• 제목/요약/키워드: R410A

검색결과 305건 처리시간 0.029초

파이프 이음부가 단동온실 구조성능에 미치는 영향: 실대형 실험적 및 해석적 연구 (Effect of the Pipe Joint on Structural Performance of a Single-span Greenhouse: A Full-scale Experimental and Numerical Study)

  • 신현호;류희룡;유인호;조명환;서태철;김승유;최만권
    • 생물환경조절학회지
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    • 제30권4호
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    • pp.410-418
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    • 2021
  • 본 연구에서는 원예특작시설 내재해형 규격서에 등록되어 있는 폭이 넓은 단동온실(10-단동-5형)을 대상으로 기초의 경계조건과 서까래 강관의 이음 유무에 대해 실물 크기 실험을 실시하고 그 결과를 수치해석 결과와 비교하여 이음부가 있을 때 구조성능 차이에 대해 알아보았다. 각 측정 위치별 변위를 실험에서 측정한 값과 수치해석으로 예측한 값을 비교한 결과에서는 기초의 조건 및 서까래 강관 이음 유무에 상관없이 모두 상당한 차이를 보였고, 힌지 조건 보다 고정 조건이 상대적으로 차이가 컸다. 그리고 모든 절점을 강접합으로 가정하고 구조해석한 결과를 구조실험과 비교한 결과에서는 힌지조건이 고정조건 보다 잘 일치하였지만 해석값이 실험값 보다 크게 나타났다. 수치해석은 모든 절점을 강접합으로 가정했기 때문에 실제 성능과 달랐다. 따라서 현재 모든 절점을 강접합으로 가정하고 온실을 설계를 하면 과소설계될 우려가 있어 앞으로 신뢰성 높은 온실 설계를 위해서는 서까래와 도리가 교차하는 교차부 성능 특성을 고려한 구조해석 기술 개발이 이루어져야 할 것으로 판단된다.

과체중 및 비만여성에서 연령이 열량 제한에 의한 체조성 변화에 미치는 영향 (Effects of age on changes of body composition through caloric restriction in overweight and obese women)

  • 임정은;김영설;조여원
    • Journal of Nutrition and Health
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    • 제46권5호
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    • pp.410-417
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    • 2013
  • 본 연구는 만 19~60세의 BMI $23kg/m^2$ 이상 여성 61명을 대상으로 12 주간 열량 섭취 제한 시 체중 감량에 영향을 미치는 요인을 분석하고 이들의 상관성을 알아보고자 하였다. 12주간의 열량 섭취 제한으로 하루 평균 451.9 kcal가 감소하였고 열량 제한 후 체중은 평균 4.5% 감소하였고, 내장지방량은 11.9%, 피하지방량은 8.2% 감소하였으며, 혈압도 유의하게 감소하였다 (p < 0.01). 혈액지표 중 GPT 농도는 감소하였으며 (p < 0.05), 아디포넥틴 농도는 증가하였다 (p < 0.01). 연령이 증가함에 따라 섭취 열량 감소량이 낮게 나타났다 (r = 0.31, p = 0.02). 젊은 연령에서 열량 섭취량 감소가 컸으며, 연령이 증가할수록 열량 섭취량 감소가 낮게 나타났다. 연령은 독립적으로 신체 조성 변화와 유의한 관련이 있었으며 (p < 0.05), 연령이 증가함에 따라 열량 섭취 제한에 따른 체중 및 내장지방과 피하지방의 감소량이 낮았으며, 특히, 내장지방 감소량이 낮게 나타났다 (p < 0.05). 또한, 연령이 증가함에 따라 열량 섭취 제한에 따른 렙틴 농도 감소량도 낮았다 (p < 0.05).

Availability of MADLDI-TOF MS for Identification of Gram Positive Bacilli Isolated from Blood Culture

  • Choi, Jin-Un;Kim, Sang-Ha;Hwang, Su-Jeong;Yu, Young-Bin;Kim, Sunghyun;Kim, Young-Kwon
    • 대한의생명과학회지
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    • 제24권2호
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    • pp.108-115
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    • 2018
  • In the present study, results of the identification of Gram-positive bacilli (GPB) were analyzed by using the MALDI-TOF MS technique to score each 2-year blood culture at a university hospital. In addition, 16S rRNA sequence analyses and MALDI-TOF MS results are compared to targeting strains that had been isolated two or more times within the same patient, to evaluate the usefulness of MALDI-TOF MS in GPB identification. According to the cut-off (${\geq}1.7$) criteria, there were 410 (57.5%) reliable strains and 303 (42.5%) non-identified strains among the GPB identification results of 713 strains, using a microflex MALDI Biotyper (Bruker Daltonik GmbH, Bremen, Germany). The isolation appeared most often in the following order: Corynebacterium striatum, Bacillus cereus, Bacillus subtilis, Paenibacillus urinalis, and Listeria monocytogenes. Nearly three-fourths, 66 out of 89 (74.2%) of the strains for Corynebacterium striatum; 44 out of 60 (73.3%) strains for Bacillus cereus; and all (25 out of 25, 100%) Listeria monocytogenes strains were identified by their high scores of 2.0 or higher. Most (293 strains out of 303) non-identified strains were strains isolated only once and not significant as infectious bacilli. A total of 43 out of 50 (86.0%) strains matched and were able to be identified based on the 16 rRNA sequencing comparison results of strains that were isolated twice or more within the same patient and significant as infection bacilli. Non-matching among 5 out of 7 strains was not identified, even with MALDI-TOF MS. In conclusion, GPB can be identified in blood cultures using MALDI-TOF MS. This can be done accurately with ease, rapidly, and at a low cost. It is also thought to be helpful in GPB diagnosis and treatment.

재열기를 사용한 고성능 VI 사이클 열펌프의 난방 성능 특성에 관한 연구 (A Study on the Characteristics of Heating Performance of High-Performance Heat Pump with VI cycle using Re-Heater)

  • 이진국;최광환
    • 동력기계공학회지
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    • 제19권4호
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    • pp.69-75
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    • 2015
  • In this study, the characteristics of heating performance of a high-performance air-cooled heat pump with vapor-injection(VI) cycle using re-heater was investigated experimentally. Devices used in the experiment is consist of a VI compressor, condenser, oil separator, refrigerant (economizer outlet refrigerant) re-heater, economizer, evaporator. And R410A was used as a working fluid. The experiment was conducted with two cycles(cycles A and B) for investigating heating performance. In case of cycle B, heat exchange was conducted by re-heater between outlet refrigerant of compressor and suction refrigerant of the VI system(Fig.1, re-heater). But the re-heater was not used in case of cycle A. As a result of this experiment, discharge temperature of refrigerator in compressor was shown higher value, when the cycle B was conducted, because of the heat exchange between suction refrigerant of VI cycle and outlet refrigerant of compressor in the re-heater than cycle A that was not use re-heater. it means that liquid hammer and the decrement of heating performance can be decreased by using re-heater. Also, Heating coefficient of performance(COPh) was shown about 2.98 in Cycle B which was 4% higher than Cycle A and from these results, It was confirmed that the improvement of the heating performance of heat pump with VI cycle can be achieved by applying re-heater.

태양열과 재열기를 사용한 VI heat pump의 성능 특성에 관한 연구 (Heating Performance Characteristics of Heat Pump with VI cycle using Re-Heater and Solar-Assisted)

  • 이진국;최광환
    • 한국태양에너지학회 논문집
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    • 제35권6호
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    • pp.25-33
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    • 2015
  • In this study, heating performance of the air-cooled heat pump with vapor-injection (VI) cycles, re-heater and solar heat storage tank was investigated experimentally. Devices used in the experiment were comprised of a VI compressor, re-heater, economizer, variable evaporator, flat-plate solar collector for hot water, thermal storage tank, etc. As working fluid, refrigerant R410A for heat pump and propylene glycol (PG) for solar collector were used. In this experiment, heating performance was compared by three cycles, A, B and C. In case of Cycle B, heat exchange was conducted between VI suction refrigerant and inlet refrigerant of condenser by re-heater (Re-heater in Fig. 3, No. 3) (Cycle B), and Cycle A was not use re-heater on the same operating conditions. In case of Cycle C, outlet refrigerant from evaporator go to thermal storage tank for getting a thermal energy from solar thermal storage tank while re-heater also used. As a result, Cycle C reached the target temperature of water in a shorter time than Cycle B and Cycle A. In addition, it was founded that, as for the coefficient of heating performance($COP_h$), the performance in Cycle C was improved by 13.6% higher than the performance of Cycle B shown the average $COP_h$ of 3.0 and by 18.9% higher than the performance of Cycle A shown the average $COP_h$ of 2.86. From this results, It was confirmed that the performance of heat pump system with refrigerant re-heater and VI cycle can be improved by applying solar thermal energy as an auxiliary heat source.

GHP 난방 모드 운전시 실시간 부하 추정방법에 관한 연구 (A Study on Estimating Real-time Thermal Load During GHP Operation in Heating Mode)

  • 서정아;신영기;오세제;정상덕;지경철;정진희
    • 설비공학논문집
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    • 제23권1호
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    • pp.32-37
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    • 2011
  • The present study has been conducted to propose an algorithm regarding real-time load estimation of a gas engine-driven heat pump. In the study, thermal load of an indoor unit is estimated in terms of air-side and refrigerant-side. The air-side estimation is based on a typical heat exchanger model and is found to be in good agreement with experimental data. When it comes to the refrigerant-side load, a pressure difference across a valve must be estimated. For the estimation, it is assumed to be proportional to a bigger pressure difference that is available either by measurement or by estimation. Relative good agreement between the air- and refrigerant-sides suggests that the assumption may be plausible for the load estimation. The summed flow rate of all of indoor units is in good agreement with the throughput of the compressor which are calculated from the manufacturer's software. Accordingly, estimated thermal loads are also in good agreement. The proposed algorithm may be further developed for improved control algorithm and fault diagnosis.

Genetic Variation and Species Identification of Thai Boesenbergia (Zingiberaceae) Analyzed by Chloroplast DNA Polymorphism

  • Techaprasan, Jiranan;Ngamriabsakul, Chatchai;Klinbunga, Sirawut;Chusacultanachai, Sudsanguan;Jenjittikul, Thaya
    • BMB Reports
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    • 제39권4호
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    • pp.361-370
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    • 2006
  • Genetic variation and molecular phylogeny of 22 taxa representing 14 extant species and 3 unidentified taxa of Boesenbergia in Thailand and four outgroup species (Cornukaempferia aurantiflora, Hedychium biflorum, Kaempferia parviflora, and Scaphochlamys rubescens) were examined by sequencing of 3 chloroplast (cp) DNA regions (matK, psbA-trnH and petA-psbJ). Low interspecific genetic divergence (0.25-1.74%) were observed in these investigated taxa. The 50% majority-rule consensus tree constructed from combined chloroplast DNA sequences allocated Boesenbergia in this study into 3 different groups. Using psbA-1F/psbA-3R primers, an insertion of 491 bp was observed in B. petiolata. Restriction analysis of the amplicon (380-410 bp) from the remaining species with Rsa I further differentiated Boesenbergia to 2 groupings; I (B. basispicata, B. longiflora, B. longipes, B. plicata, B. pulcherrima, B. tenuispicata, B. thorelii, B. xiphostachya, Boesenbergia sp.1 and Boesenbergia sp.3; phylogenetic clade A) that possesses a Rsa I restriction site and II (B. curtisii, B. regalis, B. rotunda and Boesenbergia sp.2; phylogenetic clade B and B. siamensis; phylogenetic clade C) that lacks a restriction site of Rsa I. Single nucleotide polymorphism (SNP) and indels found can be unambiguously applied to authenticate specie-origin of all investigated samples and revealed that Boesenbergia sp.1, Boesenbergia sp.2 and B. pulcherrima (Mahidol University, Kanchanaburi), B. cf. pulcherrima1 (Prachuap Khiri Khan) and B. cf. pulcherrima2 (Thong Pha Phum, Kanchanaburi) are B. plicata, B. rotunda and B. pulcherrima, respectively. In addition, molecular data also suggested that Boesenbergia sp.3 should be further differentiated from B. longiflora and regarded as a newly unidentified Boesenbergia species.

Effects of Biofertilizer Rate and Application Time on Growth Characters and Grain Quality of Rice

  • Mintah, Lemuel Ohemeng;Rico, Cyren Mendoza;Shin, Dong-Il;Chung, Il-Kyung;Son, Tae-Kwon;Lee, Sang-Chul
    • 한국작물학회지
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    • 제52권4호
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    • pp.403-410
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    • 2007
  • A field experiment was conducted to investigate effects of application time and rate of biofertilizer alone and in combination with chemical NPK fertilizer on growth, yield and quality of rice. The biofertilizer used composted food waste as substrate and added with effective microorganism. The treatments included recommended NPK fertilizer(RF, $11-5.5-4.8kg\;10a^{-1}$), half recommended NPK fertilizer(HRF, $5.5-2.8-2.4kg\;10a^{-1}$), half recommended NPK fertilizer plus $250kg\;10a^{-1}$ biofertilizer(HRF+Bio 250) and $500kg\;10a^{-1}$ biofertilizer(HRF+Bio 500). The biofertilizer treatments were applied at 0, 5 and 10 days before transplanting(DBT). Grain yield of HRF+Bio 250 at 5 DBT($648.4kg\;10a^{-1}$) was statistically similar to the highest obtained in the RF($654.1kg\;10a^{-1}$). Tiller numbers at HRF plus biofertilizer treatments were already high during the maximum tillering stage, and were similar with that of the RF and higher than that of the HRF during heading stage. Likewise, ripening ratio at HRF plus biofertilizer treatments was similar with that of the RF and higher than that of the HRF. Furthermore, all the biofertilizer treatments improved protein content but reduced the amylose content and palatability compared to treatments with chemical NPK fertilizer alone. Thus, HRF+Bio 250 at 5 DBT can be used to save 50% chemical NPK fertilizer and at the same time obtain an improved rice grain yield and quality.

Comparison of the oral microbial composition between healthy individuals and periodontitis patients in different oral sampling sites using 16S metagenome profiling

  • Kim, Yeon-Tae;Jeong, Jinuk;Mun, Seyoung;Yun, Kyeongeui;Han, Kyudong;Jeong, Seong-Nyum
    • Journal of Periodontal and Implant Science
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    • 제52권5호
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    • pp.394-410
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    • 2022
  • Purpose: The purpose of this study was to compare the microbial composition of 3 types of oral samples through 16S metagenomic sequencing to determine how to resolve some sampling issues that occur during the collection of sub-gingival plaque samples. Methods: In total, 20 subjects were recruited. In both the healthy and periodontitis groups, samples of saliva and supra-gingival plaque were collected. Additionally, in the periodontitis group, sub-gingival plaque samples were collected from the deepest periodontal pocket. After DNA extraction from each sample, polymerase chain reaction amplification was performed on the V3-V4 hypervariable region on the 16S rRNA gene, followed by metagenomic sequencing and a bioinformatics analysis. Results: When comparing the healthy and periodontitis groups in terms of alpha-diversity, the saliva samples demonstrated much more substantial differences in bacterial diversity than the supra-gingival plaque samples. Moreover, in a comparison between the samples in the case group, the diversity score of the saliva samples was higher than that of the supra-gingival plaque samples, and it was similar to that of the sub-gingival plaque samples. In the beta-diversity analysis, the sub-gingival plaque samples exhibited a clustering pattern similar to that of the periodontitis group. Bacterial relative abundance analysis at the species level indicated lower relative frequencies of bacteria in the healthy group than in the periodontitis group. A statistically significant difference in frequency was observed in the saliva samples for specific pathogenic species (Porphyromonas gingivalis, Treponema denticola, and Prevotella intermedia). The saliva samples exhibited a similar relative richness of bacterial communities to that of sub-gingival plaque samples. Conclusions: In this 16S oral microbiome study, we confirmed that saliva samples had a microbial composition that was more similar to that of sub-gingival plaque samples than to that of supra-gingival plaque samples within the periodontitis group.

Operating characteristics of 3RT heat pumps

  • Moon, Chang-Uk;Choi, Kwang-Hwan;Yoon, Jung-In;Jeon, Min-Ju;Heo, Seong-Kwan;Sung, Yo-Han;Park, Sung-Hyeon;Lee, Jin-Kook;Son, Chang-Hyo
    • Journal of Advanced Marine Engineering and Technology
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    • 제41권2호
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    • pp.140-145
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    • 2017
  • Newly designed vapor-injection heat pumps have been proposed and analyzed in the present study. An economizer-type vapor-injection (V-I) system has been employed as the standard system because of its reliability and simple control method. The V-I system has a re-cooler and re-heater for cooling and heating, respectively. Solar panels have been installed in the V-I heat pump as well as in the re-heater in order to enhance heating capacity and performance. R410A has been employed as a working fluid and performance analysis has been conducted under various conditions. Results are summarized as follows: (1) The V-I system with the re-cooler yielded a marginally higher coefficient of performance (COP) than the conventional V-I refrigeration system. (2) By increasing the re-cooler cooling capacity, enhanced system performance as compared to the conventional V-I system was observed. (3) The re-heater negatively affected the system performance; hence, the V-I heat pump with the re-heater yielded a lower COP than that of the conventional V-I heat pump used for heating. (4) Although the solar panels increased the system performance, this increase could not offset performance degradation by the re-heater.