• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.172-175
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• 2002

High speed machining is one of the most effective technologies to improve productivity. It can give great advantage for manufacture of die and Moulds. However, when machining of micro groove in high speed machining a severely thermal damage was generated on workpiece and cutting tool. Generally, the cutting fluid is used to improve penetration. lubrication. and cooling effect. In order to rise the performance of lubrication. it contains extreme pressure agents (Cl, S, P). But the environment of work room go bad by those additive. Therefore, the compressed chilly air with oil mist system was developed to replace the conventional cutting fluid system. This paper carried out the tests to evaluate the machinability by the cutting environment in high speed micro groove machining of NAK80 (HrC40). Compressed chilly air with oil mist was ejected on the contact area between cutting edge and workpiece. The effect of this developed compressed chilly air with oil mist system was evaluated in terms of tool life. The results showed that the tool lift of carbide tool coated TiAlN with compressed chilly air mist cooling was much longer than that of the dry and flood coolant when cutting the material.

• 한국항공운항학회지
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• 제22권3호
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• pp.8-14
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• 2014

Arrival management is a tool which provides efficient flow of traffic and reduces ATC workload by determining aircraft's sequence and schedules while they are in cruise phase. As a decision support tool, arrival management should advise on air traffic control service based on the understanding of human factor of its user, air traffic controller. This paper proposed a prediction model for air traffic controller sequencing strategy by analyzing the historical trajectory data. Statistical analysis is used to find how air traffic controller decides the sequence of aircraft based on the speed difference and the airspace entering time difference of aircraft. Logistic regression was applied for the proposed model and its performance was demonstrated through the comparison of the real operational data.

• 한국산학기술학회논문지
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• 제13권11호
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• pp.4944-4949
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• 2012

이 논문의 목적은 작업장에서 사용하기 위한 에어건의 개발에 관련된 것이다. 에어건은 공작기계를 사용하는 산업현장에서 공작물 칩과 절삭유의 제거를 위한 도구이다. 그리고 그것은 일반적으로 압축공기를 분사하는 용도로 사용된다. 작업자는 에어의 흡입과 분사를 위해 각각의 에어건을 준비하여야 한다. 따라서 우리는 새로운 에어건을 개발하였다. 이 논문에서 우리는 에어건의 설계와 분석을 위한 연구를 한다. 에어건은 몸체, 파이프, 개폐 유닛, 전환 유닛, 에어 튜브 그리고 조립을 위한 요소들로 구성된다. 개발된 에어건은 그 효율을 확인하기 위해 실험된다.

• International Journal of Air-Conditioning and Refrigeration
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• 제15권3호
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• pp.137-146
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• 2007

CFD simulation is a very useful tool to predict the concentration of contaminant generated from the building materials in a single room. However, there is a limitation on analyzing air movement and contaminant concentration in a multi-room when the door of each room is closed. In this study, network based simulation was coupled with contaminant simulation for the multi-room condition, using an network simulation tool 'ESP-r'. The coupled simulation was first validated with experimental measurements which performed to define the characteristics of the analyzed space prior to the simulation, and indoor air flow and contaminant concentration between rooms were then analyzed when the door of each room was open and closed in the case of natural and forced ventilation.

• 한국기계가공학회지
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• 제20권7호
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• pp.15-24
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• 2021

In this paper, to analyze the types of surface morphology error according to factors that cause machining error, the experiments were conducted in the ultra-precision diamond machine using a diamond tool. The factors causing machining error were classified into the pressure variation of compressed air, external shock, tool errors, machining conditions (rotational speed and feed rate), tool wear, and vibration. The pressure variation of compressed air causes a form accuracy error with waviness. An external shock causes a ring-shaped surface defect. The installed diamond tool for machining often has height error, feed-direction position error, and radius size error. The types of form accuracy error according to the tool's errors were analyzed by CAD simulation. The surface roughness is dependent on the tool radius, rotational speed, and feed rate. It was confirmed that the surface roughness was significantly affected by tool wear and vibration, and the surface roughness of Rz 0.0105 ㎛ was achieved.

• 대한설비공학회지:설비저널
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• 제34권12호
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• pp.5-8
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• 2005

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.271-276
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• 2010

High-speed air turbine handpieces have been used as a denture cutting tool in clinical dentistry for over 50 years. The denture high-speed air turbine handpiece is currently used as the main means of cutting tooth structure and restorative materials in a wide range of denture manufacturing. But little study has been reported on their performance analysis. This research would show the performance characteristics of denture air turbine handpiece by using CFD.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.315-320
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• 2004

Cutting fluid usually has been used in order to improve machinability, tool life, surface quality. However, problems such as pollution, costs of chip and fluid treatment caused. In this paper, compressed chilly air was used to machine aircraft parts and investigate possibility and advantage of that. The experiments were carried out in various cutting environments, such as wet and compressed chilly air. With respect to the cutting environment, compressed chilly air gave advantages such as decrease of pollution and easy chip treatment.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.429-435
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• 2006

In this study multi-zone modeling program CONTAM 2.4 which is developed by NIST is used for modeling the air disinfection system which is consist of dilution, filtration, ultra violet germicidal irradiation (UVGI) for removing the indoor microorganism such as bacteria and fungus. Developed models those protect occupants against indoor microorganism generated in our daily life are enable to use for immune building simulation tool. Also, results indicate that those models are enable to compute the real situation that is almost impossible of carrying out experiment and identify the disinfection rate with highly reliance. Results also suggest that engineers will use these models as a design tool for the immune building system.

• Asian Journal of Atmospheric Environment
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• 제11권4호
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• pp.330-343
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• 2017

Climate change is an important issue, with many researches examining not only future climatic conditions, but also the interaction of climate and air quality. In this study, a new version of the emissions processing software tool - Python-based PRocessing Operator for Climate and Emission Scenarios (PROCES) - was developed to support climate and atmospheric chemistry modeling studies. PROCES was designed to cover global and regional scale modeling domains, which correspond to GEOS-Chem and CMAQ/CAMx models, respectively. This tool comprises of one main system and two units of external software. One of the external software units for this processing system was developed using the GIS commercial program, which was used to create spatial allocation profiles as an auxiliary database. The SMOKE-Asia emissions modeling system was linked to the main system as an external software, to create model-ready emissions for regional scale air quality modeling. The main system was coded in Python version 2.7, which includes several functions allowing general emissions processing steps, such as emissions interpolation, spatial allocation and chemical speciation, to create model-ready emissions and auxiliary inputs of SMOKE-Asia, as well as user-friendly functions related to emissions analysis, such as verification and visualization. Due to its flexible software architecture, PROCES can be applied to any pregridded emission data, as well as regional inventories. The application results of our new tool for global and regional (East Asia) scale modeling domain under RCP scenario for the years 1995-2006, 2015-2025, and 2040-2055 was quantitatively in good agreement with the reference data of RCPs.