showed that when the replacement ratio of FRB was over 10%, the extension of the dough decreased while the resistance was increased. In the SEM analysis, the added dough with less than 10% FRB had similar characteristics in gluten matrix and gas bubbles to those of the control of wheat flour alone. It was concluded that an added FRB volume of below 10% is most suitable for bread making.

• Geomechanics and Engineering
• /
• v.34 no.2
• /
• pp.197-208
• /
• 2023

Rate-dependent mechanical response of sand, subjected to loading of medium to high strain rate range, is of interest for several civilian and military applications. Such rate-dependent response can vary significantly based on the initial density state of the sand, applied confining pressure, considered strain rate range, drainage condition and sand morphology. A numerical study has been carried out employing a recently proposed visco-plastic constitutive model to explore the rate-dependent mechanical behaviour of Toyoura sand under drained triaxial loading condition. The model parameters have been calibrated using the experimental data on Toyoura sand available in published literature. Under strain rates higher than a reference strain rate, the simulation results are found to be in good agreement with the experimentally observed characteristic shearing behaviour of sand, which includes increased shear strength, pronounced post-peak softening and suppressed compression. The rate-dependent response, subjected to intermediate strain rate range, has further been assessed in terms of enhancement of peak shear strength and peak friction angle over varying initial density and confining pressure. The simulation results indicate that the rate-induced strength increase is highest for the dense state and such strength enhancements remain nearly independent of the applied confinement level.

• Advances in nano research
• /
• v.16 no.3
• /
• pp.265-272
• /
• 2024

In this paper, the problem of static bending of axially functionally graded (AFG) nanobeam is formulated with the local stress(Lσ)- and strain-driven(εD) two-phase local/nonlocal integral models (TPNIMs). The novelty of the present study aims to compare the size-effects of nonlocal integral models on bending deflections of AFG Euler-Bernoulli nano-beams. The integral relation between strain and nonlocal stress components based on two types nonlocal integral models is transformed unitedly and equivalently into differential form with constitutive boundary conditions. Purely LσD- and εD-NIMs would lead to ill-posed mathematical formulation, and Purely εD- and LσD-nonlocal differential models (NDM) may result in inconsistent size-dependent bending responses. The general differential quadrature method is applied to obtain the numerical results for bending deflection and moment of AFG nanobeam subjected to different boundary and loading conditions. The influence of AFG index, nonlocal models, and nonlocal parameters on the bending deflections of AFG Euler-Bernoulli nanobeams is investigated numerically. A consistent softening effects can be obtained for both LσD- and εD-TPNIMs. The results from current work may provide useful guidelines for designing and optimizing AFG Euler-Bernoulli beam based nano instruments.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.10 no.5
• /
• pp.115-121
• /
• 2006

This paper deals with the influence of behavior of a variety of cable elements on the limit strength of steel cable-stayed bridges. The softening plastic-hinge model, which is represented in this study for the limit strength evaluation of the example bridge, considers both geometric and material nonlinearites. Geometric nonlinearity of beam-column members are accounted by using stability function, and material nonlinearity - by using CRC tangent modulus and parabolic function. Cable sag effect is considered for cable members. The result of this study shows that the limit strength of the example bridge using the equivalent of elasticity for truss straight elements is smaller than those using the cable or the catenary elements.