• Structural Engineering and Mechanics
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• v.82 no.1
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• pp.1-16
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• 2022

This work elaborately investigates the influences of the guideway geometry parameters and track irregularity on the dynamic performances of the suspended monorail vehicle-guideway system (SMVGS). Firstly, a spatial dynamic analysis model of the SMVGS is established by adopting ANSYS parameter design language. Then, the dynamic interaction between a vehicle with maximum design load and guideway is investigated by numerical simulation and field tests, revealing the vehicle-guideway dynamic features. Subsequently, the influences of the guideway geometry parameters and track irregularity on the dynamic performances of the SMVGS are analyzed and discussed in detail, and the reasonable ranges of several key geometry parameters of the guideway are also obtained. Results show that the vehicle-guideway dynamic responses change nonlinearly with an increase of the guideway span, and especially the guideway dynamic performances can be effectively improved by reducing the guideway span; based on a comprehensive consideration of all performance indices of the SMVGS, the deflection-span ratio of the suspended monorail guideway is finally recommended to be 1/1054~1/868. The train load could cause a large bending deformation of the pier, which would intensify the car-body lateral displacement and decrease the vehicle riding comfort; to well limit the bending deformation of the pier, its cross-section dimension is suggested to be more than 0.8 m×0.8 m. The addition of the track irregularity amplitude has small influences on the displacements and stress of the guideway; however, it would significantly increase the vehicle-guideway vibrations and rate of load reduction of the driving tyre.

• Animal Bioscience
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• v.35 no.3
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• pp.475-483
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• 2022

Objective: Methionine (Met) is involved in methyl group transfer besides protein synthesis. As the availability is limited and cost is high for synthetic Met, reductions in its inclusion in broiler diet may be possible by supplementing the low Met diets with methyl donors (MD) like betaine (Bet), folic acid (FA), vitamin B12 (B12), and biotin (Bio). An experiment was conducted to study the effects of supplementing the MD on performance (average daily gain [ADG], daily feed intake, feed efficiency [FE]), anti-oxidant variables, immune responses and serum protein concentration in broilers fed sub-optimal concentrations of dietary Met. Methods: Maize-soybean meal diet was used as control (CD). Different MD like Bet (0.2%), B12 (0.1 mg), FA (4 mg), or Bio (1.5 mg/kg) were supplemented to basal diet (BD) having no supplemental Met. The BD without MD was kept for comparison. Each diet was fed ad libitum to 10 replicates of 25 chicks in each from 1 to 42 d of age. Results: At the end of experiment, the ADG in MD group was higher than BD and lower than CD. The FE improved with FA or Bet compared to the BD. Breast meat weight was higher in Bet compared to the BD, while it was intermediate between BD and CD in other groups. The lipid peroxidation reduced with Bio, B12, or Bet, while the glutathione peroxidase activity improved with Bio or B12 compared to the BD. Lymphocyte proliferation improved with Bet compared to the BD. The serum protein concentrations increased with FA, Bio, or Bet compared to those fed BD. Conclusion: It can be concluded that the ADG can be improved partially with supplementation of MD while the FE improved with FA or Bet. Some MD also reduced the stress indices and improved immune responses compared to the BD fed broilers.

• Korean Journal of Agricultural Science
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• v.49 no.4
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• pp.927-936
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• 2022

The effects of seasonal differences and crating densities on the preslaughter losses, breast meat quality, and physiological indices of broilers were determined. A total of 600 broilers aged 35 days were divided into 10 treatment groups based on five crating densities (10.3, 11.5, 12.8, 14.1, 15.4 birds·m^-2) with two seasons (i.e., summer and winter) to give six replicates and were placed at various locations in the truck. The birds were transported in crates having dimensions of 1.0 m × 0.78 m × 0.26 m. The transportation distance was 20 km for 40 minutes (average 30 - 50 km·h^-1) during the early morning. The results revealed that broilers transported at densities of 14.1 and 15.4 birds·m^-2 recorded lower (p < 0.05) pH, water-holding capacity (WHC), and muscle redness compared to those at densities of 11.5 birds·m^-2. Furthermore, higher (p < 0.05) cooking loss was found in birds stocked at more than 14.1 birds·m^-2 compared to the other treatments. However, no effect (p > 0.05) with different crating densities on body weight loss, carcass traits, glucose, lactate, or muscle yellowness was observed. Crating density of 14.1 birds·m^-2 showed lower (p < 0.05) cortisol contents compared with birds at 10.3 and 15.4 birds·m^-2. Winter transportation had higher (p < 0.05) relative breast meat weight, cooking loss, muscle redness, and cortisol contents whereas summer transportation had higher (p < 0.05) glucose and lactate contents in the blood plasma of broilers. In conclusion, the stocking of 12.8 birds·m^-2 is recommended to minimize stress responses and undesirable changes that could negatively affect muscle quality.

• Steel and Composite Structures
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• v.45 no.5
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• pp.729-747
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• 2022

The critical buckling loads and buckling modes of bi-directional functionally graded porous unified higher order shear plate with elastic foundation are investigated. A mathematical model based on neutral axis rather than midplane is developed in comprehensive way for the first time in this article. The material constituents form ceramic and metal are graded through thickness and axial direction by the power function distribution. The voids and cavities inside the material are proposed by three different porosity models through the thickness of plate. The constitutive parameters and force resultants are evaluated relative to the neutral axis. Unified higher order shear plate theories are used to satisfy the zero-shear strain/stress at the top and bottom surfaces. The governing equilibrium equations of bi-directional functionally graded porous unified plate (BDFGPUP) are derived by Hamilton's principle. The equilibrium equations in the form of coupled variable coefficients partial differential equations is solved by using numerical differential integral quadrature method (DIQM). The validation of the present model is presented and compared with previous works for bucking. Deviation in buckling loads for both mid-plane and neutral plane are developed and discussed. The numerical results prove that the shear functions, distribution indices, boundary conditions, elastic foundation and porosity type have significant influence on buckling stability of BDFGPUP. The current mathematical model may be used in design and analysis of BDFGPU used in nuclear, mechanical, aerospace, and naval application.

• Geomechanics and Engineering
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• v.36 no.3
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• pp.259-276
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• 2024

The undrained shear strength is widely acknowledged as a fundamental mechanical property of soil and is considered a critical engineering parameter. In recent years, researchers have employed various methodologies to evaluate the shear strength of soil under undrained conditions. These methods encompass both numerical analyses and empirical techniques, such as the cone penetration test (CPT), to gain insights into the properties and behavior of soil. However, several of these methods rely on correlation assumptions, which can lead to inconsistent accuracy and precision. The study involved the development of innovative methods using extreme gradient boosting (XGB) to predict the pile set-up component "A" based on two distinct data sets. The first data set includes average modified cone point bearing capacity (q_t), average wall friction (f_s), and effective vertical stress (σ_vo), while the second data set comprises plasticity index (PI), soil undrained shear cohesion (S_u), and the over consolidation ratio (OCR). These data sets were utilized to develop XGBoost-based methods for predicting the pile set-up component "A". To optimize the internal hyperparameters of the XGBoost model, four optimization algorithms were employed: Particle Swarm Optimization (PSO), Social Spider Optimization (SSO), Arithmetic Optimization Algorithm (AOA), and Sine Cosine Optimization Algorithm (SCOA). The results from the first data set indicate that the XGBoost model optimized using the Arithmetic Optimization Algorithm (XGB - AOA) achieved the highest accuracy, with R2 values of 0.9962 for the training part and 0.9807 for the testing part. The performance of the developed models was further evaluated using the RMSE, MAE, and VAF indices. The results revealed that the XGBoost model optimized using XGBoost - AOA outperformed other models in terms of accuracy, with RMSE, MAE, and VAF values of 0.0078, 0.0015, and 99.6189 for the training part and 0.0141, 0.0112, and 98.0394 for the testing part, respectively. These findings suggest that XGBoost - AOA is the most accurate model for predicting the pile set-up component.

• Structural Engineering and Mechanics
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• v.90 no.3
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• pp.233-252
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• 2024

This research explores a new finite element model for the free vibration analysis of bi-directional functionally graded (BDFG) beams. The model is based on an efficient higher-order shear deformation beam theory that incorporates a trigonometric warping function for both transverse shear deformation and stress to guarantee traction-free boundary conditions without the necessity of shear correction factors. The proposed two-node beam element has three degrees of freedom per node, and the inter-element continuity is retained using both C1 and C0 continuities for kinematics variables. In addition, the mechanical properties of the (BDFG) beam vary gradually and smoothly in both the in-plane and out-of-plane beam's directions according to an exponential power-law distribution. The highly elevated performance of the developed model is shown by comparing it to conceptual frameworks and solution procedures. Detailed numerical investigations are also conducted to examine the impact of boundary conditions, the bi-directional gradient indices, and the slenderness ratio on the free vibration response of BDFG beams. The suggested finite element beam model is an excellent potential tool for the design and the mechanical behavior estimation of BDFG structures.

• Structural Engineering and Mechanics
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• v.90 no.3
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• pp.253-261
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• 2024

This research explores a new finite element model for the free vibration analysis of bi-directional functionally graded (BDFG) beams. The model is based on an efficient higher-order shear deformation beam theory that incorporates a trigonometric warping function for both transverse shear deformation and stress to guarantee traction-free boundary conditions without the necessity of shear correction factors. The proposed two-node beam element has three degrees of freedom per node, and the inter-element continuity is retained using both C1 and C0 continuities for kinematics variables. In addition, the mechanical properties of the (BDFG) beam vary gradually and smoothly in both the in-plane and out-of-plane beam's directions according to an exponential power-law distribution. The highly elevated performance of the developed model is shown by comparing it to conceptual frameworks and solution procedures. Detailed numerical investigations are also conducted to examine the impact of boundary conditions, the bi-directional gradient indices, and the slenderness ratio on the free vibration response of BDFG beams. The suggested finite element beam model is an excellent potential tool for the design and the mechanical behavior estimation of BDFG structures.

• The Korean Journal of Malacology
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• v.32 no.3
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• pp.175-184
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• 2016

In this study, we transplanted Chinese (Liaoning Dandong) and Chungnam (Taean) manila clam seeds to Gochang tidal flats in Jeonbuk province, and compared growth, mortality, and condition indices from May 2015 to August 2016. Within 2 months after transplantation, clam mortality of Chungnam and Chinese origin were $6.9{\pm}4.3%$, $16.9{\pm}7.9{\sim}21.0{\pm}6.3%$, respectively. We supposed that higher mortality of Chinese manila clams might be due to higher stress and weakening of physiological functions by air-exposure and unavailability of food intake for 5 days harvesting, transportation, quarantine procedures. Unlike the local clam farmer's opinion based on their field experience, growth of Chungnam clams in shell length and total weight were a little better than Chinese without statistical significant difference (P > 0.05). Condition indices of Chinese clams showed declining tendency after reaching a peak in May 2014, and in June 2015, respectively. Meanwhile, Chungnam clams has reached its peak of condition indices in May 2014 and in April 2015, respectively. From this result, we supposed that there might be at least one month difference in reproduction between the Chinese and Chungnam manila clams during the first-transplanted year. Because the mortality of adult clam have sharply increased from June 2015 (due to high temperature, few rainfall and spawning) in Gochang tidal flat, it would be recommendable that farmers harvest the clams before June when its shell length are larger than 40 mm. In conclusion, we could directly compare the productivity of Chinese and Chungnam manila clam at Gochang tidal flats by field experiment, and these results are also meaningful to manila clam farmers.

• Journal of Korean Orthopaedic Sports Medicine
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• v.10 no.2
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• pp.78-85
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• 2011

Purpose: To evaluate the usefulness of computerized tomography (CT) for the diagnosis and the fragment fixation of anteroinferior tibiofibular ligament avulsion fracture in ankle fracture. Materials and Methods: We retrospectively studied 108 patients with an ankle fracture who had been checked with plain radiographs and CT from July 2006 to July 2010. They were divided into two groups; patients with (19 patients) and without (89 patients) an avulsion fracture of anteroinferior tibiofibular ligament. The two groups were evaluated with Lauge-Hansen classification, the energy of trauma, and the radiologic indices for syndesmotic injury, and were compared each other. Average follow up periods of two groups were 25 and 23 months each. Those who were unstable at stress test during surgery were divided into fragment fixation of anteroinferior tibiofibular ligament avulsion fracture group (8 patients) and transfixation one (11 patients) according to treatment method. Clinical and radiological results at last follow up were also compared. Results: Fourteen avulsion fractures of anteroinferior tibiofibular ligament were diagnosed by CT only. Incidences of pronation-external rotation injury, high energy trauma, positive radiologic indices for syndesmotic injury were significantly higher in patients with an avulsion fracture of anteroinferior tibiofibular ligament than those without it. Clinical and radiological results were satisfactory in both groups at last follow up, and were not significantly different between them. Conclusion: In patients who have an ankle fracture by pronation-external rotation injury, high energy trauma, or with positive radiologic indices for syndesmotic injury, CT is useful for diagnosis of an avulsion fracture of anteroinferior tibiofibular ligament. Fragment fixation of anteroinferior tibiofibular ligament avulsion fracture is a useful treatment option for syndesmotic injury.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.4
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• pp.234-248
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• 1998

Seven box cores from the disposal areas located in the southern part of the East Sea (Stations Band B') and in the offshore to the east of Pusan (Stations J and J'), and from their surrounding areas (Stations J2, J6 and H) were collected to investigate the effect of dumped wastes on the foraminiferal assemblages. The species diversity indices [S, H(S), E] of foraminifera and the total number of foraminifera show significant differences between the ocean waste disposal areas and their adjacent areas. Ocean waste disposal areas located in southern part of the East Sea (Stations Band B') show not only smaller number of foraminifera species but also lower values of coarse fraction content in the sediment and the number of benthic and planktonic foraminifera than the surrounding areas. Another ocean disposal area located offshore Pusan (Station J') contains abnormally greater number of planktonic (approximately 300 000 individuals/lO g dried sediment) and benthic (approximately 300, 000 individuals/10 g dried sediment) foraminifera compared to those of the adjacent areas. The waste dumped at Station J' probably acts as a nutrient causing the greater number of foraminifera. Station J shows low species diversity indices [S, H(S)]. The number of benthic foraminifera decreases from the surface to the downcore at Station J, which indicates that Station J is under stress. However, Stations J', J2 and J6 are under stable conditions as evidenced by the greater species diversity indices [S, H(S)] compared to other stations. No foraminifera were found with biological disease or abnormal chambers, which commonly occur in extremely stressed environment, in both the ocean disposal and adjacent areas. The organic matter decay of the wastes dumped in the study areas has not made the bottom water corrosive.