Earticle

Advanced classification of Cs contaminated soil by using a magnetic force-assisted selection pipe was investigated. A selection pipe is a device that sort particles depending on their particle size, based on the relationship between buoyancy, drag, and gravity force acting on the particles. Radioactive cesium is concentrated in small-particle size soil components with a large specific surface area. Hence, the volume of the Cs contaminated soil can be reduced by recycling the large-particle size soil components with low radioactive concentration. One of the problems of the selection pipe was that the radioactive concentration of the stayed soil in the selection pipe exceeds 8000 Bq/kg, which is the standard value of recycling of Cs contaminated soil, due to low classification accuracy. In this study, magnetic fields were applied to the lab-scale selection pipe from upper side to improve the classification accuracy and to reduce the radioactive concentration of the stayed soil.

The trenchless entire repair technology (TERT) have many different names depending on the companies, and they have the same or similar methods as well as materials. In addition, there was quiet difficulty in application of field working and even confuse to classify for new TERT, while application criteria of TERT is not listed systematically. This study proposed standardization and method for TERT affecting by pipe condition, working materials, working method, specification/quantity per unit according to field condition, strange affairs and others. Determination criteria of defective sewer pipe has proposed to effective method which modify a criteria between Ministry of Environment and Seoul Metropolitan City. A Cured-in-place pipe (CIPP) is suitable for TERT, and the design criteria for the entire broken pipe are proposed when the pipe itself deforms more than 10%. A check lists are specimen preparing, hardening site made by clamped mold, numbers, flexural and tensile property, water leak and desquamation test, and have to use material property of minimum CIPP value depend on ISO 11296-4, ISO 11297-4, KS M3550-7 and KS M3550-9.

This paper proposes an optimum pipe material (PVC vs. PE) design & selection for open loop ground heat exchangers. Heat exchange efficiency and/or workability, and the need for trench insulation were investigated by comparing EWT (cooling mode) of each system. CFD simulations for the PVC and PE pipe with the same inner diameter show similar EWT. This is because the PVC pipe has a small thickness but a low thermal conductivity as compared to the PE pipe, and thus these two properties tend to offset each other. However, a hypothetically insulated pipe led to a meaningful drop of EWT. This means pipe insulation is of importance in performance of ground heat exchangers. From analyzing climate data and system operation, it is not advantageous to insulate trench pipes due to construction difficulties and ground temperature characteristics that are seasonally varied.

This paper describes the design of a forged fitting form to acquire a method of product design measurement by target measurement standards. The pipefitting connects each pipe and combines seals and nipples with the pipes normally. Therefore, the section combined with the fitting pipe was measured by a 3D scanner, and the acquired measurement and the design measurement were obtained after modification of the forged fitting pipe by that standard. Moreover, the accuracy of the model was verified through leakage testing of the oil and verification of the design measurement for accuracy decisions on the design measurement after modification of the product.

The purpose of this study is that there are two methods for designing firefighting piping: the hydraulic calculation method and the conventional piping method. In the field, the conventional piping method according to the ‘Fire Safety Performance Standards for Sprinkler Equipment’ [Appendix 1] is preferred. There is no mention of the basis and physical meaning of the number of heads for each water supply pipe diameter in the conventional piping method, and the types of pipes that can be used have also increased. Since there was no confirmation as to whether it was appropriate to calculate the number of heads according to [Appendix 1] for each type of pipe, an attempt was made to establish a basis through comparison of regulations in each country and hydrodynamic calculations. The research method was to confirm the basis of the ‘Fire Safety Performance Standards for Sprinkler Equipment’ [Appendix 1] through analysis of relevant standards in the US, UK, and Korea. Based on the flow rate in the pipe, the mass flow rate-based head and the number of pipe heads were calculated and compared. As for the type of pipe, KS D 3507, which is the most commonly used, was used as a standard, and KS D 5301 and 3595 pipes were compared to determine whether the number of heads was appropriate. In addition, in order to check the limits of branch piping based on the flow speed limit of branch piping (6 ㎧) and the flow speed limit of other piping (10 ㎧), 25A (25 Su), 32A (30 Su), 40A (40 Su), we checked for changes by increasing the number of branch pipes to 50A (50 Su). Through this study, it was confirmed that the basis for the method for calculating water supply pipe diameter by number of sprinkler heads is in NFPA 13. Based on the pipe flow rate, the number of heads was calculated by comparing the head number based on mass flow rate for the head and pipe. Using KS D 3507 as the calculation standard in [Appendix 1], it was confirmed that KS D 5301 and 3595 pipes can be sufficiently used as a result of comparative comparison considering the degree of irradiation. In addition, as a result of increasing the number of branch pipes, it was determined that it was appropriate to use branch pipes up to 40A, and it was confirmed that there was no change as the number of branch pipes increased. Through comparison of the standards and the number of heads based on mass flow rate, the basis of ‘Fire Safety Performance Standards for Sprinkler Equipment’ [Appendix 1] was confirmed, and it was confirmed that all KS D 3507, 5301, and 3595 are applicable. In the case of KS D 3595, there are 60 Su and 75 Su as names corresponding to 65A, so it was judged that flexibility in design could be achieved.

This paper is concerned with the selection of proper working fluids for medium temperature range heat pipe. The heat pipe which is made of SUS 316L has a total length of 700 mm as well as an outside diameter of 27.2 mm and a thickness of 2.1 mm respectively. Working fluids used in this study were Naphthalene, Biphenyl and Dowtherm A. Their charge amounts were about 40% of the inside volume of evaporator section. Experimental results shows that the Dowtherm A is good for $200^{\circ}C{\sim}300^{\circ}C$temperature range, while the Naphthalene is proper for $300^{\circ}C{\sim}430^{\circ}C$. In the case of the Naphthalene heat pipe, the heat transfer rate reaches 1500 W along with a vapor temperature of $430^{\circ}C$.

기준공정과 개선대상공정 간의 투입물(Input, Material and energy), 배출물(Output, Product, Co-product), 환경오염물(Environmental emission) 데이터를 수집하고 공정 성과를 분석하였다. 이를 통해 환경적으로 주요한 투입물과 환경오염물을 파악하였다. 제조공정의 투입물과 환경오염물 간의 상관관계 분석을 통해 각 환경오염물에 대한 기여도가 큰 투입물을 파악하였다. 주요 환경오염물 처리 시, 경제적 최적화를 통한 종말처리공정 조합을 선형 프로그래밍 기법을 사용하여 규명하였다. 사례 연구로는 동일한 형태의 시멘트를 생산하는 EU와 국내 시멘트 제조공정을 선정하였다. 국내 시멘트 제조공정에서는 석탄이 주요 투입물로, 먼지, $SO_x$가 주요 환경오염물로 파악되었다. 제조공정의 투입물과 환경오염물 간의 다중회귀분석결과 석탄>원자재>석고 순으로 $CO_2$발생량에 기여도가 큰 것으로 나타났다. $SO_x$발생량의 경우 석탄의 기여도가 가장 컸으며, Dust 발생량의 경우 석고>원자재 순으로 기여도가 큰 것으로 나타났다. Dust 종말처리공정 최적화에서 전기집진기술 100%, 섬유필터기술 2.4% 조합이 최적이었다. $SO_x$종말처리공정 최적화에서는 건식첨가공정기술 100% 습식세정기술 25.88% 조합이 최적이었다. 이 연구의 특징은 제조공정에서 문제가 되는 주요 투입물과 환경오염물을 파악하는 방법을 제시하였다는 점이다. 또한, 기술적 경제적으로 최적의 조합인 종말처리공정 선정 방법을 제시하였다는 점이다.

Process input data including material and energy, process output data including product, co-product and its environmental emissions of the reference and target processes were collected and analyzed to evaluate the process performance. Environmentally problematic input/environmental emissions of the manufacturing processes were identified using these data. Significant process inputs contributing to each of the environmental emissions were identified using multiple regression analysis between the process inputs and environmental emissions. Optimum combination of the end-of-pipe technologies for treating the environmental emissions considering economic aspects was made using the linear programming technique. The cement manufacturing processes in Korea and the EU producing same type of cement were chosen for the case study. Environmentally problematic input/environmental emissions of the domestic cement manufacturing processes include coal, dust, and $SO_x$. Multiple regression analysis among the process inputs and environmental emissions revealed that $CO_2$ emission was influenced most by coal, followed by the input raw materials and gypsum. $SO_x$ emission was influenced by coal, and dust emission by gypsum followed by raw material. Optimization of the end-of-pipe technologies treating dust showed that a combination of 100% of the electro precipitator and 2.4% of the fiber filter gives the lowest cost. The $SO_x$ case showed that a combination of 100% of the dry addition process and 25.88% of the wet scrubber gives the lowest cost. Salient feature of this research is that it proposed a method for identifying environmentally problematic input/environmental emissions of the manufacturing processes, in particular, cement manufacturing process. Another feature is that it showed a method for selecting the optimum combination of the end-of-pipe treatment technologies.

Measurement and analysis for earth resistivity and grounding resistance of Jeon-Ju's widearea-waterworks water pipe line. This result propose to improvement method for exactness analyze the causes for lack of corrosion voltage.

This study presents the selection of cutting conditions in high speed pipe cutting machine for the better quality. A high speed pipe cutting machine which uses a rotary knife can make good quality products in short time. But, the machine is much sensitive by cutting conditions because of the complicated mechanism. In this reason, many experiments for cutting condition selection are necessary to improve quality of production. This study carried out cutting experiments with the three factors that are cutting RPM, cutting force and pooling force. 2-dimensional profile measuring instrument is used to measure which is represented by ${\Delta}h$, a sum of burr and collapse height. The effects of factors are analyzed by using MINITAB, the commercial software.

본 연구는 열수송관의 체계적 성능평가와 안전한 유지관리 방안을 마련하기 위해, 열수송관의 안전성능, 내구성능, 사용성능을 종합적으로 평가할 수 있는 성능평가인자를 선정 및 현장조사 방안을 제시하는 것을 목표로 한다. 현재 열수송관은 다른 지하시설물에 비해 관리 기준이 미흡하여, 노후화에 따른 사고 예방을 위한 평가 기준의 정립이 요구되고 있다. 이를 위해 본 연구는 기존의 관련 법령과 성능평가 매뉴얼을 검토하고, 상수도와 같은 유사 기반시설의 평가 기준을 참고하여 열수송관의 주요 평가 인자를 도출하였다. 주요 평가 인자로는 사용기간, 관경, 매설깊이, 보온재 손상, 감시시스템 정보 등이 있으며, 열수송관의 안전성, 내구성, 사용성과 밀접한 관련이 있는 항목으로 선정되었다. 또한, 집단에너지 사업자를 대상으로 설문조사를 실시하여 각 평가인자의 적합성과 데이터 확보 가능성을 분석하였다. 분석 결과를 토대로 데이터 확보가 용이하고 실효성이 높은 인자들을 기본과업과 선택과업으로 구분하였으며, 이를 통해 열수송관의 성능을 체계적으로 평가할 수 있는 조사 방안을 구체화하였다. 특히 현장조사와 사전조사를 병행하여 효율적인 데이터 수집과 평가가 가능하도록 하였다. 본 연구에서 제안된 평가 절차와 방안은 열수송관의 안전성 및 기능성을 유지하기 위한 기초자료로서 활용 가능하며, 향후 열수송관의 지속적이고 체계적인 관리 및 성능 개선 작업에 실질적으로 기여할 것으로 기대된다. 특히 기반시설관리법에 따라 2025년까지 마련되어야 하는 열수송관 성능평가 기준 수립 시 활용 가능한 연구로 판단된다.

This study aims to propose performance evaluation factors and a field survey plan for the comprehensive evaluation of the safety, durability, and usability of district heating pipes, thereby establishing a systematic performance assessment and safe maintenance approach. Currently, district heating pipes lack the same management standards as other underground infrastructure, underscoring the need for developing evaluation standards to prevent accidents due to aging. To address this, we reviewed existing regulations and performance assessment manuals, referencing evaluation criteria from similar infrastructure, such as water supply systems, to identify key evaluation factors for district heating pipes. Key factors identified include service life, pipe diameter, burial depth, insulation damage, and monitoring system data, all of which are closely related to the safety, durability, and usability of district heating pipes. Additionally, a survey of district energy operators was conducted to analyze the suitability and data availability of each evaluation factor. Based on the analysis results, factors with high feasibility and effectiveness were classified into essential and optional tasks, concretizing a field survey plan for a systematic pipe performance evaluation. In particular, combining field and preliminary investigations allows efficient data collection and assessment. The proposed evaluation procedures and methods in this study serve as fundamental data to maintain the safety and functionality of district heating pipes and are expected to contribute significantly to the continuous and systematic management and performance improvement of these systems. This research is especially relevant for establishing the district heating pipe performance evaluation standards required by 2025.