• Title/Summary/Keyword: Cooling characteristic

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Assessing the resilience of urban water management to climate change

  • James A. Griffiths
    • Proceedings of the Korea Water Resources Association Conference
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    • 2023.05a
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    • pp.32-32
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    • 2023
  • Incidences of urban flood and extreme heat waves (due to the urban heat island effect) are expected to increase in New Zealand under future climate change (IPCC 2022; MfE 2020). Increasingly, the mitigation of such events will depend on the resilience of a range Nature-Based Solutions (NBS) used in Sustainable Urban Drainage Schemes (SUDS), or Water Sensitive Urban Design (WSUD) (Jamei and Tapper 2019; Johnson et al 2021). Understanding the impact of changing precipitation and temperature regimes due climate change is therefore critical to the long-term resilience of such urban infrastructure and design. Cuthbert et al (2022) have assessed the trade-offs between the water retention and cooling benefits of different urban greening methods (such as WSUD) relative to global location and climate. Using the Budyko water-energy balance framework (Budyko 1974), they demonstrated that the potential for water infiltration and storage (thus flood mitigation) was greater where potential evaporation is high relative to precipitation. Similarly, they found that the potential for mitigation of drought conditions was greater in cooler environments. Subsequently, Jaramillo et al. (2022) have illustrated the locations worldwide that will deviate from their current Budyko curve characteristic under climate change scenarios, as the relationship between actual evapotranspiration (AET) and potential evapotranspiration (PET) changes relative to precipitation. Using the above approach we assess the impact of future climate change on the urban water-energy balance in three contrasting New Zealand cities (Auckland, Wellington, Christchurch and Invercargill). The variation in Budyko curve characteristics is then used to describe expected changes in water storage and cooling potential in each urban area as a result of climate change. The implications of the results are then considered with respect to existing WSUD guidelines according to both the current and future climate in each location. It was concluded that calculation of Budyko curve deviation due to climate change could be calculated for any location and land-use type combination in New Zealand and could therefore be used to advance the general understanding of climate change impacts. Moreover, the approach could be used to better define the concept of urban infrastructure resilience and contribute to a better understanding of Budyko curve dynamics under climate change (questions raised by Berghuijs et al 2020)). Whilst this knowledge will assist in implementation of national climate change adaptation (MfE, 2022; UNEP, 2022) and improve climate resilience in urban areas in New Zealand, the approach could be repeated for any global location for which present and future mean precipitation and temperature conditions are known.

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A Study on the Genesis of Fluorite Deposits of South Korea (남한(南韓)의 형석광상(螢石鑛床)의 성인(成因)에 관(關)한 연구(硏究))

  • Chi, Jeong Mahn
    • Economic and Environmental Geology
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    • v.8 no.1
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    • pp.25-56
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    • 1975
  • Most fluorite deposits of South Korea are distributed in three metallogenic zones namly as: Hwacheon, Hwangangni and Geumsan metallogenic zones. Fluorite deposits of each zone show The characteristic features owing to the geological setting, the structural patterns and their forming processes. deposits of the Hwacheon metallogenic zone are wholly fissure filling hydrothermal veins emThe bedded in shear fractures of the granite gneiss or schists of Precambrian age or in the cooling fractures of the granite and acidic hypabyssal rocks which are assumed to be a differentiated sister rock of the granite. Localization of most fluorite veins of the region is structurally controlled by NW and EW fracture systems and genetically related to the granite intrusion which ascertained as motivating rock of the fluorite mineralization. Fluorites are in most cases accompanied by quartz, chalcedony mainly and rarely agate, calcite, barite and sulphide base metals in some localities. The deposits of the Hwangangni metallogenic zone were formed at the last stage of hydrothermal polymineralization of W, Mo, Cu, Pb, Zn. The majority of the fluorite ore bodies were originated from replacement in limestone beds of Great Limestone Series or in calcareous interbeds of metasediments, whereas some cavity-filling ore bodies were embedded in phyllites and schists of the Ockcheon system and along the fissures in the replaced beds which were originated by volume decrease. The localization of fluorite deposits in this region is genetically related to the Moongyong granite which has been dated as middle Cretaceous, and controlled structurally by the $N20^{\circ}{\sim}50^{\circ}W$ extension fracture system or axial planes of folds, and by faults of NE direction that acted as paths of ore solution. The deposits of the Geumsan metallogenic zone are seemed to be formed through the similar process as that of Hwangangni metallogenic zone, but characteristic distinctions are in that they are more prevailing fracture filling veins and large number of the deposits are localized in roof-pendants or xenolithes of limestone in granites and porphyries. Igneous rocks that presumably motivated the mineraltzation are middle Cretaceous Geumsan granite and porphyries. Metallogenic epoch of the fluorite mineralization of South Korea are puesumably limited in early-middle Cretaceous. Studies of the fluid inclusions in fluorites of the region reveal that the homogenization temperature of the fluorite deposits are as follows: Hwacheon metallogenic zone : $95^{\circ}C{\sim}165^{\circ}C$; Hwangangni metallogenic zone : $97^{\circ}C{\sim}235^{\circ}C$; Geumsan metallogenic zone : $93^{\circ}C{\sim}236^{\circ}C$. Judging from the above results, the deposits of the Hwancheon region were formed at the epithermal stage, and those in the Hwangangni and Geumsan regions, were deposited at epithermal stage preceded by mesothermal mineralization of small scale in which some sulphide minerals were deposited. The analytical data of minor elements in the fluorites reveal that ore solutions of Hwangangni metallogenic zone seemed to be emanated in more acidic stage of magma differentiation than Hwacheon metallogenic zone did.

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Study on Ammonia Emission Characteristic of Pig Slurry (양돈 슬러리의 암모니아 발생 특성에 관한 연구)

  • Lee S.H.;Yun N.K.;Lee K.W.;Lee I.B.;Kim T.I.;Chang J.T.
    • Journal of Animal Environmental Science
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    • v.12 no.1
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    • pp.7-12
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    • 2006
  • Ammonia emission from swine production process originates from three major sources: manure storage facility, swine housing, and land application of manure. Most of the ammonia gas that are emitted from swine production operations is the by-product of aerobic or anaerobic decomposition of swine waste by microorganism. Knowing the ammonia emission rate is necessary to understand how management practices or alternative manure handling process could reduce impacts of this emission on the environment and neighbors. Ammonia gas emission from pig slurry is very difficult to predict because it is affected by many factors including wind speed of slurry surface, temperature or pH of the swine slurry, sort breed differences and classes, and diets. This study was carried out to effects of pH and temperature on ammonia gas emission from growing-finishing pig slurry. Treated far slurry in this study were pH and temperature. Results showed that pH of slurry variable changes 5, 6, 7, 8 upon an addition of NaOH and $HNO_3$, respectively. The temperature of the slurry which was contained in a water bath maintained at increasing levels ranging from 10 to $35^{\circ}C$. Ammonia emission rate of influenced pH and temperature such that the increase in pH or temperature resulted to an increase in ammonia emission. The ammonia gas was not detected at pH 5 and 6. Moreover, at a slurry of pH 8, the ammonia ranged from 28 to 60ppm and 8-29 ppm at slurry pH of 7 while temperature was 13 to $33^{\circ}C$. When slurry pH was>6, the ammonia emission was significantly increased according to rise in temperature in contrast to acid treatment of the pH. There was also a significantly increase in ammonia emission relative to slurry pH of 7 to 8. The above findings showed that to effectively reduce ammonia emission from slurry of growing-finishing pigs, the pH and temperature should be maintained a low levels.

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Evaluation of Freezing Patterns for Sand and Clay by Using X-ray CT (X-ray CT를 통한 사질토와 점성토의 간극수 동결 패턴 분석)

  • Song, Jun Young;Lee, Jangguen;Lee, Seong-Won;Lee, Junhwan;Yun, Tae Sup
    • Journal of the Korean Geotechnical Society
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    • v.34 no.3
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    • pp.57-65
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    • 2018
  • This study adopts high resolution 3D X-ray CT imaging technique to visualize and evaluate the internal structure of experimentally frozen soils. Temperature and elastic wave velocity are also measured during the freezing process. The X-ray images of frozen specimens reveal that no changes in internal structure are observed for sand specimen, whereas systematic growth pattern of pore ice is observed within clay specimen. The freezing patterns are then quantified by a set of X-ray images with the aid of two-point correlation method by computing characteristic length Lr. The results reveal that characteristic length for pore ice freezing pattern in clay linearly increases with respect to the distance from the cooling source, so that Lr at the bottom layer is 2.5 times greater than the top layer when freezing process is completed. Furthermore, during the freezing process, local temperature differences are not observed in sand, but observed in clay specimen due to its relatively low thermal conductivity.

Infrared Spectroscopic Evidences for the Superconductivity of $La_2CuO_4$-related Compounds: A Superconductivity Probe

  • Park, Jeong Cheol;Jo, Seon Woog;Jeong, Jong Hak;Jeong, Gi Ho
    • Bulletin of the Korean Chemical Society
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    • v.21 no.10
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    • pp.1041-1043
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    • 2000
  • We present the effects of temperature (between 10 K and 298 K) and of hole concentration on the frequency and intensity of characteristic phonons in polycrystalline $La_2CuO_4-related$ compounds using FT-IR spectros-copy. The influences of the concentration of carrier doped on the phonon modes are prominent in the IR spectra of $La_2CuO_4-related$ compounds. For $La_2-xSrxCuO_4({\chi}=$ 0.00, 0.03, 0.07, 0.10, and 0.15) and electrochemically (or chemically) oxidized $La_2CuO_4$, the intensities of the transverse oxygen mode around 680cm $-^1$ which cor-responds mainly to Cu-O(1) stretching vibration in the basal plane of CuO6 octahedron, are decreased and dis-appeared depending on the Sr-substitution rate and the amount of excess oxygen, while the longitudinal oxygen mode around 510 cm $-^1$ corresponding to the Cu-O(2) stretching in the basal plane of CuO6 octahedron are near-ly invariable. In particular, after two cycles of cooling-heating between 10 K and 298 K for these sample, the phonons around 680 cm $-^1$ are blue shif 13-15 cm $-^1$, while the phonons around 510 cm $-^1$ are nearly constant. The introduction of the charge carrier by doping would give rise to the small contraction of CuO6 oc-tahedron as Cu $^3+$ requires a smaller site than Cu $^2+$, which results in the shortening of the Cu-O(1) bond length and Cu-O(2) bond length with the increased La-O(2) bond length. These results in the frequency shift of the characteristic phonons. The IR spectra of $La_2Li0.5Cu0.5O_4$ which exhibits an insulator behavior despite the $Cu^3+$ of nearly 100%, corroborate our IR interpretations. The mode around 710 cm $-^1$ corresponding to Cu-O(1) stretching vibration is still strongly remained even at low temperature (10 K). Thus, we conclude that the con-duction electrons formed within $CuO_2$ planes of $La_2CuO_4-related$ superconductors screen more effectively the transverse oxygen breathing mode around 680 $cm-^1$ depending on the concentration of the doped charge carrier in $La_2CuO_4-related$ compounds, which might use as a superconductivity probe.

A Study on the Development of Low Pass Filter for Chopper Gate Control Unit of Electric Rolling Stock (부산도시철도 1호선 전동차 Low Pass Filter 개발연구)

  • Kang, Hyun-Chul;Kim, Hae-Chang;Park, Hee-Chul
    • Proceedings of the KSR Conference
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    • 2011.05a
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    • pp.1445-1456
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    • 2011
  • This paper presents the research of Low Pass Filter(hereinafter called "LPF") which is the part of Chopper Gate Control Unit on the electric rolling stock. Chopper Gate Control Unit controling the propulsive equipments of electric rolling stock consists of several electronic parts, PCB, Power Supply, Gate Circuit Amp, Freon Cooling Device, and has been used the parts made by japan manufacturer Mitsubish. But these parts recently have been more broken down and slow down performance because of long-term use, deterioration. Most of the malfunctions are low performance of LPF. Furthermore, it is physically impossible to repair LPF. Because it is molding type part and no longer manufactured. Also it needs high cost for custom-building. Therefore, it is now making up for through self-developed LPF and operating on Busan metro 1st after on-board testing. This research performed the PS Pice simulation testing, analysis of self-developed LPF performance and the wave form characteristic by multi-function synthesizer, spectrum analyzer, oscilloscope.

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Petrological Study on the Bulgugsa Acidic Igneous Rocks in Busan Area (부산지역(釜山地域)의 불국사산성화성암류(佛國寺酸性火成岩類)의 암석학적(岩石學的) 연구(硏究))

  • Cha, Moon-Sung
    • Economic and Environmental Geology
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    • v.9 no.2
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    • pp.85-106
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    • 1976
  • The Bulgugsa acidic igneous rocks of the late Cretaceous age are largely distributed in Busan area, which is located in the southeastern corner of the Korean Peninsula. These igneous rocks comprise in ascending order, felsite, dacitic-rhyolitic welded tuffs, granite porphyry and granitic rocks. The former three members represent the early phase of volcanic activities, so that they are named as Jangsan volcanic rocks. The granitic rocks consist of granodiorite, hornblende biotite granite, Kumjongsan granite, fine grained granite, and Daebyen granite, represent the late phase of igneous activities. The Kumjongsan grainte, the largest pluton of the granitic mass, emplaced between two great vertical faults trending NNE. New chemical analyses of 33 rock samples of these acidic rocks are given. Their chemical compositions are generally similar to those of the late Mesozoic acidic igneous rocks of the northern Ashio mountains, and C-Zone granite group of the Ogcheon geosyncline, with their characteristic variation trends of several oxides. Their chemical compositions also show that $Al_2O_3$ is high value, and differentiation index is high, too. Systematically developing joints in Kumjungsan granite are divisible into two types at least. One is the NS-N $20^{\circ}E$ trendirig, $85^{\circ}{\sim}90^{\circ}$ dipping type of joint system which coincides with the trends of distribution of the granite mass and the dikes intruding this granite. Joints of this type may be cooling joints generated as tension cracks. The other is the $N60^{\circ}{\sim}70^{\circ}W$ or $N40^{\circ}{\sim}60^{\circ}E$ trending type of joint systems. It is considered that. joints belonging to this type may be shear joint occurring under the state of south-north tectonic couple acting at the east and west side of the granite mass. Igneous activities of the the Bulgugsa acidic igneous rocks in Busan area was taken place as. follows, formation of the magma reservoir, eruption and intrusion of felsite, consolidation of vents. and increasing vapor pressure in magma reservoir, eruption of pyroclastic flows, caldera collapse, intrusion of granite porphyry, and intrusion of granitic rocks at the latest stage.

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Development of SMH Actuator System Using Hydrogen-Absorbing Alloy (수소저장합금을 이용한 SMH 액추에이터 시스템 개발)

  • Kwon, Tae-Kyu;Hong, Kyung-Ju;Kim, Kyung;Jeon, Won-Suk;Pang, Du-Yeol;Lee, Seong-Cheol;Kim, Nam-Gyun
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.11
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    • pp.1067-1073
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    • 2007
  • This paper presents development of an special metal hydride(SMH) actuator system using a peltier module. The newly developed simple SMH actuator, consisting of the plated hydrogen-absorbing alloy as a power source, Peltier elements as a heat source and a cylinder with metal bellows as a functioning part, has been developed. The SMH actuator is characterized by its small size, low weight, noiseless operation and a compliance similar to that of human body. A new SMH actuator that uses reversible reactions between the heat energy and mechanical energy of a hydrogen absorbing alloy. It is well known that hydrogen-absorbing alloys can reversibly absorb and desorb a large amount of hydrogen, more than about 1000 times of their own volume. To improve the thermal conductivity of the hydrogen-absorbing alloy, an electro-less copper plating has been carried out. For this purpose, the effects of the electro-less copper plating and the dynamic characteristics of the SMH actuator have been studied. The hydrogen equilibrium pressure increases and hydrogen is desorbed by heating the hydrogen-absorbing alloys, whereas by cooling the alloys, the hydrogen equilibrium pressure decreases and hydrogen is absorbed. The SMH actuator has the characteristic of being light and easy to use. Therefore, it is suitable for medical and rehabilitation applications.

Ozone Production Characteristics of the DBD Discharge the Electrode Shape at the Same Electrode surface area (동일한 전극 표면적에서 DBD방전형 내부전극 형상에 따른 오존생성특성 연구)

  • Kwon, Young-Hak;Park, Hyunmi;Song, HyunGig;Park, Won-Zoo
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.30 no.2
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    • pp.71-77
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    • 2016
  • The dielectric barrier discharge (DBD) has low efficiency due to about 70% input power is consumed as thermal energy in the discharge space. However, because of the usage of DBD ozone generator is easier than other methods. The DBD ozone generator has been widely applied for high concentration ozone generation in the industrial application. But, the low-capacity compact DBD ozone generator is not applied so far. Therefore, the DBD ozone generator is necessary to improve ozone production efficiency and reduce the capacity. In this paper, the stainless steel pipe inner electrode was designed with hall type and screw type to improve the ozone production yield. The manufactured two inner electrodes were experimented with normal type for comparison of the discharge characteristics and the ozone generating characteristics. As the experimental results, the discharge current effective value of designed inner electrodes with hall type and screw type are higher than the normal type, due to unequal electric field is formed at the boundary. However, the difference of designed and original electrodes is less than 0.1mA that has no effect on the discharge characteristic. On the other hand, the screw type inner electrode increased higher than original model about 7 times when the flow rate of the oxygen source gas was increased from $0.6{\ell}/min$ to $1.0{\ell}/min$ The reason was assumed by the flow rate of the raw gas through the inner electrode was became fast that has a cooling effect. The designed hall type and screw type inner electrodes have shown good performances in ozone generation and ozone production that better than normal type in the same electrode surface area.

Design and Development of SMH Actuator System (SMH 액추에이터 시스템 설계 및 개발)

  • Kwon T.K.;Choi. K.H.;Pang. D.Y.;Lee. S.C.;Kim N.G.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.551-555
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    • 2005
  • This paper presents the temperature-pressure characteristics of SMH actuator using a peltier module. The simple SMH actuator, consisting of the plated hydrogen-absorbing alloy as a power source, Peltier elements as a heat source and a cylinder with metal bellows a functioning part has been developed. The SMH actuator is characterized by its small size, low weight, noiseless operation and a compliance similar to that of the human body. A new special metal hydride(SMH) actuator that uses the reversible reaction between the heat energy and mechanical energy of a hydrogen absorbing ally. It is well known that hydrogen-absorbing alloys can reversibly absorb and desorb a large amount of hydrogen, more than about 1000 times as their own volume. To improve the thermal conductivity of the hydrogen-absorbing alloy, an electro-less copper plating has been carried out. The effects of the electro-less copper plating and the dynamic characteristics of the SMH actuator have been studied. The hydrogen equilibrium pressure increases and hydrogen is desorbed by heating the hydrogen-absorbing alloys, whereas by cooling the alloys, the hydrogen equilibrium pressure decreases and hydrogen is absorbed. Therefor, the SMH actuator has the characteristic of being light and easy to use and so is suitable for use in medical and rehabilitation applications.

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