• Title/Summary/Keyword: Metal Bearing

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The Design of Flat Linear Induction Pump for Transferring Reactor Coolant (원자로 냉각재 이송을 위한 평편형 리니어 유도펌프의 설계)

  • Jang, S.M.;Wu, J.S.;Kim, H.K.
    • Proceedings of the KIEE Conference
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    • 1998.11a
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    • pp.10-12
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    • 1998
  • Pumping liquid metal in nuclear power plant application by conventional centrifugal pumps pose difficulties such as bearing wear out at high temperatures and leak proof sealing of the liquid metal. MHD machine is obtained by replacing solid conducting secondary of conventional motors with ionized gas or liquid metal. It is used for reactor cooling pump because of construction simplicity, perfect sealing and easy operation/maintenance MHD pump is complicated because it includes electromagnetic and hydrodynamic phenomena. The principle of MHD Pumps is described in this paper. We design small laboratory size Flat Linear Induction Pump(FLIP) for transferring sodium.

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Biosorption Technology Using Algal Biomass in Canadian Environment Industries (캐나다 환경산업의 조류 바이오매스 이용 생흡착 기술)

  • Volesky, Bohumil;Kong, Surk-Key
    • Proceedings of the Korean Institute of Resources Recycling Conference
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    • 2005.11a
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    • pp.3-14
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    • 2005
  • We Investigated minutely how the biosorption technology using algal biomass is opened in Canadian technology society. Making comparative study for relative technologies in views of overall unit operation cost, we could grasp next facts. - Algal biomass plays the competitive performance for various metals. - Algal biomass biosorbent is regenerated. - Reactor system is not and involved one. This means that algal biomass occupies the strong position as biosorbent. Especially, in North America, for the purpose of metal bearing wastewater treatment, 20 hundred million US dollars was appropriated a sum for the purchase of ion exchange resin. But it is only thirty million US dollars if algal biomass biosorbent is used on behalf of ion exchange resin. Furthermore, the expenses for same treatment can be cut down additively through metal recovery.

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Shape Optimization of Uniaxial Vibrating Metal Damper (일축 진동형 금속제진장치 형상 최적설계)

  • Yoon, Ji-Hoon;Park, Ji-Woon;Lim, Yun-Mook;Yoon, Gil-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.4
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    • pp.313-318
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    • 2017
  • This study performs the structural analysis and the optimum design of a vibrating metal damper to absorb vibration energy. Unlike other dampers such as rubber bearing, friction or viscose dampers, the present vibrating metal damper utilizes the plastic deformation of a steel and its associated hysteresis phenomenon to reduce vibrations of structures. To optimize this vibrating metal damper, it is important to obtain plastic deformation through the damper. To achieve this, the shape optimization method is developed and applied to find out optimal envelopes of the metal damper. Depending on the parameterization scheme, some novel optimal shapes can be found.

Effect of Heat Treatment on High Temperature Fatigue Strength Characteristics of STB2 Bearing Steel (STB2강의 고온피로강도 특성에 미치는 열처리의 영향)

  • Oh, Sae-Kyoo;Kim, Yeon-Ho;Lee, Sang-Guk;Lee, Jong-Du
    • Journal of Ocean Engineering and Technology
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    • v.3 no.2
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    • pp.138-144
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    • 1989
  • It has been very important in various industry fields to improve the fatigue strength characteristics of bearings such as bearing life, fatigue limit, etc., because such poor properties could result in shortening the machinery life as well as in decreasing the accuracy. However, no successful heat treatment criterion seems to be available at present. In this study, the effect of the $170^{\circ}C\times120min$ tempering cycles repeated after $380^{\circ}C\times80min$ oil quenching for $800^{\circ}C$ spheroidizing-annealed bearing steel (STB2) as base metal on the $120^{\circ}C$ high temperature rotary bending fatigue strength characteristics were investigated, including the effects on hardness, Charpy impact value and micro-structure, in order to seek for the best heat treatment condition finally. The important results obtained are as follows : 1) The optimal cycle of tempering so that the fatigue strength .sigma. could become the highest was the 4th cycle. And it is confirmed that this $\sigma_{F}$ is about 6 times more increased than that of base metal, and about 1.3 times more increased than the case of the 1 cycle tempered. 2) As a result of the investigation for the effects of tempering cycles on hardness, the hardness at the tempering number of 2 thru 5 cyles was not decreased severely ; only about 10% decrease from those of the quenched and 1 cycle tempered case. Such hardness is equivalent to $H_{R}$/C61-62 with no bad effect on anti-abrasion of bearing steel. 3) In the case of 2 thru 5 cycle tempering as well as 1 cycle tempering, the impact value was not so improved comparing with the case of quenching, but an increase of 5 to 10% could be expected at least. 4) It was experimentally confirmed that the control of the mechanical properties improvement such as fatigue strength and fatigue life for bearing steels could be possible by the number of tempering cycles.

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Effect of Heat Treatment on High Temperature Fatigue Strength Characteristics of STB2 Bearing Steel (STB2강의 고온피로강도 특성에 미치는 열처리의 영향)

  • Oh, Sae-Kyoo;Kim, Yeon-Ho;Lee, Sang-Guk;Lee, Jong-Du
    • Journal of Ocean Engineering and Technology
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    • v.3 no.2
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    • pp.638-638
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    • 1989
  • It has been very important in various industry fields to improve the fatigue strength characteristics of bearings such as bearing life, fatigue limit, etc., because such poor properties could result in shortening the machinery life as well as in decreasing the accuracy. However, no successful heat treatment criterion seems to be available at present. In this study, the effect of the $170^{\circ}C\times120min$ tempering cycles repeated after $380^{\circ}C\times80min$ oil quenching for $800^{\circ}C$ spheroidizing-annealed bearing steel (STB2) as base metal on the $120^{\circ}C$ high temperature rotary bending fatigue strength characteristics were investigated, including the effects on hardness, Charpy impact value and micro-structure, in order to seek for the best heat treatment condition finally. The important results obtained are as follows : 1) The optimal cycle of tempering so that the fatigue strength .sigma. could become the highest was the 4th cycle. And it is confirmed that this $\sigma_{F}$ is about 6 times more increased than that of base metal, and about 1.3 times more increased than the case of the 1 cycle tempered. 2) As a result of the investigation for the effects of tempering cycles on hardness, the hardness at the tempering number of 2 thru 5 cyles was not decreased severely ; only about 10% decrease from those of the quenched and 1 cycle tempered case. Such hardness is equivalent to $H_{R}$/C61-62 with no bad effect on anti-abrasion of bearing steel. 3) In the case of 2 thru 5 cycle tempering as well as 1 cycle tempering, the impact value was not so improved comparing with the case of quenching, but an increase of 5 to 10% could be expected at least. 4) It was experimentally confirmed that the control of the mechanical properties improvement such as fatigue strength and fatigue life for bearing steels could be possible by the number of tempering cycles.

Evaluation on Fatigue Behavior of EP(Engineering Plastic) Friction Pendulum Bearing System (EP가 적용된 마찰 진자형 지진격리받침의 피로거동분석)

  • Choi, Jung-Youl;Park, Hee-Soo;Chung, Jee-Seung
    • The Journal of the Convergence on Culture Technology
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    • v.6 no.4
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    • pp.703-708
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    • 2020
  • As the risk of earthquakes increases recently, earthquake-resistant designs were getting interest. For this reason, this study applies that Friction pendulum-type seismic isolator is a device that attenuates seismic energy by friction and pendulum motion. The friction pendulum-type seismic isolator of this study is very easy to transport, install and maintain with light weight of metal by applying the slider using high strength engineering plastic. In addition, there is an advantage that the corrosion resistance is very excellent compared to the existing metal parts. However, there is concern about long-term durability by replacing metal materials. In this study, the frictional pendulum-type seismic isolator with EP was applied to compressive-shear test, repeated fatigue test, and ultimate load test after fatigue test, and analyzed the deformation and shear or properties after the test. As the results, the adequacy of long term fatigue durability was experimentally proven.

Wear Analysis at the Interface of Connecting-Rod Small-End Bushing and Piston-Pin Boss with a Floating Piston-Pin at Constant Angular Velocity during Engine Firing (엔진 파이어링동안 일정 축 각속도에서 비고정식 피스톤-핀과 연결봉-소단부 부싱 및 피스톤-핀 보스의 접촉면 마모해석)

  • Chun, Sang Myung
    • Tribology and Lubricants
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    • v.36 no.3
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    • pp.168-192
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    • 2020
  • In recently designed diesel engines, the running conditions for piston-pin bearings have become severe because of the higher combustion pressure and increased temperature. Moreover, the metal removal from the bushing material has strongly reduced the ability of the antifriction material to accept asperity contacts. Therefore, it is necessary to find ways of reducing wear scar on the connecting-rod small-end bushing and piston-pin boss bearing related to the higher combustion pressure on the power cell of an engine. In this work, the position and level of material removal from the surfaces of the bushing and bearing under such severe operating conditions - for example, maximum power and torque conditions of a passenger car diesel engine - are estimated for several combinations of surface roughness. First, piston-pin rotating motion is investigated by calculating the friction coefficient at piston-pin bearings, the oil film thickness, and the frictional torques induced by hydrodynamic shear stress. Subsequently, the wear scarring on the surfaces of a connecting-rod small-end bushing and two piston-pin boss bearings related to piston-pin rotational motion is numerically calculated under the maximum power and torque operating conditions. This work is helpful to determine the reasonable surface roughness of the bushing and bearing for reducing wear volume occurring at the interface between a bearing and a shaft.

Experiment and bearing capacity analyses of dual-lintel column joints in Chinese traditional style buildings

  • Xue, Jianyang;Ma, Linlin;Wu, Zhanjing;Zhai, Lei;Zhang, Xin
    • Steel and Composite Structures
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    • v.28 no.5
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    • pp.641-653
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    • 2018
  • This paper presents experiment and bearing capacity analyses of steel dual-lintel column (SDC) joints in Chinese traditional style buildings. Two SDC interior joints and two SDC exterior joints, which consisted of dual box-section lintels, circular column and square column, were designed and tested under low cyclic loading. The force transferring mechanisms at the panel zone of SDC joints were proposed. And also, the load-strain curves at the panel zone, failure modes, hysteretic loops and skeleton curves of the joints were analyzed. It is shown that the typical failure modes of the joints are shear buckling at bottom panel zone, bending failure at middle panel zone, welds fracturing at the panel zone, and tension failure of base metal in the heat-affected zone of the joints. The ultimate bearing capacity of SDC joints appears to decrease with the increment of axial compression ratio. However, the bearing capacities of exterior joints are lower than those of interior joints at the same axial compression ratio. In order to predict the formulas of the bending capacity at the middle panel zone and the shear capacity at the bottom panel zone, the calculation model and the stress state of the element at the panel zone of SDC joints were studied. As the calculated values showed good agreements with the test results, the proposed formulas can be reliably applied to the analysis and design of SDC joints in Chinese traditional style buildings.

Recent updates for biomaterials used in total hip arthroplasty

  • Hu, Chang Yong;Yoon, Taek-Rim
    • Biomaterials Research
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    • v.22 no.4
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    • pp.259-270
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    • 2018
  • Background: Total hip arthroplasty (THA) is probably one of the most successful surgical interventions performed in medicine. Through the revolution of hip arthroplasty by principles of low friction arthroplasty was introduced by Sir John Charnley in 1960s. Thereafter, new bearing materials, fixation methods, and new designs has been improved. The main concern regarding failure of THA has been the biological response to particulate polyethylene debris generated by conventional metal on polyethylene bearing surfaces leading to osteolysis and aseptic loosening of the prosthesis. To resolve these problems, the materials of the modern THA were developed since then. Methods: A literature search strategy was conducted using various search terms in PUBMED. The highest quality articles that met the inclusion criteria and best answered the topics of focus of this review were selected. Key search terms included 'total hip arthroplasty', 'biomaterials', 'stainless steel', 'cobalt-chromium', 'titanium', 'polyethylene', and 'ceramic'. Results: The initial search retrieved 6921 articles. Thirty-two articles were selected and used in the review. Conclusion: This article introduces biomaterials used in THA and discusses various bearing materials in currentclinical use in THA as well as the newer biomaterials which may even further decrease wear and improve THA survivorship.

Temporal Variations of Ore Mineralogy and Sulfur Isotope Data from the Boguk Cobalt Mine, Korea: Implication for Genesis and Geochemistry of Co-bearing Hydrothermal System (보국 코발트 광상의 산출 광물종 및 황동위원소 조성의 시간적 변화: 함코발트 열수계의 성인과 지화학적 특성 고찰)

  • Yun, Seong-Taek;Youm, Seung-Jun
    • Economic and Environmental Geology
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    • v.30 no.4
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    • pp.289-301
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    • 1997
  • The Boguk cobalt mine is located within the Cretaceous Gyeongsang Sedimentary Basin. Major ore minerals including cobalt-bearing minerals (loellingite, cobaltite, and glaucodot) and Co-bearing arsenopyrite occur together with base-metal sulfides (pyrrhotite, chalcopyrite, pyrite, sphalerite, etc.) and minor amounts of oxides (magnetite and hematite) within fracture-filling $quartz{\pm}actinolite{\pm}carbonate$ veins. These veins are developed within an epicrustal micrographic granite stock which intrudes the Konchonri Formation (mainly of shale). Radiometric date of the granite (85.98 Ma) indicates a Late Cretaceous age for granite emplacement and associated cobalt mineralization. The vein mineralogy is relatively complex and changes with time: cobalt-bearing minerals with actinolite, carbonates, and quartz gangues (stages I and II) ${\rightarrow}$ base-metal sulfides, gold, and Fe oxides with quartz gangues (stage III) ${\rightarrow}$ barren carbonates (stages IV and V). The common occurrence of high-temperature minerals (cobalt-bearing minerals, molybdenite and actinolite) with low-temperature minerals (base-metal sulfides, gold and carbonates) in veins indicates a xenothermal condition of the hydrothermal mineralization. High enrichment of Co in the granite (avg. 50.90 ppm) indicates the magmatic hydrothermal derivation of cobalt from this cooling granite stock, whereas higher amounts of Cu and Zn in the Konchonri Formation shale suggest their derivations largely from shale. The decrease in temperature of hydrothermal fluids with a concomitant increase in fugacity of oxygen with time (for cobalt deposition in stages I and II, $T=560^{\circ}C-390^{\circ}C$ and log $fO_2=$ >-32.7 to -30.7 atm at $350^{\circ}C$; for base-metal sulfide deposition in stage III, $T=380^{\circ}-345^{\circ}C$ and log $fO_2={\geq}-30.7$ atm at $350^{\circ}C$) indicates a transition of the hydrothermal system from a magmatic-water domination toward a less-evolved meteoric-water domination. Sulfur isotope data of stage II sulfide minerals evidence that early, Co-bearing hydrothermal fluids derived originally from an igneous source with a ${\delta}^{34}S_{{\Sigma}S}$ value near 3 to 5‰. The remarkable increase in ${\delta}^{34}S_{H2S}$ values of hydrothermal fluids with time from cobalt deposition in stage II (3-5‰) to base-metal sulfide deposition in stage III (up to about 20‰) also indicates the change of the hydrothermal system toward the meteoric water domination, which resulted in the leaching-out and concentration of isotopically heavier sulfur (sedimentary sulfates), base metals (Cu, Zn, etc.) and gold from surrounding sedimentary rocks during the huge, meteoric water circulation. We suggest that without the formation of the later, meteoric water circulation extensively through surrounding sedimentary rocks the Boguk cobalt deposits would be simple veins only with actinolite + quartz + cobalt-bearing minerals. Furthermore, the formation of the meteoric water circulation after the culmination of a magmatic hydrothermal system resulted in the common occurrence of high-temperature minerals with later, lower-temperature minerals, resulting in a xenothermal feature of the mineralization.

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