• Title/Summary/Keyword: Warm-up process

Search Result 44, Processing Time 0.022 seconds

The Physical Property of Nylon/PP Warm-up Knitted Fabric for High Emotional Garment (고감성 의류용 Nylon/PP 온감 니트 소재의 물성)

  • Kim, Hyun Ah;Jang, Hong Won;Heo, Kyoung;Kim, Seung Jin;Kwon, Sang Jun
    • Textile Coloration and Finishing
    • /
    • v.26 no.1
    • /
    • pp.22-31
    • /
    • 2014
  • This study investigated the physical properties of warm up yarns and their knitted fabrics including the dye affinity and color fastness to washing of these knitted fabrics according to the various dyeing times and temperatures on dyeing process. The results were summarized as follows. The tenacity of Nylon/PP warm-up yarn was 4g/d and breaking strain was 4.5%. The wet and dry thermal shrinkages were higher than those of PET warm-up yarn. The maximum heat flow rate(Qmax) of Nylon/PP warm-up knitted fabric was lower than that of PET warm-up knitted fabric and heat keeping rate(a) of Nylon/PP warm-up knitted fabric was higher as 47% than that of PET warm-up knitted fabric. It was shown that the shape retention and wearing comfort of Nylon/PP warm-up knitted fabric were better than those of PET warm-up knitted fabric. The dye-affinity(K/S) of Nylon/PP warm-up knitted fabric showed maximum value at the dyeing condition of 40minute or 50minute dyeing time with $80^{\circ}C$ dyeing temperature, but PET warm-up knitted fabric showed maximum value at the 30minute or 40minute with $110^{\circ}C$ dyeing temperature. Finally, the color fastness to washing of Nylon/PP warm-up knitted fabric showed good value as between 4 and 5 grade.

The Simulations on the Formability of AZ31 Magnesium Alloy Sheet in Warm Deep Drawing (AZ31 마그네슘합금판의 온간 디프드로잉 성형성해석)

  • Kang, Dae-Min;Hwang, Jong-Kwan
    • Journal of the Korean Society of Manufacturing Process Engineers
    • /
    • v.3 no.1
    • /
    • pp.52-58
    • /
    • 2004
  • The material used is a commercial magnesium based alloy AZ31(Mg-3Al-1Zn)sheet with a thickness of 1.0mm. Uniaxial tension tests at warm temperature were carried out to investigate the material characteristics of K, m, and n. A warm drawing process with a local heating and cooling technique was developed to improve formability in this study with results of uniaxial tension tests because it is very difficult for Mg alloy to deform at room temperature by the conventional method. The die and blank holder were heated up, while the punch was water-cooled during deformation. FE simulations considering heat transfer were executed with Mg alloy to investigate the Improvement of deep drawability. For the assessment of improvement those were compare with the results of no considering heat transfer and room temperature.

  • PDF

An Experimental Study on the Reduction of Exhaust Emissions by using Glow Plug during Cold-start and Warm-up in Gasoline Engine (가솔린기관의 냉시동시 Glow Plug를 이용한 배기가스저감에 관한 실험적 연구)

  • 문영호;김종호;오영택
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.10 no.4
    • /
    • pp.7-14
    • /
    • 2002
  • In order to reduce exhaust omissions of spark ignition engine, it is important not only to improve catalyst conversion efficiency but also to directly reduce engine out exhaust emissions, during cold starting and warm up process. Therefore many researchers have been attracted to develop an early fuel evaporator(EFE) by Introducing a ceramic heater fur a solution of engine out exhaust emissions in SI engine. But, the performance of the EFE in MPI engine to reduce the exhaust emissions and to improve the cold startability has not been clarified yet. The purpose of this study is to evaluate the feasibility of a glow plug far EFE. Impinging spray using heated and unheated glow plug helps the vaporization of the fuel and heat up the three way catalyst sufficiently. The amount of CO, and UHC is reduced overall. The amount of NOx is higher at the initial stage, but become lower as time goes on than without glow plug.

The Experimental Study of Early Fuel Evaporation Characteristics Gasoline Engine Using Glow-Plug (Glow-Plug를 이용한 가솔린 연료의 조기증발 특성 실험 연구)

  • 문영호;김진구;오영택
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.9 no.2
    • /
    • pp.1-10
    • /
    • 2001
  • In order to reduce hydrocarbon emissions of spark ignition engine, it is important not only to improve catalyst conversion efficiency but also to reduce direct engine out hydrocarbon emissions, during cold starting and warm up process. Tjerefore many researchers have been attracted to develop an early fuel evaporator (EFE) by introducing a ceramic heater for a solution of engine out hydrocarbon emissions in SI engine. But, the performance of the EFE in MPI engine to reduce the exhaust emissions and to improve the cold startability has nat been clarified yet. The purpose of this study is to evaluate the feasibility of a glow plug for EFE.

  • PDF

Comparison of EG/AD/S and EG/AD model ice properties

  • Kim, Jung-Hyun;Choi, Kyung-Sik
    • International Journal of Ocean System Engineering
    • /
    • v.1 no.1
    • /
    • pp.32-36
    • /
    • 2011
  • EG/AD/S type model ice was originally selected as the primary model ice material for the MOERI ice tank in Korea. The existence of a sugar component in the EG/AD/S mixture may cause a serious maintenance problem. In order to understand the influence of sugar in the original model ice, a series of tests with EG/AD/S and EG/AD model ices were performed, and their material properties compared. Because the target strength of model ice in the full-scale MOERI ice tank is expensive and difficult to control, tests were performed under cold room conditions using a miniature ice tank. This paper describes the material properties of EG/AD/S and EG/AD model ices, such as flexural strength, compressive strength and elastic modulus. In order to obtain the desired strength and stiffness levels for the model ice, a warm-up process was introduced.

Study of Warm Forging Process for Non-Heat-Treated Steel (비조질강 온간단조를 위한 공정검토)

  • Park, J.S.;Kang, J.D.;Lee, Y.S.;Lee, J.H.
    • Proceedings of the KSME Conference
    • /
    • 2001.06c
    • /
    • pp.525-530
    • /
    • 2001
  • As a part of efforts to examine feasibility of warm forging near-net-shape process for non-heat-treated steel to replace quenched and tempered S45C steel, the optimized process condition has been determined to be $820^{\circ}C$ for heating, 10/sec for strain rate of forging and approximately 250MPa for flow stress from observed results such as the $A_{3}$ transformation temperature of about $790^{\circ}C$, the fully dynamic recrystallized behavior between $800^{\circ}C\;and\;850^{\circ}C$ when compressed up to 63% engineering strain at 10/sec strain rate, and the high temperature microsturctural stability. Also, controlled cooling rate of $6.3^{\circ}C/sec$ by water-spraying at a rate of $0.10cc/sec-cm^{2}$ for 60seconds followed by air-cooling right after forging process has been considered in this study as a feasible approach based on examination of the microsturcture of mixed ${\alpha}-ferrite$ and pearlite, the hardness and tensile properties meeting specification, and the reduced total cooling time to room temperature. Successive works would be carried out for the impact strength, machinalility, and forgeability at this process in the near future.

  • PDF

OXIDATION CHARACTERISTICS OF PARTICULATE MATTER ON DIESEL WARM-UP CATALYTIC CONVERTER

  • Choi, B.C.;Yoon, Y.B.;Kang, H.Y.;Lim, M.T.
    • International Journal of Automotive Technology
    • /
    • v.7 no.5
    • /
    • pp.527-534
    • /
    • 2006
  • Modern passenger cars with diesel engines are equipped with DOC(diesel oxidation catalyst) for the purpose of reducing HC and CO in the exhaust stream. Cold start exhaust emissions pose troubles here as on gasoline engine vehicles. As a result, some of the diesel passenger cars roll off todays the assembly lines with WCC(warm-up catalytic converter). Oxidation characteristics of the particulates in WCC is analyzed in this study by EEPS(engine exhaust particulate size spectrometer). The maximum number of PM is found to come out of WCC in sizes near 10nm when an HSDI diesel engine is operated under the conditions of high speed and medium to heavy load. When the temperature of the WCC exceeds $300^{\circ}C$, the number of PM smaller than 30 nm in diameter sharply increases upon passing through the WCC. Total mass of emitted PM gets reduced downstream of the WCC under low speed and light load conditions due to adsorption of PM onto the catalyst. Under conditions of high speed and medium to heavy load, the relatively large PM shrink or break into fine particles during oxidation process within the WCC, which results in more mass fraction of fine particles downstream of the WCC.

Self-excited Variability of the East Korea Warm Current: A Quasi-Geostyophic Model Study

  • Lee, Sang-Ki
    • Journal of the korean society of oceanography
    • /
    • v.34 no.1
    • /
    • pp.1-21
    • /
    • 1999
  • A two-layer quasi-geostrophic numerical model is used to investigate the temporal variability of the East Korea Warm Current (EKWC), especially the separation from the Korean coast and the generation of warm eddies. An attention is given on the active role of the nonlinear boundary layer process. For this, an idealized flat bottom model of the East Sea is forced with the annual mean wind curl and with the inflow-outflow specified at the Korea (Tsushima) and Tsugaru Straits. Two types of separation mechanisms are identified. The first one is influenced by the westward movement of the recirculating leg of the EKWC (externally driven separation),the second one is solely driven by the boundary layer dynamics (internally driven separation). However, these two processes are not independent, and usually coexist. It is hypothesized that 'internally driven separation' arises as the result of relative vorticity production at the wall, its subsequent advection via the EKWC, and its accumulation up to a critical level characterized by the separation of the boundary flow from the coast. It is found that the sharp southeastern corner of the Korean peninsula provides a favorable condition for the accumulation of relative vorticity. The separation of the EKWC usually accompanies the generation of a warm eddy with a diameter of about 120 km. The warm eddy has a typical layer-averaged velocity of 0.3 m/s and its lifespan is up to a year. In general, the characteristics of the simulated warm eddy are compatible with observations. A conclusion is therefore drawn that the variability of the EKWC is at least partially self-excited, not being influenced by any sources of perturbation in the forcing field, and that the likely source of the variability is the barotropic instability although the extent of contribution from the baroclinic instability remains unknown. The effects of the seasonal wind curl and inflow-outflow strength are also investigated.

  • PDF

Clothing Temperature Changes of Phase Change Material-Treated Warm-up in Cold and Warm Environments

  • Choi Kyeyoun;Chung Hyejin;Lee Boram;Chung Kyunghee;Cho Gilsoo;Park Mikyung;Kim Yonkyu;Watanuki Shigeki
    • Fibers and Polymers
    • /
    • v.6 no.4
    • /
    • pp.343-347
    • /
    • 2005
  • The purpose of this study was to investigate the appropriate amounts of phase change materials to give objective and subjective wear sensations. Vapor-permeable water-repellent fabrics with (WR-PCM) and without (WR) octadecane containing microcapsules were obtained by wet-porous coating process. Then, calculating the area of the WR-PCM treated clothes, we estimated the total calories of the clothing by multiplying the heat of fusion and heat of crystallization of PCM to the calculated area. Wear tests were conducted in both warm environment $(30^{\circ}C,\;65\%\;RH)$ and cold environment $(5^{\circ}C,\;65\%\;RH)$ with sports warm up style experimental garments made with WR and WR-PCM fabrics. Rectal, skin, and clothing microclimate temperatures, saliva and subjective evaluation measurements were done during the wear test. There was no difference of rectal and mean skin temperatures between WR and WR-PCM, but the clothing microclimate temperature of WR-PCM under warm environment was slightly lower than that of WR. In cold environment, WR-PCM showed much higher temperature than in WR. Saliva change did not appear between clothes, but did between two environments. Although subjective sensation between WR and WR-PCM was not significantly different, WR-PCM was rated as cooler than WR in warm environment and as warmer than WR in cold environment. The results of this study indicated that octadecane containing microcapsules in water-repellent fabric provide cooling effect.

A Research on the improvement scheme for manufacturing bronze warm forging die through environment-friendly workshop (황동제 온간단조용 금형제작과 환경친화형 작업장 개선에 관한 연구)

  • Kim, Sei-Hwan
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.11 no.2
    • /
    • pp.420-425
    • /
    • 2010
  • In the process of warm forging, billet is heated up to $800^{\circ}C$ and located in the upper part of die block impression. The scattered oxidized scale may cause workers burn and shortening of die life sticking to the die block impression. The separating materials sprayed in die block cause harmful dust, harmful mist, fume, and bad odor which contaminate workshop environment. The process is classified as one of the avoided jobs and make the planned output achievement difficult. Development of an elimination device to clear out the contaminating materials in the workshop and improvement of the unsatisfactory maintenance method to fix the abrasion of die block impression which delays the dead line, cost increases needs to be developed. In this research, I tried to solve the problems caused in warm forging of bronze pipe joint such as the billet heating process, die maintenance, and manufacturing cost through improvement of warming forging manufacturing method and die maintenance method and eliminating harmful gas which will make the workshop more environment friendly.