• Title/Summary/Keyword: center pin

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Effect of Center Pin in Free Fall Test for a Cylindrical Li-ion Cell (원형 리튬 전지의 센터 핀이 낙하 충격에 미치는 영향)

  • Kim, Simon;Lee, Young Shin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.6
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    • pp.639-644
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    • 2015
  • A cylindrical secondary Li-ion cell is a device in which stored chemical energy is converted to electrical energy via an electrochemical reaction. These cells are widely used for applications that require high capacity and rate power, such as notebooks, power tools, and electric vehicles. The role of a center pin is to retain the channel for gas release, preventing blockage of the hollow of the jelly roll during a charge-discharge cycle, and to prevent an internal short circuit for tearing of separator under mechanical free fall. In this paper, two experiments are conducted with and without the center pin to experimentally verify the importance of the role of the center pin. The first experiment is a 50-cycle charge-discharge cycle test, and the second is a free fall test conducted according to the Underwriters Laboratories (UL) standards. Based on these experiments, we demonstrate that the center pin in a cylindrical cell is a very important component in terms of safety.

A Study on Formation of Ejector-Pin Hollowness in Injection Molding (사출성형에서 밀핀 흔적의 형성에 관한 연구)

  • Hwang, Geum-Jong;Lee, Hui-Gwan;Yang, Gyun-Ui
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.6
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    • pp.29-34
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    • 2002
  • This paper presents formation of ejector-pin hollowness in injection molding. Injection molding process is widely used in production of plastic part for good dimensional accuracy and high productivity. However, the injection molding leaves ejector-pin hollowness on pal, which causes bad part surface and quality. Dimensions and profiles of ejector-pin hollowness are measured for formation or ejector-pin hollowness. The formation of ejector-pin hollowness is traced with dimensions and profiles of ejector-pin hollowness. The compression force and moment cause ejector-pin to form hollowness on part surface.

A Study on the Effect of Process Parameters to Mechanical Property in Forward Extrusion of Milli-size Cylindrical Pin (밀리 단위의 원형핀 전방압출에 있어서 공정인자가 기계적 성질에 미치는 영향 연구)

  • 심경섭;김용일;이용신;김종호
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.797-801
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    • 2003
  • The mechanical properties such as shear strength and the hardness of milli-size products that manufactured for various process parameters by forward extrusion using square dies are investigated. Shear strength test is implemented for the observation of relation between vickers hardness and shear strength in the interface of head and shaft part of a stepped pin. When the extrusion ratios of pure aluminum and pure copper billets increase, the hardness on both the surface and the center line of a pin also increase, especially the hardness on the surface is shown to be a little higher than on the center. The existence of knock-out pad in extrusion die caused hardness increase in the interface of a extruded pin. As compared shear strength with hardness of a pin, the approximated linear relations are suggested in this study.

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REMOVAL TORQUE OF BICORTICALLY STABILIZED RBM(RESORBABLE BLAST MEDIA) PIN IMPLANTS IN RABBIT TIBIA

  • Kim, Kwon-Sik;Suh, Kyu-Won;Lee, Richard Sung-Bok;Ryu, Jae-Jun
    • The Journal of Korean Academy of Prosthodontics
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    • v.44 no.6
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    • pp.722-733
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    • 2006
  • Statement of problem. The use of small diameter implants having less than 3 mm in diameter were restricted because of lack of bonding strength to bone. Purpose. The purpose of this study was to observe how much resorbable blast media pin implants increase the binding force to the bone compared to machined transitional pin implants by measuring removal torque, and whether they can be used as final implants for replacement of small diameter teeth. Material and method. Fifteen rabbits were used in this study. Two kinds of implants (resorbable blast media pin implants and machined transitional pin implants) were inserted in each tibia bicortically. After healing time of 2, 4 and 8 weeks, the removal torque values were recorded and the rabbits were sacrificed for histological analysis. Linear finite element method analyses were conducted to compare bicortical fixation with monocortical fixation. Result and conclusion. Within the limitation of this in vivo study, the following conclusions were drawn: 1) The removal torque value of RBM pin implants showed statistically significant increase compared to machined pin implants at 2, 4, and 8 weeks respectively (p<0.05). 2) The removal torque value of RBM pin implants at 2, 4, and 8 weeks was increased statistically significantly with time (p<0.05). 3) Bicortical fixation showed better stress distribution compared with monocortical fixation in a linear finite element method analysis. 4) RBM pin implants are not recommended as transitional implants because they showed a lot of bone fracture in histologic specimens.

Parametric Analysis and Design Optimization of a Pyrotechnically Actuated Device

  • Han, Doo-Hee;Sung, Hong-Gye;Jang, Seung-Gyo;Ryu, Byung-Tae
    • International Journal of Aeronautical and Space Sciences
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    • v.17 no.3
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    • pp.409-422
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    • 2016
  • A parametric study based on an unsteady mathematical model of a pyrotechnically actuated device was performed for design optimization. The model simulates time histories for the chamber pressure, temperature, mass transfer and pin motion. It is validated through a comparison with experimentally measured pressure and pin displacement. Parametric analyses were conducted to observe the detailed effects of the design parameters using a validated performance analysis code. The detailed effects of the design variables on the performance were evaluated using the one-at-a-time (OAT) method, while the scatter plot method was used to evaluate relative sensitivity. Finally, the design optimization was conducted by employing a genetic algorithm (GA). Six major design parameters for the GA were chosen based on the results of the sensitivity analysis. A fitness function was suggested, which included the following targets: minimum explosive mass for the uniform ignition (small deviation), light casing weight, short operational time, allowable pyrotechnic shock force and finally the designated pin kinetic energy. The propellant mass and cross-sectional area were the first and the second most sensitive parameters, which significantly affected the pin's kinetic energy. Even though the peak chamber pressure decreased, the pin kinetic energy maintained its designated value because the widened pin cross-sectional area induced enough force at low pressure.

A Study on the Oil Film Behaviors of Pin Bush Bearings for Diesel Engines with Various Engine Oil Viscosities (오일점도에 따른 디젤엔진용 핀부시 베어링의 유막거동에 관한 연구)

  • Kim, Chung-Kyun;Lee, Byoung-Kwan
    • Tribology and Lubricants
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    • v.24 no.1
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    • pp.21-26
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    • 2008
  • A pin bush bearing is one of the most important element in the piston engine which is joined a piston to a connecting rod. A pin bush is suffered by heat and changeable repeat loads, which are come from the explosive gas heat and pressures during a reciprocating stroke. Therefore, a tribological behavior of pin bush bearings is very severe compared to other parts of a piston assembly. To keep a stable operation of pin bush bearings effectively, it would be satisfied with proper oil film strength for severe operating conditions and durability, which are strongly related to the oil film thickness, oil film pressure, and a friction loss power. The computed results show that the viscosity of engine oils slightly affects to the minimum oil film thickness and oil film pressure distribution, but is an influential parameter on a total friction loss power. Thus the low viscosity engine oils for an increased operation condition should select a high level of base oil and add a viscosity index improver as an oil film additive.

Optimization of Pin-hole Location to Minimize Stress Concentration around Hole in Rotating Disc under Centrifugal Force (원심력을 받는 회전원판내 원공주위 응력집중 최소화를 위한 핀홀위치 최적화)

  • 한동섭;한근조;김태형;심재준
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.6
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    • pp.131-138
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    • 2004
  • The objective of this paper is to decide optimal location of a pin-hole to minimize stress concentration around the hole in a rotating disc. The focus of this investigation is to evaluate the effect of pin-hole on stress distribution around the hole using optimum design technique and finite element analysis. Design variables are the radial and the angular location of pin-hole from center of the hole and objective function is the maximum stress around hole in a rotating disc. Using first order method of optimization technique, we found that the maximum equivalent stress around the hole with optimized pin-hole could be reduced by 15.1% compared to that without pin-hole.

Abrasive Wear Characteristics of Materials for Diesel Engine Cylinder Liner and Piston Ring (디젤엔진 실린더 라이너-피스톤 링 소재의 연삭 마멸 특성)

  • Jang, Jeong-Hwan;Kim, Jung-Hoon;Kim, Chang-Hee;Moon, Young-Hoon
    • Journal of the Korean Society for Heat Treatment
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    • v.20 no.2
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    • pp.72-77
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    • 2007
  • Abrasive wear between piston ring face and cylinder liner is an extremely unpredictable and hard-to-reproduce phenomenon that significantly decreases engine performance. Wear by abrasion are forms of wear caused by contact between a particle and solid material. Abrasive wear is the loss of material by the passage of hard particles over a surface. From the pin-on-disk test, particle dent test and scuffing test, abrasive wear characteristics of diesel engine cylinder liner-piston ring have been investigated. Pin-on-disk test results indicate that abrasive wear resistance is not simply related to the hardness of materials, but is influenced also by the microstructure, temperature, lubricity and micro- fracture properties. In particle dent test, dent resistance stress decreases with increasing temperature. From the scuffing test by using pin-on-disk tester, scuffing mechanisms for the soft coating and hard coating were proposed and experimentally confirmed.

Treatment of Radius Fracture Using a Shuttle Pin in a Cinereous Vulture (Aegypius monachus): A Case Study

  • Jinho Jang;Hee-Jong Kim;Young-Seok Park;YoungMin Yun
    • Journal of Veterinary Clinics
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    • v.41 no.3
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    • pp.189-194
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    • 2024
  • Cinereous vulture (Aegypius monachus) is a large raptor that belongs to the family Accipitridae in the order Falconiformes. It is a migratory bird that returns to Mongolia after wintering in the Korean Peninsula. In February 2015, a cinereous vulture was rescued from Asan-si, Chungcheongnam-do Province as it could not fly. It was transferred to the Chungnam Wild Animal Rescue Center in Korea. It was found to have a closed fracture on the right radius through radiographic examination, a basic procedure. Surgery was performed at the fracture site using a shuttle pin and wire. After successful physical therapy and rehabilitation, the cinereous vulture was released in October 2015. A metal ring (150-00713) and wing tags (G/BL 3) were attached to the bird before its release for subsequent identification. Two years and 4 months later, in March 2018, the cinereous vulture was rescued and brought back to the center. It was diagnosed with secondary pesticide poisoning. After receiving treatment, a radiography test revealed no specific findings related to the previous fracture surgery. Considering that migratory birds travel long distances, it was confirmed that the treatment for reducing the fracture in the radius using a shuttle pin and a cerclage wire was suitable.

Pedicle Screw Placement in the Thoracolumbar Spine Using a Novel, Simple, Safe, and Effective Guide-Pin : A Computerized Tomography Analysis

  • Hyun, Seung-Jae;Kim, Yongjung J.;Rhim, Seung-Chul;Cheh, Gene;Cho, Samuel K.
    • Journal of Korean Neurosurgical Society
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    • v.58 no.1
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    • pp.9-13
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    • 2015
  • Objective : To improve pedicle screw placement accuracy with minimal radiation and low cost, we developed specially designed K-wire with a marker. To evaluate the accuracy of thoracolumbar pedicle screws placed using the novel guide-pin and portable X-rays. Methods : Observational cohort study with computerized tomography (CT) analysis of in vivo and in vitro pedicle screw placement. Postoperative CT scans of 183 titanium pedicle screws (85 lumbar and 98 thoracic from T1 to L5) placed into 2 cadavers and 18 patients were assessed. A specially designed guide-pin with a marker was inserted into the pedicle to identify the correct starting point (2 mm lateral to the center of the pedicle) and aiming point (center of the pedicle isthmus) in posteroanterior and lateral X-rays. After radiographically confirming the exact starting and aiming points desired, a gearshift was inserted into the pedicle from the starting point into the vertebral body through the center of pedicle isthmus. Results : Ninety-nine percent (181/183) of screws were contained within the pedicle (total 183 pedicle screws : 98 thoracic pedicle screws and 85 lumbar screws). Only two of 183 (1.0%) thoracic pedicle screws demonstrated breach (1 lateral in a patient and 1 medial in a cadaver specimen). None of the pedicle breaches were associated with neurologic or other clinical sequelae. Conclusion : A simple, specially designed guide-pin with portable X-rays can provide correct starting and aiming points and allows for accurate pedicle screw placement without preoperative CT scan and intraoperative fluoroscopic assistance.