• 한국물환경학회지
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• 제20권6호
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• pp.652-656
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• 2004

Both surface wash and backwash are considered as one of the most important methods that can improve the filtration efficiency in the existing water treatment plant. This study has mainly focused on the improvement of filtering efficiency by controlling surface wash and backwash time, and water level before backwash (when drained up to the trough, when drained up to 10 cm above filter bed, and when drained below 10 cm filter bed). Filtration efficiency was shown a little bit of differences depending on the operating conditions like surface wash injection pressure, the distance control between filter bed and the facility, and the types of surface wash. When the water level before backwash was reached up to 10 cm below filter bed after draining, however, the filtration velocity and the turbidity removal efficiency in the filter bed was improved. When the surface wash followed by backwash is longer, it showed a similar result. Because the proper adjustment of surface washing time makes filtration efficiency higher, therefore, it is necessary to set up the backwash time moderately.

• 한국염색가공학회지
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• 제11권6호
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• pp.24-35
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• 1999

This study was carried out to investigate the changes of surface characteristics of polyester fabrics on the deposition and the removal of oily soils from polyester fabrics in detergency, The relations between the removal of soil and the changes of surface properties of polyester fabrics treated with water- and oil-repellent agents were discussed before and after various wash cycles. Two kinds of fluoropolymers were selected as water-and oil-repellent finishing agents. The effects of water- and oil-repellent finishes were determined by the water repellency and oil repellency. The surface properties of untreated and treated polyester fabrics were evaluated with respect to contact angle and wicking time. The treatment of polyester fabrics with fluoropolymers improved efficiently water repellency, oil repellency, contact angle and wicking time. But those properties were greatly decreased after 3 times of wash cycles in detergency The deposition of oily soils on the untreated fabrics was drastically increased with increasing of wash cycles. The deposition and the removal of oily soils from fabrics treated with fluoropolymer having hydrophobic components were very low after various wash cycles. The deposition and the removal of oily soils on the fabrics treated with fluoropolymer having hydrophilic components were high comparatively after various wash cycles. Even though the surface properties of treated fabrics were greatly decreased with the increasing of wash cycles, the remains of oily soils on the fabrics were lower than those of untreated fabrics in various wash cycles. But the remains of soils were drastically increased after 10 times of wash cycles in any cases.

• 대한치과보철학회지
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• 제49권2호
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• pp.138-144
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• 2011

연구 목적: 본 연구는 최근 개발된 알칼리 이온수 e-WASH의 의치에 부착된 미생물 의치세정 효과에 대해 위상차현미경을 이용한 미생물 관찰법을 통하여 알아보고자 하였다. 연구 재료 및 방법: 실험군 41개, 대조군 26개의 의치를 무작위로 선정하여 실험군에서는 알칼리 이온수e-WASH로, 대조군에서는 수돗물에 5분간 침지 전, 후 의치 내면의 치면세균막을 채취하였다. 위상차현미경으로 구강미생물의 형태적, 종류별 양과 운동성에 대하여 세정 전, 후별 구강미생물의 상태를 관찰하였다. 결과: 1. 알칼리 이온수 e-WASH로 의치를 세정한 실험군에서는 세정 전보다 세정 후 구균의 양, 간균의 양, 간균의 운동성, 실사균의 양, 실사균의 운동성, 콤마/나선균의 양, 콤마/나선균의 운동성 등 모든 조사항목에서 감소하였다 (P<.05). 한편 대조군에서는 구균의 양은 감소하였으나 (P<.05), 다른 조사항목에서는 모두 세정 전, 후 간에 차이가 없었다. 2. 알칼리 이온수e-WASH로 의치를 세정한 실험군에서는 구균의 양, 간균의 양, 간균의 운동성, 실사균의 양, 실사균의 운동성, 콤마/나선균의 양, 콤마/나선균의 운동성 등 모든 조사항목에서 수돗물로 의치를 세정한 대조군보다 각 구강미생물의 양과 운동성이 적게 나타났다 (P<.05). 결론: 위의 결과를 통해 알칼리 이온수 e-WASH가 의치표면의 각종 미생물의 양과 운동성을 효과적으로 감소시키므로 의치세정제로 추천된다.

• Fibers and Polymers
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• 제4권3호
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• pp.124-128
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• 2003

Dark brown Alpaca fiber was reduced in shade via selective bleaching with peroxide. Two selective oxidative bleaching methods were tested on alpaca top to assess their effectiveness for color removal and fiber quality properties. Color change, bundle strength, weight loss, fiber diameter, surface modification, dye-ability and dye wash fastness were assessed for both methods and compared with the original brown top. Bleach method 1 (BL-I) showed little surface modification, 5.8% weight loss and 2.4% strength loss. D1925 yellowness index was reduced to 74.3 from 83.1 and provided a good base for the dyeing of medium to deep shades. Bleach method 2 (BL-II) displayed considerable surface modification, 7.8% weight loss and 18% strength loss. BL-II also resulted in a mean diameter reduction of 1.9 micron during bleaching. Yellowness was reduced to 64.5 from 83.1 and provided a very good base for the dyeing of medium to deep shades. BL-I showed better exhaustion of the premetallised dye Lanaset Violet B than BL-II. Wash fastness for BL-II was 1 grey scale unit poorer than BL-I. BL-II showed far better color clarity at pale depths however the wash fastness of the finished product was not good enough to maintain the depth or clarity of the color. BL-I showed poorer clarity of color but exhibited better wash fastness results.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.357-360
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• 2006

In the present study, the air jet flow characteristics of the dryer in the automatic car wash machine were numerically predicted by commercial CFD code. The effects of the dryer shape and the nozzle width variations on the performance of the automatic car wash machine were discussed. To optimize the geometric parameters, the response surface method(RSM) with CFD was used. Predicted jet velocity distributions for the optimized geometry were compared with experimental data and the comparisons show generally good agreements. Also, the performance of the dryer was improved with the optimized results.

• Asian Journal of Atmospheric Environment
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• 제7권1호
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• pp.1-7
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• 2013

To establish the method for investigating the behavior of aerosol particles deposited on the leaf surface against fog water under natural conditions, scanning electron microscopy with energy-dispersive X-ray (SEM-EDX) analysis and wash water analysis by ion chromatography after the washing treatment were performed using leaves of white birch collected from low part of the tree crown and the top of the tree in Sapporo City, Hokkaido, northern Japan. Each of collected leaves was divided into two parts according to the treatment performed: leaf surface (adaxial side) was 1) untreated, and 2) washed with deionized water with a pipette. In untreated samples, many particles of various shapes, including soil particles and organic debris, were deposited on the surface. Particles containing S were found on the surface of samples collected from only low part of the tree crown. After the washing treatment, SEM-EDX analysis revealed that soil particles and particles containing S had been washed off with water, although some particles such as soil particles and organic debris still remained on the leaf surface. The major anion such as $SO{_4}^{2-}$ was detected in wash water of all samples, although the peak of S in X-ray spectra was not detected from samples collected at top of the tree. The combination of SEM-EDX analysis with wash water analysis indicated that $SO{_4}^{2-}$ was deposited on the leaf surface in dissolved state and/or in state of submicron particles. These results suggested that fog water could remove soil particles and particles containing S and $SO{_4}^{2-}$ from the leaf surfaces, but not all particles. There was no difference in sampling position in the tree crown. Our study suggested that combination with SEM-EDX analysis and wash water analysis would be effective for investigation of the behavior of particles on the leaf surface against fog water.

• 대한기계학회논문집A
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• 제21권9호
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• pp.1491-1497
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• 1997

The purpose of this research is to improve the surface roughness of cast-iron pipe porduced by the centrifugal casting. A twin-fluid atomizer of mold-wash slurry is designed for this project. New atomizer is equipped with the existing manufacturing facility to produce pipes. Cast-iron pipes (.cent.125*L3000mm) are produced and the surface roughnesses of those are analysed by UBM. The average surface roughness of new products is 6.7.mu.m while the old products of sand-resin coating method have 17.0.mu.m of average surface roughness. The surface roughness of cast-iron pipe is improved very much than before.

• 한국유체기계학회 논문집
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• 제10권5호
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• pp.34-40
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• 2007

An optimization approach is investigated for the design of new nozzle system in a automatic car wash machine. Three-dimensional computational fluid dynamics and design of experiment methods have been employed to know the mutual interaction between the nozzle shape in the automatic car wash machine and the airflow velocity distribution on the vehicle surface. The performances of air nozzle system were defined as the velocity magnitude and the uniformity of the velocity on the surface of the car. Predicted jet velocity distributions for the optimized geometry were compared with experimental data and the comparisons showed generally good agreements. Also, the performance of the dryer was improved with the optimized results.

• 보존과학연구
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• 통권24호
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• pp.81-98
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• 2003

The biodeterioration on Iksan Mireuksaji pagoda has been studied with fucus on application of K201 as a chemical treatment. Total of 39species, including 10 algae, 16 lichens, 6 mosses and 7 unidentified bacteria and fungi, were collected and identified on the surface of the pagoda. Most of them caused serious discoloration on the surface. The effectiveness and stability of K201 was examined by applying it on some part of the pagoda. A mild spraying of solution diluted to half of original reagent was good enough to eliminate all the deteriorating species on the surface. Most of discoloration disappeared after the treatment except the red color caused by iron substance. The effectiveness of the regent was compared with water wash. The stone was first washed with water and the dirt on the surface was scrubbed off from the surface. The initial surface of the stone was clearer in water wash. However, many of the deteriorating species reappear in 4 weeks after water wash. Although spraying of the reagent K201 could noteliminate all the remnant of dead organisms as good as scrubbing the surface, no deteriorating algae or lichen was observed until two month after treatment. Therefore, spraying method with chemicals seems more stable and reliable way to remove the biodeterioration than physical scrubbing of the surface.

• 청정기술
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• 제25권3호
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• pp.256-262
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• 2019

Hydroxylammonium nitrate (HAN) 기반 액상 추진제는 발암물질이 아니며 연소가스 또한 독성이 거의 없어서 환경 친화적인 추진제로 주목을 받고 있다. 추력기에서 HAN 기반 액체추진제를 분해하는데 사용되는 촉매는 저온 활성 및 고내열성을 동시에 보유하고 있어야 한다. 본 연구의 목적은 metal foam 표면에 alumina slurry를 wash coating 방법으로 담지한 후, 루테늄(ruthenium) 전구체를 그 위에 담지하여 Ru/alumina/metal foam 촉매를 제조하고, 이 촉매의 HAN 수용액 분해 활성을 평가하는 것이다. Wash coating 방법으로 metal foam 지지체에 알루미나를 담지시키는 과정에서 wash coating 반복 횟수가 alumina/metal foam의 물리적 특성에 미치는 영향을 분석하였다. 알루미나 wash coating 횟수가 증가할수록 약 7 nm의 직경을 갖는 메조기공이 지속적으로 발달하여 표면적과 기공 부피가 증가하는데, metal foam에 알루미나를 코팅하는 과정을 12 회 반복하는 것이 최적이라고 판단하였다. 이 지지체에 Ru을 담지한 Ru/alumina/metal foam 촉매의 표면에도 메조기공이 잘 발달하였다. 활성금속과 알루미나를 담지하지 않은 metal foam 자체만으로도 HAN 수용액의 분해반응을 촉진할 수 있음을 알 수 있었다. Ru/alumina/metal foam-550촉매의 경우는 열분해 반응에 비해서 분해개시온도를 큰 폭으로 낮추었고, ${\Delta}P$를 크게 증가시킬 수 있어서, HAN 수용액 분해 반응에서 우수한 활성을 보였다. 그러나 이 촉매를 $1,200^{\circ}C$에서 소성하면 반응 활성이 저하되는데 이는 촉매의 표면적과 기공 부피가 급격하게 감소하고 Ru이 소결되기 때문이다. 추가적인 연구를 통해서 Ru/alumina/metal foam의 내열성을 개선할 필요성이 있다.