An advanced online monitoring approach to study the scaling behavior in direct contact membrane distillation

Lee, Jung-Gil,Jang, Yongsun,Fortunato, Luca,Jeong, Sanghyun,Lee, Sangho,Leiknes, TorOve,Ghaffour, Noreddine Elsevier 2018 Journal of membrane science Vol.546 No.-

<P><B>Abstract</B></P> <P>One of the major challenges in membrane distillation (MD) desalination is scaling, mainly CaSO<SUB>4</SUB> and CaCO<SUB>3</SUB>. In this study, in order to achieve a better understanding and establish a strategy for controlling scaling, a detailed investigation on the MD scaling was performed by using various analytical methods, especially an in-situ monitoring technique using an optical coherence tomography (OCT) to observe the cross-sectional view on the membrane surface during operation. Different concentrations of CaSO<SUB>4</SUB>, CaCO<SUB>3</SUB>, as well as NaCl were tested separately and in different mixed feed solutions. Results showed that when CaSO<SUB>4</SUB> alone was employed in the feed solution, the mean permeate flux (MPF) has significantly dropped at lower volume concentration factor (VCF) compared to other feed solutions and this critical point was observed to be influenced by the solubility changes of CaSO<SUB>4</SUB> resulting from the various inlet feed temperatures. Although the inlet feed and permeate flow rates could contribute to the initial MPF value, the VCF, which showed a sharp MPF decline, was not affected. It was clearly observed that the scaling on the membrane surface due to crystal growth in the bulk and the deposition of aggregated crystals on the membrane surface abruptly appeared close to the critical point of VCF by using OCT observation in a real time. On the other hand, NaCl + CaSO<SUB>4</SUB> mixed feed solution resulted in a linear MPF decline as VCF increases and delayed the critical point to higher VCF values. In addition, CaCO<SUB>3</SUB> alone in feed solution did not affect the scaling, however, when CaSO<SUB>4</SUB> was added to CaCO<SUB>3</SUB>, the initial MPF decline and VCF met the critical point earlier. In summary, calcium scaling crystal formed at different conditions influenced the filtration dynamics and MD performances.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A comprehensive analysis of calcium-based scaling behavior in DCMD was investigated. </LI> <LI> OCT was employed to monitor the scaling behavior in real-time during MD operation. </LI> <LI> CaSO<SUB>4</SUB>, CaCO<SUB>3</SUB>, and NaCl were tested separately and in mixed feed solutions. </LI> <LI> CaSO4 scaling occurred by deposition of bulk crystal on the membrane surface. </LI> <LI> A critical point of VCF at which MPF decreased significantly has been observed. </LI> </UL> </P>

A Low Phase Noise Injection-Locked Programmable Reference Clock Multiplier With a Two-Phase PVT-Calibrator for <tex> $\Delta\Sigma$</tex> PLLs

Lee, Yongsun,Kim, Mina,Seong, Taeho,Choi, Jaehyouk IEEE 2015 IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS PART 1 R Vol.62 No.3

<P>A low phase noise injection-locked reference clock multiplier that can suppress the delta-sigma <TEX>$(\Delta\Sigma)$</TEX> noise of <TEX>$\Delta\Sigma$</TEX> phase-locked loops (PLLs) is proposed. By adopting a two-phase PVT-calibrator that switches the calibration resolution, the clock multiplier can reduce the frequency-acquisition time, as well as tightly regulate the real-time degradation of the phase noise. To improve the performance of the calibration method utilizing two identical oscillators, the self-injection pulse generator that balances the loadings of two oscillators is proposed. In addition, this work presents a systematic design methodology that minimizes the degradation of the phase noise over the PVT variations, based on the phase noise analysis of injection-locking. The clock multiplier was designed with the prototype <TEX>$\Delta\Sigma$</TEX> PLL in the 65-nm CMOS process. It can provide five reference frequencies, i.e., 19.2, 28.8, 48, 57.6, and 96 MHz. The phase noise of the 96-MHz signal was <TEX>$-$</TEX>130.0 and <TEX>$-$</TEX>131.8 dBc/Hz at 100 kHz and 1 MHz offsets, respectively; the performance of low phase noise was confirmed over temperature variations. The total active area was 0.062 mm2, and the power consumption was 1.6–1.9 mW. By switching the reference frequency from 19.2 to 96 MHz, the phase noise of the prototype PLL at the 10-MHz offset from the 4.4-GHz signal was improved from <TEX>$-$</TEX>120.1 to <TEX>$-$</TEX>138.6 dBc/Hz.</P>

A Low-Jitter and Low-Reference-Spur Ring-VCO-Based Switched-Loop Filter PLL Using a Fast Phase-Error Correction Technique

Lee, Yongsun,Seong, Taeho,Yoo, Seyeon,Choi, Jaehyouk IEEE 2018 IEEE journal of solid-state circuits Vol.53 No.4

<P>A low-jitter and low-reference-spur ring-type voltage-controlled oscillator (VCO)-based switched-loop filter (SLF) phase-locked loop (PLL) is presented. To enhance the capability of suppressing jitter of a VCO, we propose a fast phase-error correction (FPEC) technique that emulates the phase-realignment mechanism of an injection-locked clock multiplier. By the proposed FPEC technique, accumulated jitter of a VCO can be removed intensively in a short interval, thereby suppressing jitter dramatically. Based on a PLL topology having an intrinsic integrator in a VCO, the proposed architecture can also achieve a low reference spur despite a high multiplication factor (i.e., 64). This paper also presents the selective frequency-tuning technique used in the VCO that helps the proposed architecture further suppress the level of reference spur. The proposed PLL was fabricated in a 65-nm CMOS process. The measured rms jitter integrated from 1 kHz to 80 MHz and the reference spur of the output signal with a 3.008-GHz frequency were 357 fs and −71 dBc, respectively. The total active area was 0.047 mm<SUP>2</SUP>, and the power consumption was 4.6 mW.</P>

중소 식품업체의 안정적 성장을 위한 정책과제

이용선(Lee Yongsun),박미성(Park Misung),한정훈(Han Junghoon) 한국농촌경제연구원 2019 한국농촌경제연구원 기본연구보고서 Vol.- No.-

시간 기반의 활동 유사성 중심의 온라인 관계 형성에 관한 연구 : 은둔형 외톨이의 대인관계 개선을 중심으로

임용선(Yongsun Im),오예슬(Yeseul Oh),이라희(Lahee Lee),이영인(Youngin Lee),이혜윤(Hyeyoon Lee),박수이(Sue Park) 한국HCI학회 2011 한국HCI학회 학술대회 Vol.2011 No.1

채소 계약재배 활성화 방안

이용선(Lee Yongsun),송성환(Song Sunghwan),이형용(Lee Hyungyong),박지원(Park Jiwon) 한국농촌경제연구원 2015 한국농촌경제연구원 기본연구보고서 Vol.- No.-

토마스 리베라 작품에 나타난 치카노 이미지 연구

이용선 ( Lee Yongsun ) 한국스페인어문학회 2016 스페인어문학 Vol.0 No.80

Tomas Rivera started working in the fields located in the southwest of the United States from his childhood as coming along with his parents who had immigrated to Texas from Mexico. He earned a living by picking crops. The novel "...And the Earth Did Not Devour Him" was based on the experiences of migrant farm workers. This novel was published while the Chicano Movement was at the peak and contributed reinvigorate the Chicano spirit against the white supremacy in the United States. It acted as a literary protest against racial, socio-economic discrimination and political injustice. The objective of this study is to analyze the anecdotes related to migrant Chicano and to specify the Chicano images reflected in this novel. Due to their migratory life, the characters in the novel suffer from insecurity; they could not enjoy a home that gives them both economic and emotional stability. In summary, this novel documents the struggle of the minority Chicano, who was neglected and exploited while resisting the dominance culture by Anglo who exploits the labor of people. Also, it shows us the importance of the Chicano culture and Catholic religion that contain many critical important aspects derived from the Mexican life. This work became a land-mark in the Mexican American community`s search for identity.

농업·농촌·식품산업의 미래 비전과 지역발전 전략

이용선(Lee Yongsun),박미성(Park Mi-seong),한석호(Han Sukho),문한필(Moon Hanpil),박한울(Park Hanul),박지원(Park jiwon),박성진(Park Seongjin),정도채(Jung Dochae),정대희(Chung Daehee),강마야,김윤식,한재환 한국농촌경제연구원 2016 한국농촌경제연구원 정책연구보고서 Vol.- No.-

2014년 쌀 관세화 전환에 이어 2015년에는 한·중 FTA 체결로 미국, EU, 중국 등 주요국과의 자유무역협정이 대부분 이루어져 농업분야의 시장개방이 일단락된 것으로 평가된다. 이 연구는 완전개방시대에 처한 한국 농업·농촌·식품산업의 미래 비전을 정립하고 분야별 발전과제와 지역 발전방향을 제시하기 위해 수행되었다. 이 연구를 위해 선행연구 결과와 전문가 포럼 운영 결과 등을 바탕으로 농업·농촌·식품산업의 미래 환경에 대한 SWOT 분석을 실시하고 비전과 발전과제들을 도출하였다. 농업·농촌 관련 지표의 20년간 전망치 산출을 위해 한국농촌경제연구원의 농업전망모형인 KREI-KASMO를 이용하였다. 미래 비전과 과제의 우선순위를 분석하기 위해 전문가 심층조사를 실시하고 AHP(계층의사법)를 사용하였다. 지역의 발전방향을 도출하기 위해 3개 권역의 대학과 연구소에 연구를 위탁하였다. 농업·농촌·식품산업의 20년 후 미래 비전을 ‘지속가능한 농식품 산업과 살고 싶은 농촌’으로 설정하였다. 분야별 발전방향 중 ‘안전한 농식품의 안정적 공급’이 ‘미래성장산업화’, ‘국토환경보전과 농업·농촌의 다원적 기능 극대화’, ‘도농격차 해소와 살고 싶은 농촌 건설’ 등의 방향보다 우선되는 것으로 나타났다. 이는 국민의식 조사 결과와도 일치하는 것으로 정부의 정책 방향도 안전한 먹거리의 안정적 공급시스템 구축을 최우선 순위로 두어야 함을 의미한다. 농업·농촌·식품산업의 미래 비전을 달성하기 위한 분야별 과제로서 농업 선도 주체 및 인력 양성, 안전한 농축산물 관리체계 구축, 농촌 일자리 창출 전략이 중요도 측면과 시급성 측면 모두에서 우선되는 것으로 분석되었다. 따라서 정부도 향후 농업을 주도적으로 이끌어갈 경영체 육성을 비롯한 안전 관리 체계의 구축과 농촌지역의 일자리 창출을 최우선 과제로 삼아야 한다. 지역 발전 방향으로 충남 지역은 먹거리를 중심으로 한 지역순환 농식품 체계 구축 계획을 수립해야 한다. 특히 기존 정책과 사업, 주체, 부문과 영역을 연결하기 위해 독립적인 위원회에 의한 거버넌스 기능이 강화되어야 한다. 거버넌스 기능을 수행하려면 역량 강화가 중요하며 이를 위해서는 교육 활동을 강화해야 한다. 전남지역의 농업 발전을 위해서는 친환경 농업을 내실화함으로써 경제적·환경적·안전한 농식품을 주도하는 전략이 주효하다. 친환경 농업을 내실화하기 위해서는 농가의 실천 의지와 책임 의식 고양을 위한 교육 강화와 인재 육성, 유기농 농업 기술의 개발과 현장 보급·지원체계가 강화되어야 한다. 경남지역 농가는 아열대 과일·채소 등 새로운 품목 도입에 적극적인데, 지역혁신체계 구축을 통해 발전을 도모해야 한다. 지역 농정과 전문 지식 및 인력을 갖춘 대학·연구소와의 긴밀한 협력을 통해 연구 확산 활동이 현장과 밀착되면 지역 혁신의 결과를 가져올 수 있다. With rice tariffication in 2014 and the signing of the Korea-China FTA in 2015, Korea concluded free trade agreements with most major countries including the US, the EU, and China, finishing one stage of the agricultural sector’s market opening. In an era of full market opening, this study aimed to establish a vision of the future of Korea’s agriculture, rural communities, and food industry and present each field’s tasks for development and regional development strategies. For this research, we conducted a SWOT analysis of the future environment of agriculture, rural areas, and the food industry based on the results of previous studies and the expert forum, and derived the vision and tasks for development. We utilized KREI-KASMO, the Korea Rural Economic Institute’s agricultural outlook model to calculate the estimates of indices for 20 years related to farming and rural regions. To analyze the order of priority of the tasks and the vision, we carried out in-depth expert research and employed AHP. To draw regional development strategies, we commissioned a study to universities and research institutes in three areas. We set the following vision of the future of agriculture, rural communities, and the food industry in 20 years: “the sustainable agri-food industry and livable rural areas.” Among the directions for development of each field, “stable supply of safe agri-food” took priority over “future growth industrialization of agriculture,” “environment conservation and maximization of multifunctionality of farming and rural regions,” and “a reduction in the urban-rural gap and the creation of livable rural communities.” This accords with the public opinion survey results, implying that the government policy direction should put top priority on constructing a stable supply system of safe food. As tasks by field for achieving the vision of agriculture, rural areas, and the food industry, training leading agricultural players and human resources, establishing a management system of safe agricultural and livestock products, and creating rural jobs were given priority in terms of both importance and urgency. Therefore, the government should also place top priority on nurturing enterprises that will lead future agriculture, building the safety control system, and creating jobs in rural regions. For regional development strategies, Chungcheongnam-do should set up a food-centered plan to construct a regional circulation system of agri-food, and should strengthen an independent committee’s governance function to link existing policies and projects, agents, sectors and fields. For the function of governance, capacity building is important and educational activities for it need to be reinforced. For Jeollanam-do’s agricultural development, it will be effective to pursue a strategy for safe, economic, and eco-friendly agro-food by promoting environment-friendly farming. To strengthen environmentally friendly agriculture, it is necessary to reinforce education for enhancing farmers’ will to practice and sense of responsibility, nurture talents, and improve a system for developing and disseminating organic farming technologies. The farms in Gyeongsangnam-do are actively cultivating new items such as subtropical fruit and vegetables. This province needs to pursue its development by building a regional innovation system. Regional innovation can result from research dissemination in the field through close cooperation between local agricultural policy and universities and research institutes with expertise and human resources.

청탁금지법 시행에 따른 농식품 분야 영향과 정책 패러다임 전환

이용선(Lee Yongsun),민경택(Min Kyungtaek),박성진(Park Seongjin),이형우(Lee Hyungwoo),박한울(Park Hanul),변승연(Byun Seungyeon) 한국농촌경제연구원 2017 한국농촌경제연구원 정책연구보고서 Vol.- No.-

스페인과 영국의 아메리카식민지정책 비교 연구

이용선 ( Yongsun Lee ) 한국스페인어문학회 2015 스페인어문학 Vol.0 No.76

Principalmente en los siglos XVi y XVii, los paises europeos como Espana, Portugal, inglaterra y Francia dominaron la mayor parte de America y empezaron a desplegar su colonialismo. A pesar del colonialismo emprendido en el mismo continente al tiempo sincronico por los paises europeos, el resultado despues del termino del colonialismo se distinguio por la presencia tan desemejante entre los paises colonizados. Aqui podemos poner en relieve la influencia sumamente importante de las politicas coloniales desarrolladas en esta zona. El objetivo de este estudio es analizar las politicas coloniales de Espana e inglaterra hacia America y verificar el efecto del sistema colonial y entender la situacion actual derivada de los hechos historicos. En el caso de Espana, se inicio un nuevo hito en 1492 por la propuesta hecha por Cristobal Colon a buscar nuevas rutas para el comercio de especies y por la llegada a tierras americanas. America se convirtio en el foco principal de la politica expansionista impulsada por la corona. Toneladas de plata y oro se llevaron del nuevo continente. Consecuentemente, Espana se convirtio en una de las naciones mas poderosas del mundo. El encuentro de dos mundos diferentes bajo el dominio de un sistema colonial trajo consigo una serie de problemas, abusos y cambios radicales para los pueblos colonizados. y por ende su destruccion. En el caso de inglaterra, el avance del colonialismo en America tardo un poco por la situacion politica interna, pero despues de la victoria contra la Armada invencible de Espana se desplego activamente el colonialismo. La expectativa de encontrar el oro y manipular la mano de obra indigena como Espana no se cumplio en su zona colonizada y la unica manera de consolidar su colonia en America es su propio sudor. La circunstacia no tan favorable les obligo a los colonos buscar su propio modo de ser. Ademas los colonos de inglaterra entraron en America para encontrar un nuevo terreno que puediera ser mas aclimatado y esta mentalidad contribuyo a formar la politica colonal del tipo ‘asentamiento’. A diferencia de inglaterra, Espana desarrollo la politica colonial del tipo ‘explotacion’ puesto que la circunstancia era favorable para maximazar la ganancia por la abundancia de oro y plata bajo el yugo de la mano de obra indigena. Estas politicas coloniales tan diferentes dejaron dos resultados: un pais fuerte como Estados Unidos y los paises que siguen luchando para seguir adelante.