• Clinics in Shoulder and Elbow
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• 제22권1호
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• pp.37-39
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• 2019

Irreducible dislocation of the elbow is an uncommon event. We present the case of a posterolateral elbow dislocation after a fall injury in a 67-year-old woman. A closed reduction performed in the emergency department was unsuccessful since the limited passive range of motion resulted in difficulty to perform longitudinal traction and flexion. Computed tomography images showed that the posterolateral aspect of the capitellum was impacted by the tip of the coronoid process, thus appearing similar to the Hill-Sachs lesion in the humeral head. Subsequent open reduction of the elbow revealed the dislocation to be irreducible since the tip of the coronoid process had wedged into a triangular Hill-Sachs-like lesion in the capitellum. The joint was reduced by providing distal traction on the forearm, and main fragments were disengaged using digital pressure. At the 3-month follow-up, the patient reported no dislocations, and had an acceptable range of motion. Thus, we propose that to avoid iatrogenic injury to the joint or other nearby structures, irreducible dislocations should not be subjected to repeated manipulation.

• Wind and Structures
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• 제32권3호
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• pp.267-281
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• 2021

Bending-twisting coupling induced in big composite wind turbine blades is one of the passive control mechanisms which is exploited to mitigate loads incurred due to deformation of the blades. In the present study, flutter characteristics of bend-twist coupled blades, designed for load alleviation in wind turbine systems, are investigated by time-domain analysis. For this purpose, a baseline full GFRP blade, a bend-twist coupled full GFRP blade, and a hybrid GFRP and CFRP bend-twist coupled blade is designed for load reduction purpose for a 5 MW wind turbine model that is set up in the wind turbine multi-body dynamic code PHATAS. For the study of flutter characteristics of the blades, an over-speed analysis of the wind turbine system is performed without using any blade control and applying slowly increasing wind velocity. A detailed procedure of obtaining the flutter wind and rotational speeds from the time responses of the rotational speed of the rotor, flapwise and torsional deformation of the blade tip, and angle of attack and lift coefficient of the tip section of the blade is explained. Results show that flutter wind and rotational speeds of bend-twist coupled blades are lower than the flutter wind and rotational speeds of the baseline blade mainly due to the kinematic coupling between the bending and torsional deformation in bend-twist coupled blades.

• Journal of Oral Medicine and Pain
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• 제48권4호
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• pp.144-151
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• 2023

Purpose: The aim of this study was to assess the repeatability of the electrical measurement of taste detection on different dates and in different sessions in healthy young females. Methods: The sites of electrical stimulation were the tip of the tongue, the posterolateral border of the tongue and the soft palate on the right side unilaterally. The measurements were repeated over three consecutive days, three sessions per day and three times for each session in seventeen healthy females. The repeatability of the measurement was assessed by the intraclass correlation coefficient (ICC). Results: In the dB unit, the ICC of the tip of the tongue and the soft palate was good (61.03 and 66.03, respectively); however, the lateral border of the tongue was a little lower (58.07). In the ㎂ unit, all three test sites had poor ICC. Variability was more significantly associated with the subject factor than with other factors such as trials, sessions and days in dB and ㎂ units. Conclusions: Electrogustometry, which measures electrical taste detection thresholds in the dB unit, is repeatable and acceptable for clinical use in assessing taste function in healthy young females.

• 정보처리학회논문지C
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• 제13C권7호
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• pp.803-812
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• 2006

본 논문에서는 저속의 무선 센서 네트워크(WSN: Wireless Sensor Network)에서 블록 FEC(Forward Error Correction) 알고리즘의 심볼 크기의 변화에 따른 802.11 MAC 프로토콜의 전송 효율과 전송 에너지를 해석적으로 분석한다. 블록 FEC 알고리즘은 심볼(symbol) 단위로 오류를 복원하므로, 주어진 무선 센서 채널에서 같은 FEC 체크 비트(check bit) 량을 사용하더라도 블록 FEC 알고리즘의 오류 패킷 복원률은 블록 FEC 심볼 크기에 의존적이다. 즉, 같은 양의 FEC 체크 비트를 사용하는 경우에, 연속된 군집 오류 길이는 작으면서 군집 오류가 자주 발생하는 채널에서는 작은 FEC 심볼이, 이에 반해 군집 오류의 길이는 크고 군집 오류 개수가 작은 군집적 분포를 보이는 채널에서 큰 FEC 심볼이 효율적이다. 심볼 크기의 영향을 평가하기 위해서 본 논문에서는 센서 노드 TIP50CM을 사용하는 WSN에서 수집한 패킷 트레이스를 기반으로 WSN 채널을 Gilbert 모델로 모델링하고, 심볼 크기가 다른 RS(Reed-Solomon) 코드를 생성하고 해석하기 위한 에너지를 측정하였다. 이러한 모델링된 채널과 각 RS 코드 생성과 해석 에너지를 이용하여 FEC 심볼 크기에 따른 RS FEC 코드를 채택한 802.11 MAC 프로토콜의 전송 효율과 전송 에너지를 계산하였다. 실제 측정 데이터와 해석적으로 계산한 데이터를 결합한 계산에 의하면 비슷한 FEC 체크 비트 량을 사용하더라도 FEC 심볼 크기에 따라 전송 효율은 최대 4.2%, 그리고 소요 에너지는 최대 35%의 차이가 발생한다.

• 한국결정성장학회지
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• 제8권3호
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• pp.454-462
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• 1998

AUC 침전과정중 AUC 입차를 둥글게 제조하는 조건과 기구를 조사하였다. 둥근 AUC 제조는 교반기를 이용한 내부순환 시는 불가능했으나 펌프를 사용한 외부순환 시는 가능했다. 둥근 AUC 제조속도($dn_p$/dt)는 침전조건인 슬러리 밀도($M_t:U/l)$, 슬러리 회전율($T_o$:turn-over ratio), 임펠러 속도(U:Impelle tip velocity)에 비례하여 관계식을 $ dn_p/dt{\propto}M_t{\cdot}T_o{\cdot}U^2$로 표기할 수 있었으며, 이 속도식은 실험결과와 정성적으로 일치하였다. 그리고 두 개의 둥근 AUC 제조 기구가 제시되었는데, 하나는 균일형성기구이고 다른 하나는 etch-pit 형성기구이다. 전자는 AUC 침전과정에서 초기에 발생되고 후자는 침전과정 말기에 발생되는 것으로 확인되었다.

• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4146-4158
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• 2022

Ultra-high performance concrete (UHPC) has been widely utilized in military and civil protective structures to resist intensive loadings attributed to its excellent properties, e.g., high tensile/compressive strength, high dynamic toughness and impact resistance. At present, aiming to improve the defects of the traditional vertical concrete cask (VCC), i.e., the external storage facility of spent fuel, with normal strength concrete (NSC) shield, e.g., heavy weight and difficult to fabricate/transform, the feasibility of UHPC applied in the shield of VCC is numerically examined considering its high radiation and corrosion resistance. Firstly, the finite element (FE) analyses approach and material model parameters of NSC and UHPC are verified based on the 1/3 scaled VCC tip-over test and drop hammer test on UHPC members, respectively. Then, the refined FE model of prototypical VCC is established and utilized to examine its dynamic behaviors and damage distribution in accidental tip-over and end-drop events, in which the various influential factors, e.g., UHPC shield thickness, concrete ground thickness, and sealing methods of steel container are considered. In conclusion, by quantitatively evaluating the safety of VCC in terms of the shield damage and vibrations, it is found that adopting the 300 mm-thick UHPC shield instead of the conventional 650 mm-thick NSC shield can reduce about 1/3 of the total weight of VCC, i.e., about 50 t, and 37% floor space, as well as guarantee the structural integrity of VCC during the accidental drop simultaneously. Besides, based on the parametric analyses, the thickness of concrete ground in the VCC storage site is recommended as less than 500 mm, and the welded connection is recommended for the sealing method of steel containers.

• Applied Microscopy
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• 제47권3호
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• pp.86-94
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• 2017

In this study, we will describe a new design of carbon nanotubes tip. Single-walled carbon nanotubes produced using high-pressure CO over Fe particles (HiPCO) at CNI, Houston, TX used in this study. These tips were manufactured by employing a drawing technique using glass puller. Field electron microscopies with tips (cathode) to screen (Anode) separation of ~10 mm was used to characterize the electron emitters. The system was evacuated down to base pressure of (${\sim}10^{-8}$ mbar) when baked at up to (${\sim}200^{\circ}C$) over night. An electron field emission patterns, as well as current versus voltage characteristics and Fowler-Nordheim plots, are discussed.

• 대한기계학회논문집B
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• 제24권1호
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• pp.75-84
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• 2000

Performance and flow characteristics of a small forward swept propeller fan for home refrigerators are studied experimentally. An unusual discontinuity is observed in the performance curve of the fan. Mean flow fields measured with as-hole Pitot probe reveal that the flow is axial at the high flow rate and radial at the low flow rate. The flow structure changes abruptly across the discontinuity. Unsteady flow measurements with a set of hot-wire probes indicate that near the discontinuity a single-cell stall rotates at 40% speed of the fan speed, while away from the discontinuity the flow shows periodic variation corresponding to the blade passage frequency. Phase-lock averaged flow fields measured with a triple-sensor hot-wire probe show that there appears radially inward flow over the pressure side of the blade and the outward passage flow over the tip.

• Journal of Welding and Joining
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• 제12권3호
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• pp.56-62
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• 1994

The spot weldability of high strength steel sheet and two stories galvannealed high strength steel sheet has been studied. 1) Tensile shear strength decreased inversely as welding current increased over 12KA in the case of two stories galvannealed high strength steel sheet. 2) When heat flux input over 12KA, hardening region become narrow in case of two stories galvannealed high strength steel sheet. 3) The size of hardening region affect the strength of nuggets.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.245-249
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• 2002

Tungsten carbide microshaft is used as various micro-tools in MEMS because it has high hardness and good rigidity. In this study, experiments were performed to produce tungsten carbide microshaft using electrochemical machining. $H_2SO_4$solution was used as electrolyte because it can dissolve tungsten and cobalt simultaneously. Optimal electrolyte concentration and machining voltage satisfying uniform shape and large MRR of workpiece were found. For one-step machining, the immersion depth over 1 mm was selected for avoidance of concentration of electric charge at the tip of the microshaft. The limit diameter with good straightness was shown and an empirical formula for WC-microshaft machining was suggested. By controlling the various machining parameters, a straight microshaft with 30 $\mu\textrm{m}$ diameter, over 1 mm length and under 0.5$^{\circ}$ taper angle was obtained.