Knelson Concentrator를 이용한 저품위 회중석의 전처리 기술개발

전호석 ( Ho Seok Jeon ),양정일 ( Jeong Il Yang ),이은선 ( Eun Seon Lee ),최희경 ( Hee Kyoung Choi ),백상호 ( Sang Ho Baek ) 한국광물학회 2013 광물과산업 Vol.26 No.-

This study is carried out experiments on various factors for improving the grade of low grade scheelite by Knelson concentrator prior to the main beneficiation process. Even though there are several gravity separators such as Jig, Spirals and etc. for rougher concentrate, the KC3 Knelson Concentrator was adopted to get better separation efficiency and beneficiating effects for pre-concentration of the low grade scheelite ore. The feed samples was prepared to minus 1㎜in size by crushing and grinding. The important factors in the KC3 Knelson Concentrator test were examined in terms of the variations such as number of treatment, feed rate, rotation speed of bowl(G force), water flow rate, pre-removal of magnetic minerals, feed size and feed grade. According to the result of experiment, it shows that the important technical variations are limited in terms of number of treatment, feed rate, feed size and feed grade. The final result shows that the KC3 Knelson Concentrator obtains the scheelite pre-concentrate of about 3%WO3 grade and 90% recovery, respectively, from the feed containing about 0.8-1.0%WO3 grade.

Design of an Ultrasonic Concentrator for Vibro-tactile Sensors Using Electro-mechanical Analogy

Yanjun Qian,한상욱,권혁주 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.10

Vibro-tactile sensors have been utilized to measure the mechanical properties of soft materials based on the shift of resonant frequency. However, their low signal to noise ratio (SNR) has impeded them from critical applications where accurate measurements are required. One of the ways to improve the SNR is to add an ultrasonic concentrator as a mechanical filter to the vibro-tactile sensor. In order to maximize the SNR, the concentrator should be optimally designed; however, systematic design approach of the concentrator has rarely been considered so far. In this paper, a hybrid design approach employing both analytical analysis and numerical simulation is presented. For analytical analysis, impedance analogy was used to facilitate the designing process, and the numerical simulation using FEA was conducted to carry out the parametric refinement of the design. The performance of the final design was verified by mechanical and electrical characteristics tests. Tests results indicate that the longitudinal resonance mode of the sensor was significantly enhanced and the increase in its mechanical quality factor was achieved by the ultrasonic concentrator. The tactile sensing experiments on the silicone rubber samples showed the high potential of the vibro-tactile sensor in estimating the elastic moduli of soft materials in the range of 5–100 kPa, which is not readily available with conventional testing methods.

유한요소법을 이용한 자기센서용 자속집속기의 해석

신광호(Kwang-Ho Shin) 한국자기학회 2013 韓國磁氣學會誌 Vol.23 No.3

In this study, magnetic concentrators which could be used to enhance sensitivity of Hall effect sensor were analyzed by using FEM. The parameters for FEM analysis were the thickness and edge shape of magnetic concentrator and relative position of magnetic concentrator against Hall element. Magnetic field in z direction decreased with increasing of the thickness of magnetic concentrator, of which tendency was similar to apparent relative permeability calculated with demagnetizing factor of magnetic concentrator. There were optimal thickness and edge shape of magnetic concentrator according to the relative position of magnetic concentrator against Hall element.

Performance Analysis of Fresnel Concentrator Using Nanofluid

( Kyeong Sik Kang ),( Gwi Hyun Lee ) 한국농업기계학회 2023 한국농업기계학회 학술발표논문집 Vol.28 No.1

Solar energy is an infinite energy source, which and can be used for heating system with producing the hot water by absorbing and storing solar heat. Previously, solar heat collectors mainly use water as the thermal medium for absorbing and storing heat. With the recent development of nanotechnology, nanofluids using nanoparticles have been studied and used. In order to improve the efficiency of the Fresnel concentrator, nanofluid and water were applied as the thermal medium of the system and compared after performance analysis. A nanofluid was a fluid prepared with dispersing nanoparticles having high thermal conductivity using distilled water as a base fluid. Nanofluids have higher thermal conductivity than common heat media such as water, so it can possible to expect an increase the efficiency of the concentrator. In this study, nanofluids were fabricated by adding aluminum nanoparticles at a concentration of 0.05% and to improve the dispersion stability of the nanoparticles, the surfactant CTAB was added at 1/10 times, 1 time, and 10 times based on the CMC concentration. Among them, 1/10 times the highest thermal conductivity was selected as the thermal medium of the concentrator. The experiment was conducted for 240 minutes under the same conditions on a clear day using water and aluminum nanofluid as a thermal medium. As the results of the experiment, nanofluids showed higher efficiency than water, and among them, the higher the flow rate, the higher the efficiency.

300-W-class Side-pumped Solar Laser

Hongfei Qi,Lanling Lan,Yan Liu,Pengfei Xiang,Yulong Tang 한국광학회 2022 Current Optics and Photonics Vol.6 No.6

To realize uniform side pumping of solar lasers and improve their output power, a solar concentrating system based on off-axis parabolic mirrors is proposed. Four identical off-axis parabolic mirrors with focal length of 1,000 mm are toroidally arranged as the primary concentrator. Four two-dimensional compound parabolic concentrators (2D-CPCs) are designed as a secondary concentrator to further compress the focused spot induced by the parabolic mirrors, and the focused light is then homogenized by four rectangular diffusers and provides uniform pumping for a laser-crystal rod to achieve solar laser emission. Simulation results show that the solar power received by the laser rod, uniformity of the light spot, and output power of the solar laser are 7,872.7 W, 98%, and 351.8 W respectively. This uniform pumping configuration and concentrator design thus provide a new means for developing high-power side-pumped solid-state solar lasers.

Manufacturing of Compound Parabolic Concentrator Devices Using an Ultra-fine Planing Method for Enhancing Efficiency of a Solar Cell

Hwan-Jin Choi,Changsoon Cho,Sangwon Woo,Jung-Yong Lee,Yeong-Eun Yoo,Minwoo Jeon,Geon-Hee Kim,Tae-Jin Je,Eun-chae Jeon 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.5

Various structural patterns are used to control light properties during propagation. In particular, when light is trapped and concentrated onto solar cells, they generate more electricity than without concentration. Since the sun moves continuously, a compound parabolic concentrator (CPC) can enhance the efficiency of solar cells by light-trapping and concentration because a CPC minimizes optical loss by reducing the reflection and the scattering on the surface of solar cells. However, CPC devices are generally expensive to manufacture and are too large in size to be used for applications requiring portability. Here, we developed a novel manufacturing process for a small CPC device and verified the enhanced efficiency of solar cells. Based on ultra-fine planing and injection molding, this process is an efficient method for mass production because it relies on replication. Two metal molds were precisely machined using an ultra-fine planing method with a diamond tool, and a CPC device was accurately manufactured by injection molding at low cost and within one minute. The variation of the specific cutting resistance during machining of the metal molds increased by four times, and the minimum uncut chip thickness decreased from 1.3 to 0.5 μm, which is called a size effect. The finished CPC device exhibited a surface roughness less than 40 nm and showed high optical efficiency in virtue of light-trapping. Finally, the efficiency of a solar cell with the CPC device was enhanced about 10%.

실내외 겸용 산소발생기 제품 디자인 개발

SooBin Lee,TaeKyun Kim 한국서비스디자인학회 2018 서비스디자인융합연구 Vol.2 No.2

본 연구는 기존 산소발생기의 현황을 파악하여 문제점을 도출하고, 이를 개선한 새로운 컨셉(Concept)의 산소발생기를 개발하는데 그 목적이 있다. 최근 미세먼지가 기승을 부리며 각종 호흡기 질환을 유발하고 있으며, 고령화 사회로 진입이 가속화되면서 폐질환 환자가 증가하고 있다. 이러한 현대 사회에 대응하여, 경증 폐질환 환자를 위한 산소발생기를 주제로 선정하였다. 산소발생기는 일반적으로 실내 공간에서 사용되지만, 실외 공간에서도 필요한 경우가 있기 때문에 실내뿐만 아니라 실외에서도 사용할 수 있는 산소발생기의 필요성이 증가하고 있다. 이를 고려하여 실내용 산소발생기에 실외용 산소발생기의 탈착이 가능하도록 구상하였으며, 환자는 하나의 제품으로 실내·외 두 공간에서 자유롭게 활동할 수 있다. 또한 실내용 산소저장탱크에 충전된 산소가 이동하여 실외용 산소저장탱크에도 충전되므로, 실내·외 저장탱크를 각각 충전하기 위한 장치를 별도로 필요로 하지 않아 경제적이다. 분리 가능하게 구비되는 탈착 산소발생기를 개발함으로써 사용자의 편의성과 경제성을 도모하는데 본 연구의 의의가 있다. The purpose of this study is to develop new concept of oxygen concentrator improved the product’s problem by understanding existing oxygen concentrators. Recently, the fine dust is a serious problem that causes all kinds of the respiratory disease by adsorbing our bronchial tubes and lung. As rapidly becoming an aging society, the umber of pulmonary disease patients is increasing now also. In view of this facts, I selected subject of research on an oxygen concentrator for mild pulmonary disease patients. The product is generally used in home, however, patients can need it for outdoor use also. So the product that can be used not only indoors but outdoors is in increasing demand now. On the basis of this facts, I designed a detachable oxygen concentrator so patients can free without space restriction. They can use ONE product in TWO spaces: Indoor and outdoor. An economic advantage is that it’s unnecessary extra devices to storage oxygen between two parts.

Design of Agricultural Drying System using Conical Solar Concentrators

( Seong Geon Hwang ),( Mun Soo Na ),( Joo Hee Lee ),( Gwi Hyun Lee ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

The main purpose of this study is to utilize solar power effectively in agricultural drying system. Since solar energy is low-density energy, it should have more collecting efficiency. In this study, we intend to design an agricultural drying system using the conical solar concentrator. Drying room was manufactured with insulated polyurethane panel of 100mm and a control box was installed to control the appropriate drying temperature. Inside the drying room, heat exchanger was installed to use the heating medium accumulated by conical solar concentrators with a fan to circulate heated air, and a temperature sensor was fixed to measure the drying temperature. Also, solenoid valves and temperature control limits were installed to control the circulation of heating medium. When heating medium in the storage tank heated by the conical solar concentrators is reached at the set drying temperature, a control device detects the temperature of the heating medium and operates the circulation pump and the solenoid valve of ON/OFF. When the temperature of the heating medium in the heat storage tank was reached at 70˚C, it was begun with an initial temperature of around 28˚C inside the drying room. Temperature and humidity changes in the drying room were measured, when the set drying temperatures were reached to 40˚C, 50˚C, and 60˚C, respectively. As the set drying temperature was higher, the degree of temperature and humidity change was lower.

조명 소프트웨어를 이용한 추적식 디쉬형 집광기의 배광분포 분석 및 자연채광 성능 예측

오승진(Oh Seung Jin),한현주,신상웅,천원기(Chun wongee) 한국태양에너지학회 2012 한국태양에너지학회 학술대회논문집 Vol.2012 No.3

Daylighting software is an important component to predict the performance of daylighting system in advance of a field demonstration study with installing them in buildings. PHOTOPIA is a powerful software to generate a candela distribution curve(CDC) of an active daylighting system like a tracking dish concentrator. With PHOTOPIA, a set of candela distribution curves was generated under clear sky conditions and different solar altitude angles. The candela distribution curves were then imported to RADIANCE for rendering and analysis on the daylighting performance of a tracking dish concentrator when it installed in a actual class room without windows. As a result, the daylight collection efficiency of the dish concentrator was 68.4% when we assumed that there was no tracking error. It was found that candela(cd) and total lumens(lm) increased with solar altitude rising, whereas the distribution angle was fixed. The illuminance uniformity on the work plane in the class room was relatively low, 0.12, while the illuminance uniformity on the area of 2.7m to which the light was illuminated was considerably high, 0.60. The maximum illuminance was 1,3401ux with a solar altitude angle of 80 degrees.

넬슨선별기를 이용한 퇴적토 중 중금속 성분의 분리

고병헌,김종걸,전상희,유경근,김수곤,백승한 한국자원공학회 2015 한국자원공학회지 Vol.52 No.6

항만에는 미립토가 퇴적되며 정기적인 준설이 실시되나 중금속으로 오염된 퇴적토의 경우 준설 후적절한 처리가 필요하다. 비중선별공정을 적용하여 중금속 오염성분을 분리하기 위해 넬슨선별기를 이용한 분리실험을 진행하였고, 중액선별을 실시하여 두 선별법의 결과를 비교하였다. 넬슨선별기 분리실험에서 원심가속도의 증가에 따라 납, 구리, 아연 모두 회수율은 감소하고, 상향흐름 산물 중 함유량은 증가하는 것으로 나타났다. 중액선별결과 중금속 성분은 넬슨선별분리결과와 반대로 침강된 산물에서 높게 분석되었다. 중금속 성분은 섬유상 물질에 함유되어 있어 수류작용에 의해 넬슨선별실험에서는 상향흐름 산물에 포함되고, 중액선별에서는 비중때문에 침강된 산물에 함유된 것으로 분석되었다. 넬슨선별기 내에 잔존하는 산물의 중금속 함량을 분석한 결과, 납, 구리, 아연의 함량은 각각 91.1 mg/kg, 238 mg/kg, 89.3 mg/kg으로 감소하여 성공적으로 중금속 성분이제거되었다. Fine particles are deposited in port area, and the sediments are dredged regularly. The dredged sediments contaminated with heavy metals must be treated properly. The heavy metal contaminants were separated from the sediments by gravity separation processes such as Knelson concentrator, and the results were compared with those by dense medium separation. The recovery of Pb, Cu, Zn decreases and the contents in the overflow product increases with increasing centrifugal acceleration speed of Knelson concentrator. In the dense medium separation test, the contents of heavy metals in sunk product are higher than those in floated product. Because the heavy metal contaminants were contained in fibrous materials, the components were separated into overflow product in Knelson separation by waterstream working, whereas they precipitated in the dense medium test due to high density. The contents of Pb, Cu, Zn in trapped-product of Knelson separation were 91.1 mg/kg, 238 mg/kg, 89.3 mg/kg, respectively, which indicated that the heavy metals were removed successfully by Knelson separation process.