• Journal of Animal Science and Technology
• /
• v.65 no.6
• /
• pp.1323-1340
• /
• 2023

There are several factors that affect the welfare and meat quality of pigs during pre-slaughter transport. Among various factors, the effects of weather conditions and loading density were studied. A total of 3,726 finishing pigs were allotted to one of nine groups arranged in a 3 × 3 factorial design according to the weather conditions (low temperature [LT], under 10℃; normal temperature [NT], 10℃-24℃; high temperature [HT], upper 24℃), and loading density (low density [LD], upper 0.43 m²/100 kg; normal density [ND], 0.37-0.43 m²/100 kg; high density [HD], under 0.37 m²/100 kg). Each treatment group follow as: LTLD, LTND, LTHD, NTLD, NTND, NTHD, HTLD, HTND, HTHD. In terms of carcass composition, pigs had the highest carcass weight and backfat thickness at LT. Comparing the HD transport to the ND transport, the meat quality indicated a lower pH and more drip loss. The incidence rate of pale, soft, exudative (PSE) pork was high in the order of the HD, LD, and the ND transport (20%, 9%, and 2%, respectively). The HT transport showed the lowest pH and greatest L^* value under the given weather conditions. Pigs transported under the HTHD and LTLD conditions had the greatest rates of PSE pork (40% and 20%, respectively). Pigs exposed to HD transport had the shortest laying time and the highest overplap behavior. The LDLT transport pigs had a shorter laying time than the LDNT and LDHT transport pigs. In conclusion, too high or too low density transport is generally not excellent for meat quality or animal welfare, however it is preferable to transport at a slightly low density at high temperature and at a slightly high density at low temperature.

• Nuclear Engineering and Technology
• /
• v.38 no.3
• /
• pp.293-300
• /
• 2006

A liquid metal reactor (LMR) operated at high temperatures is subjected to both cyclic mechanical loading and thermal loading; thus, creep-fatigue is a major concern to be addressed with regard to maintaining structural integrity. The Korea Advanced Liquid Metal Reactor (KALIMER), which has a normal operating temperature of $545^{\circ}C$ and a total service life time of 60 years, is composed of various cylindrical structures, such as the reactor vessel and the reactor baffle. This study focuses on the creepfatigue crack initiation for a cylindrical Y-junction structure made of 316 stainless steel (SS), which is subjected to cyclic axial tensile loading and thermal loading at a high-temperature hold time of $545^{\circ}C$. The evaluation of the considered creep-fatigue crack initiation was carried out utilizing the ${\sigma}_d$ approach of the RCC-MR A16 guide, which is the high-temperature defect assessment procedure. This procedure is based on the total accumulated strain during the service time. To confirm the evaluated result, a high-temperature creep-fatigue structural test was performed. The test model had a circumferential through wall defect at the center of the model. The defect front of the test model was investigated after the $100^{th}$ cycle of the testing by utilizing a metallurgical inspection technique with an optical microscope, after which the test result was compared with the evaluation result. This study shows how creep-fatigue crack initiation for a high-temperature structure can be predicted with conservatism per the RCC-MR A16 guide.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.5 no.4
• /
• pp.466-473
• /
• 2017

RC (Reinforced Concrete) member has varying service life due to varying diffusion characteristics with loading conditions even if it is exposed to constant exterior conditions. In the paper, quantitative parameters are obtained through adopting the previous results for effects of compressive, tensile, and cold joint on chloride diffusion in OPC (Ordinary Portland Cement) and GGBFS (Ground Granulated Blast Furnace Slag) concrete. Service life is evaluated in RC simple beam with 10.0m of span through increasing loading from self weight (2.5kN/m) to the loading to cracking moment (5.5kN/m). In OPC concrete without cold joint, service life changes to 89.4% for tensile region and 101% for compressive region with loadings while GGBFS concrete has 80.0% and 106%, respectively. For cold joint area, GGBFS concrete shows much reduced service life to 82~80% in compressive region and 69~61% in tensile region, which is caused by the lower diffusion in normal condition but relatively higher increasing cold joint effect than OPC concrete.

• Journal of the Korean Society of Physical Medicine
• /
• v.5 no.1
• /
• pp.15-24
• /
• 2010

Purpose : The purpose of this study was to investigate the effect of loading position on plantar center of pressure(COP) displacement when carrying a schoolbag during walking. Methods : Forty-four normal subjects were randomly assigned to five groups according to the method of carrying a schoolbag. The carrying a schoolbag methods were classified into five conditions: no bag (condition 1), a backpack (condition 2), a shoulder bag (condition 3), a cross bag (condition 4), a one-hand bag (condition 5). COP displacement such as anteroposterior distance and mediolateral distance of COP were measured with F-scan system. The repeated one-way analysis of variance (ANOVA) and independent t-test were used to confirm the statistical significance. Results : In the comparison of parameters of COP displacement between conditions, anteroposterior distance and mediolateral distance in the left foot and mediolateral distance in the right foot were not significantly different(p>.05), but anteroposterior diatance in the right foot was significantly different(p>.05). Between left and right foot, at condition 1 and 5 the mediolateral distance of COP was significantly different(p<.05) but anteroposterior distance at condition 1 and 5, anteroposterior distance and mediolateral distance of COP at condition 2, 3 and 4 were not significantly different(p>.05). Conclusion : These findings showed that the various loading position by five types of carrying a schoolbag didn't have influence significantly on COP displacement on during walking because of mechanism of postural adaption.

• Korean Chemical Engineering Research
• /
• v.46 no.5
• /
• pp.983-987
• /
• 2008

Computational simulation has been performed to design optimally the filtration system for IGCC pilot plant. It was analyzed how the different inflow pattern influences the flow field and the particle behavior in a filter vessel. The particle loading onto the filter surface lowers significantly and decreases dramatically with particle size when the dusty gas flows into the filter vessel with a shroud tube through a tangential inlet setup tangentially on the vessel outer wall. However, the particle loading is considerably high when the dusty gas enters the filter vessel through a normal inlet setup vertically on the vessel top wall, and the decrease of the particle loading with particle size is not steeper compared with the tangential inflow pattern.

• Nuclear Engineering and Technology
• /
• v.49 no.4
• /
• pp.855-864
• /
• 2017

The control rod assembly controls reactor power by adjusting its position during normal operation and shuts down chain reactions by its free drop under scram conditions. Therefore, the drop performance of the control rod assembly is important for the safety of a nuclear reactor. In this study, the drop performance of the conceptually designed control rod assembly for the prototype generation IV sodium-cooled fast reactor that is being developed at the Korea Atomic Energy Research Institute as a next-generation nuclear reactor was experimentally investigated. For the performance test, the test facility and test procedure were established first, and several free drop performance tests of the control rod assembly under different flow rate conditions were then carried out. Moreover, performance tests under several types and magnitudes of seismic loading conditions were also conducted to investigate the effects of seismic loading on the drop performance of the control rod assembly. The drop time of the conceptually designed control rod assembly for 0% of the tentatively designed flow rate was measured to be 1.527 seconds, and this agrees well with the analytically calculated drop time. It was also observed that the effect of seismic loading on the drop time was not significant.

• Structural Engineering and Mechanics
• /
• v.86 no.2
• /
• pp.167-180
• /
• 2023

This work applies a four-known quasi-3D shear deformation theory to investigate the bending behavior of a functionally graded plate resting on a viscoelastic foundation and subjected to hygro-thermo-mechanical loading. The theory utilizes a hyperbolic shape function to predict the transverse shear stress, and the transverse stretching effect of the plate is considered. The principle of virtual displacement is applied to obtain the governing differential equations, and the Navier method, which comprises an exponential term, is used to obtain the solution. Novel to the current study, the impact of the viscoelastic foundation model, which includes a time-dependent viscosity parameter in addition to Winkler's and Pasternak parameters, is carefully investigated. Numerical examples are presented to validate the theory. A parametric study is conducted to study the effect of the damping coefficient, the linear and nonlinear loadings, the power-law index, and the plate width-tothickness ratio on the plate bending response. The results show that the presence of the viscoelastic foundation causes an 18% decrease in the plate deflection and about a 10% increase in transverse shear stresses under both linear and nonlinear loading conditions. Additionally, nonlinear loading causes a one-and-a-half times increase in horizontal stresses and a nearly two-times increase in normal transverse stresses compared to linear loading. Based on the article's findings, it can be concluded that the viscosity effect plays a significant role in the bending response of plates in hygrothermal environments. Hence it shall be considered in the design.

• Smart Structures and Systems
• /
• v.19 no.2
• /
• pp.203-211
• /
• 2017

This paper provides a numerical solution for multiple confocal elliptic dissimilar cylinders. In the problem, the inner elliptic notch is under the traction free condition. The medium is composed of many confocal elliptic dissimilar cylinders. The transfer matrix method is used to study the continuity condition for the stress and displacement along the interfaces. Two cases, or the infinite matrix case and the finite matrix case, are studied in this paper. In the former case, the remote tension is applied in y- direction. In the latter case, the normal loading is applied along the exterior elliptic contour. For two cases, several numerical results are provided.

• Journal of Mechanical Science and Technology
• /
• v.14 no.8
• /
• pp.845-850
• /
• 2000

We consider the problem of determining the singular stresses and electric fields in a piezoelectric ceramic strip containing a Griffith crack under in-plane normal loading within the framework of linear piezoelectricity. The potential theory method and Fourier transforms are used to reduce the problem to the solution of dual integral equations, which are then expressed to a Fredholm integral equation of the second kind. Numerical values on the field intensity factors are obtained, and the influences of the electric fields for PZT-6B piezoelectric ceramic are discussed.

• Structural Engineering and Mechanics
• /
• v.24 no.5
• /
• pp.601-620
• /
• 2006

The paper presents an effective stiffness model for deformational analysis of reinforced concrete cracked members in bending throughout the short-term loading up to the near failure. The method generally involves the analytical derivation of an effective moment of inertia based on the smeared crack technique. The method, in a simplified way, enables us to take into account the non linear properties of concrete, the effects of cracking and tension stiffening. A statistical analysis has shown that proposed technique is of adequate accuracy of calculated and experimental deflections data provided for beams with small, average and normal reinforcement ratios.