• Title/Summary/Keyword: pcm

Search Result 702, Processing Time 0.046 seconds

Mix Design and Mechanical Properties of Aerated Concrete for Incorporation of Low Temperature PCM (저온 PCM 혼입을 위한 경량기포콘크리트의 배합설계 및 기계적 특성)

  • Baasankhuu, Batzaya;Lim, Myung-Kwan;Lim, Hee-Seob;Choi, Dong-Uk
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.21 no.4
    • /
    • pp.110-115
    • /
    • 2017
  • This research was performed to investigate the mechanical performance of lightweight concrete including phase changing material(Low temperature PCM). Micro capsulised PCM consisted of wax type core and melamine based wall. Also, for PCM of one single kind, paraffin wax was inserted into Vermiculite and the surface was coated with melamine resin. Interfacial polymerization is based on the principle that macromolecule reaction takes place on the surfaces between 1-dodecanol(core material) and water (solvent) to form the wall material. Lightweight concrete has compressive strength of 10 MPa, tensile strength of 1.5 MPa, and oven dried density of 1.0kg/liter which included 10%, 20%, or 30% PCM by weight. To do so, this study fabricated light-weight foamed concrete ($1.0kg/m^3$) in pre-foaming method and mixed it with PCM micro capsule of 1-dodecanol and melamine to examine its physical properties.

Extraction of Intestinal Obstruction in X-Ray Images Using PCM (PCM 클러스터링을 이용한 X-Ray 영상에서 장폐색 추출)

  • Kim, Kwang Baek;Woo, Young Woon
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.24 no.12
    • /
    • pp.1618-1624
    • /
    • 2020
  • Intestinal obstruction diagnosis method based on X-ray can affect objective diagnosis because it includes subjective factors of the examiner. Therefore, in this paper, a detection method of Intestinal Obstruction from X-Ray image using Hough transform and PCM is proposed. The proposed method uses Hough transform to detect straight lines from the extracted ROI of the intestinal obstruction X-Ray image and bowel obstruction is extracted by using air fluid level's morphological characteristic detected by the straight lines. Then, ROI is quantized by applying PCM clustering algorithm to the extracted ROI. From the quantized ROI, cluster group that includes bowel obstruction's characteristic is selected and small bowel regions are extracted by using object search from the selected cluster group. The proposed method of using PCM is applied to 30 X-Ray images of intestinal obstruction patients and setting the initial cluster number of PCM to 4 showed excellent performance in detection and the TPR was 81.47%.

A Study on the Reactivity Effect due to Expansion of Diagrid and Pad (Diagram와 Pad의 팽창에 의한 반응도 효과에 대한 연구)

  • Young In Kim;Keun Bae Oh;Kun Jong Yoo;Mann Cho
    • Nuclear Engineering and Technology
    • /
    • v.16 no.2
    • /
    • pp.70-79
    • /
    • 1984
  • With the help of the nuclear computational system for a large LMFBR (KAERI-26 group cross section library/1DX/2DB), the reactivity coefficients for the diagrid expansion and the pad expansion at the beginning of cycle of the equilibrium core of SUPER-PHENIX I are calculated and reviewed. the core is described using R-Z geometry model, and a two-dimensional multigroup diffusion theory is used. For reference cases, reactivity calculations for radial and axial uniform expansion are performed, and also calculated are reactivity variations due to changes in material density and core volume. The reactivity coefficient for the diagrid expansion is calculated to be -0.553pcm/mil. The temperature coefficient corresponding to the above value is -1.0766pcm/$^{\circ}C$ and is well in accord with the French datum of -1.09pcm/$^{\circ}C$ within 1.2% difference. With the use of 4he calculational method for the diagrid expansion effect, reactivity calculations for the pad expansion bringing about nonuniform expansion are performed, which show that the calculational method is very useful in the analysis of the pad expansion effect. The reactivity coefficients for the pad expansion are calculated to be -0.2743 pcm/mil and -0.2786pcm1mi1 for the averaged expansion model and for the integrated pancake model, respectively. Under the assumption of the free expanding core the temperature reactivity coefficients for each model are obtained to be -0.5766pcm/$^{\circ}C$ and -0.5858pcm/$^{\circ}C$, both of which agree with the French datum of -0.574pcm/$^{\circ}C$ within 2% difference.

  • PDF

LDF-CLOCK: The Least-Dirty-First CLOCK Replacement Policy for PCM-based Swap Devices

  • Yoo, Seunghoon;Lee, Eunji;Bahn, Hyokyung
    • JSTS:Journal of Semiconductor Technology and Science
    • /
    • v.15 no.1
    • /
    • pp.68-76
    • /
    • 2015
  • Phase-change memory (PCM) is a promising technology that is anticipated to be used in the memory hierarchy of future computer systems. However, its access time is relatively slower than DRAM and it has limited endurance cycle. Due to this reason, PCM is being considered as a high-speed storage medium (like swap device) or long-latency memory. In this paper, we adopt PCM as a virtual memory swap device and present a new page replacement policy that considers the characteristics of PCM. Specifically, we aim to reduce the write traffic to PCM by considering the dirtiness of pages when making a replacement decision. The proposed replacement policy tracks the dirtiness of a page at the granularity of a sub-page and replaces the least dirty page among pages not recently used. Experimental results with various workloads show that the proposed policy reduces the amount of data written to PCM by 22.9% on average and up to 73.7% compared to CLOCK. It also extends the lifespan of PCM by 49.0% and reduces the energy consumption of PCM by 3.0% on average.

(An) experimental study on the development of lightweight concrete using the PCM (PCM 혼입 경량기포콘크리트 패널 개발을 위한 기초적 연구)

  • Lim, Myung Kwan;Enkhbold, Odontuya;Kim, Young Ho;Choi, Dong Uk
    • KIEAE Journal
    • /
    • v.14 no.4
    • /
    • pp.133-138
    • /
    • 2014
  • The present study was carried out to assess the basic material properties and thermal behavior of light-weight foamed concrete panel mixed with PCM (Phase Changing Material). To do so, this study fabricated light-weight foamed concrete (1.0kg/m3) in pre-foaming method and mixed it with PCM micro capsule of 1-dodecanol and melamine to examine its physical and thermal properties. The results confirmed strength reinforcement effect by proper replacement ratio of fly-ash, which is an industrial by-product, and PCM. In addition, it found out that PCM-mixed light-weight foamed concrete had time delay and temperature reduction effect within the range of PCM phase transition according to the rise of outdoor temperature. It was also observed that the insulation performance of PCM-mixed light-weight foamed concrete was more dependent upon thickness than PCM replacement ratio.

Preparation and characteristic analysis of PCM/diatomite composites for building energy saving (건물에너지 저감을 위한 PCM/diatomite composites의 제조 및 특성 분석)

  • Jeon, Ji-Soo;Jeong, Su-Gwang;Kim, Su-Min
    • 한국태양에너지학회:학술대회논문집
    • /
    • 2012.03a
    • /
    • pp.470-474
    • /
    • 2012
  • This paper deals with the thermal performances of PCM/diatomite composites for energy saving. The PCM/diatomite composites were prepared by incorporating PCMs in the pores of diatomite to increase form stability of PCMs. In experiment, we used the hexadecane, octadecane and paraffin as PCM and they have each 254.7 J/g, 247.6 J/g and 144.6 J/g of latent heat capacity, and those melting points are $20.84^{\circ}C$, $30.40^{\circ}C$ and $57.09^{\circ}C$, respectively. Thermal properties of PCM/diatomite composites were determined by using DSC. And PCM/diatomite composites were characterized by SEM and FTIR analysis. The results showed that the PCMs are well infiltrated into the structure of diatomite andt he latent heat capacity of PCM/diatomite composites was obtained by 40% of pure PCMs.

  • PDF

Experimental Development of the PCM Encoder for Telemetry (Telemetry PCM Encoder의 개발연구)

  • 강정수;이만영
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.9 no.1
    • /
    • pp.1-10
    • /
    • 1984
  • The time division multiplexing PCM encoder which is constructed for an airborne telemetering system is investigated. Selected by program switch, the PCM encoder has 0~64 words/framd($\pm$5V full scale) of allowable analog input channels, 0~30bits(5V$\pm$1V or 0V$\pm$1V dc) of discrete channels, 70 and 140K bits/sec of bit rate and 8~12bits/word of resolution. And filtered output PCM code is NRZ-L and Bi-S through the 5 pole Bessel LPF(f=100kHz), and the maximum accuracy of PCM encoder is $\pm$0.2% of its full scale.

  • PDF

An Experimental Study on the Cooling Characteristics of the Liquid Cooling Radiator of the Natural Convection Type by Using the PCM (PCM을 적용한 자연대류형 수냉식 방열기의 냉각특성에 관한 실험적 연구)

  • Sung, Dae-Hoon;Kim, Joung-Ha;Yun, Jae-Ho;Kim, Woo-Seung;Peck, Jong-Hyeon
    • Proceedings of the SAREK Conference
    • /
    • 2008.11a
    • /
    • pp.324-329
    • /
    • 2008
  • The liquid cooling effect of a natural convection type radiator by using the PCM has been investigated experimentally. The radiator size is $423{\times}295{\times}83$ mm and PCM container size is $398{\times}270{\times}26$ mm. The objective is elapsed time higher than maximum time to reach for maximum operating temperature of a general liquid cooling radiator. This study, in order to study on the effects of the phase-change phenomenon, carried out the various mass flow rate, input electric power, ambient and melting point of three type PCM. For the above experimental parameter, the melting time was performed about 180/250/560 min at input power 150 W and ambient $30^{\circ}C$ from using the three type PCM(PCM_S1/S2/S3) respectively. Furthermore, the effects of the thermal dissipation was decreased higher input power than lower input power at heating block and melting time of PCM. However, the effects of mass flow rate did not nearly affect of the thermal performance especially.

  • PDF

Inhibitory Effect of adding Phase Change Material (PCM) to Fire Fighter Protective Clothing on Burn Injuries (Phase Change Material (PCM) 소재 적용 소방보호복의 화상발생 억제효과에 관한 연구)

  • Lee, Jun Kyoung
    • Fire Science and Engineering
    • /
    • v.30 no.3
    • /
    • pp.16-22
    • /
    • 2016
  • Fire fighters rely on fire fighter protective clothing (FFPC) to provide adequate protection in the various hazardous environments. To enhance its protection performance, the FFPC material must be thick and thus it is difficult to achieve weight reduction. One of the methods of overcoming this problem, the addition of phase change material (PCM) to FFPC, is a new technology. In previous studies, the researches was mostly related to the temperature characteristics of the fibers incorporating PCM, but little information is available about its effect on burn injuries. Thus, in this study, the inhibitory effects of adding PCM to FFPC on second degree burns were investigated through numerical calculations. Thermal analyses of biological tissues and FFPC with embedded PCM exposed to several fire conditions causing severe tissue damage were studied by using a finite difference method based on the Pennes bio-heat equation. FFPC with embedded PCM was found to provide significantly greater protection than conventional fire fighting clothing, because the heat of absorption due to the phase change within the material is used to limit the heat conduction of the material.

Greenhouse Heating Characteristics of Heat Pump-Latent Heat Storage System (열펌프-잠열축열 시스템의 온실 난방 특성 연구)

  • 강연구;송현갑
    • Journal of Biosystems Engineering
    • /
    • v.25 no.5
    • /
    • pp.379-384
    • /
    • 2000
  • In order to use the natural thermal energy as much as possible for greenhouse heating, the air-air heat pump system involved PCM(phase change material) latent heat storage system was composed, and three types of greenhouse heating system(greenhouse system, greenhouse-PCM latent heat storage system, greenhouse-PCM latent heat storage-heat pump system) were recomposed from the greenhouse heating units to analyze the heating characteristics. The results could be concluded as follows; 1) In the greenhouse heated by the heat pump under the solar radiation of 406.39W/$m^2$, the maximum PCM temperature in the latent heat storage system was 24$^{\circ}C$ and the accumulated thermal energy stored in PCM mass of 816kg during the daytime was 100,320kJ. In the greenhouse without heat pump under the maximum solar radiation of 452.83W/$m^2$, the maximum PCM temperature in the latent heat storage system was 22$^{\circ}C$ and the accumulated thermal energy stored during the daytime was 52.250kJ. 2) In the greenhouse-PCM system without heat pump the heat stored in soil layers from the surface to 30cm of the soil depth was 450㎉/$m^2$. 3) In all of the greenhouse heating systems, the difference between the air temperature in greenhouse and the ambient temperature was about 20~23$^{\circ}C$ in the daytime. In the greenhouse without heat pump and PCM latent heat storage system the difference between the ambient temperature and the air temperature in the greenhouse was about 6~7$^{\circ}C$ in the nighttime, in the greenhouse with only PCM latent heat storage system the temperature difference about 7~13$^{\circ}C$ in the nighttime and in the greenhouse with the heat pump and PCM latent heat storage system about 9~14$^{\circ}C$ in the nighttime.

  • PDF