• Journal of Korean Society of Water and Wastewater
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• v.38 no.1
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• pp.29-38
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• 2024

Wastewater management is increasingly emphasizing economic and environmental sustainability. Traditional methods in sewage treatment plants have significant implications for the environment and the economy due to power and chemical consumption, and sludge generation. To address these challenges, a study was conducted to develop the Intermittent Cycle Extended Aeration System (ICEAS). This approach was implemented as the primary technique in a full-scale wastewater treatment facility, utilizing key operational factors within the standard Sequencing Batch Reactor (SBR) process. The optimal operational approach, identified in this study, was put into practice at the research facility from January 2020 to December 2022. By implementing management strategies within the biological reactor, it was shown that maintaining and reducing chemical quantities, sludge generation, power consumption, and related costs could yield economic benefits. Moreover, adapting operations to influent characteristics and seasonal conditions allowed for efficient blower operation, reducing unnecessary electricity consumption and ensuring proper dissolved oxygen levels. Despite annual increases in influent flow rate and concentration, this study demonstrated the ability to maintain and reduce sludge production, electricity consumption, and chemical usage. Additionally, systematic responses to emergencies and abnormal situations significantly contributed to economic, technical, and environmental benefits.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.2
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• pp.263-270
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• 2016

This study was conducted to investigate the effects of raw material ratio on the physicochemical characteristics of emulsion-type pork sausages. Experiment design was divided into 12 treatments, based on protein level (P), fat level (3P, 3.5P, and 4P), and water level (4P+10, 4P+15, 4P+20, and 4P+25). The pH and shear force values were significantly higher in T7 (3.5P fat and 4P+20 water) than those of other treatments. The lightness and redness were greatly reduced by increasing the quantity of water. The treatments containing 3P fat and 4P+20 water had the highest values of cohesiveness, springiness, gumminess, and chewiness. On the whole, when the protein (P) and fat (3P, 3.5P, 4P) levels were fixed, an increase over the appropriate moisture level deteriorated many physicochemical characteristics.

• Journal of the Korean Applied Science and Technology
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• v.22 no.2
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• pp.191-199
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• 2005

Removable protective adhesives for automobiles were synthesized by an emulsion polymerization of monomers such as n-butyl acrylate (BA), n-butyl methacrylate (BMA), acrylonitrile (AN), acrylic acid (AA) and 2-hydroxyethyl methacrylate (2-HEMA), in which AA and 2-HEMA were functional monomers. Potassium persulfate (KPS) was used as an initiator and sodium lauryl sulfate (SLS) was used as an emulsifier, and polyvinyl alcohol (PVA) was used as a stabilizer. Emulsion polymerization was carried out in a semi-batch type reactor. Tensile strength, extension, peel strength, viscosity and solid content of the synthesized adhesives were tested. The optimum physical properties of the removable protective adhesives for automobiles were obtained with the composition of 0.43 mole BA, 0.57 mole AN, 0.21 mole BMA, 0.03 mole AA, and 0.03 mole 2-HEMA.

• Journal of the Korean Applied Science and Technology
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• v.32 no.3
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• pp.480-487
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• 2015

In this study, several kinds of active carbons with high specific surface area and micro pore structure were prepared from the coconut shell charcoal using chemical activation method. The physical property of prepared active carbon was investigated by experimental variables such as activating chemical agents to char coal ratio, flow rate of inert gas and temperature. It was shown that chemical activation with KOH and NaOH was successfully able to make active carbons with high surface area of $1900{\sim}2500m^2/g$ and mean pore size of 1.85~2.32 nm. The coin cell using water-based binder in the electrolyte of LiPF6 dissolved in mixed organic solvents (EC:DMC:EMC=1:1:1 vol%) showed better capacity than that of oil-based binder. Also, it was found that the coin cell of water-based binder shows an improved cycling performance and coulombic efficiency.

• Journal of the Korean Wood Science and Technology
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• v.49 no.5
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• pp.416-429
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• 2021

Raru is a lesser-known plant species originating from North Sumatra, Indonesia. Information on the characteristics is still limited, especially its chemical component. Therefore, this study aims to examine the chemical composition information of Cotylelobium lanceolatum, Cotylelobium melanoxylon, and Vatica pauciflora woods based on their axial log positions (bottom, middle, and top). The wood chemical analysis was performed in terms of the Indonesian National Standard (SNI) method. Furthermore, the analysis measured holocellulose, 𝛼-cellulose, hemicellulose, lignin content, alcohol benzene extractive content, the extractive substance in hot and water, and solubility in NaOH 1%. The results indicated that the species and their log axial positions affected different chemical components, which included 𝛼-cellulose, hemicellulose, and lignin of C. lanceolatum amounting to 41.88%, 19.39%, and 28.68% respectively. Meanwhile, for C. Melanoxylon, they were 42.01%, 21.11%, and 24.76% respectively; and for V. pauciflora wood, they were 42.95%, 23.24%, and 30.11% respectively. The average values of the extractive contents including the solubility in 1: 2 ethanol benzene, NaOH, and hot water for C. lanceolatum, C. melanoxylon, and V. pauciflora wood were (10.58%, 27.62%, 8.13%), (14.54%, 28.22%, 7.82%), and (10.95%, 28.60%, 7.57%) respectively. The wood species had a significant effect on chemical components including lignin, cellulose and hemicellulose, and extractive solubility in cold water. Furthermore, the axial log position had a significant effect on all the parameters of the chemical composition of the wood being tested.

• Journal of Environmental Impact Assessment
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• v.19 no.2
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• pp.127-140
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• 2010

This study investigates the relation between the location of a habitat and the ecological connections according to the habitat type in the riparian zone at the Nonsan Stream and Yanghwa Stream. Stream habitat is classified into nine types for the aquatic insects and fish. For vegetation and birds, habitat is classified into two types of medium-scale streams, including both physical and chemical streams are analyzed accordingly. Nowadays, The fundamental goal of the river environment restoration enterprise is the rehabilitation or the restoration of the characteristic the river scenic or environment. For instance, The Channel habitats which has physical nature environment such as flat, speedy rapids, or closed-channel wetland, pool are constructed by artificial, Consequently, make them autogenesis smoothy eco-environment. However, the river environment are controlled not only physical environment, but it also need reasonable the quality of the water to compose smoothly. Finally, understanding what influence are effecting on physical habitat environment which are made by natural factors to water quality are very important factor for the river environment restoration enterprise Therefore, In this research, we are targeting to a basin to investigate the environment of the physical channel habitat and evaluate the changing of the water quality. This results will be a important characteristic that can judge the physical habitat and reciprocality connected to the water quality or adequacy of restoration technology. Therefore in this study, as a step to quantify functions and values of habitats and definite factors to perform habitat, we selected a representative stream of sand-stream, gravel-stream to classify habitat characteristics and quantified the physical, chemical, biological characteristics.

• Fashion & Textile Research Journal
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• v.10 no.3
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• pp.389-393
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• 2008

The purpose of this study is to provide beauticians with the fundamental material for them to use effectively heat permanent wave and satisfy their customers. It carried out an experiment with hair of a woman in her late twenties to investigate the change of physical and morphologic characteristics by its water content when performing heat permanent wave. It evaluated the water content as 0g, 1g, 2g, 3g and 4g respectively when performing the heat permanent wave on hair, then it compared and observed the wave type, tensile strength and elongation for its physical change also observed the morphologic change by scanning electronic microscope and transmission electronic microscope. The result of experiment on the physical specificity revealed that the wave was the most ideal when the water content was 2 g. The material with much water content made wave but the result was not satisfied. In the case of hair with water content of nearly 0g didn't make wave. In terms of tensile strength and elongation, the tensile strength was generally reduced as hair was damaged, on the contrary, the elongation was increased. It observed the change of morphologic characteristic and got the result that the damage on hair cuticle was deepen as its water content was decreased. It also showed the result that damage happened on hair cuticle more than hair cortex with the observation of fine structure on hair section by transmission electronic microscope. Generally chemical treatment damaged hair. Under consideration of this aspect, the ultimate goal of this thesis is to minimize the damage of hair caused by chemical treatment and get the satisfaction on the hair style. The result of experiment presented that the hair showed the best result when its water content was 2 g.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.3
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• pp.194-201
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• 2009

The e1ectrocatalytic properties of heteropolyacids(HPAs) entrapped in covalently cross-linked sulfonated polyetheretherketone(CL-SPEEK/HPA) membranes have been studied for water electrolysis. The HPAs, including tungstophosphoric acid(TPA), molybdophosphoric acid(MoPA), and tungstosilicic acid(TSiA) were used as additives in the composite membranes. The MEA was prepared by a non-equilibrium impregnation-reduction(I-R) method, using reducing agent, sodium borohydride(NaBH4) and tetraamineplatinum(II) chloride(pt(NH$_3$)$_4$Cl$_2$). The electrocatalytic properties of composite membranes such as the cell voltage were in the order of magnitude CL-SPEEKlMoPA40 (wt%) > /TPA30 > /TSiA40. In the optimum cell applications for water electrolysis, the cell voltage of PtlPEM/Pt-Ru MEA with CL-SPEEKlTPA30 membrane was 1.75 V at 80$^{\circ}$C and I A/cm$^2$ and this voltage carried lower than that of 1.81 V of Nafion 117. Consequently, in regards of electrochemical and mechanical characteristics and oxidation durability, the newly developed CL-SPEEKITPA30 composite membrane exhibited a better performance than the others, but CLSPEEKlMoPA40 showed the best electrocatalytic activity (1.71 Vat 80$^{\circ}$C and 1 A/cm$^2$) among the composite membranes.

• Clean Technology
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• v.5 no.2
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• pp.69-78
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• 1999

Separation characteristics of cutting oil-in-water emulsions were studied experimentally by using various kinds of flat-type microfiltration and ultrafiltration membranes. For ultrafiltration membranes the permeation behavior of cutting oil emulsions obeys the film model, whereas a significant deviation from the model was observed for ASYPOR microfiltration membranes. The experimental data obtained for all the membranes showed that the effect of operating pressure on the permeation flux of oil-in-water emulsions is not very significant. At low transmembrane pressures the permeation flux decreased gradually with increasing filtration time, whereas the permeation flux at high transmembrane pressures decreased steeply for early filtration time. However, every flux eventually reached a constant value that depends only on the applied transmembrane pressure. For the hydrophobic polycarbonate microfiltration membrane the permeation flux increased with the filtration time. The critical permeation pressures were also determined from the data obtained from unstirred cell experiments.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3183-3193
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• 2023

The water radiolysis in-core at light water reactors (LWRs) produces various radicals with other ionic species/molecules and radioactive nitrogen species in the reactor coolant. Nitrogen species can exist in many different chemical forms and recirculate in water and steam, and consequently contribute to what extent the environmental safety at nuclear power plants. Therefore, a clear understanding of formation kinetics and chemical behaviors of nitrogen species under irradiation is crucial for better insight into the characteristics of major radioactive species released to the main steam or relevant coolant systems and eventually development of advanced processes/methodologies to enhance the environmental safety at nuclear power plants. This paper thus focuses on basic principles on electrochemical interaction kinetics of radiolytic molecules and various nitrogen species in high temperature water, fundamental approaches for calculating thermodynamic values to predict their stability and domain in LWRs, and the effect of nitrogen species on crevice chemistry/corrosion and intergranular stress corrosion cracking (IGSCC) susceptibility of structure materials in high temperature water.