• Computers and Concrete
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• 제33권5호
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• pp.573-594
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• 2024

This article presents a research study, with both laboratory and field tests, of a deep foundation in a markedly anisotropic medium. Particularly it has focused on the evaluation of the behavior of a pile, one meter in diameter, embedded in a rocky environment with difficult conditions, in the Flysch of the Spanish city of San Sebastián. To carry out the research, the site of a bridge over the Urumea River was chosen, which was supported by pre-excavated reinforced concrete piles. 4 borings were carried out, by the rotation and washing method, with continuous sampling and combined with flexible dilatometer tests. In the field, an Osterberg load test (O-cell) was performed, while in the laboratory, determinations of natural moisture, natural unit weight, uniaxial compressive strength (UCS), point load strength (PLS), compressive wave propagation velocity (V_c) and also triaxial and direct shear tests were carried out. The research results indicate the following: a) the empirical functions that correlate the UCS with the PLS are not always linear; b) for the studied Flysch it is possible to obtain empirical functions that correlate the UCS with the PLS and with the V_c; c) the bearing capacity of the studied Flysch is much greater than if it is evaluated by different load capacity theories; d) it is possible to propose an empirical function that allows evaluating the mobilized shear strength (τ_m), as a function of the UCS and the displacement relative of the pile (δ_r).

• Archives of Plastic Surgery
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• 제40권4호
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• pp.359-366
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• 2013

Background Pedicled transverse rectus abdominis musculocutaneous flaps typically sacrifice the entire muscle. In our experience, the lateral strip of the rectus abdominis muscle can be spared in an attempt to maintain function and reduce morbidity. When the intercostal nerves are injured, muscle atrophy appears with time. The severed intercostal nerve was reinserted into the remnant lateral strip of the rectus abdominis muscle to reduce muscle atrophy. Methods The authors retrospectively reviewed 9 neurotized cases and 10 non-neurotized cases. Abdominal computed tomography was performed to determine the area of the rectus muscles. Electromyography (EMG) was performed to check contractile function of the remnant muscle. A single investigator measured the mean areas of randomly selected locations (second lumbar spine) using ImageJ software in a series of 10 cross-sectional slices. We compared the Hounsfield unit (HU) pre- and postoperatively to evaluate regeneration quality. Results In the neurotization group, 7 of 9 cases maintained the mass of remnant muscle. However, in the non-neurotization group, 8 of 10 lost their mass. The number of totally atrophied muscles in each of the two groups was significantly different (P=0.027). All of the remnant muscles showed contractile function on EMG. The 9 remaining remnant rectus abdominis muscles showed declined the HU value after surgery but also within a normal range of muscle. Conclusions Neurotization was found to be effective in maintaining the mass of remnant muscle. Neurotized remnant muscle had contractile function on EMG and no fatty degeneration by HU value.

• 한국추진공학회지
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• 제25권1호
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• pp.1-11
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• 2021

포고 현상은 액체추진 로켓에서 발생하는 축방향의 동적 불안정 진동이다. 동체의 고유진동수와 추진제 공급계의 주파수가 가까와 지면 전체 시스템이 불안정 현상을 보인다. 포고 현상을 예측하기 위해 1단의 추진제 (산화제 및 연료) 탱크는 쉘 요소로, 나머지 구성 요소인 엔진 및 상단은 mass-spring으로 모델링하여 구조해석을 수행하였다. 추진제 공급계의 압력 및 유량 섭동예측에는 transmission line model이 사용되었다. 본 논문에서는 이와 같이 수행된 구조 및 유체 모델링을 통합하여 폐루프 전달함수를 구성하였다. 포고 억제기는 수동적인 방법으로 압력 섭동을 흡수하는 분 기관 및 accumulator로 구성되며 추진제 공급계 중간에 위치한다. 발사체의 비행과정 동안 포고현상을 억제하는 설계 최적화를 위한 설계변수로는 분기관 및 accumulator의 직경 및 길이로 설정하였다. 목적함수로는 포고 억제기의 질량, 그리고 추진제 질량에 따른 폐루프 전달함수의 에너지 최소화로 설정하여 다목적함수 최적화를 수행하였다.

• 대한기계학회논문집B
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• 제22권5호
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• pp.607-617
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• 1998

Comparisons of joint probability density distribution obtained from the raw data of measured droplet sizes and velocities in a transient diesel fuel spray with computed joint probability density function were made. Simultaneous droplet sizes and velocities were obtained using PDPA. Mathematical probability density functions which can fit the experimental distributions were extracted using the principle of maximum likelihood. Through the statistical process of functions, mean droplet diameters, non-dimensional mass, momentum and kinetic energy were estimated and compared with the experimental ones. A joint log-hyperbolic density function presents quite well the experimental joint density distribution which were extracted from experimental data.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.708-713
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• 2007

Finite element model updating has been performed using an optimization technique in the paper. The objective function consists of natural frequencies, modal assurance criterion values, and bandwidths of modes, which are obtained from finite element analysis and experiment. Young's modulus and damping coefficient of the material are selected as design variables whose values are modified to make the objective function as small as possible. To consider the loading effect of an accelerometer, its mass and moment of inertia are added to design variables. This model updating method has been applied to a cantilever beam, and experimental data are measured by modal test.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2014년도 춘계학술대회
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• pp.244-245
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• 2014

Recently, the studies on submerged breakwater are increased due to needs considering the quality of water and the scenic view. In this paper, waves coming to permeable submerged breakwater coming with oblique angle are computed numerically by using wave pressure function. The wave pressure function throughout the analytical region including the fluid and submerged breakwaters is used. An unknown quantity expressed by the wave pressure function is simulated by boundary element method. The maximum reflection coefficient shows the tendency of decrease with the increase of oblique angle and The reflection coefficient shows the tendency of increase with the increase of the values of the linear dissipation coefficient and the added mass coefficient. It is means that the reflection coefficients are strongly dependent on the oblique angle and resistance coefficients.

• 한국소음진동공학회논문집
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• 제17권7호
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• pp.579-586
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• 2007

Analytical method to analyze the effect of tolerance on the modal characteristic of multi-body systems in dynamic equilibrium position is suggested in this paper. Monte-Carlo method is conventionally employed to perform the tolerance analysis. However, Monte-Carlo method spends too much time for analysis and has a greater or less accuracy depending on sample condition. To resolve these problems, an analytical method is suggested in this paper. Sensitivity equations for damped natural frequencies and the transfer function are derived at the dynamic equilibrium position. By employing the sensitivity information of mass, damping and stiffness matrices, the sensitivities of damped natural frequencies and the transfer function can be calculated.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1997년도 춘계학술대회논문집
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• pp.107-113
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• 1997

In this paper, an interfacing method to control rehabilitation assitance system with bio-signal is proposed. Controlling with EMG signals method has certain advantage on signal-collecting, but has some drawbacks in the function resolution of EMG signals because data-processing process is not efficient. To improve function-resolution and to increase the efficiency of EMG signal interfacing with rehabilitation assistance system, Multi-layer Perception which is highly effective with static signal and hidden-Markov model for dynamic signal resolving are fused together. In proposed method. The direction and average speed of the rehabilitation assitance system are controlled by the trajectory control and estimation of the moving direction result from the fused model. From the experiment, proposed GMM and 2-level MLP hybrid-classifier yielded 8.6% perception-error rate, improving function resolution. New acceleration control method constructed with 3 nested linear filter produced continuous acceleration paths without the information of destination point. Thus, the mass output caused by non- continuous acceleration-deceleration was eliminated. In the simulation, the necessary calculation, in the case of multiplication, was reduced by 11.54%.

• BMB Reports
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• 제32권1호
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• pp.72-75
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• 1999

In an effort to understand the function of the eryBVII gene in the erythromycin biosynthetic gene cluster, we overexpressed the eryBVII gene in E. coli and TDP-6-deoxy-L-threo-D-glycero-4-hexulose was used as a substrate of the overexpressed EryBVII enzyme. The enzymatic reaction product was chemically modified by reduction and peracetylation. Structural analysis of the derivatized enzymatic products by GC-Mass Spectrophotometry indicated that TDP-6-deoxy-L-threo-D-glycero-4-hexulose could be converted into its epimer by EryBVII enzyme. Based on this result, TDP-6-deoxy-L-threo-D-glycero-4-hexulose was indeed the substrate of EryBVII enzyme and the function of the eryBVII gene was confirmed.

• 한국연소학회지
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• 제22권3호
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• pp.29-34
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• 2017

The multi-environment probability density function model has been applied to simulate a turbulent premixed flame in a swirl combustor. To realistically account for the unsteady flow motion inside the combustor, the formulations are derived for the large eddy simulation. The Flamelet generated manifolds is utilized to simplify a multi-dimensional composition space with reasonable accuracy. The sub grid scale mixing is modeled by the interaction by exchange with the mean mixing model. To validate the present approach, the simulation results are compared with experimental data in terms of mean velocity, temperature, and species mass fractions.