Earticle

본 연구는 일회용 종이컵의 대안으로 관공서 업무환경에 도입된 다회용컵의 환경영향 저감효과를 분석하였다. ISO 14044 표준 절차에 따라, 1회 대여-반납-세척 사이클을 연구의 기능단위로 설정하여 요람에서 무덤까지(Cradle-to-Grave) 전과정평가(LCA)를 수행하였다. 다회용컵 생산 업체와 세척 서비스 제공업체로부터 데이터를 수집하고, 유틸리티(전력, 용수) 사용량에 대하여서는 경제적 할당을 수행하였다. EDP2013 방법을 사용하여 6가지 영향 범주를 평가한 결과, 세척 중 물 사용량은 지구온난화, 자원고갈, 산성화, 부영양화의 주요 원인으로 나타났으며, 오존층영향은 세제의 생산, 광화학스모그는 폴리프로필렌 생산으로 인한 환경영향이 높았다. 이를 일회용 종이컵 사용과 비교했을 때, 다회용컵 1회 사용은 4가지 범주에서 더 높은 환경 부담을 유발했지만, 오존층영향과 광화학스모그에서는 감소했다. 이는 다회용컵 사용에서 환경영향 저감효과를 얻기 위해서는 4-5개의 종이컵 사용 대체가 필요하며, 다회용컵의 환경적 이점이 충분한 재사용 횟수와 세척 시스템의 효율에 달려 있음을 의미한다. 그리고 이를 관공서 업무 환경에 적용하기 위해서는 다회용컵 관리 과정에서 소모되는 물과 에너지 사용에 대한 고려가 반드시 이루어져야만 정책의 지속 가능성을 확보하는 데 매우 중요함을 시사한다.

This study evaluates the environmental performance of reusable cups introduced in public offices as an alternative to single-use paper cups. A cradle-to-grave Life Cycle Assessment (LCA), following ISO 14044, was conducted using a functional unit of one rent–return–wash cycle. Data were collected from a reusable cup manufacturer and a washing service provider, with utilities allocated economically. Six impact categories were assessed under the EDP2013 method. Findings reveal that water use during washing dominated global warming, resource depletion, acidification, and eutrophication, while ozone depletion was driven by detergents and photochemical smog by polypropylene production. Compared with one-time paper cup use, a single reusable cycle produced higher burdens in four categories but reduced ozone depletion and smog formation. Break-even analysis showed that four to five paper cups must be displaced before net environmental benefits occur. The results highlight that environmental advantages of reusable cups depend on high reuse frequency and efficient washing systems. For public agencies, improving water- and energy-use efficiency in washing is critical to realizing the intended sustainability gains.

Ultrasonic wave is usually used to wash the glasses. This investigation is based on curiosity about the efficiency of ultrasonic wave in washing fabrics. General washing and ultrasonic wave washing are compared to check which one is more practicable. Next, we compared washing efficiency by changing the various parameters, which are temperature, types of fabric, and types of pollutant. The best condition for the ultrasonic wave washing was figured out. From the comparison, we suggest polyester+ hydrophile property pollutant +70°C water is the best condition for ultrasonic wave washing for fabric.

본 연구에서는 주로 결정질 산화물(fraction 4)과 잔류상(fraction 5) 형태로 존재하는 비소 오염 토양에 대해 효과적인 정화 방법을 설계하기 위해 물리적 선별과 토양세척공법에 대한 효율성을 평가하였다. 자력 선별을 적용한 결과, fraction 5 형태의 비소가 효과적으로 제거되었으며, 자력의 세기가 높을수록 좋은 효과를 보였다. 부유 선별에서는 P.E.X 포수제가 P.A.X 포수제 보다 높은 제거효율을 보였으나, 투입되는 포수제의 양에서는 효율 차이가 크지 않았다. 토양세척에서는 옥살산과 디씨오나이트를 혼합한 세척액이 가장 효과적이었으며, fraction 5에서 높은 효율을 보인 아스코빅산을 추가한 단계적 세척을 통해 최대 61.4%의 비소 제거율을 달성할 수 있었다. 이러한 연구결과는 향후 fraction 4와 5 형태로 존재하는 비소 오염 토양에서 최적의 정화공법을 설계하기 위한기초자료로 활용될 수 있을 것으로 판단된다.

In this study, the efficiency of physical screening and soil washing methods was evaluated to assess the effective remediation of arsenic (As)-contaminated soils, which mainly exist in the form of crystalline oxides (fraction 4) and the residual phase (fraction 5). The results showed that magnetic separation effectively removed the As in fraction 5, and the stronger the magnetic force, the better the effect. In the flotation separation method, the potassium ethyl xanthate (PEX) collectors showed a higher removal efficiency than the potassium amyl xanthate (PAX) collectors, with the amount used exerting a minimal impact. In soil washing, a mixture of oxalic acid and dithionite was the most effective, and As removal rates of up to 61.4% were achieved by cascade washing with the addition of ascorbic acid, which was highly efficient in removing fraction 5. These results provide a foundation for designing optimal remediation processes for As-contaminated soils, especially those dominated by fractions 4 and 5.

The global power generation industry is becoming a key power generation industry with gas power generation and renewable energy solar power generation. This research aims to focus on solving two problems as a method to improve the solar light collection efficiency among fixed variable deformation methods. Maintaining the proper temperature of the water injection device through automatic temperature detection to solve efficiency degradation, and establishing an automatic operation system by finding the optimal angle for each season, are intended to derive a value that can represent the optimal power generation.

In this paper, internal and external flow analysis of nozzle for a automatic bike washing machine was performed using Ansys Fluent, by varying nozzle injection pressure and angle. The pressure and velocity distributions generated at the nozzle outlet from internal flow analysis were applied for inlet condition of the external flow analysis of the nozzle. As a criterion for the cleaning efficiency, the shear stress condition provided by EHEDG[5] was used and an area of shear stress of 3 Pa or more according to the spray angle and pressure was compared. It is expected that the results of this paper will be applied to the development of automatic contactless bike washing nozzle.

Concentrated flux interior permanent magnet (CFIPM) motors have the advantage that their utilization of flux linkage is more efficient than that of general IPM motors and CFIPM motors are suitable for washing machine motors, which demand low-speed, high-torque specifications. However, low efficiency occurs in the low-speed high-torque mode considering the high-speed operation for spin mode. This paper proposes a magnet overhang structure between the rotor core that reduces leakage flux and improves efficiency for a CFIPM in wash mode. Optimization of the 3D design of magnet overhang structures is performed to improve the efficiency with the same quantity of permanent magnets. The validity of the optimal design is experimentally verified through the fabrication of prototypes.

본 연구는 표면 세척 시스템을 이용하여 유자의 미생물과 잔류농약 제거 효과를 살펴보았다. 선행 연구로 오징어 먹물을 제거 효과를 보기 위해 스프레이 회전 속도 0.11, 0.42, 0.73 m/s, 수압 0.6, 0.9, 1.2 MPa과 컨베이어 속도 0.046, 0.092, 0.138 m/s 으로 세척 조건을 달리하였다. 오징어 먹물 제거 실험 결과 먹물 제거 효율은 컨베이어 속도와 분사 노즐 회전수와는 높은 상관관계를 나타내었으며 수압의 조건에서는 반응표면 분석 결과 0.9 MPa에서 가장 제거율이 높게 분석되었다. 이에 미생물과 잔류농약 제거률 실험의 위해 세척 조건으로 수압을 0.9 MPa로 고정하였으며 스프레이 회전 속도(0.11, 0.42, 0.73 m/s)와 컨베이어 속도(0.046, 0.092, 0.138 m/s)를 달리하여 수행하였다. 미생물은 컨베이어 속도 2.76 m/min 일 때 스프레이 회전속도 0.43과 0.73 m/s에서 각각 2.20, 2.05 log CFU/g 수준 감소하여 가장 높은 감소율을 나타내었다. 또한 스프레이 회전속도 0.11 m/s와 컨베이어 속도 0.138 m/min을 제외한 모든 처리구의 미생물 제거효과는 수도수 처리보다 높았다. 잔류농약 실험 결과 컨베이어 속도가 느릴수록, 분사노즐 회전수가 많을수록 제거효과가 높았으나 spirodichlofen, deltamethrin, benomyl, thiophanate-methyl과 acequinocyl 의 경우 컨베이어 속도 0.046 m/s에서 분사노즐 0.42 m/s이상에서 처리구들 간에 유의적인 차이를 보이지 않았다. Benomyl과 thiophanate-methyl 의 잔류 농약은 컨베이어 속도 0.092 m/s 이하의 조건에서 90% 이상 제거되었다. 이상의 결과에서 표면 세척 시스템의 조건을 컨베이어 속도 0.092 m/min 이하, 노즐 회전수 0.043 m/s 이상에서 세척 시 유자의 미생물과 잔류농약을 효율적으로 제거할 수 있을 것으로 판단된다.

This study was conducted to assess the effects of the removal of pesticide residues and microorganisms from yuja (Citrus junos Sieb ex Tanaka) using a surface-washing system, under the following washing conditions: 0.11, 0.42, and 0.73 m/s spray rotation speeds; 0.6, 0.9, and 1.2 MPa water pressure and 0.046, 0.092, and 0.138 m/s conveying speeds. Tap-water treatment was used as the control. The washing efficiency when using squid ink was highly correlated with the conveying speed and the spray rotation speed. In addition, the highest washing efficiency was achieved when the water pressure was 0.9 MPa. The microorganisms were reduced to 0.40 log CFU/g for the tap-water treatment, and all the treatments, except those at the conveying speed of 0.138 m/s and the spray rotation speed of 0.11 rpm (6.07 log CFU/g), produced higher removal efficiencies compared with the tap-water treatment. Reductions of 2.20 and 2.05 log CFU/g were achieved at the spray rotation speeds of 0.42 and 0.73, respectively. The largest reductions were observed when the conveying speed was 0.046 m/s. Higher pesticide residue removal efficiency values were obtained at slower conveying speeds and higher spray rotation speeds. Higher than 50% removal efficiency was achieved when the spray rotation speed was 0.046 m/s for spirodichlofen, deltamethrin, benomyl, thiophanate-methyl, and acequinocyl. Especially, the removal efficiency for benomyl and thiophanate-methyl was more than 90%. It can thus be concluded that the pesticide residues in yuja can be effectively reduced by washing the latter with a less-than-0.092-m/s conveying speed and a higher-than-0.42-m/s spray rotation speed.

In typical remediation practices, separate washing systems have to be applied to clean up the soils contaminated with both oil and heavy metals. In this study, we evaluated the efficiency of successive two-stage soil washing in removal of mixed-contaminants from soil matrix. Two-stage soil washing experiments were conducted using different combinations of chemical agent: 1) persulfate oxidation, followed by organic acid washing, and 2) Fenton oxidation, followed by inorganic acid washing. Persulfate oxidation-organic acid washing efficiently removed both organic and inorganic contaminants to meet the regulatory soil quality standard. The average removal rates of total petroleum hydrocarbons (TPH), Cu, Pb, and Zn were 88.9%, 82.2%, 77.5%, and 66.3% respectively, (S/L 1:10, reaction time 1 h, persulfate 0.5 M, persulfate:activator 3:1, citric acid 2 M). Fenton oxidation-inorganic acid washing also gave satisfactory performances to give 89%, 80.9%, 87.1%, and 67.7% removal of TPH, Cu, Pb, and Zn, respectively (S/L 1:10, reaction time 1 hr, hydrogen peroxide 0.3 M, hydrogen peroxide:activator 5:1, inorganic acid 1 M).

Backwashing is an important process for the efficient operation of granular filters, and the efficiency of the surface washing among the backwashing processes can affect the filtrations rate and filter run-time. In this study, the efficiency of surface washing is evaluated using real filters for three cases: with surface washing (with and without drainage of water to the surface of filter bed) and without surface washing. As a result, in the case of adopting both the drainage and surface washing, the filter of which condition is initially worse than those of the other filters shows improvement in head-loss development, filtration velocity, filter run-time, and total filtration volume. On the other hand, the conventional method of surface washing rarely has an effect on the filter washing.

Objectives: This study was designed to evaluate the changes in the particle filtration efficiencies of five cloth masks (4 plate types, 1 cup type) with an increasing number of machine washings and the degree of cloth expansion. Methods: NaCl aerosols were generated using an atomizer and passed through cloth masks in a dynamic aerosol chamber. Particle concentrations were measured both before and after for the cloth masks using an optical particle counter (OPC) in the size range of $0.3{\sim}10{\mu}m$. Results: In the original condition, the filtration efficiencies of the five cloth masks were A: 20.1%, B:30.9%, C: 25.0%, D: 26.5%, and E: 40.9%. As the number of washings increased in the order of one, two, and four times, the filtration efficiencies of cloth mask C increased. The filtration efficiency of A, D, and E increased after the first washing. With the exception of B, the filtration efficiency of cloth masks increased after the second washing and those of all cloth masks increased after the fourth washing. This might be caused by the fibers untangling from the yarn and being freed at one end. In this status, the packing density of the textile will not change, but the distances between fibers will increase, which might bring about an increase in filtration efficiency. When the cloth masks were extended by 10% and 20% in one direction, the filtration efficiencies of cloth masks B, D, and E decreased at 10% extension, and those of all cloth masks decreased at 20% extension. When the cloth masks were expanded by 10% and 20% in two directions, the filtration efficiencies of all cloth masks decreased by at least 34.7% at 10% extension, and by at least 60.9% at 20% extension Conclusions: The filtration efficiency of cloth masks could decrease after one to two machine washings, but will increase after four washings in comparison with their original performances. The filtration efficiency of cloth masks will decrease when they are expanded, such as when stretching over the nose during wearing status.

In soil washing, there are many variables including types of reagent and contaminant, washing time, soil-liquid ratio, washing cycles, washing agent concentrations, and etc. To identify the most influencing factors on soil washing process, regression analysis was performed for eight single variables and five combined variables. A quantitative model that employs W/H (molar ratio of washing agent to heavy metal) as a major variable was established based on the regression. The validity of the model was demonstrated by conducting lab experiments with Cu, Pb, Zn, Ni and As-contaminated soils, and various washing reagents including acetic acid, citric acid, malic acid, oxalic acid, ethylenediamine tetraacetic acid (EDTA) and nitriloacetic acid (NTA). The washing efficiencies were compared with the EDTA washing data reported in the literature. The correlation between W/H and removal efficiency was analyzed after dividing data into two groups according to the heavy metal mobility.

This study was aimed at determining the changes in heavy metal removal efficiency at different acid concentrations in a micro-nanobubble soil washing system and pickling process that is used to dispose of heavy metals. For this purpose, the initial and final heavy metal concentrations were measured to calculate the heavy metal removal efficiency 5, 10, 20, 30, 60, and 120 min into the experiment. Soil contaminated by heavy metals and extracted from 0~15 cm below the surface of a vehicle junkyard in the city of U was used in the experiment. The extracted soil was air-dried for 24 h, after which a No. 10 (2 mm) was used as a filter to remove large particles and other substances from the soil as well as to even out the samples. As for the operating conditions, the air inflow rate in the micro-nano bubble soil washing system was fixed at 2 L/min,; with the concentration of hydrogen peroxide being adjusted to 5%, 10%, or 15%. The treatment lasted 120 min. The results showed that when the concentration of hydrogen peroxide was 5%, the efficiency of Zn removal was 27.4%, whereas those of Ni and Pb were 28.7% and 22.8%, respectively. When the concentration of hydrogen peroxide was 10%, the efficiency of Zn removal was 38.7%, whereas those of Ni and Pb were 42.6% and 28.6%, respectively. When the concentration of hydrogen peroxide was 15%, the efficiency of Zn removal was 49.7%, whereas those of Ni and Pb were 57.1% and 42.6%, respectively. Therefore, the efficiency of removal of all three heavy metals was the highest when the hydrogen peroxide concentration was 15%.