Reinforced concrete (RC) columns exhibit cyclic damage, such as strength degradation, under cyclic lateral loading, such as earthquakes. Considering the cyclic damage, the nonlinear load-deformation response of RC columns can be simulated using a lumped plasticity model. Based on an experimental database, this study calibrates lumped plasticity model parameters for 371 rectangular and 290 circular RC columns. The model parameters for adequate flexural rigidity, plastic rotation capacity, post-capping rotation capacity, moment strength, and cyclic strength degradation parameter are adjusted to match each experimentally observed load-deformation response. We have developed predictive equations that accurately relate the model parameters to the design characteristics of RC columns through regression analyses, providing a reliable tool for engineers and researchers. To demonstrate their application, the proposed and existing models numerically simulate the earthquake response of a bridge pier in a metropolitan railway bridge. The pier is subjected to several ground motions, increasing intensity until collapse occurs. The proposed lumped plasticity model showed about 41% less vulnerable to collapse.

Piloti-type buildings are widely constructed in urban areas of South Korea. Due to stiffness irregularities, piloti-type buildings are vulnerable to lateral loads such as earthquakes. Although seismic retrofitting is necessary for piloti-type buildings, many of these structures are privately owned, and the extensive number of buildings creates significant challenges in terms of cost and time for regional seismic performance evaluation. This study proposes a methodology for determining the seismic performance of multiple piloti-type buildings within a region by utilizing structural parameters. Information on piloti-type buildings is classified into public building data and exterior building data, which are integrated to define structural parameters for estimating the first natural period of the buildings. Linear regression analysis was performed to develop a regression equation correlating structural parameters with the natural period. Additionally, the natural period and structural parameters are used to perform another linear regression analysis to estimate the yield and ultimate points of the capacity curve. The capacity curves derived from the regression equations facilitate seismic performance evaluation based on structural parameters.

Genetic algorithms (GAs) are used to optimize solutions to problems, particularly those that are analytically impossible to solve. As their name suggests, they are inspired by the biological concepts of genetics and evolution. Our work aims to study and model a silicon-based photovoltaic generator (PVG). Among the various models available is that of the diode. Modeling was used to approximate the PVG output (voltage, current) as a function of two inputs: temperature and irradiation. The parameters of our model were identified using a real coding algorithm, with the cumulative square error was used for selection. To test the effectiveness of our model, we carried out simulation tests on the power-voltage (P-V) and current-voltage (I-V) characteristics of a wide range of irradiation and temperature variations. This study demonstrates the effectiveness and accuracy of the proposed approach (GAs) and validates the parameters obtained and used in the single-diode electrical model. The results indicate that the GA technique is a better conventional parameter extraction strategy in terms of convergence. It provides globally optimal solutions.

In the field of oscillating hydrofoil research, the choice of hydrofoils is still mainly based on traditional NACA airfoils. The article explores the hydrodynamic characteristics of other airfoil structures to further improve the applicable range of hydrofoil working environments. By applying the swept structure of fish tail fins through biomimetic methods to oscillating hydrofoils, a motion model of the swept oscillating hydrofoil is established, and the relevant mathematical expressions and parameter definitions are described. Through numerical simulation methods, the effects of the pitch axis position and the tip-to-root ratio on the performance of the swept oscillating hydrofoil are analyzed. The simulation results show that the pitch axis position has a significant impact on the various force characteristics and energy acquisition efficiency of the hydrofoil, while the tip-to-root ratio mainly reflects the degree of sweep of the hydrofoil, thereby affecting the lift-to-drag ratio and the moment coefficient of the swept hydrofoil. Selecting the appropriate pitch axis position and tip-to-root ratio will enhance the lift of the hydrofoil while reducing the drag experienced.

Gait analysis can objectively assess abnormal walking, and some walking parameters can help recognize the disease. Existing commercial systems are either too expensive and require attachments to the body or have limitations in detecting abnormal gait. A vision system has been proposed to address this. However it had limitations where the accuracy was inferior in some parameters such as gait phase, step length and width, etc. Therefore we developed a Tactile sensor-based treadmill to detect gait phase, step length, and width. A pilot test was performed and analyzed through an infrared marker-based motion capture system to compare the accuracy of the proposed system. The measured spatiotemporal gait parameters were analyzed through mean and standard deviation and compared to the baseline system. As a result of the experiments, it was confirmed that higher step width performance was achieved compared to previous studies. Future studies will validate the system with many participants and conduct clinical studies on gait recognition through abnormal gait analysis.

구조물에 작용하는 바람하중을 정량적으로 예측하는 것을 거의 불가능하다. 그러나 그 하중이 백색잡음으로부터 재생될 수 있다는 가정은 동적해석을 위한 수치시뮬레이션에 매우 유용할 뿐만 아니라 역해석과정에서 바람하중에 대한 유일 해를 추정할 수 있 는 가능성을 높일 수 있는 추가적인 구속조건을 제공한다는 측면에서 매우 유리하다. 그러한 가정에 의하여, 구조물 응답에 영향을 미 치는 동적특성과 하중특성(하중모델)을 차례로 제거하고 나면 순수한 백색잡음만 남게 되므로 이러한 백색화과정을 통하여 구조물의 동적 특성과 하중특성을 동시에 추정할 수 있는 방안을 모색할 수 있을 것이다. 본 연구에서는 스펙트럼 백색화과정을 통하여 구조물 의 모달 파라미터와 모달하중(하중모델을 구성하는 파라미터)을 동시에 추정하는 새로운 역해석 기법을 제안한다. 백색화과정을 모달 응답에 적용하여 모달 파라미터과 하중모델 파라미터를 구하는 과정을 유도하였으며, 제안된 동시 추정기법을 단자유도 모형, 공탄성 모델에 대한 풍동실험에 적용하여 모달파라미터 특히 감쇠비추정의 신뢰성을 검증하였으며, 그 결과 신뢰도가 높은 모달 파라미터, 하 중모델 파라미터 추정이 가능함을 알 수 있었다.

강도다리 대상 수인성 카드뮴 독성 영향을 확인하기 위해 96시간 동안 0, 2.5, 5, 10, 20, 40 mg Cd2+/L 에 노출시켰으며, 96시간 반수치사농도(LC50)는 21.42 mg Cd2+/L로 나타났다. 혈액학적 성상분석에서 Hematocrit와 Hemoglobin은 20 mg Cd2+/L에서 유의하게 증가하였다. 혈장 무기성분에서 calcium은 20 mg Cd2+/L에서 유의적으로 감소한 반면 magnesium은 유의적 변화가 없었다. 혈장 유기성분인 glucose는 카드뮴 노출에 의해 유의적으로 증가하였다. 혈장 효소 성분인 AST, ALT 및 ALP는 수인성 카드뮴 노출에 의해 20 mg Cd2+/L에서 유의적으로 증가하였다. 본 연구를 통해 수인성 카드뮴 급성 노출이 강도다리 혈액학적 성상 및 혈장성분 내 독성을 유발함을 확인하였으며, 이로 인한 사망률 유발 가능성을 예상할 수 있다.

본 연구는 대서양연어 (Salmo salar) 파르를 대상으로 다른 광주기 (L24:D0, L15:D9, L12:D12, L9:D15, L0:D24)에 60일간 노출시킨 후에 생존, 성장 및 혈액성분에 관한 영향을 연구하였다. 실험종료 시 생존율의 측정결과 L24:D0 실험구는 90.0± 7.1%, L12:D12 실험구는 87.5±3.5%, L9:D15 실험구는 97.5±3.5%, L24:D0 실험구는 97.5±3.5%로 나타났으나 각 실험구 간의 유의한 차이는 없었다. 실험종료 시 각 실험구의 증체율 (weight gain, WG), 일간성장률 (specific growth rate, SGR) 및 사료효율 (feed efficiency, FE)의 변화를 측정한 결과, 광주기 차이에 따른 유의한 변화는 보이지 않았다. 혈장 성분 중 ALT (alanine aminotransferase), AST(Aspartate Aminotransferase) 및 glucose는 L24:D0 실험구가 다른 실험구에 비해 유의하게 상승한 것으로 나타났다. 혈장 cortisol은 L24:D0와 L0:D24가 가장 높았으며, L15:D9와 L9:D15와는 유의한 차이는 보이지 않았지만, L12:D12보다는 유의하게 높은 것으로 나타났다. 혈장 sodium (Na+), potassium (K+), chloride (Cl-) 및 osmolality는 각 실험구 간에 유의한 차이는 보이지 않았다. 본 연구결과, 대서양연어 파트에 대해서 60일간 다른 광주기에 노출 시켰을 때 생존 및 성장도의 변화는 보이지 않았으나, L24:D0 실험구에서 조직손상과 스트레스 지표인 혈장 ALT, AST, cortisol 및 glucose 농도가 유의하게 상승하는 것으로 나타났다.

Clinical pathology, including hematology and serum chemistry, is an important indicator of biological changes. Animals for inhalation studies are kept in specific chambers and require historical data for accuracy. Age-related characteristics are essential for interpreting experimental results. This study aimed to provide historical clinical pathology data and analyze age-related trends in these parameters. We collected hematological and biochemical parameters from control groups of male and female F344 rats in the 4-, 13-, 26-, and 52-week repeated inhalation toxicity tests. The number of F344 rats from collected control groups were 24, 60, 50, and 25 males and 25, 60, 50, and 25 females in the 4-, 13-, 26-, and 52-week studies, respectively. Mean comparison, correlation analysis and simple linear regression analysis was conducted to reveal age-related trends. Neutrophil count, eosinophil count, neutrophil percentage, monocyte percentage, total protein, albumin, triglyceride, total cholesterol (TCHO) showed increasing trends, whereas lymphocyte count, lymphocyte percent, platelet count, alkaline phosphatase, albumin/globulin ratio, and inorganic phosphate showed decreasing trends in both the mean comparison and regression analyses. TCHO was considered the most affected parameter by aging in both sexes based on statistical results. In this study, we presented clinicopathological data from F344 rats for inhalation toxicity studies. We confirmed aging trends in clinicopathological parameters and identified TCHO as the parameter most affected by aging in F344 rats. These results would be helpful for inhalation research using F344 rats.

This research introduces a novel probabilistic approach to consider the effects of uncertainty parameters during the design and construction process, providing a fresh perspective on the evaluation of the structural performance of reinforced concrete structures. The study, which categorized various random design and construction process variables into three groups, selected a two-story reinforced concrete frame as a prototype and evaluated it using a nonlinear analytical model. The effects of the uncertainty propagations to seismic responses of the prototype RC frame were probabilistically evaluated using non-linear dynamic analyses based on the Monte-Carlo simulation sampling with the Latin hypercube method. The derivation of seismic fragility curves of the RC frame from the probabilistic distributions as the results of uncertainty-propagation and the verification of whether the RC frame can meet the seismic performance objective from a probabilistic point of view represent a novel and significant contribution to the field of structural engineering.

테트로도톡신(tetrodotoxin, TTX)은 강력한 해양생물 유 래 신경독소로, 수산물 내 TTX를 검출하기 위해 기존에 주로 사용되는 mouse bioassay (MBA)와 LC-MS/MS 기법 은 낮은 검출한계와 동물 윤리 문제 등의 한계가 있어 이 를 대체할 새로운 시험법 개발이 필요합니다. Neuro-2a assay는 대표적인 세포기반 대체 시험법으로, 이 방법은 마우스 신경모세포인 Neuro-2a 세포주에 ouabain (O)과 veratridine (V)을 처리하여 과도한 Na+ 유입으로 인한 세 포 사멸을 유도한 후, Na+ 채널 억제제인 TTX가 Na+ 유 입을 차단해 세포를 보호하는 원리를 이용해 TTX를 정량 합니다. 본 연구에서는 Neuro-2a assay를 국내 실험실 환경에 적용하기 위해 TTX 처리 조건과 O/V 농도 등의 매 개변수를 최적화하였습니다. 그 결과, 최적 O/V 농도로 600/60 μM를 설정하였으며, S자형 용량-반응 곡선이 도출 되는 8가지 농도(50-0.195 ng/mL)를 확인하였습니다. 또한, 24번의 반복 실험을 통해 데이터의 신뢰도를 평가할 수 있는 6가지 data criteria를 확립하였으며, 이 중 EC50 값 은 약 3.824-1.268 ng/mL로 나타났습니다. 실험실 간 변동 성 비교 결과, COV+와 Bottom OD값을 제외한 모든 품 질 관리 기준(quality control criteria)과 데이터 기준(data criteria)의 변동계수(CVs)는 1.31-14.92%로 도출되어, 실험 의 적정성과 재현성이 확인되었습니다. 본 연구는 국내에 서 활용 가능한 TTX 검출용 Neuro-2a assay의 최적 조 건과 신뢰성을 평가할 수 있는 quality control criteria와 data criteria를 제시하였습니다. 아울러, TTX뿐만 아니라 유사체인 4,9-anhydroTTX에 대한 TEF 값을 0.2098로 산 출하여, TTX뿐 아니라 다양한 유사체의 검출이 가능함 을 확인하였습니다. 향후, 본 시험법은 국내 수산물 내 TTX 검출을 위한 MBA 대체법으로 활용될 것으로 기대 됩니다.

Pyrochemical processing and molten-salt reactors have recently garnered significant attention as they are promising options for future nuclear technologies, such as those for recycling spent nuclear fuels and the next generation of nuclear reactors. Both of these technologies require the use of high-temperature molten salt. To implement these technologies, one must understand the electrochemical behavior of fission products in molten salts, lanthanides, and actinides. In this study, a rotating-disk-electrode (RDE) measurement system for high-temperature molten salts is constructed and tested by investigating the electrochemical reactions of Sm3+ in LiCl–KCl melts. The results show that the reduction of Sm3+ presents the Levich behavior in LiCl–KCl melts. Using the RDE system, not only is the diffusion-layer thickness of Sm3+ measured in high-temperature molten salts but also various electrochemical parameters for Sm3+ in LiCl–KCl melts, including the diffusion coefficient, Tafel slope, and exchange current density, are determined.

Seismic fragility curves present the conditional probability of damage to target structures due to external seismic load and are widely used in various ways. When constructing such a seismic fragility curve, it is essential to consider various types and numbers of ground motions. In general, the earthquake occurrence characteristics of an area where the target structure of the seismic fragility curve exists are analyzed, and based on this, appropriate ground motions are selected to derive the seismic fragility curve. If the number of selected ground motions is large, the diversity of ground motions is considered, but a large amount of computational time is required. Conversely, if the number of ground motions is too small, the diversity of ground motions cannot be considered, which may distort the seismic fragility curve. Therefore, this study analyzed the relationship between the number of ground motions considered when deriving the seismic fragility curve and the parameters of the seismic fragility curve. Using two example structures, numerical analysis was performed by selecting a random number of ground motions from a total of two hundred, and a seismic fragility curve was derived based on the results. Analysis of the relationship of the parameter of the seismic fragility curve and the number of selected ground motions was performed. As the number of ground motions considered increases, uncertainty in ground motion selection decreases, and when deriving seismic fragility curves considering the same number of ground motions, uncertainty increases relatively as the degree of freedom of the target structure increases. However, considering a relatively large number of ground motions, uncertainty appeared insignificant regardless of increased degrees of freedom. Finally, it is possible that the increase in the number of ground motions could lower the epistemic uncertainty and thus improve the reliability of the results.

This study evaluates the potential of various coagulants to enhance the efficiency of total phosphorus removal facilities in a sewage treatment plant. After analyzing the existing water quality conditions of the sewage treatment plant, the coagulant of poly aluminium chloride was experimentally applied to measure its effectiveness. In this process, the use of poly aluminium chloride and polymers in various ratios was explored to identify the optimal combination of coagulants. The experimental results showed that the a coagulants combination demonstrated higher treatment efficiency compared to exclusive use of large amounts of poly aluminium chloride methods. Particularly, the appropriate combination of poly aluminium chloride and polymers played a significant role. The optimal coagulant combination derived from the experiments was applied in a micro flotation method of real sewage treatment plant to evaluate its effectiveness. This study presents a new methodology that can contribute to enhancing the efficiency of sewage treatment processes and reducing environmental pollution. This research is expected to make an important contribution to improving to phosphorus remove efficiency of similar wastewater treatment plant and reducing the ecological impact from using coagulants in the future.

Background: The Hanwoo industry must develop technologies that can increase the production of preferred cuts to match changing consumer trends. In this study, we aimed to estimate the genetic parameters for carcass traits (carcass weight, eye muscle area, back fat thickness, and intramuscular fat) and primal cut traits (tenderloin, loin, strip loin, neck, clod, top round, bottom round, brisket, shank, and rib) in a Hanwoo population to obtain basic data for improving primal cut productivity. Methods: Data from 1,905 Hanwoo steers, including carcass traits and primal cut weights, were collected. Genetic parameters were estimated using REMLF90 in a multi-trait analysis. Results: High heritability was found for carcass weight (0.52) and strip loin yield (0.63). Genetic correlations between carcass weight and primal cut weights ranged from 0.52 to 0.93. Conclusions: This study demonstrates the significant potential for genetic improvement in Hanwoo cattle through selective breeding, particularly for traits with high heritability and genetic correlations. These findings provide crucial insights into optimizing breeding programs to improve Hanwoo cattle production efficiency.

In order to predict the process window of laser powder bed fusion (LPBF) for printing metallic components, the calculation of volumetric energy density (VED) has been widely calculated for controlling process parameters. However, because it is assumed that the process parameters contribute equally to heat input, the VED still has limitation for predicting the process window of LPBF-processed materials. In this study, an explainable machine learning (xML) approach was adopted to predict and understand the contribution of each process parameter to defect evolution in Ti alloys in the LPBF process. Various ML models were trained, and the Shapley additive explanation method was adopted to quantify the importance of each process parameter. This study can offer effective guidelines for fine-tuning process parameters to fabricate high-quality products using LPBF.