• Title/Summary/Keyword: Changes of state of water

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Overfishing and recent risk for collapse of fishery in coastal Mediterranean lagoon ecosystem (Karavasta lagoon, southeastern Adriatic sea)

  • Spase Shumka;Yukio Nagahama;Sarjmir Hoxha;Koji Asano
    • Fisheries and Aquatic Sciences
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    • v.26 no.4
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    • pp.294-303
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    • 2023
  • Beside that the fish species and their sub-populations are highly important as a keystone species in the coastal and marine ecosystem, there are very few studies on their presence, distribution and temporal variations within and around the lagoon ecosystems in Albania. This paper provides an updated review on the life cycle, fishery, exploitation state and management of the main species that are subject of commercial fishing in the Karavasta lagoon, southeastern Adriatic coast of Albania. Due to the fact that lagoons represent a continuum between continental and marine aquatic ecosystems they play a crucial role in species life cycles. Further on in the circumstances of rapid utilizations and environmental changes, anomalies in salinity and temperatures, accelerated anthropogenic influences their rate of vulnerability is highly increased. Following the requirements of the Water Framework Directive, transitional water, coastal lagoons and estuaries there is a need for urgent monitoring and management approaches. The commercial species include: European eel (Anguilla anguilla), species of Family Mugilidae (Mugil cephalus, Liza ramada, Liza salienes and Chelon labrosus), Seabream (Sparus aurata), Seabass (Dincentrarchus labrax), etc. Fish productivity is oscillating from maximum value of 61.95 kg/ha is recorded in period of 1975-80 and lower value of 31 kg/ha in year 2020. Our study highlights importance of fish and fishery long-term monitoring, and contributes to understand the driving factors in productivity, migration patterns and species ecology in the vital coastal ecosystems.

Mixing Process of Double Diffusive Salt Wedge (이중확산의 영향을 받는 염수침입의 혼합과정 연구)

  • Hwang, Jin-Hwan
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.11 no.2
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    • pp.92-97
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    • 2008
  • Salt wedge into the river from the sea or fresh water flume (fresh wedge) in the ocean from the sea has density current characteristics. However, when temperature and salinity simultaneously determine the density of wedges, one of salinity and temperature can distributed in the reversed profiles against gravity, even though the density profile is stable. In this case, the double diffusive process is critical in determining mixing rate. The present work studies relative contribution of shear driven mechanical mixing component and double diffusive layering process, when warm salty denser water is introduced into the cold fresh lighter water column. Laboratory experiment releases warm salty denser water into cold fresh lighter water controlling discharge amount to achieve the steady state of density current. When longitudinal density rate becomes 15, the released amount ratio of salt and heat changes sharply and in the releasing point, vigorous mixing occurs with increase of discharged amount due to double diffusion. Double diffusion distabilizes gravitational stability and enhances the mixing rate up to $6{\times}10$ times at the lower density ratio comparing to the higher density ratio.

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Feasibility of Streaming Potential Signal on Estimation of Solute Transport Characteristics

  • Kabir, Mohammad Lutful;Ji, Sung- Hoon;Lee, Jin-Yong;Koh, Yong- Kwon
    • Journal of Soil and Groundwater Environment
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    • v.20 no.2
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    • pp.41-46
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    • 2015
  • The drag of the excess charge in an electrical double layer at the solid fluid interface due to water flow induces the streaming current, i.e., the streaming potential (SP). Here we introduce a sandbox experiment to study this hydroelectric coupling in case of a tracer test. An acrylic tank was filled up with homogeneous sand as a sand aquifer, and the upstream and downstream reservoirs were connected to the sand aquifer to control the hydraulic gradient. Under a steady-state water flow condition, a tracer test was performed in the sandbox with the help of peristaltic pump, and tracer samples were collected from the same interval of five screened wells in the sandbox. During the tracer test, SP signals resulting from the distribution of 20 nonpolarizable electrodes were measured at the top of the tank by a multichannel meter. The results showed that there were changes in the observed SP after injection of tracer, which indicated that the SP was likely to be related to the solute transport.

A Retrospective Chart Review of the Clinical Use of Euphorbia kansui Radix, Melonis Calyx (감수(甘遂), 과체(瓜蔕)의 임상활용에 관한 후향적 차트리뷰)

  • Kim, Dong-hyun;Noh, Ji-won;Jeong, Su-min;Ahn, Se-young;Ahn, Young-min;Lee, Byung-cheol;Yoo, Jung-hwa
    • The Journal of Internal Korean Medicine
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    • v.40 no.6
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    • pp.1015-1025
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    • 2019
  • Objectives: There have been many studies reporting the clinical value of Euphorbia kansui Radix or Melonis Calyx, but few systematic studies of the changes that may occur after taking such herbal medication. This study aimed to investigate the characteristics of the patient group, possible changes in blood test and InBody test results, and to discover the current state and future direction of clinical use of Euphorbia kansui Radix or Melonis Calyx. Methods: This study investigated patients who were hospitalized at Kyung-Hee University Korean Medicine Hospital for at least two days from 1 March 2016 to 1 March 2019, specifically evaluating patients aged 19 and over who underwent blood tests, including an electrolyte test and an InBody test before and after taking Euphorbia kansui Radix or Melonis Calyx. Results: Among a total of 134 patients, 72 patients (53.7%) were treated with Euphorbia kansui Radix and 62 patients (46.3%) were treated with Melonis Calyx, in the context of previously diagnosed abnormal weight gain. Laboratory findings were that Na and K levels were significantly reduced in both groups. In an InBody test, body mass index (BMI), intracellular water, extracellular water, protein, mineral, and skeletal muscle were significantly reduced in both groups. Conclusions: From these results, we suggest that, although Euphorbia kansui Radix and Melonis Calyx may not induce serious adverse effects, attention should be paid to the electrolyte level with the use of these treatments. In terms of syndrome differentiation, more clinical uses will be available in the future.

Laundering Factors in Soil Removal

  • Kadolph, Sara J.;Schofield-Tomschin, Sherryl A.;Kwon, Young-Ah
    • Fashion & Textile Research Journal
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    • v.3 no.5
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    • pp.455-465
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    • 2001
  • Assessing soil removal is of interest to the washing machine industry because of government-mandated energy savings and changes in detergent formulation and consumer laundry practices. We designed this study to examine the laundry process from a holistic perspective by integrating factors perceived to be of importance. Our purpose was to assess the impact of selected variables (fabric and soil type, wash temperature and time. detergent amount, and degree of agitation) on soil removal using accelerated laundry conditions. We used the Taguchi method to develop the research design and ANOVA to analyze the data. Although soil removal was affected by fabric type, soil type, type and amount of detergent, degree of agitation, wash time and temperature, and water hardness and volume, wash temperature was the most significant variable.

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Cognitive Dysfunction and Hippocampal Damage Induced by Hypoxic-Ischemic Brain Injury and Prolonged Febrile Convulsions in Immature Rats

  • Byeon, Jung Hye;Kim, Gun-Ha;Kim, Joo Yeon;Sun, Woong;Kim, Hyun;Eun, Baik-Lin
    • Journal of Korean Neurosurgical Society
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    • v.58 no.1
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    • pp.22-29
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    • 2015
  • Objective : Perinatal hypoxic-ischemic encephalopathy (HIE) and prolonged febrile seizures (pFS) are common neurologic problems that occur during childhood. However, there is insufficient evidence from experimental studies to conclude that pFS directly induces hippocampal injury. We studied cognitive function and histological changes in a rat model and investigated which among pFS, HIE, or a dual pathologic effect is most detrimental to the health of children. Methods : A rat model of HIE at postnatal day (PD) 7 and a pFS model at PD10 were used. Behavioral and cognitive functions were investigated by means of weekly open field tests from postnatal week (PW) 3 to PW7, and by daily testing with the Morris water maze test at PW8. Pathological changes in the hippocampus were observed in the control, pFS, HIE, and HIE+pFS groups at PW9. Results : The HIE priming group showed a seizure-prone state. The Morris water maze test revealed a decline in cognitive function in the HIE and HIE+pFS groups compared with the pFS and control groups. Additionally, the HIE and HIE+pFS groups showed significant hippocampal neuronal damage, astrogliosis, and volume loss, after maturation. The pFS alone induced minimal hippocampal neuronal damage without astrogliosis or volume loss. Conclusion : Our findings suggest that pFS alone causes no considerable memory or behavioral impairment, or cellular change. In contrast, HIE results in lasting memory impairment and neuronal damage, gliosis, and tissue loss. These findings may contribute to the understanding of the developing brain concerning conditions caused by HIE or pFS.

Experimental simulation of activity release from leaking fuel rods

  • Somfai, Barbara;Hozer, Zoltan;Nagy, Imre
    • Nuclear Engineering and Technology
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    • v.50 no.7
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    • pp.1148-1153
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    • 2018
  • The Leaking Fuel Experiment test facility was designed to simulate the activity release from spent leaking fuel rods under steady state and transient conditions in the spent fuel pool. The experimental rig included an electrically heated fuel rod with different defects and a cooling system. The fission product transport was simulated by potassium-chloride. The conductivity changes of the water in the cooling system were measured to provide information about the amount of released solution. Defects of different sizes and positions were applied, together with a wide range of rod powers to simulate decay heat. The produced data can be used for predicting the activity release from leaking fuel under storage conditions and for the interpretation of fuel examination procedures.

Forced Convection Modelling of a Solar Central Receiver using Nonisothermal Cylinders in Crossflow (비등온 실린더 모델을 이용한 태양로의 강제 대류에 의한 열 손실 분석)

  • Chun, Won-Gee;Jeon, Myung-Seok;Jeon, Hong-Seok;Auh, P. Chung-Moo;Boehn, Robert F.
    • Solar Energy
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    • v.10 no.3
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    • pp.13-18
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    • 1990
  • When nonuniform thermal boundary conditions are imposed on the surface of a circular cylinder in crossflow, the heat transfer characteristics can be quite different compared to what is found for isothermal or constant heat flux boundary conditions. In the present analysis, two kinds of nonuniform boundary conditions along the circumference of the cylinder are considered in a uniform stream of air: step changes and linear profiles. Step changes in temperature can arise on the surface of an external, cylindrical, solar central receiver. As the working fluid(water) flows through the vertical tubes that ring the circumference of Solar One(a solar central receiver in Barstow, California), the solar flux on the receiver heats the water from a liquid to a superheated state. In this process, portions of the receiver panels, and thus portions of the circumference of the cylinder, function as a preheater, boiler, or superheater. Hence the surface temperature can vary significantly around the cylinder. Common engineering practice has been to use an average wall temperature with an isothermal cylinder heat transfer coefficient when estimating the convective loss in these kinds of situations.

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Analysis of the Water Quality Change Due to Water Level Control of Sayeon Dam (사연댐 수위조절시 수질변화 분석)

  • Lee, Sang Hyeon;Cho, Hong Je
    • Journal of Korea Water Resources Association
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    • v.46 no.11
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    • pp.1069-1078
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    • 2013
  • The Bangudae Petroglyphs, national treasure No. 285 is located within submerged upper districts of Sayeon dam supplying the main residential water in Ulsan. Of the many ways for the reservation of Petroglyphs located the altitude at 53~57 m, the plan that we take it out of the water lowering the water level from 60 m to 52 m has been examined mainly in case of controlling artificially the water level of the dam. In this paper, we examined expected problems from the loss of dam function and the change of water quality from water deterioration caused by the water level control of the Sayeon dam. Using the model of Vollenweider and CSTR (Continuous Stirred Tank Reactor), we analyzed the density change of BOD and COD, representative water quality index and the TP and TN, the main reason of algae growth. The result showed that the density of COD lowered a little but the density of TP and TN went up over 130% when controlling the water level from 60 m to 52 m. These changes cause a serious algae problem and if doing the water quality management as the density of TN and TP, the water quality would become worse. Water storage and supply residential water decreases, and the water quality becomes worse because of eutrophic state.

Channel Evaluation for Abandoned Channel Restoration Using Image Analysis Technique (영상분석기법을 이용한 구하도 복원 대상하천의 하도평가)

  • Hong, Il;Kang, Joon-Gu;Kwon, Bo-Ae;Yeo, Hong-Koo
    • Journal of Korea Water Resources Association
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    • v.42 no.5
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    • pp.397-406
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    • 2009
  • River is able to change by various environmental factors. In order to conduct restoration design of abandoned river channels, it is necessary to evaluate the river through the analysis of past and present river channels. River evaluation requires various data, such as geometry, hydraulic and hydrology, but there is a lot of difficulty to understand topographical information of river change on time and space due to a lack of past data by domestic conditions. This study analyzes the changes in past and present river channels and examines the applicability of river channel evaluation through image analysis using aerial photographs and 1918 year's map. Aerial photograph analysis was conducted by applying the image analysis method and GIS analysis method on Cheongmicheon. As a result of this analysis, we have quantitatively identified the form and size of abandoned channels, changes in the vertical-section and cross-section length of rivers, and micro-landform changes. More importantly, we verified that morphological changes in sandbars due to artificial straightening are important data in identifying the state of current river channels. In these results, although image analysis technique has limitations in two-dimensional information from aerial photographs, we were able to evaluate the changes in river channel morphology after artificial maintenance of the river.