• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.6
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• pp.521-537
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• 2012

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2011. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) Research trends of thermal and fluid engineering have been surveyed as groups of fluid machinery and fluid flow, thermodynamic cycle, and new and renewable energy. Various topics were presented in the field of fluid machinery and fluid flow. Research issues mainly focused on the rankine cycle in the field of thermodynamic cycle. In the new and renewable energy area, researches were presented on geothermal energy, fuel cell, biogas, reformer, solar water heating system, and metane hydration. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer, nanofluids and industrial heat exchangers. Researches on heat transfer characteristics included heat transfer above liquid helium surface in a cryostat, methane hydrate formation, heat and mass transfer in a liquid desiccant dehumidifier, thermoelectric air-cooling system, heat transfer in multiple slot impinging jet, and heat transfer enhancement by protrusion-in-dimples. In the area of pool boiling and condensing heat transfer, researches on pool boiling of water in low-fin and turbo-B surfaces, pool boiling of R245a, convective boiling two-phase flow in trapezoidal microchannels, condensing of FC-72 on pin-finned surfaces, and natural circulation vertical evaporator were actively performed. In the area of nanofluids, thermal characteristics of heat pipes using water-based MWCNT nanofluids and the thermal conductivity and viscosity were measured. In the area of industrial heat exchangers, researches on fin-tube heat exchangers for waste gas heat recovery and Chevron type plate heat exchanger were implemented. (3) Refrigeration systems with alternative refrigerants such as $CO_2$, hydrocarbons, and mixed refrigerants were studied. Heating performance improvement of heat pump systems were tried applying supplementary components such as a refrigerant heater or a solar collector. The effects of frost growth were studied on the operation characteristic of refrigeration systems and the energy performance of various defrost methods were evaluated. The current situation of the domestic cold storage facilities was analyzed and the future demand was predicted. (4) In building mechanical system fields, a variety of studies were conducted to achieve effective consumption of heat and maximize efficiency of heat in buildings. Various researches were performed to maximize performance of mechanical devices and optimize the operation of HVAC systems. (5) In the fields of architectural environment and energy, diverse purposes of studies were conducted such as indoor environment, building energy, and renewable energy. In particular, renewable energy and building energy-related researches have mainly been studied as reflecting the global interests. In addition, various researches have been performed for reducing cooling load in a building using spot exhaust air, natural ventilation and energy efficiency systems.

• Food Science of Animal Resources
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• v.30 no.2
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• pp.336-344
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• 2010

Considering the increasing trends of the consumption of livestock products in Korea, proper hygienic management and policies for ensuring their safety to protect public health and strengthen consumer confidence are demanded. It is particularly important to manage the livestock distribution processes to provide safe meat and meat products. This study was conducted to examine factors related to the hygiene management of livestock products and to check out the condition of hygienic management in meat markets. To accomplish this, 156 meat markets divided into HACCP-certified and non certified and evaluated for five factors, which received the following scores: facility and equipment management (1.00/2.0 points, 50.0%), storage and transport management (1.93/2.0 points, 96.5%), work place management (0.76/2.0 points, 38.0%), personal hygiene management (0.75/2.0 points, 37.5%), and inspection management (0.22/2.0 points, 11.0%). The results revealed that the scores of HACCP-certified meat markets were significantly higher than those of the non certified markets (p<0.05, p<0.01, p<0.001). These findings suggest that meat markets that are not HACCP-certified must improve hygienic management conditions and educate their employees to improve the safety of livestock products during distribution.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.6
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• pp.256-268
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• 2016

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2015. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering were carried out in the areas of flow, heat and mass transfer, cooling and heating, and air-conditioning, the renewable energy system and the flow inside building rooms. Research issues dealing with air-conditioning machines and fire and exhausting smoke were reduced. CFD seems to be spreading to more research areas. (2) Research works on heat transfer area were carried out in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the economic analysis of GHG emission, micro channel heat exchanger, effect of rib angle on thermal performance, the airside performance of fin-and-tube heat exchangers, theoretical analysis of a rotary heat exchanger, heat exchanger in a cryogenic environment, the performance of a cross-flow-type, indirect evaporative cooler made of paper/plastic film. In the area of pool boiling and condensing, the bubble jet loop heat pipe was studied. In the area of industrial heat exchangers, researches were performed on fin-tube heat exchanger, KSTAR PFC and vacuum vessel at baking phase, the performance of small-sized dehumidification rotor, design of gas-injection port of an asymmetric scroll compressor, effect of slot discharge-angle change on exhaust efficiency of range hood system with air curtain. (3) In the field of refrigeration, various studies were carried in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, a cold-climate heat pump system, $CO_2$ cascade systems, ejector cycles and a PCM-based continuous heating system were investigated. In the alternative refrigeration/energy system category, a polymer adsorption heat pump, an alcohol absorption heat pump and a desiccant-based hybrid refrigeration system were investigated. In the system control category, turbo-refrigerator capacity controls and an absorption chiller fault diagnostics were investigated. (4) In building mechanical system research fields, eighteen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the user and location awareness technology applied dimming lighting control system, the lighting performance evaluation for light-shelves, the improvement evaluation of air quality through analysis of ventilation efficiency and the evaluation of airtightness of sliding and LS window systems. The subjects of building energy were worked on the energy saving estimation of existing buildings, the developing model to predict heating energy usage in domestic city area and the performance evaluation of cooling applied with economizer control. The studies were also performed related to the experimental measurement of weight variation and thermal conductivity in polyurethane foam, the development of flame spread prevention system for sandwich panels, the utilization of heat from waste-incineration facility in large-scale horticultural facilities.

• Journal of Korea Water Resources Association
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• v.55 no.11
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• pp.923-929
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• 2022

The Chuncheon Mullori area is an underprivileged area of water welfare where local water supply is not supplied, and it is supplying water to the villages with small water supply facilities using lateral flow and groundwater as water sources. This is an area with poor water supply conditions, such as relying on water trucks due to water shortages during the recent severe drought. Therefore, in order to solve the problem of water shortage during drought and to prepare for the increasing water demand, a sand dam was installed along the valley, and this facility has been operating since May 2022. In this study, repeated simulations were performed according to the hydraulic conductivity of the filler material and the storage coefficient value for the inflow condition for about two years from mid-March 2020 to mid-March 2022. For each case, the amount of discharge through the perforated drain pipe was calculated. Overall, as the hydraulic conductivity increased, the amount of discharge and its ratio increased. However, when the hydraulic conductivity of the second floor was relatively low, the amount of discharge increased and then decreased as the hydraulic conductivity of the third floor increased. This is considered to be due to the fact that the water level was kept low due to the rapid drainage compared to the net inflow into the third floor because the water permeability of the third floor and the drainage coefficient of the drain pipe were large. As a result of simulating the flow of the open channel in the upper part of the sand dam as a hypothetical groundwater layer with very high hydraulic conductivity, the decrease in discharge rate was slower than the increase in the hydraulic conductivity of the hypothetical layer, but it was clearly shown that the discharge volume decreased relatively as the hydraulic conductivity of the virtual layer increased.

• Journal of Wetlands Research
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• v.24 no.3
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• pp.204-212
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• 2022

The LID technique began to be applied in Korea after 2009, and LID facilities are installed and operated for rainwater management in business districts such as the Ministry of Environment, the Ministry of Land, Infrastructure and Transport, and LH Corporation, public institutions, commercial land, housing, parks, and schools. However, looking at domestic cases, the application cases and operation periods are insufficient compared to those outside the country, so appropriate design standards and measures for operation and maintenance are insufficient. In particular, LID facilities constructed using LID techniques need to maintain the environment inside LID facilities because hydrological and environmental effects are expressed by material circulation and energy flow. The LID facility is designed with the treatment capacity planned for the water circulation target, and the proper maintenance, vegetation, and soil conditions are periodically identified, and the efficiency is maintained as much as possible. In other words, the soil created in LID is a very important design element because LID facilities are expected to have effects such as water pollution reduction, flood reduction, water resource acquisition, and temperature reduction while increasing water storage and penetration capacity through water circulation construction. In order to maintain and manage the functions of LID facilities accurately, the current state of the facilities and the cycle of replacement and maintenance should be accurately known through various quantitative data such as soil contamination, snow removal effects, and vegetation criteria. This study was conducted to investigate the current status of LID facilities installed in Korea from 2009 to 2020, and analyze soil changes through the continuity and current status of LID facilities applied over the past 10 years after collecting soil samples from the soil layer. Through analysis of Saturn, organic matter, hardness, water contents, pH, electrical conductivity, and salt, some vegetation-type LID facilities more than 5 to 7 years after construction showed results corresponding to the lower grade of landscape design. Facilities below the lower level can be recognized as a point of time when maintenance is necessary in a state that may cause problems in soil permeability and vegetation growth. Accordingly, it was found that LID facilities should be managed through soil replacement and replacement.

• Journal of Wetlands Research
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• v.26 no.2
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• pp.168-181
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• 2024

Constructed wetlands (CWs) deliver a range of ecosystem services, including the removal of contaminants, sequestration and storage of carbon, and enhancement of biodiversity. These services are facilitated through hydrological and ecological processes such as infiltration, adsorption, water retention, and evapotranspiration by plants and microorganisms. This study investigated the correlations between microbial populations, soil physicochemical properties, and treatment efficiency in a horizontal subsurface flow constructed wetland (HSSF CW) treating runoff from roads and parking lots. The methods employed included storm event monitoring, water quality analysis, soil sampling, soil quality parameter analysis, and microbial analysis. The facility achieved its highest pollutant removal efficiencies during the warm season (>15℃), with rates ranging from 33% to 74% for TSS, COD, TN, TP, and specific heavy metals including Fe, Zn, and Cd. Meanwhile, the highest removal efficiency was 35% for TOC during the cold season (≤15℃). These high removal rates can be attributed to sedimentation, adsorption, precipitation, plant uptake, and microbial transformations within the CW. Soil analysis revealed that the soil from HSSF CW had a soil organic carbon content 3.3 times higher than that of soil collected from a nearby landscape. Stoichiometric ratios of carbon (C), nitrogen (N), and phosphorus (P) in the inflow and outflow were recorded as C:N:P of 120:1.5:1 and 135.2:0.4:1, respectively, indicating an extremely low proportion of N and P compared to C, which may challenge microbial remediation efficiency. Additionally, microbial analyses indicated that the warm season was more conducive to microorganism growth, with higher abundance, richness, diversity, homogeneity, and evenness of the microbial community, as manifested in the biodiversity indices, compared to the cold season. Pollutants in stormwater runoff entering the HSSF CW fostered microbial growth, particularly for dominant phyla such as Proteobacteria, Actinobacteria, Acidobacteria, and Bacteroidetes, which have shown moderate to strong correlations with specific soil properties and changes in influent-effluent concentrations of water quality parameters.

• The Korean Journal of Air & Space Law and Policy
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• v.30 no.2
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• pp.83-153
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• 2015

As our economy grows and the number of aircraft increase, the number of civil execution against aircraft cases are likely to increase as well in the future. The purpose of this article is to present the legal theory on the civil execution against aircrafts by drawing on the legal theory on the civil execution against vessels which constitute a relatively large number of cases thus observed. The provisions of the civil execution against immovables or vessel, shall basically apply mutatis mutandis to the civil execution against aircraft or light aircraft. The civil execution against ultra-light flying devices or a foreign aircraft shall be executed in conformity with the civil execution against movables. There are a compulsory auction, an auction to execute a security right to aircraft, and an auction under the right of retention, etc. in the civil execution against an aircraft. A compulsory execution against an aircraft means an execution carried out by a creditor against a debtor's aircraft to obtain satisfaction of claims for the purpose of payment of money. The court of execution of a compulsory execution against an aircraft shall be the district court having jurisdiction over the airport of stoppage or storage of such aircraft at the time of seizure. The forums of execution of a compulsory execution against an aircraft shall be exclusive forums. When a court has rendered an order on commencing an auction, it shall order an execution officer to receive a certificate of the aircraft's registration and other documents as required for its operation, and to submit them to the court. A court may revoke the procedures for a compulsory auction when an execution officer fails to obtain a transfer of the aircraft's registration certificate, etc. and the location of the aircraft is not evident, not later than an elapse of 2 months from the date on which an order on commencing an auction has been rendered. In the case where it is deemed that there exists a business-related need or other based on proper reasoning, the court may permit the aircraft's operation, upon the motion submitted by the debtor. In this case, there shall be a consent from the creditor, the highest bidder, the next highest bidder and successful bidder. A court may, upon a motion submitted by the creditor, make the dispositions required for observing and preserving the aircraft. When a debtor has submitted the documents under subparagraph 2 or 4 of the Article 49 of the Civil Execution Act, and furnished the guarantee equivalent to the claims of the execution creditors and the creditors demanding a distribution and to the costs for execution, before a declaration of bid, the court shall, upon request, revoke other procedures than those for distribution. The provisions of a obligatory auction against vessel or aircraft and an auction to execute a security right to real estate or vessel, shall apply mutatis mutandis to an auction to execute the security right to aircraft. In an auction to execute the security right to aircraft case, an executive title is not necessary. An executory exemplification is not necessary in an application for an auction to execute the security right to aircraft. A court should examine the existence of security right and claim secured. No order on commencing an auction procedure shall be issued with non-existence or invalidity of the security right and absence or extinguishment of the claim secured. Furthermore, these prohibitions are the reason of a decision on non-permit for sale, the court overlooked these prohibitions, and the decision on a permit for sale became final and conclusive, the successful bidder who paid the price and registered of ownership could not acquire ownership of the aircraft sold. A court may render a ruling to put plural aircrafts up for a blanket auction, only when they are in restraint and related matter (Supreme Court Order 2001Ma3688 dated on August 22, 2001). A righter of retention on aircraft may file a request for an auction against the aircraft. The provisions of an auction to execute a security right to aircraft shall apply mutatis mutandis to the formal auction. Airport facility fee and an aircraft are not in restraint and related matter, so an airport management corporation does not hold the right of retention on the aircraft (Supreme Court Decision 2011Da29291 decided on April 10, 2014). In an auction in accordance with the right of retention, all encumbrances (e.g., mortgages) on the sold aircraft shall be extinguished by a sale under the legal conditions for sale. Not only creditors who have claims for preferential payment but also general creditors could demand for distribution. The precedence of the claim of the right of retention on aircraft and that of general creditor's claims are equal.