• Title/Summary/Keyword: Dry Air

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Measurement of Dry Deposition Flux of Air Pollutants to the Waterbody (수체로의 대기오염물질 건식침적량 측정)

  • 김영성;진현철;김용표
    • Journal of Korean Society for Atmospheric Environment
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    • v.20 no.3
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    • pp.421-426
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    • 2004
  • Dry deposition fluxes of inorganic acidic species to the waterbody were measured by the dry deposition sampler (DDS). DDS was composed of three pans filled with pure water. An average concentration increase during the sampling time, after removing an abnormal value if existed, was considered as the input by deposition. Important operation parameters such as the amount of water used and sampling time were determined through a series of laboratory experiments. The deposition flux measured by DDS was compared with that by the water surface sampler developed by Yi et ai. (1997a,b).

Experimental Study on Ignition of Flammable Gas by Spark of Dry Battery (건전지의 방전에 의한 폭발성 가스의 점화에 관한 실험적 연구)

  • Lee, Chun-Ha;Song, Hyun-Jig;Lee, Kwang-Sik;Lee, Dong-In
    • Proceedings of the KIEE Conference
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    • 1994.07b
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    • pp.1543-1546
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    • 1994
  • Ignitabilility of explosive gas mixture by spark of dry cell in case of short circuit by accident was studied for the purpose of evaluation of intrinsically safe characteristics of dry cell that manufactured in Korea. IEC type spark test apparatus, $21{\pm}2$ Vol% of hydrogen - air mixture, and dry cell that produced in Korea was used for the experiment. The result of this research could be used for design, manufacturing, and using the intrinsically safe electrical apparatus.

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Effects of Aging and Aging Method on Physicochemical and Sensory Traits of Different Beef Cuts

  • Kim, Minsu;Choe, Juhui;Lee, Hyun Jung;Yoon, Yeongkwon;Yoon, Sungho;Jo, Cheorun
    • Food Science of Animal Resources
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    • v.39 no.1
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    • pp.54-64
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    • 2019
  • Wet and dry aging methods were applied to improve the quality of three different beef cuts (butt, rump, and sirloin) from Hanwoo cows (quality grade 2, approximately 50-mon-old). After 28 d of wet aging (vacuum packaged; temperature, $2{\pm}1^{\circ}C$) and dry aging (air velocity, 2-7 m/s; temperature, $1{\pm}1^{\circ}C$; humidity, $85{\pm}10%$), proximate composition, cooking loss, water holding capacity, shear force, color, nucleotides content, and sensory properties were compared with a non-aged control (2 d postmortem). Both wet and dry aging significantly increased the water holding capacity of the butt cuts. Dry aging in all beef cuts induced lower cooking loss than that in wet-aged cuts. Shear force of all beef cuts was decreased after both wet and dry aging and CIE $L^*$, $a^*$, and $b^*$ color values in butt and sirloin cuts were higher in both wet and dry aging (p<0.05) groups than those in the non-aged control. Regardless of the aging method used, inosine-5'-monophosphate content among beef cuts was the same. The sensory panel scored significantly higher values in tenderness, flavor, and overall acceptability for dry-aged beef regardless of the beef cuts tested compared to non- and wet-aged cuts. In addition, dry-aged beef resulted in similar overall acceptability among the different beef cuts, whereas that in wet-aged meat was significantly different by different beef cuts. In conclusion, both wet and dry aging improved the quality of different beef cuts; however, dry aging was more suitable for improving the quality of less preferred beef cuts.

A Study on the Efficiency of Smoke-pipe, Internal-fan Type Dry Kiln Heated with Smokeless Coal (무연탄을 열원으로 한 연도측위 내부 송풍식 목재 건조실의 제작에 관하여)

  • Jo, Jae-Myeong;Yoo, Pill-Soo;Chung, Byeong-Jae
    • Journal of the Korean Wood Science and Technology
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    • v.2 no.2
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    • pp.13-21
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    • 1974
  • 1. In the past, the smoke-pipe type dry kiln being characterized by the low cost of installation and easy operation was only used by the small scale of wood processing enterprisers for drying softwood and finishing air-dried stocks that were belonged to easy drying properties. The smoke-pipe type dry kiln usually was not suitable for drying hardwoods and green woods because of the difficulties of controlling drying conditions. 2. However, the smoke-pipe type dry kiln heated with smokeless coal which was designed and constructed by the authers was demonstrated to maintain higher accuracy of controlling temperature and humidity than the other smillar types of kiln. Also, since it was constructed with home made equipments, it is supposed to offer the opportunity to install the kiln by the small scale of wood processing enterprisers who could not install the dry kiln because of economical and technical difficulties. Thus, it is expected that promoting the spread of installing the dry kiln will realize the rational use of wood.

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Three dimensional deformation of dry-stored complete denture base at room temperature

  • Lim, Seo-Ryeon;Lee, Joon-Seok
    • The Journal of Advanced Prosthodontics
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    • v.8 no.4
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    • pp.296-303
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    • 2016
  • PURPOSE. The aim of this study was to evaluate whether there is any typical deformation pattern existing in complete denture when it was dried by using the 3D scanner and surface matching program. MATERIALS AND METHODS. A total of 28 denture bases were fabricated with heat curing acrylic resin (each 14 upper and lower denture bases), and 14 denture bases (each 7 upper and lower denture bases) were stored in the water bottle (water stored), and another 14 denture bases were stored in the air (dry stored). Each specimen was scanned at $1^{st}$ day after deflasking, $14^{th}$ day after deflasking, and $28^{th}$ day after deflasking, and digitalized. Three dimensional deformation patterns were acquired by comparison of the data within storage group using surface matching program. For evaluating differences between groups, these data were compared statisticallyusing Kruskal Wallis and Mann Whitney-U test (${\alpha}$=.05). RESULTS. When evaluating 3D deformation of denture base, obvious deformations were not found in maxillary and mandibular water storage group. However, in dry stored group, typical deformation pattern was detected as storage time passes. It occurred mostly in first two weeks. Major deformations were found in the bilateral posterior area in both maxillary and mandibular group. In maxillary dry stored group, a statistical significance was found. CONCLUSION. It was proved that in both upper and lower denture bases, dry storage caused more dimensional deformation than water storage with typical pattern.

Investigation of the Environment for Conservation in the Facilities of Exhibition and Collection for Cultural Properties (문화재 전시 및 수장시설 내에서의 보존환경 조사연구)

  • Hong, Jung-Ki;Kim, Sa-Dug;Kim, Soon-Kwan;Kang, Dai-Ill;Lee, Myeong-Hui
    • 보존과학연구
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    • s.22
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    • pp.155-171
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    • 2001
  • The facilities of exhibition and collection for cultural properties is affected by environmental pollution. In order to accumulate a store of basic data, we was investigated eight points(three points at exhibition room and five points at collection room) at four institutes, from December 2000 to March 2001.As a result of investigation, the temperature of A-Exhibition room measured low because of don’t moved HVAC(Heating, Ventilation and Air-Conditioning) System, B Exhibition room is dry for the effect of air-conditioner and the air pollutants concentration of C-Exhibition room is high for the kind of an exhibition room. The air-condition was varied within the open period. The air pollutants concentration of A-Collection room is measured high because the air-pollutants is generated in a new buildings and the air pollutants concentration of C-1 & C-2-Collection room is high for the kind of an collection room. It is necessary to ventilate sufficiently.

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Evaluation of Air-side Heat Transfer and Friction Characteristics on Design Conditions of Evaporator (증발기의 설계조건에서 공기측 열전달계수 및 압력강하 산출)

  • 김창덕;이진호
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.12
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    • pp.1007-1017
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    • 2003
  • An experimental study on the air-side pressure drop and heat transfer coefficient of slit fin-tube heat exchanger has been carried out. The data reduction methodology for air-side heat transfer coefficients in the literature is not based on a consistent approach. This paper focuses on new method of data reduction to obtain the air-side performance of fin-tube heat exchanger using R22 and recommends standard procedures for dry and wet surface heat transfer estimation in fin-tube heat exchanger having refrigerant on the tube-side. Results are presented as plots of friction f-factor and Colburn j -factor against Reynolds number based on the fin collar outside diameter and compared with previous studies. The data covers a range of refrigerant mass fluxes of 150∼250 kg/$m^2$s with air flows at velocity ranges from 0.3 m/s to 0.8 m/s.

A Study on the Grade Efficiency of Sturtevant Type Air Classifier (스터테반트 공기분급기의 분리효율에 대한 연구)

  • 정인기;박시우
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.5
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    • pp.773-781
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    • 2004
  • This research was Performed to raise grade efficiency of Sturtevant type air classifier. to treat powder less than $74\mu\textrm{m}$ particle produced at the crushing process of the dry aggregates manufacturing system or concrete wastes recycling system. The experimental conditions were in the ranges. 0.85 to 5.15 $m^3$/s of primary air flow rate. 0.005 to 0.015 $m^3$/s of secondary air flow rate $30^{\circ}$ to $70^{\circ}$ of auxiliary blades angle. respectively. for 1.7~3.3 kg/min of the powder feed rate. It was found that the grade efficiency of the air classifier was increased as the baffle plate was attached at the expansion region. and the optimal operating conditions of the air flow rates and the blade angle were obtained. The fractional recovery curves from the experiments were well agreement with the theoretical one of Molerus model.

A Study on the Performance for Heavy-duty Diesel Engine with Intake Air Filter (대형디젤기관에서 자동차 흡기 에어필터 장착에 따른 성능에 관한 연구)

  • Rha, Wan-Yong;Oh, Sang-Ki
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.2
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    • pp.114-117
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    • 2005
  • Air cleaners in all of the automotive engines have been used for decades. In the early 1920's the oil bath type was the popular shape of air cleaners. The air cleaners of the oil wetted bath type were introduced in 1940's. The shape of the dry pleated paper type media was introduced in the 1950's. This trend still continues with new and innovative media being introduced. Engine air cleaners should have effectively removed and reduced harmful contaminants being ingested into engines. This studies show that both, the ingested contaminant size and concentration need to be controlled. This paper com pare and analyze the characteristics over the economics, engine performances and reduction of noises of power-plus air filters with wet paper which were sticked to heavy duty diesel engine.

Evaluation of Air-side Heat Transfer and Friction Characteristics on Design Conditions of Condenser (응축기의 설계조건에서 공기측 열전달계수 및 압력강하 산출)

  • 김창덕;전창덕;이진호
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.3
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    • pp.220-229
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    • 2003
  • An experimental study on the air-side pressure drop and heat transfer coefficient of slit fin-tube heat exchanger has been carried out. The data reduction methodology for air-side heat transfer coefficients in the literature is not based on a consistent approach. This paper focuses on new method of data reduction to obtain the air-side performance of fin-tube heat exchanger using R22 and recommends standard procedures for dry surface heat transfer estimation in fin-tube heat exchanger having refrigerant on the tube-side. Results are presented as plots of friction f-factor and Colburn j -factor against Reynolds number based on the fin collar outside diameter and compared with previous studies. The data covers a range of refrigerant mass fluxes of 150~250 kg/$m^2$s with air flows at velocity ranges from 0.6 m/s to 1.6 m/s.