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Diagnostic metallurgy of porphyry copper-gold deposits in the Pan-Pacific

  • Kim Joe Y.;Kim Sun S.;Shin Hyung J.;Kong Bong S.;Lee Keon K.
    • 한국지구물리탐사학회:학술대회논문집
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    • 2003.11a
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    • pp.581-589
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    • 2003
  • The variable flotation response ores from different deposits results basically from mineralogical association and their differences. Development of new techniques for analyzing the metallurgical performance of flotation and other concentration processes is demanded even in the treatment of rather simple ores such as porphyry ores. Diagnostic metallurgical analysis can be used to quantify the most possible recovery processes. Several porphyry copper/gold ores around the world were used to examine the responses in flotation, gravity separation and cyanidation in order to define the linkage between the recovery processes for both copper and old values. Laboratory batch flotation, gravity separation and cyanidation tests were carried out on these samples. All results were used to correlate the relative recovery of copper and gold, and to predict the highest possible metal recovery in the system. The metallurgical predictions were made according to the flotation conditions used and gravity separation. The results of various concentration processes on each porphyry ore samples are presented and discussed. All seven samples have shown significantly different gold/copper metallurgy. The grade/recovery relationships of gold and copper in the laboratory batch tests for the best results and the plants are given in the Figures below. The results of laboratory tests show that the copper recoveries converged to about $90\%$, but the gold recoveries were spread over $55-80\%$, except the K S ore. Series of standard cyanidation tests on the flotation concentrate samples and gravity separation using Knelson Separator on heads ores were carried out to cross-link the metallurgy and mineralogy of gold in the porphyry ores.

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Optimal Design and Analysis of Ducted Fan Clutch With or Without Mechanical Lock-up (기계적 잠금장치의 적용여부에 따른 덕티드팬 클러치의 최적설계 및 분석)

  • Su-chul Kim;Jae-seung Kim;Sang-gon Moon;Geun-ho Lee
    • Journal of Aerospace System Engineering
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    • v.17 no.1
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    • pp.10-15
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    • 2023
  • Wet multi-disk clutch, a power switching device of the ducted fan, was optimized and results were analyzed. The clutch was divided into two types depending on whether a mechanical lock-up was applied or not. It was optimized under each design condition. Transfer torque capacity, friction material surface pressure, friction surface temperature, and drag torque were calculated as factors to optimize the clutch. The volume of separator plate and drag torque were used as the objective function for optimization. In the case of Type 1, which did not include a mechanical lock-up, the clutch could be operated regardless of the pitch angle of the ducted fan. However, the outer diameter of the friction surface was doubled, the volume was increased by 5~7 times, and the drag torque was increased by 7~12 times compared to those of Type 2, which included a mechanical lock-up.

A Study on the prediction of SOH estimation of waste lithium-ion batteries based on SVM model (서포트 벡터 머신 기반 폐리튬이온전지의 건전성(SOH)추정 예측에 관한 연구)

  • KIM SANGBUM;KIM KYUHA;LEE SANGHYUN
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.3
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    • pp.727-730
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    • 2023
  • The operation of electric automatic windows is used in harsh environments, and the energy density decreases as charging and discharging are repeated, and as soundness deteriorates due to damage to the internal separator, the vehicle's mileage decreases and the charging speed slows down, so about 5 to 10 Batteries that have been used for about a year are classified as waste batteries, and for this reason, as the risk of battery fire and explosion increases, it is essential to diagnose batteries and estimate SOH. Estimation of current battery SOH is a very important content, and it evaluates the state of the battery by measuring the time, temperature, and voltage required while repeatedly charging and discharging the battery. There are disadvantages. In this paper, measurement of discharge capacity (C-rate) using a waste battery of a Tesla car in order to predict SOH estimation of a lithium-ion battery. A Support Vector Machine (SVM), one of the machine models, was applied using the data measured from the waste battery.

Study on Dust Explosion Characteristics of Acetylene Black (Acetylene Black의 분진폭발 특성 연구)

  • Jae Jun Choi;Dong Myeong Ha
    • Journal of the Korean Society of Safety
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    • v.39 no.2
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    • pp.38-43
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    • 2024
  • Recently, with the expanding market for electronic devices and electric vehicles, secondary battery usage has been on the rise. Lithium-ion batteries are particularly popular due to their fast charging times and lightweight nature compared to other types of batteries. A secondary battery consists of four components: anode, cathode, electrolyte, and separator. Generally, the positive and negative electrode materials of secondary batteries are composed of an active material, a binder, and a conductive material. Acetylene Black (AB) is utilized to enhance conductivity between active material particles or metal dust collectors, preventing the binder from acting as an insulator. However, when recycling waste batteries that have been subject to high usage, there is a risk of fire and explosion accidents, as accurately identifying the characteristics of Acetylene Black dust proves to be challenging. In this study, the lower explosion limit for Acetylene Black dust with an average particle size of 0.042 ㎛ was determined to be 153.64 mg/L using a Hartmann-type dust explosion device. Notably, the dust did not explode at values below 168 mg, rendering the lower explosion limit calculation unfeasible. Analysis of explosion delay times with varying electrode gaps revealed the shortest delay time at 3 mm, with a noticeable increase in delay times for gaps of 4 mm or greater. The findings offer fundamental data for fire and explosion prevention measures in Acetylene Black waste recycling processes via a predictive model for lower explosion limits and ignition delay time.

Optimum Sieve-slit width for Effective Removal of Immature Kernels based on Varietal Characteristics of Rice to Improve Milling Efficiency (도정효율 증진을 위한 벼 품종특성별 현미선별체 적정크기)

  • Lee, Choon-Ki;Kim, Jung-Tae;Choi, Yoon-Hee;Lee, Jae-Eun;Seo, Jong-Ho;Kim, Mi-Jung;Jeong, Eung-Gi;Kim, Chung-Kon
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.54 no.4
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    • pp.357-365
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    • 2009
  • On the purpose to improve the milling efficiency as well as head-rice percentage after milling, an experiment to improve the removal ability of immature kernels in the immature brown rice separator (IBRS) was performed focused on varietal characteristics. The removal ability of immature grains by the IBRS was absolutely depending on kernel thickness of brown rice. The kernel thickness of the tested rice varieties distributed from 1.79 mm in Nonganbyeo to 2.16 mm in Daeribbyeo 1. Although there were some variation among rice varieties, it was roughly suggested that the suitable sieve-slit widths for good separation of the immature kernels were 1.9 mm for the varieties thicker than 2.08 mm in thickness, 1.8 mm for the varieties with 2.00-2.08 mm thickness, 1.7 mm for the varieties with 1.90-2.00 mm thickness, and 1.60-1.65 mm for the varieties thinner than 1.7 mm. It was found out that the higher the proportions of immature kernels in brown rice, the more conspicuous the improvement of milling efficiency as well as head rice rates by their removals. With increasing the sieve slit-widths beyond an optimum range, the losses of mature grains increased sharply. For effective separation of immature kernels, it was suggested that the optimum sieve-slit width should be set up depending on both of the kernel thickness and the critical loss limit of mature kernel.

Effects of Mixing Time for Total Mixed Rations using Corn Silage on Ruminal In situ Dry Matter Degradation and Milk Production in Dairy Cows (옥수수 사일리지 이용 섬유질배합사료의 배합시간에 따른 In situ 반추위 분해율 및 착유우의 산유특성에 미치는 영향)

  • Lim, Dong-Hyun;Ki, Kwang-Seok;Choi, Sun-Ho;Kim, Tae-Il;Park, Seong-Min;Park, Su-Bum;Kwon, Eung-Gi;Kim, Eun-Tae
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.34 no.4
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    • pp.288-295
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    • 2014
  • This study was conducted to evaluate the effect of mixing time for TMR (total mixed rations) mixed with corn silage on particle size, peNDF (physically effective neutral detergent fiber), laceration, and ruminal in situ dry matter degradation. The study also aimed to evaluate the effect of consumption of the TMR on the milk yield and milk components of mid-lactational dairy cows. TMRs were mixed for 30 minutes (T1) and 50 minutes (T2) using the same material. All samples were then analyzed with a Penn State Particle Size Separator (PSPS). The particle size of T1 was significantly lower in the bottom pan (8 mm>) than that of T2 (p<0.01). $peNDF_{&gt;8.0}$ was significantly higher in T1 (17.18%) than in T2 (13.85%) (p<0.01). For ruminal in situ dry matter degradation of particle retention (>19 mm), no significant difference was found after 72 hours incubation, although T1 degradation was significantly higher after 24 hours incubation (p<0.01). Milk yield was no different between the groups of cows, whereas the milk fat from T1 fed cows was significantly higher (p<0.01). The results show that feeding TMR mixed for 30 minutes to dairy cows may improve the physical value of forage without negative effects on the milk yield and milk components.

Empirical Study of Biogas Purification Equipment (바이오가스 정제 설비의 실증 연구)

  • Hwan Cheol Lee;Jae-Heon Lee
    • Plant Journal
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    • v.18 no.4
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    • pp.58-65
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    • 2023
  • In this study, to increase the methane content of biogas supplied from Nanji Water Regeneration Center and to purify impurities, a three-stage membrane purification process was designed and installed to demonstrate operation. The methane concentration of biomethane produced in the 2 Nm3/h purification process was set to three cases: 95%, 96.5%, and 98%, and the membrane area ratio of the membrane was 1:1, 1:2, 1:1:1, The optimum conditions for the membrane area of the separator were derived by changing to five of 1:2:1 and 1:2:2. 3 stage separation membrane process of 30 Nm3/h was installed to reflect the optimum condition of 2 Nm3/h, and biomethane production of 98% or more of methane concentration was demonstrated. As a result of the operation of the 2 Nm3/h refining device, the methane recovery rate at the 98% methane concentration was 95.6% when the membrane area ratio was 1:1 as the result of the two-stage operation of the separator, and the recovery rate of methane at 1:2 was increased to 96.8%. The methane recovery rate of the membrane three-stage operation was highest at 96.8% when the membrane area ratio was operated at 1:2:1. The carbon dioxide removal rate was 16.4 to 96.4% and the 2:2 to 95.7% film area ratio in the two-step process. In the three-step process, the film area ratio was 1:2:1 to 95.4%, and the two-step process showed higher results than the three-step process. In the 30 Nm3/h scale biogas purification demonstration operation, the methane concentration after purification was 98%, the recovery rate of methane was 97.1%, the removal rate of carbon dioxide was 95.7%, and hydrogen sulfide, the cause of corrosion, was not detected, and the membrane area ratio was 1:2:1 demonstration operation, biomethane production with a methane concentration of 98% or higher was possible.

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Trajectory Simulation of ASR Particles in Induction Electrostatic Separation (유도형 정전선별에서 ASR 입자의 궤적모사)

  • Kim, Beom-uk;Park, Chul-hyun
    • Resources Recycling
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    • v.28 no.6
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    • pp.96-105
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    • 2019
  • Automobile shredder residue (ASR) is the final waste produced when end-of-life vehicles (ELVs) are shredded. ASR can be separated using mineral-processing operations such as comminution, air classification, magnetic separation, and/or electrostatic separation. In this work, trajectory analyses of conductors (copper) and non-conductors (glass) in the ASR have been carried out using induction electrostatic separator for predicting or improving the ASR-separation efficiency. From results of trajectory analysis for conductors, the trajectories of copper wire by observation versus simulation for coarse particles of 0.5 and 0.25 mm showed consistent congruity. The observed 0.06 mm fine-particles trajectory was deflected toward the (-) attractive electrode owing to the charge-density effects due to the particle characteristics and relative humidity. In the case of non-conductors, the actual trajectory of dielectric glass deflected toward the (-) electrode, showing characteristics similar to those of conductive particles. The analyses of stereoscopic microscope and SEM & EDS found heterologous materials (fine ferrous particles and conductive organics) on the glass surface. This demonstrates the glass decreasing separation efficiency for non-ferrous metals during electrostatic separation for the recycling of ASR. Future work will require a pretreatment process for eliminating impurities from the glass and advanced trajectory-simulation processes.

Cooling Performance Characteristics of High-Performance Heat Pump with VI Cycle Using Re-Cooler (재냉기를 이용한 고성능 VI(Vapor Injection)사이클 열펌프의 냉방 성능특성에 관한 연구)

  • Lee, Jin-Kook;Choi, Kwang-Hwan
    • Journal of Advanced Marine Engineering and Technology
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    • v.39 no.6
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    • pp.592-598
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    • 2015
  • In this study, we experimentally investigate the performance characteristics of a high-performance summer-cooling heat pump for an R410A by applying an air-cooled-type vapor-injection (VI) cycle. The devices used for the experiment consist of a VI compressor, condenser, oil separator, plate-type heat-exchanger, economizer, evaporator, and re-cooler. The experimental conditions employed for the cooling performance were divided into three cycles. First, in Cycle A, we apply a VI cycle and with no heat exchange between the evaporator outlet refrigerant and the VI cycle suction refrigerant in the re-cooler. For Cycle B, there is heat exchange, and for Cycle C, there is neither a VI cycle nor heat exchange between the evaporator outlet refrigerant and the VI cycle suction refrigerant. From the analysis results, we observe that the performance was highest in the VI cycle with heat exchange between the evaporator outlet refrigerant and the VI cycle suction refrigerant (Cycle B), while it was lowest in Cycle C without application of the VI cycle. Moreover, the cooling coefficient of Performance ($COP_C$) averaged 3.5 in Cycle B, which was 8.6% higher than the corresponding value in Cycle A, and 33% higher than that in Cycle C.

TREATMENT OF ECTOPIC ERUPTING MANDIBULAR FIRST PERMANENT MOLAR CAUSED BY IMPROPERLY RESTORED STAINLESS STEEL CROWN : CASE REPORT (부적절하게 수복된 stainless steel crown에 의해 야기된 하악 제1대구치 이소맹출의 치험례)

  • Park, Chu-Seok;Choi, Byung-Jai;Sohn, Heung-Kyu
    • Journal of the korean academy of Pediatric Dentistry
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    • v.27 no.1
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    • pp.98-102
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    • 2000
  • Ectopic eruption is out of a normal position by local eruption disturbance in the developing permanent molar. The prevalence of ectopic eruption is reported to be the between 2 and 6%, most often associated maxillary first permanent molar whereas, the occurrence for the mandibular is quite rare. The etiologic factors of ectopic eruption are inadequate arch length, lack of growth in the posterior region of the jaw, mesially inclined eruption path of first permanent molars, abnormally large first permanent molars, hereditary factor and a stainless steel crown which has been improperly restored. Ectopic eruption can be treated by the use of brass wire, separating elastics, distal disking and Humphrey appliance and the use of removable appliance and cervical traction headgear after extraction of the second primary molar. This case was that lower right first permanent molar was mesially tilted state by locking on the stainless steel crown of a lower right second primary molar. The stainless steel crown was removed and Humphrey appliance was set. Like this case, ectopic eruption could be happened by the stainless steel crown which improperly restored. In restoration of the stainless steel crown, selection of proper size, trimming and contouring are very important.

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