• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.15 no.2
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• pp.1-9
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• 2019

In a ground-source heat pump (GSHP) system, a vertical ground heat exchanger (GHE) is widely accepted due to a higher thermal performance. In the vertical GHE, grout (also called grouting material) plays an important role in the heat transfer performance and the initial installation cost of the GHE. Bentonite-based grout has been used in practice because of its high swelling potential and low hydraulic conductivity. This study evaluated the thermo-physical properties of the bentonite-based grouts through lab-scale measurements. In addition, we conducted performance simulation to analyze the effect of mixed ratio of grouts on the design length and thermal performance of the vertical GHE. The simulation results show that thermally-enhanced grouts improve the heat transfer performance of the vertical GHE and thus reduce the design length of GHE pipe.

• Journal of Soil and Groundwater Environment
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• v.22 no.5
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• pp.23-29
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• 2017

This study was conducted to evaluate performance of geothermal heat exchanger (GHE) in the combined well and open-closed loops geothermal (CWG) systems. The CWG systems were designed to combine open loop geothermal heat pumps and closed loop geothermal heat pumps for high energy efficiency. GHE of the CWG systems could be installed at pumping wells for agricultural usage. To get optimal heat exchange capacity of GHE of the CWG systems, 4 GHEs with various materials and apertures were tested at laboratory scale. Polyethylene (PE) and stainless steel (STS) were selected as GHE materials. The maximum heat exchange capacity of GHEs were estimated to be in the range of 33.0~104 kcal/min. The heat exchange capacity of STS GHEs was 2.4~3.2 times higher than that of PE GHE. The optimal cross section area of GHE and flow rate of circulating water of GHE were estimated to be $2,500mm^2$ and 113 L/min, respectively. For more complicated GHE of the CWG systems, it is necessary to evaluate GHEs at various scales.

• Journal of Convergence Korean Medicine
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• v.5 no.2
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• pp.17-22
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• 2023

Objectives: This study aimed to investigate the anti-atopic properties of Glechoma hederacea var. longituba extracts (GHE) in murine atopic dermatitis model. Methods: BALB/c mouse ear stimulated with oxazolone (OX) for 4 weeks, then 1% GHE was topically applied every two days for 3 weeks to mouse. Ear thickness was measured by a digital thickness gauge. The ears tissues were collected and subjected to hematoxylin-eosin (H&E) and toluidine blue (TB) staining. Results: Treatment with GHE successfully alleviated the symptoms of atopic dermatitis, such as erythema, horny substance, and swelling. The infiltration of lymphocytes and mast cells were significantly reduced following GHE treatment. Conclusion: Taken together, our results showed that GHE possessed the potential to be a novel immunomodulatory drug against atopic dermatitis.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.4
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• pp.1-10
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• 2006

In this paper, a calculation method of the thermodynamic parameters of cryogenic propellant is proposed when a cryogenic propellant tank is pressurized by gaseous helium(GHe) bubbling. Temperature of cryogenic propellant and mass of dissolved GHe into propellant were analyzed at the various operation of pressurization of tile liquid oxygen(LOX) and hydrogen($LH_2$) tank using helium bubbling. It was evaluated how the GHe bubbling influences to the thermodynamic parameters of LOX and $LH_2$ with results of the analysis. With the proposed calculation method, It will be able to confirm the feasibility of GHe bubbling as a pressurization system of cryogenic propellant tank and to optimize the pressurization system using GHe bubbling.

• Korean Medical Education Review
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• v.15 no.2
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• pp.93-99
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• 2013

As a result of the globalization of diseases and the delivery of health care, physicians today are required to understand global health (GH) including the global burden of disease, health inequities, and effective medical aid. Interest in GH among medical students has also increased significantly. To meet these needs and to reflect an increasing focus on social accountability in medical education, global health education (GHE) programs have already been well-established, particularly in North America. Korea's official developmental aid (ODA) volume almost tripled from 2006 to 2011. Korea has committed to double its ODA/gross national income ratio over the next three years. With these increases, interest in GH among medical students has significantly increased. Despite significant interest among medical students, GHE programs have not been properly established in Korea. To develop GHE programs in Korea, proposed GHE curriculum frameworks were reviewed and core values, guiding principles, and GH competencies were identified in the context of the current literature. To identify key themes essential to the development of GHE programs in Korea, the curriculum frameworks should be focused on a global context and should be taught from the perspective of the social, political, and economic causes of ill health.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.11
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• pp.739-745
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• 2008

This paper presents the measurement of ground thermal conductivity and the characteristics of ground thermal diffusion by a ground heat exchanger(GHE). A borehole is installed to a depth of 175 m with a diameter of 150 mm. To analyze the thermal diffusion property of the GHE, thermocouples are installed under the ground near the GHE. The outdoor temperature, the ground temperature, and the water temperature of the GHE are monitored for evaluating the characteristics of ground thermal diffusion. The ground thermal conductivity is evaluated by the in-situ thermal response tester and the line source model. It is found to be 3.08 W/$m^{\circ}C$ in this study. The ground temperature is greatly dependent on the outdoor temperature from the ground surface to 2.5 m in depth and is stable below 10 m in depth. The surface temperature of the GHE varies as a function of the temperature of circulating water. But the ground temperature at 1.5 m far from the GHE is not changed in accordance with the temperature of circulating water.

• Korean Medical Education Review
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• v.25 no.3
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• pp.258-272
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• 2023

This study investigated the current status and educational needs of global health education (GHE) at medical schools in Korea. Among the 40 medical schools nationwide, 32 schools that agreed to participate in the study collected data through a survey in 2022, and the results were examined by frequency analysis and content analysis. In total, 87.5% of medical schools included global health-related graduation outcomes. In the curriculum, global health lessons within courses were present at 71.9% of medical schools. Regarding extracurricular activities, 66.7% and 63.0% of medical schools offered overseas clerkships and overseas volunteer work, respectively. Although there were not many medical schools with a global health-related educational environment, 96.9% of schools agreed with the necessity of GHE in medical education. The prevailing opinion was that it was appropriate to continuously cover GHE as lessons within courses throughout all years of the program in medical education. The main opinions regarding the improvement of GHE related to curriculum development, personnel expansion, and awareness improvement at medical schools. These findings are expected to serve as a basis for identifying the current status of GHE at Korean medical schools and specifying future directions of GHE.

• Transactions of the KSME C: Technology and Education
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• v.4 no.1
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• pp.49-56
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• 2016

Commercial buildings are generally cooling-dominated and therefore reject more heat to a vertical ground heat exchanger(GHE) than they extract over the annual cycle. Shallow ponds can provide a cost-effective means to balance the thermal loads to the ground and to reduce the length of GHE. The objective of this work has been to develop a design tool for surface water heat exchanger(SWHE) submerged in shallow pond. This paper presents the analysis results of the impact of design parameters on the length of SWHE and its application effect on geothermal heat pump(GHP) system using vertical GHE. In order to analysis, We applied ${\epsilon}-NTU$ method on designing the length of SWHE. Analysis results show that the required pipe length of SWHE was decreased with the increase of approach temperature difference and with the decrease of pipe wall thickness. In addition, when the SWHE was applied to the GHP system, the temperature of vertical GHE was more stable than that of standalone GHE system.

• The Journal of Korean Medicine
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• v.30 no.2
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• pp.17-29
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• 2009

Objectives: The present study is focused on the inhibitory effect of the rhizome hexane fraction extract of Zingiberis Rhizoma Crudus (ginger hexan extract; GHE) on the production of inflammatory mediators such as NO, $PGE_2$, and proinflammatory cytokines in lipopolysaccharide (LPS)-stimulated BV2 cells, a mouse microglial cell line. Methods: We separated the hexane fraction from Zingiberis Rhizoma Crudus's methanol extract. The inhibitory and anti-inflammatory effect of GHE was examined on microglial activation. Results: GHE significantly inhibited the excessive production of NO, $PGE_2$, TNF-${\alpha}$, and IL-1${\beta}$ in LPS-stimulated BV2 cells. In addition, GHE attenuated the mRNA expressions and protein levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and proinflammatory cytokines. Conclusion: The anti-inflammatory properties of GHE may make it useful as a therapeutic candidate for the treatment of human neurodegenerative diseases.

• The Korea Journal of Herbology
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• v.25 no.3
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• pp.97-101
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• 2010

Objectives : The present study investigated the anti-nociceptive and anti-inflammatory properties of the water extract of Geranii Herba (The stem and leaves of Geranium thunbergii Sieb. et Zucc.) in the animal models of pain and inflammation. Methods : We evaluated the anti-nociceptive and anti-inflammatory activities of Geranii Herba extract (GHE) using the writhing test, tail-flick test, carrageenan-induced paw edema and xylene-induced ear edema models. Two dose of GHE (100 and 1000 mg/kg) was administrated orally to the mice. Control group received normal saline and ibuprofen (50 mg/kg) was used as a positive control drug. Results : GHE 1000 mg/kg treated group showed an increased tail-flick response time in the tail-flick test and inhibitory effect on writhing syndrome induced by acetic acid. Treatment with GHE at the same dose inhibited ear edema induced by xylene and foot edema induced by carrageenan toxicity. Conclusion : The results demonstrate that GHE has anti-nociceptive and anti-inflammatory effects in the various models of nociception and inflammation.