• Title/Summary/Keyword: Hot zone

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Adsorption and Thermal Regeneration of Toluene and Benzene on the Fixed Bed Packed with Activated Carbon and Activated Carbon Fiber

  • Kim, Jong-Hwa;Oh, Ok-Kyun;Haam, Seung-Joo;Lee, Chang-Ha;Kim, Woo-Sik
    • Carbon letters
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    • v.2 no.1
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    • pp.44-54
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    • 2001
  • The characteristics of adsorption and desorption of benzene and toluene were investigated at a fixed bed packed with the activated carbon and activated carbon fiber. Through breakthrough experiments under various feed concentration conditions, it was found that the slope of mass transfer zone and the tailing in the breakthrough curves were different from the feed conditions due to different heats of adsorption. In hot nitrogen desorption, the regeneration time and mass transfer zone of the toluene desorption curve were longer than those of the benzene desorption curve because of the difference in adsorption affinity. With an increase in the regeneration temperature, the height of roll-up and the sharpness of desorption curves increased but the regeneration times decreased. The adsorption capacities of the activated carbon and activated carbon fiber after three-time thermal regenerations decreased about 25% and 37% for benzene and 18% and 25% for toluene, respectively. To investigate the effect of the regeneration temperature on the energetic efficiency, the characteristic desorption temperatures of toluene and benzene were investigated by calculating purge gas consumption and temperature.

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Effect Analysis in Laser Metal Deposition of SKD61 by Track Pitch (트랙 이행거리에 따른 SKD61 재질의 레이저 메탈 디포지션 기초 특성 분석)

  • Kim, Won-Hyuck;Jung, Byung-Hun;Oh, Myeong-Hwan;Choi, Seong-Won;Kang, Dae Min
    • Journal of Power System Engineering
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    • v.18 no.5
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    • pp.94-99
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    • 2014
  • In this study, AISI M2 powder was selected primarily through various literature in order to improve the hardness and wear resistance. Among the laser metal deposition parameters, laser power was studied to improve the deposition efficiency in the laser metal deposition using a diode pumped disk laser. SKD61 hot work steel plate and AISI M2 powder were used as a substrate and powder for laser metal deposition, respectively. Fixed parameters are CTWD, focal position, travel speed, powder feed rate, etc. Experiments for the laser metal deposition were carried out by changing laser power. Through optical micrographs analysis of cross-section in LMD track, effect of the major parameters were predicted by track pitch. As the track pitch increased, so the reheated zone width, the overlap width and the minimum thickness was decreased. The hardness was decreased in the HAZ area, the hardness in the reheated HAZ area was decreased significantly and regularly in particular.

Effects of a Flow Guide on the Arcing History in a Thermal Puffer Plasma Chamber (유동 가이드가 열파퍼 플라즈마 챔버의 아크현상 이력에 미치는 영향)

  • Lee, Jong-Chul;Kim, Youn-Jea
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.10
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    • pp.832-839
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    • 2007
  • The geometry and dimensions of an expansion chamber are decisive factors in thermal puffer plasma chamber designs. Because they together dominate the temperature and speed at which the cooling gas from the chamber flows back through a flow channel to the arcing zone for the successful interruption of fault currents. In this study, we calculated the flow and mass transfer driven by arc plasma, and investigated the effects of a flow guide installed inside a thermal puffer plasma chamber. It is found that the existing cold gas of the chamber mixes with hot gases entrained from the arcing zone and is subjected to compression due to pressure build-up in the chamber. The pressure build-up with the flow guide is larger than that without due to a vortex which rotates clockwise around the chamber center. By the reverse pressure gradient, the mixing gas of the chamber flows back out for cooling down the residual plasma near current zero. In the case with the flow guide, the temperature just before current zero is lower than that without, and the Cu concentration with high electrical conductivity is also less than that without the flow guide.

The Effect of the Heat Treatment Conditions on the Microstructure and Hardness of Ti-Nb Alloys (Ti-Nb계 합금의 미세조직 및 경도변화에 미치는 열처리 조건의 영향)

  • Lee, Doh-Jae;Lee, Kyung-Ku;Lee, Kwang-Min;Hwang, Ju-Young
    • Journal of Korea Foundry Society
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    • v.23 no.4
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    • pp.204-211
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    • 2003
  • Ti-3wt.%Nb(${\alpha}$type), Ti-20wt.%Nb(${\alpha}+{\beta}$,type) and Ti-40wt.%Nb(${\beta}$type) alloys were melted by vacuum are remelting. The specimens were homogenized at 1050$^{\circ}C$ for 24 hr and were then hot rolled to 50% reduction. Each alloys were solution heat treated at ${\beta}$ zone and ${\alpha}+{\beta}$, zone after homogenization, and then aged. The microstructural and hardness changes in Ti-Nb alloys with Nb contents were investigated by SEM, XRD and hardness tester. The microstructural change from equiaxied to acicular and the increase of ${\beta}$ phase in Ti-Nb alloys were obtained when the Nb content increased. The higher hardness value of ${\alpha}+{\beta}$type alloy was obtained compared to the other alloys.

A Study of the Weld Strength of Extru-Rivet Spot Welding Using Electrodes Heated by Electric Resistance (전기저항가열 압출점접합공정에 있어서 접합강도에 관한 연구)

  • Lee, S.J.;Jin, I.T.
    • Transactions of Materials Processing
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    • v.22 no.4
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    • pp.189-195
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    • 2013
  • In this study, the weld strength of extru-rivet spot welding was investigated by simulation and experiment. In order to obtain hot plasticity flow bonding of the two plates by a single rivet, electrodes are used for heating of the two plates and the rivet by electric resistance. Because weld strength is influenced by the temperature in the weld zone, the diameter of the electrodes and the amount of current supplied to the electrodes are important variables. For the simulation, heat distribution and weld strength were calculated using DEFORM-3D. The weld strength in the weld zone was calculated for various values of the experimental parameters. The simulation results showed that the weld strength was the highest when the weld current was 37kA, the electrode diameter was 12mm, and the welding frequency was 90cycle. Aluminum 5052 was used for the experimental study. A total of three aluminum plates, two welding plates with 1mm thickness and one plate with 2mm thickness for the inserting rivet, were used for the experimental extru-rivet spot welding.

A Study of Fetishism in Fashion -Underwear Fetish- (패션에 나타난 페티시즘 연구 -언더웨어 페티시(Underwear Fetish)-)

  • 이의정;양숙희
    • Journal of the Korean Society of Clothing and Textiles
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    • v.23 no.2
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    • pp.272-283
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    • 1999
  • Fetishism originated from the cultural and social products is related to many aspects of arts and sciences ; postmodernism psychoanalysis and subculture of pornography. Fetishism was reflected on fashion and now has been one of hot issues in high fashion, Waist was one of the erotic zone of body both in man and woman and sadomasockhistic fetishism was originated from physical damages on this zone. The aim of this experiment was to study what kind of fetishism was revealed on fashion especially in women and men's underwear fetish. In conclusion fetishism which has a long history and now been a one of popular high fashions in Western society is still unfamiliar to Korean fashion society. Researches of fetishism including deviant sex was still restricted in Korean society due to "Confuncianism" which has been a ruling philosophies in Korean culture. However the sex moral in modern Korean society is now being generous year by year and sex is no more a toboo to talk with. Fashion fashion will increase its market share in near future in Korea and 력\ulcorner studies of fetishism is needed.

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A Study on the Wear Behavior of the Cu-TiB2 Composites (Cu-TiB2 복합재료의 마모거동에 관한 연구)

  • Kim Jung-Nam;Choi Jong-Un;Kang Kae-Myung
    • Korean Journal of Materials Research
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    • v.15 no.1
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    • pp.61-65
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    • 2005
  • The titanium $diboride(TiB_2)$ has high strength(750MPa), high melting point $(3225^{\circ}C)\;and\;10\%$ IACS electrical conductivity. On this account, the dispersion hardening $Cu-TiB_2$ composites(MMCs) are a promising candidate for applications as electrical contact materials. MMCs for electrical contact materials can reduce material cost and resource consumption caused by wear, due to its good mechanical and electrical property. In this study, we attempt to prepare MMCs with various volume fraction and particle size of $TiB_2$ by means of hot extruded and cold drawn process. Dry sliding wear tests were performed on a pin-on-disk type wear tester, sliding against SM45C under the different applied loads. After wear testing, the microstructures of the worn surfaces were observed by SEM and the microhardnesses of the subsurface zone were measured.

Effect of Antimicrobiotic of Opuntia ficus-indica on Surface Disinfection (제주도 손바닥선인장 추출물의 표면소독제로써의 항균효과)

  • Kwon, Young-ran;Kim, Da-Song;Shin, Hyun-Jae
    • Journal of Korean Biological Nursing Science
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    • v.23 no.1
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    • pp.1-10
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    • 2021
  • Purpose: To verify the anti-microbiotic activity and to develop eco-friendly surface disinfectants using the Opuntia ficus-indica extract. Methods: The stem and fruits of the Opuntia cultivated in Jeju Island were extracted with hot water, 70% EtOH and 100% MeOH, respectively. To examine the antimicrobial activity of the extracts, gram positive bacteria (Bacillus subtilis, Staphylococcus aureus), gram negative bacteria (Escherichia coli, Salmonella typhimurium), yeast (Candida albicans), mold (Aspergillus flavus) and antibiotic resistant bacteria (E. coli, S. aureus) were measured to form a clear zone. Results: The antibacterial activity of the fruit extract was higher than that of the stem extract, and the antibacterial activity of the 100% MeOH (FM) extract and the 70% EtOH (FE) extract of the palm cactus fruit was suitable for the surface disinfectant overall, and clear-zone formed even at relatively low concentrations (250 mg/mL). The FM and FE have antibacterial activity against various bacteria, therefore they can be used as disinfectants. Conclusion: The antimicrobial activity of Opuntia ficus-indica extract from Jeju Island by stem and fruit was determined at relatively low concentrations (250 mg/mL). The Opuntia ficus-indica extract will be useful for surface disinfectants dissolving the patients' bath, oral gargling, and powdered powder in water or ethanol in appropriate concentrations.

Development of Good Manufacturing facility for Radiopharmaceuticals (우수방사성의약품 생산시설 개발)

  • Shin, Byung-Chul;Choung, Won-Myung;Park, San-Hyun;Lee, Kyu-Il;Park, Kyung-Bae;Park, Jin-Ho
    • Journal of Pharmaceutical Investigation
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    • v.33 no.2
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    • pp.145-149
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    • 2003
  • Manufacturing facilities of the pharmaceuticals must meet certain level of the cleanness required so that foreign substances such as dust, moisture, heat, microorganism, or virus do not contaminate the product. In case of radiopharmaceuticals for medical treatment and diagnosis, not only should the operators and environment be protected from radiation but also need to be isolated from the foreign contaminant. Therefore, manufacturing facilities for radiopharmaceuticals must satisfy the design standards of both hot cell and clean room which are specified by GMP. However, standards of maintaining negative pressure for preventing spread of radioactive contaminant in isolated facilities conflict with the standards of maintaining positive pressure for keeping cleanness. To solve this problem, air pressure of hot cell was designed lower than in the adjacent area to meet standards of the radiation safety. To keep higher cleanness in certain part of the hot cell for filling, minimal relative positive pressure allows. In order to effectively maintain the cleanness that is required for production of Tc-99m generator, which takes 70% of whole demand of radiopharmaceuticals, the rooms placed in each side of production room are used as a buffer area and three lead hot cells are installed in production room. In this research, we established the appropriate engineered design concept for Tc-99m generator manufacturing facility, which satisfies both GMP cleanness standard for preventing particles, bacteria, other contaminants and the regulations of radiation safety for supervising and controlling the amount of radiation exposure and exhausted radioactivity. And the concept of multi-barrier buffer zones is introduced to apply negative air pressure for hot cell with first priority and to continue relative positive air pressure for clean room.

Evaluation of Corrosion Resistance and Weldability for the Butt Welding Zone of Hot Rolled Clad Steel Plates (열간압연 클래드강의 맞대기용접부 내식성 및 용접성 평가)

  • Park, Jae-Won;Lee, Chul-Ku
    • Journal of Welding and Joining
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    • v.31 no.5
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    • pp.47-53
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    • 2013
  • We have investigated the traits of clad metals in hot-rolled clad steel plates, including the sensitization and mechanical properties of STS 316 steel plate and carbon steel (A516), under various specific circumstances regarding post heat treatment, multilayered welds, and thick or repeated welds for repair. For evaluations, sectioned weldments and external surfaces were investigated to reveal the degree of sensitization by micro vickers hardness, tensile, and etching tests the results were compared with those of EPR tests. The clad steel plates were butt-welded using FCAW and SAW with the time of heat treatment as the variable, a that was conducted at $625^{\circ}C$, for 80, 160, 320, 640, and 1280 min. Then, the change in corrosion resistance was evaluated in these specimens. With carbon steel (A516), as the heat treatment time increased, the annealing effect caused the tensile strength to decrease. The micro-hardness gradually increased and decreased after 640 min. The elongation and contraction of the area also increased gradually. The oxalic acid etch test and EPR test on STS316 and the clad metal showed STEP structure and no sensitization. From the test results on multi-layered and repair welds, it could be concluded that there is no effect on the corrosion resistance of clad metals. The purpose of this study was to suggest some considerations for developing on-site techniques to evaluate the sensitization of stainless steels.