• Computers and Concrete
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• 제24권1호
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• pp.1-6
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• 2019

Within the scope of this study, the foam solution was prepared by properly mixing sulfonate based foam agent with water. Furthermore, this solution was mixed with the mixture of fine sand, cement, and water to produce foamed concrete. The mixture ratios which are the percentage of foam solution used in foam concrete were chosen as 0, 20, 40 and 60% by vol. After these groups reached 28 days of strength, they were heated to 20, 100, 400 and $700^{\circ}C$ respectively. Afterward, high-temperature effects on the foamed concrete were obtained by employing physical and mechanical properties tests. Additionally, SEM (scanning electron microscope) and EDX (energy-dispersive X-ray spectroscopy) tests were employed to analyze the microstructure, and ${\mu}-CT$ (micro computed tomography) images were used to reconstruct 3-D models of the heat-treated specimens. Then, these models are analyzed to examine the void structures and the changes in these structures due to the high temperatures. The study has shown that the void structures reduce the high-temperature effects and the foam solution could be mixed with concrete up to 40 % by vol. where the high strength of foamed concrete is non-mandatory.

• Journal of Ceramic Processing Research
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• 제19권5호
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• pp.413-418
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• 2018

All-solid-state lithium batteries (ASSBs) using inorganic sulfide-based solid electrolytes are considered prospective alternatives to existing liquid electrolyte-based batteries owing to benefits such as non-flammability. However, it is difficult to form a favorable solid-solid interface among electrode constituents because all the constituents are solid particles. It is important to form an effective electron conduction network in composite cathode while increasing utilization of active materials and not blocking the lithium ion path, resulting in excellent cell performance. In this study, a mixture of fibrous VGCF and spherical nano-sized Super P was used to improve rate performance by fabricating valid conduction paths in composite cathodes. Then, composite cathodes of ASSBs containing 70% and 80% active materials ($LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$) were prepared by a solution-based process to achieve uniform dispersion of the electrode components in the slurry. We investigated the influence of binary carbon additives in the cathode of all-solid-state batteries to improve rate performance by constructing an effective electron conduction network.

• 한국산업융합학회 논문집
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• 제24권6_2호
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• pp.737-744
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• 2021

An investigation is conducted to study a solid-liquid mixture vertically upward hydraulic transport of solid particles by non-Newtonian fluids in the Mud system. Rheology of particulate suspensions in viscoelastic fluids is of importance in many applications such as particle removal from surfaces, transport of proppants in fractured reservoir and cleaning of drilling holes, etc. In this study a clear acrylic pipe was used in order to observe the movement of solid particles. Annular velocities varied from 0.4 m/s to 1.2 m/s. The mud systems which were utilized included aqueous solution of sodium carboxymethyl cellulose (CMC) solutions. Main parameters considered in the study were inner-pipe rotary speed, fluid flow regime and particle injection rate. Solid volumetric concentration and pressure drops were measured for the various parameters such as inclination angle, flow rate, and rotational speed of inner cylinder.

• 한국건설순환자원학회논문집
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• 제3권4호
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• pp.313-319
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• 2015

본 연구에서는 비가열 제조법에 의한 BP슬러지의 반건조 제조공정 개발에 관한 연구로 고함수율(50% 이상)의 BP부산물을 건설 재료로의 대량 활용하기 위하여 산업부산물과 혼합에 따른 함수율 저감에 관한 연구를 수행하였다. BP부산물에 함수저감재(1:0.5)의 투입비율에서 함수저감율을 측정결과 PA+CFA(1:0.5) 배합에서 함수율이 18.5%로 가장 낮게 나타났다. 또한, 에이징 온도조건 $20{\sim}30^{\circ}C$일 경우 에이징 기간 1~2일 사이에 약 9.2~11.4%의 함수율을 나타내 본 연구에서 건설재료로 활용하기 위한 10% 이내의 함수율 저감에 근접하였다. 에이징 공정 이후 분쇄방법에 따른 비가열 BP부산물의 물성을 비교 평가한 결과, 분쇄방식에 따라서 차이는 많이 발생하지 않았으며, 생산효율 및 경제성을 고려할 경우 연속생산이 가능한 미립자분쇄기 또는 핀밀을 사용하는 것이 적합할 것으로 나타났다.

• 대한전자공학회논문지SP
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• 제42권4호
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• pp.79-86
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• 2005

본 논문에서는 실시간 얼굴인식 시스템을 위한 새로운 LINF(Linear Independent Non-negative Factorization) 알고리즘을 제안한다. 시스템은 크게 얼굴추출 부분과 얼굴인식 부분으로 구성 되어 있으며, 얼굴추출 부분에는 차영상, 눈과 입의 영역 검출 그리고 정규화 방법을 사용하였고, 얼굴인식 부분에는 추출된 얼굴 후보 영역 영상에 LINF 를 적용하였다. 기존의 PCA(Principal Component Analysis)만을 사용한 인식시스템은 낮은 인식률을 보였으며, LDA(Linear Discriminants Analysis)만을 사용한 인식시스템에서는 학습데이터의 수에 비하여 영상의 화소 개수가 많은 경우 LDA를 그대로 적용하기 곤란하였다. 이러한 단점을 극복하기 위하여, 본 논문에서 제안하는 시스템은 기존의 고유얼굴과 달리 비음수 값을 갖는 행렬로 차원을 축소하여 LDA를 적용하였다. 제안한 시스템의 성능을 평가하기 위하여 자체 제작한 DAUface 데이터베이스와 영국 Cambridge 에 있는 AT&T 연구소에서 제공하는 ORL 데이터베이스를 가지고 실험을 하였다. 실험 결과, 제안된 방법이 PCA 방법과 LDA 방법, ICA(Independent Component Analysis) 방법, 그리고 PLMA(PCA-based LDA mixture algorithm)에 비해 인식률이 상당히 우수함을 알 수 있었다.

• 자원리싸이클링
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• 제17권6호
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• pp.43-49
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• 2008

본 연구에서는 라인스캔 카메라를 이용한 색도인식 스크랩 선별시스템을 설계 제작하고 제작한 시스템을 이용하여 철스크랩에 혼합되어 있는 Cu 스크랩을 자동으로 분리하는 연구를 수행하였다. 스크랩 자동선별 시스템은 크게 측정부, 이송부 그리고 이젝터로 구분되며 라인스캔 카메라, 광원 및 frame grabber로 구성된 측정부에서 스크랩 표면의 색도를 이메지 프로쎄싱 알고리즘에 의해 인식함으로써. 임의로 지정한 특정한 표면색상의 스크랩만에 에어노즐을 작동케 하여 선별하도록 되어 있다. 본 연구에서는 선별처리의 고속화에 대응하기 위하여 주파수 가변 광원시스템을 제작하여 선별시스템에 적용하였으며, 최적실험조건으로 스크랩 이송속도 25 m/min.에서 철스크랩중에 포함되어 있는 Cu스크랩을 90%이상 인식하여 약 80%의 선별효율을 얻었다.

• 한국응용곤충학회지
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• 제22권2호
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• pp.130-137
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• 1983

A wide variety of pathogens are known io be seedborne, carried either as infectious mycelium internally or as contaminants on the seed coat. When seed is infected with a pathogen, the seed nay be rendered nonviable or it may remain viable but produce weak seedling. In some cases, the Infected seedling nay not be severely weakened, but nay serve as a source of primary inoculum within a community of plants. A recent problem nay be the dissemination of seedborne pathogens occurring as a result of the massive movements of seed, as a part of the 'Green revolution' Disease of great danger to agriculture may be introduced with seed from other parts of world. Seed treatment with organic mercury compounds in liquid form had become popular since about 1955. Organic mercury compounds contributed considerably to the increase in production of many crops and vegetables. In 1975, however, the use of organic mercury compound was forbidden because of doubts regarding their residual mammalian toxicity in agricultural products. Benomyl-thiram mixture, thiophanate methyl-;hiram mixture and TCMB have now been registered as seed disinfectants for the use of rice blast, brown spot and Bakanae disease. Oxathiinsthiram mixture has been registered as seed disinfectant for barley and wheat loose smut and leaf stripe of barley. Agricultural techniques have made such rapid progress that the nursery methods changed from the use of paddy nursery to box nursery designed for machine-transplanting. The spread of rice transplanting machines has caused increase of seedborne diseases. Among seedborne diseases, Bakanae disease has remarkably increased and causes much damage recently. In order to counter this trend, seed disinfectants must also be diversified. First, effective non-selective disinfectants need to be developed, and second, appropriate control methods always need to be prepared in parallel with the development of new techniques for cultivation.

• 한국산업보건학회지
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• 제1권1호
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• pp.16-28
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• 1991

A study on comparison of standard charcoal tube method, infrared gas analyzer, and detector tube method were conducted. Measurements were performed simultaneously at same sampling points in an air chamber containing benzene, toluene and xylene vapors. Charcoal tube samles were collected at sampling flowrates of 0.05, 0.2, 0.5, and 1.0 1pm. Results are as follows : 1. Coefficients of variation of results with charcoal tube method for bezene, toluene and xylene mixture vapor were 14.34 % in benzene(0.28-11.12 ppm), 9.20 % in toluene (2.68-135.09 ppm) and 10.21 % in xylene (2.56-82.64 ppm), respectively. 2. Results of infrared gas analyzer in mixture air were non-specific on benzene and toluene. Ratio of results of infrared gas analyzer to those of charcoal tube on benzene, toluene and xylene were 696.4 %, 30.3 % and 36.6 %, respectively. 3. Ratio of responses of detector tubes to those of charcoal tube were 49.4 % in benzene, 22.1 % in toluene and 223.9 % in xylene. Xylene detector tube were interfered by toluene greately. 4. Collection efficiencies of charcoal tubes at low concentraton(benzene : 1 ppm, toluene : 10 ppm, xylene : 10 ppm) were stable on various flowrate from 0.05 to 1.0 1pm, but at high concentrations the efficiency decreased at high flowrate above 0.5 1pm. 5. Within the saturation capacity of charcoal, collection effiency decreased at 0.5-1.0 1pm. Smpling feowrates of 0.05-0.20 1pm were appropriate for sampling organic vapors.

• 한국환경과학회지
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• 제27권9호
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• pp.737-742
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• 2018

Livestock manure treatments have become a more serious problem because massive environmental pollutions such as green and red tides caused by non-point pollution sources from livestock manures have emerged as a serious social issue. In addition, more food wastes are being produced due to population growth and increased income level. Since the London Convention has banned the ocean dumping of wastes, some other waste treatment methods for land disposal had to be developed and applied. At the same time, researches have been conducted to develop alternative energy sources from various types of wastes. As a result, anaerobic digestion as a waste treatment method has become an attractive solution. In this study has three objectives: first, to identify the physical properties of the mixture of livestock wastewater and food waste when combining food waste treatment with the conventional livestock manure treatment based on anaerobic mesophilic digestion; second, to find the ideal ratio of waste mixture that could maximize the collection efficiency of methane ($CH_4$) from the anaerobic digestion process; and third, to promote $CH_4$ production by comparing the biodegradability. As a result of comparing the reactors R1, R2, and R3, each containing a mixture of food waste and livestock manure at the ratio of 5:5, 7:3, and 3:7, respectively, R2 showed the optimum treatment efficiencies for the removal of Total Solids (TS) and Volatile Solids (VS), $CH_4$ production, and biodegradability.

• 한국자동차공학회논문집
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• 제13권5호
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• pp.82-89
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• 2005

This study was performed to investigate the behavior and spatial distribution of fuel mixtures with different wall angle and diameter of piston cavity in a DI gasoline engine. The spatial distribution of fuel mixtures after impingement of the spray against a piston cavity is one of the most important. factors for the stratification of fuel mixture. Thus, it is informative to understand in detail the behavior and spatial distribution of fuel mixtures after impingement in the cavity. Two dimensional spray fluorescence images of liquid and vapor phase were acquired to analyze the behavior and distribution of fuel mixtures inside cylinder by exciplex fluorescence method. The exciplex system of fluorobenzene/DEMA in non-fluorescing base fuel of hexane was employed. Cavity wall angle was defined as an exterior angle of piston cavity. Wall angles of the piston cavity were set to 30, 60 and 90 degrees, respectively. The spray impinges on the cavity and diffuses along the cavity wall by its momentum. In the case of 30 degrees, the rolling-up moved from the impinging location to the round and fuel-rich mixture distributed at periphery of cylinder. In the case of 60 and 90 degrees, the rolling-up recircurated in the cavity and fuel mixtures concentrated at center region. High concentrated fuel vapor phase was observed in the cavity with 90 degrees. From. present study, it was found that the desirable cavity wall angle with cavity diameter for stratification in a Dl gasoline engine was demonstrated.