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A study on coil temperature bariation in 75% hydrogen batch annealing furnace (75% 수소 BATCH 소둔시에서의 코일 온도변화에 관한 연구)

  • Jeon, Eon-Chan;Kim, Soon-Kyung
    • Journal of the Korean Society for Precision Engineering
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    • v.11 no.2
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    • pp.173-181
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    • 1994
  • A Cold spot temperature control system for the batch annealing furnace has been estabilished in order to reduce energy consumption to improve productivity and stabilize the propertics of products. Therefore we confirmed a relation between annealing cycle time and atmospheric gas, variation of coil cold spot temperature with time during heating and actual temperature measurements at mid-width of each coil during heating and actual temperature measurements at mid-width of each coil during soaking. The results of the tempaeature variation effect on the batch annealing are as follows. 1) Heating time is reduced to one half with increasing atmospheric gas flow rate and changing of atmospheric gas component from HNx to Ax gas, and annealing cycle time is reduced to 2.7 times. 2) In case of short time healing, the slowest heating part is the center of B coil, in case of long time heating, the low temperature point moves from the center of coil to inside coil. And the temperature in this part is higher than other parts when cooling. When finished heating, the cold spot is located 1/3 of coil inside in case of HNx atmospheric gas. But center of coil in case of Ax atmospheric gas. 3) The outside of top coil is the highest temperature point when heating, which becomes the lowest temperature point when cooling. So, this point becomes high temperature zone at heating and low temperature zone at cooling, It has relation according to atmospheric gas component and flow rate. 4) Soaking time at batch annealing cycle determination is made a decision by the input coil width, and soaking time for quality homogenization of 1214mm width coil must be 2.5 hours longer than that of 914mm width coil for the same ciol weight. 5) Annealing cycle time with Ax atmospheric gas is extended 1 hour in of slow cooling during 5 hours in order to avoid rapid cooling.

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Prediction of Air Movement and Temperature Distribution at Different Store Methods Using 3-D CFD Simulation in Forced-Air Cooling Facility

  • Yang, G.M.;Koh, H.K.
    • Agricultural and Biosystems Engineering
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    • v.3 no.2
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    • pp.65-72
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    • 2002
  • Temperature is the most influential environment parameter which affects the quality change of agricultural products in cold storage. Therefore, it is essential to keep the uniform temperature distribution in the storage room. This study was performed to analyze the air movement and temperature distribution in the forced recirculating cold storage facility and to simulate optimum storage method of green groceries using 3-D CFD(three dimensional computational fluid dynamics) computer simulation which applied the standard $textsc{k}$-$\varepsilon$ turbulence model and FVM(finite volume method). The simulation was validated by the experimental results for onion storage and the simulation model was used to simulate the temperature and velocity distribution in the storage room with reference to the change of storage method such as location of storage, no stores, bulk storage, and pallet storage. In case of no stores, internal airflow was circulated without stagnation and consequently air movement and temperature distribution were uniform. In case of bulk storage, air movement was stagnated so much and temperature distribution of onion was not uniform. Furthermore, the inner temperature of onion roses more than the initial temperature of storage. In case of pallet storage, air movement and temperature distribution of onion were so uniform that the danger of quality change was decreased.

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3-D Simulation of Air Flow in Cold Storage Room for Uniform Temperature Distribution (저온저장고 내부의 균일한 온도분포를 위한 3차원 공기유동 분석)

  • 성제중;고학균;조성인;양길모
    • Journal of Biosystems Engineering
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    • v.25 no.4
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    • pp.279-286
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    • 2000
  • Most of the domestic cold storage rooms are inefficient for agricultural products because of temperature gradients inside the storage rooms. Temperature gradients are developed mainly by improper airflow pattern inside the storage room, which is a main cause of the spoilage of the agricultural products. There proper airflow pattern is essential to minimize these temperature gradients and the spoilage. The performance and characteristics of a cold storage room were determined as a function of airflow pattern and temperature distribution in forced circulation cold storage room. A commercial CFD(computational fluid dynamics) code was used to simulate 3-D airflow in the cold storage room. Solving the flow equations for the storage room, a standard k-$\varepsilon$ turbulent model was implemented to calculate steady state turbulent velocity distribution. The CFD prediction results were compared with temperature measurements inside the cold storage room. In case of pallet storage, Temperature gradients inside pallet storage was reduced because the contact area of cold air expanded through an alley of airflow in storage. But is case of bulk storage, the last temperature of storage considerably rose more than the initial temperature of storage. The reason was that bulk storage didn't include any alley of airflow in storage.

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A Clinical case study for the diagnosis and assessment of abdominal cold hypersensitivity treatment by DITI (적외선 체열검사(DITI)로 복부냉증의 진단과 치료 경과를 평가한 단일 임상례)

  • Kim, Eun-Gyung;Hwang, Deok-Sang;Lee, Chang-Hoon;Lee, Kyung-Sub
    • Journal of Oriental Medical Thermology
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    • v.7 no.1
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    • pp.55-65
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    • 2009
  • Purpose: This study was performed to evaluate DITI (Digital Infrared Thermographic Imaging)'s potential for diagnosis and indicator of abdominal cold hypersensitivity treatment from the clinical case study. Methods: The patient was a 35-year-old woman who was suffered by general coldness, sweating and general pain. The patient was treated by Herb medicine, Acupuncture treatment, Moxa treatment and Physical Treatment. The progress of symptoms was evaluated by checking the change of VAS, and inspecting the DITI. We studied the statistical significance from the difference of DITI results before and after treatment by paired T-test using SPSS windows (version 12.0). Results: The general coldness, sweating and general pain of this patient have declined, especially the abdominal coldness improvement showing. As a results, the temperature of four abdominal sites(GV4,6,12,17) after treatment were statistically higher than those before treatment. With comparison of Indang, DITI difference of abdominal sites before and after treatment were statistically significant from paired T-tests. Conclusion: The results suggest that DITI can be used for the diagnosis and assessment of abdominal cold hypersensitivity treatment.

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A Study on Temperature Variation of Coil on BAF Annealing in HNx Atmospheric Gas (HNx 분위기가스중에서 BAF소둔시 코일의 온도변화에 관한 연구)

  • 전언찬;김순경
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.5
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    • pp.1227-1234
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    • 1994
  • A cold spot temperature control system for the batch annealing furnace has been established in order to reduce energy consumption which is essential to improve productivity and stabilize the properties of products. A relationship between annealing cycle time and gas flow rate is developed and also for the variation of coil cold spot temperature with time during heating, and actual temperature measurements at mid-width of each coil during soaking. The results of the temperature variation effect on the cold rolled steel sheet batch annealing are as follows. (1) Cooling rate increasing gradually with increasing atmospheric gas flow, but heating rate is hardly increasing without atmospheric gas component change. (2) In case of short time heating, the slowest heating part is the center of B coil and in case of ling time heating, the low temperature point moves from the center of coil to inside coil. (3) The outside of top coil is the highest temperature point under heating, which becomes the lowest temperature point under cooling. (4) Soaking time determination depends on the input coil width, and soaking time for quality homogenization of 1214 mm width coil must be 2 hours longer than that of 914 mm width coil.

Studies on Artificial Hatching of Hibernating Eggs, Bombyx mori L. (월년잠종의 인공부화에 관한 연구)

  • 김윤식;손해용
    • Journal of Sericultural and Entomological Science
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    • v.18 no.1
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    • pp.7-10
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    • 1976
  • This experiments were carried out to know hatching power on treatments of cold temperature and hydrochioric acid Iron Late January to Early February. Used silkworm variety was Jam 103${\times}$ Jam 104 laying in Spring. The results may be summarized as follows: 1. The resting of silkworm eggs activated to Late January, to longer cold treatment was, the more effects of activating increased completely. So activated eggs were possible to incubation. 2. How to the light or short hours of hycrochloric acid were compare with heavy or long each other, it was inclined that the former seems to be worse than the latter. 3. On the interaction of cold treatments and hydrochloric acid, in case of short cold treatment, hatching power was better effect all treatments of hydrochloric acid than control, but no difference between specific gravity or treatment hours. On tile contrary, in case of more longer of cold treatments, hatching power depended not only upon the specific gravity, but also upon the treatment hours.

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Vascular dysfunction in patients with type 2 diabetes mellitus

  • Ekta, Khandelwal;Mahaveer Jain;Sumeet Tripathi
    • Annals of Clinical Neurophysiology
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    • v.25 no.1
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    • pp.32-37
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    • 2023
  • Background: Type 2 diabetic mellitus (T2DM) is an emerging global pandemic which is associated with lots of co-morbidities and reported vascular dysfunctions. T2DM associated vascular dysfunctions leads to vasculopathy in the form of altered peripheral vascular dynamics. Cold stress test (CST) is a reliable sympathetic reactivity test used for assessing vascular dysfunctions. In this study we are trying to quantify vascular dysfunctions in T2DM patients non invasively by various parameters of photoplethysmography (PPG) of cold stress test. Methods: Case control study had done in referral health center AIIMS, Raipur. Parameters are recorded by finger-PPG before, during and after CST (1 min) in 2 groups, control (n = 20 healthy volunteers) and case (n = 20 diagnosed T2DM patients). Results: Due to cold stress, PPG parameter peak amplitude was significantly decreased in both healthy and T2DM groups (p <0.001 and p <0.001, respectively). However, recovery trend of amplitude was significantly slow in T2DM compared to healthy subjects. Another PPG parameter peak to peak interval was significantly higher in healthy group compared to T2DM patients. Conclusions: This study showed that T2DM patients has significant deranged pulse volume parameters like amplitude and peak to peak interval can be used to objectively quantify the vasculopathy in T2DM patients by using sympathetic reactivity to cold stress.

Enhancement of the round-trip efficiency of liquid air energy storage (LAES) system using cascade cold storage units

  • Kim, Jhongkwon;Byeon, Byeongchang;Kim, Kyoung Joong;Jeong, Sangkwon
    • Progress in Superconductivity and Cryogenics
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    • v.22 no.4
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    • pp.45-50
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    • 2020
  • In this research, the variation of round-trip efficiency in a liquid air energy storage system (LAES) is calculated and an optimal configuration is found. The multiple stages of cold energy storage are simulated with several materials that process latent heat at different temperature ranges. The effectiveness in the charging and discharging processes of LAES is newly defined, and its relationship with the round-trip efficiency is examined. According to defined correlation, the effectiveness of the discharging process significantly affects the overall system performance. The round-trip efficiency is calculated for the combined cold energy storage materials of aqueous dimethyl sulfoxide (DMSO) solution, ethanol, and pentane theoretically. The performance of LAES varies depending on the freezing point of the cold storage materials. In particular, when the LAES uses several cold storage materials, those materials whose freezing points are close to room temperature and liquid air temperature should be included in the cold storage materials. In this paper, it is assumed that only latent heat is used for cold energy storage, but for more realistic analyzes, the additional consideration of the transient thermal situation to utilize sensible heat is required. In the case of such a dynamic system, since there is certainly more increased heat capacity of the entire storage system, the volume of the cold energy storage system will be greatly reduced.

A Study on the Quality Control for the Circulation Steps including Productipn, Transportation, Selling about Hamburger & Sandwich in Convenience Store (편의점에서 판매되는 햄버거와 샌드위치의 유통과정중 품질관리에 관한 연구)

  • Kim, Heh-Young;Song, Yong-Hye
    • Journal of the Korean Society of Food Culture
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    • v.11 no.4
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    • pp.465-473
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    • 1996
  • The purpose of this study was to evaluate microbiological hazards in the steps of production, transportation and selling of hamburger and sandwich that were marketed in CVS, then to identify methods of control. The reasults are as follows: As the reasult of operation surroundings of manufacturerand reserch of circulation, $4{\sim}6$ hours are needed from manufacturer to CVS. Also transportation car mean temperature was $10^{\circ}C$ which exceeds the standard of $7^{\circ}C$ or below. Hamburger: Critical control points identified were purchasing, cooking, post-preparation, transportation and holding at CVS. As the reasult of microbial analysis following the case of holding methods and reheating at CVS, microbes of cold holding and reheat after cold holding was within standard value. But in the case of room temperature microbes exceeded standard value. Sandwich: Critical control points identified were purchasing, cooking, post-preparation, transportation and holding at CVS. As the reasult of microbial analysis following the case of holding methods and reheating at CVS, total plate counts of cold holding and reheat after cold holding was within standard value. But in the case of room temperature holding after 24 hours total plate counts exceeded standard value. In the case of room temperature holding the number of microbes increased according to the passage of time. As a reasult of food poisoning bacteria, it was negative in every test in sample against V. parahaemolyticus, Salmonella, S. aureus.

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Powder Characteristics of Fly Ash Beneficiated by Cold Plasma and Heat Treatment

  • Lee, Seung-Heun;Cho, Un-Jin;Kwon, Sung-Ku
    • Journal of the Korean Ceramic Society
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    • v.53 no.1
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    • pp.93-98
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    • 2016
  • Cold plasma and heat treatment were selected as technologies to reduce unburned carbon in fly ash to less than 1.0%. Both cold plasma and heat treatment made it possible to eliminate unburned carbon to less than 1.0%. In the case of fly ash, which almost entirely eliminated unburned carbon with an ignition loss of 0.5%, heat treatment caused adhesion among particles and the BET specific surface area rapidly decreased as the mean particle size increased. On the other hand, with cold plasma, unburned carbon elimination caused the BET specific surface area to decrease and, as no adhesion occurred among particles, the mean particle size became small. Also, cold plasma treatment allowed small spherical particles confined within the unburned carbon particles to be released with the elimination of the unburned carbon frame, so that the quantity of fine particles had a tendency to slightly increase.