• Ocean and Polar Research
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• v.35 no.4
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• pp.323-349
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• 2013

The mud shrimp Upogebia major (Upogebiidae: Decapoda: Crustacea) is a common species on muddy and sandy mud tidal flats in the west coast of Korea. They reside in Y-shaped burrows that can extend up to more than 2 meters below the sediment surface. They feed on suspended detritus carried into their burrow by the beating of their pleopods and captured by their hairy first two pairs of thoracic legs. Mud shrimp burrows provide a habitat for a variety of small organisms such as crabs, shrimps, polychaetes, and mollusks. Ovigerous females are observed from December to May. Females deposit eggs only once per breeding season. They start hatching in March and the pelagic larvae of first zoea appear in March and April, followed by benthic settlement in May. Growth over the first year is rapid, and females deposit their first eggs in the third breeding season, 31 months after their settlement. Adult shrimps live for 4~5 years. Depth of the burrow increases with body length. The deep burrows provide refuge from predators and physical stress, allowing the shrimps to survive for a long time. The mud shrimps supply oxygen-rich water to their deep burrows, and exert a great influence on the structure and metabolism of the tidal flat benthic community. However, recently this type of mud shrimp has posed a serious threat to the Korean clam industry along the west coast of Korea. The extensive burrowing shrimp populations suddenly invaded the tidal flats from 2010 where the clams (Ruditapes philippinarum) are raised. As a consequence, clam production has decreased by about 10% over the past three years in some Korean clam beds. Therefore, the objective of this study is to review the biology of this mud shrimp in order to seek solutions to control the burrowing of these shrimps.

• International Journal of Industrial Entomology and Biomaterials
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• v.22 no.1
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• pp.17-20
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• 2011

The average life expectancy has continuously increased with the development of medical industry. As women get older, they experience the deficit of estrogen caused by decreased function of ovarian. Specifically, they suffer from temporary fever because of unstable vasomotion and, in the long term experience, degeneration of urogenital organs, tooth loss, arteriosclerosis, demantia, snores and so on. Because of these symptoms the estrogen medical supply is getting required. Along with this, many studies have conducted to find out substitutional medicals without any side effects. This research was carried out to find out such substitutable materials. For the purpose of study, we examined the change of estrogen using the rats fed with the pupa powder immediately before the eclosion, eclosed adult, the pupa extract immediately before the eclosion, and the silkworm powder prepared at $3^{rd}$ day of $5^{th}$ instar. The result showed no significant chance in weight, feeding and water intake quantity among variables. However, the estrogen hormone secretion effects was very high at 73 pg/ml in the rats fed with the freeze-dried powder of the Yeonnokjam male pupa prepared immediately before the eclosion, compared with the control at 59 pg/ml. The next was Yangwonjam male adult at 71 pg/ml.

• Journal of Animal Environmental Science
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• v.5 no.3
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• pp.189-196
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• 1999

Anaerobic digestion is a naturally occuring microbial process involving the decomposition of organic materials such as livestock manure. This study explores the effect of the operating conditions, HRT (Hydraulic Retention Time) and feeding frequency on treatment efficiency for digestion of pig slurry, which has been one of most difficult organic waste for proper treatment in livestock production industry in Korea at the present time. The pilot-scale CSTR of 5 m3 in volume was designed. manufactured, and operated at the temperature of 35$\pm$1$^{\circ}C$. The digester was designed to hydraulically stir for complete mixing and to supply heat from the water bath to maintain mesophilic temperature. The HRT of the digester for Test 1 and Test 2, and Test 3 was set for 17 days and 13 days respectively and pig slurry was fed once a day with 300$\ell$ each for Test 1 and Test 3, while twice with 150$\ell$each for Test 2. Test 2 showed better performance by increase of 4% in VS removal efficiency and 5% in biogas production rate. This is mainly attributed to smaller temperature drop by feeding frequently with half amount, which eventually led to lesser impact on anaerobic mocrobes in the digester. Test 2 maintained optimum pH 7.8 which uplifted the activaton of sulfur-reduction bacteria, alkalinity of around 4,000mg/$\ell$, VA of over 3,000mg/$\ell$ for whole period of experiment. Further research may require to provide the practical operation strategy of anaerobic treatment system for treatment of pig slurry.

• Journal of Korea Port Economic Association
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• v.37 no.4
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• pp.51-70
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• 2021

This study measured the environmental efficiency of 21 international airports based on sustainability reports issued by each airport for 2018. As many sectors in the industry paid attention to social and environmental responsibilities, airport operators comprise one of the leading sectors that streamlined their facilities to become increasingly sustainable and environmental. Nevertheless, studies on the environmental operations of airports are insufficient compared with studies on economic or operational efficiency. Therefore, the current study aims to determine any possible improvement in the environmental inefficiency of airports with the utilization of directional distance function (DDF) and to examine operational efficiency with the application of the data envelopment analysis (DEA). The majority of airports have operated their facilities efficiently, but not all have effectively managed pollutants generated by airports. Furthermore, many airports can still potentially reduce CO₂ and water consumption. This study suggests several implementable environmental improvements to the aviation sector. Moreover, other industrial sectors may use the research as a benchmark for enhancing environmental efficiency.

• Advances in concrete construction
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• v.16 no.1
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• pp.69-78
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• 2023

This investigation delves into the adverse repercussions stemming from the impact of arsenic on steel pipes concealed within soil designated for rice cultivation. Simultaneously, the study aims to ascertain effective techniques for detecting arsenic in the soil and to provide strategies for mitigating the corrosion of steel pipes. The realm of nanotechnology presents promising avenues for addressing the intricate intersection of renewable energy, oil, and environmental pollution from a novel perspective. Nanostructured materials, characterized by distinct chemical and physical attributes, unveil novel pathways for pioneering materials that exert a substantial impact across diverse realms of food production, storage, packaging, and quality control. Within the scope of the food industry, the scope of nanotechnology encompasses processes, storage methodologies, packaging paradigms, and safeguards to ensure the safety of consumables. Of particular note, silver nanoparticles, in addition to their commendable antibacterial efficacy, boast anti-fungal and anti-inflammatory prowess, environmental compatibility, minimal irritability and allergenicity, resilience to microbial antagonism, thermal stability, and robustness. Confronting the pressing issue of arsenic contamination within both environmental settings and the food supply is of paramount importance to preserve public health and ecological equilibrium. In response, this study introduces detection kits predicated upon silver nanoparticles, providing an expeditious and economically feasible avenue for identifying arsenic concentrations ranging from 0.5 to 3 ppm within rice. Subsequent quantification employs Hydride Atomic Absorption Spectroscopy (HG-AAS), which features a detection threshold of 0.05 ㎍/l. A salient advantage inherent in the HG-AAS methodology lies in its capacity to segregate analytes from the sample matrix, thereby significantly reducing instances of spectral interference. Importantly, the presence of arsenic in the soil beneath rice cultivation establishes a causative link to steel pipe corrosion, with potential consequences extending to food contamination-an intricate facet embedded within the broader tapestry of renewable energy, oil, and environmental pollution.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.971-976
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• 2007

In the U.S., utility damages or utility delay caused by conflicts during the underground utility relocation is one of the weighty problem in the construction industry. Also, in domestic case, delay and additional cost caused by underground utility(i.e, electricity, communication, gas, water supply and sewerage) relocation has been happened so that there is an increase of claims for responsibility between owners and contractors. However, there is insufficient survey for the recent circumstance of additional cost for delay and design changes caused by utility relocation and shortage of enough research for solving and analyzing of causes and their ripple effect. This research presents a result of the study about the best practices of FHWA(Federal Highway Administration), SHAs(State Highway Agencies) and the utility companies managing utility relocation. Also, it presents the basic concept of SUE(Subsurface Utility Engineering), the most reliable tool of FHWA presented, and investigates the developing status about SUE in Korea. At the end of this paper, this research proposes a practical and more applicable study about the efficient utility relocation focusing on local industry.

• Membrane Journal
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• v.33 no.4
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• pp.181-190
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• 2023

Wastewater purification is one of the most important techniques for controlling environmental pollution and fulfilling the demand for freshwater supply. Various technologies, such as different types of distillations and reverse osmosis processes, need higher energy input. Capacitive deionization (CDI) is an alternative method in which power consumption is deficient and works on the supercapacitor principle. Research is going on to improve the electrode materials to improve the efficiency of the process. A reverse electrodialysis (RED) is the most commonly used desalination technology and osmotic power generator. Among many studies conducted to enhance the efficiency of RED, MXene, as an ion exchange membrane (IEM) and 2D nanofluidic channels in IEM, is rising as a promising way to improve the physical and electrochemical properties of RED. It is used alone and other polymeric materials are mixed with MXene to enhance the performance of the membrane further. The maximum desalination performances of MXene with preconditioning, Ti₃C₂T_x, Nafion, and hetero-structures were respectively measured, proving the potential of MXene for a promising material in the desalination industry. In terms of osmotic power generating via RED, adopting MXene as asymmetric nanofluidic ion channels in IEM significantly improved the maximum osmotic output power density, most of them surpassing the commercialization benchmark, 5 Wm^-2. By connecting the number of unit cells, the output voltage reaches the point where it can directly power the electronic devices without any intermediate aid. The studies around MXene have significantly increased in recent years, yet there is more to be revealed about the application of MXene in the membrane and osmotic power-generating industry. This review discusses the electrodialysis process based on MXene composite membrane.

• Korea Science and Art Forum
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• v.16
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• pp.157-169
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• 2014

Lake Biwa Canal was a dream project that reminds us the passion and innovation of Kyoto Citizens more than water supply. It is a modernization project combining engineering knowledge and scientific technology, which started transportation by ship through big-scale civil construction as well as supplying electricity as the first waterpower plant in Japan, and it overcame the physiographic limit through adopting unique method of waterway transportation. Lake Biwa Canal, which has tangible and intangible culture heritage value as the traditional space of Kyoto, the Old Capital of 1200 years, conceives a cultural meaning that is connected through various mutual relation as well as scientific technologic factor. Lake Biwa Canal is not only the function for supplying water to gardens and temples of Kyoto region, but it is also a cultural fruit that is formed by complex causal relationship of various contents such as geographical and environmental background, the phases of the times, local development policy, political circumstances and religions. This study is aimed at interpreting the value of Lake Biwa Canal multilaterally by the convergence of cultural and technological aspects through the view of the world which the age tried to pursue, focusing on the construction of Lake Biwa Canal which was accomplished in the process of promoting the modernization of Kyoto.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.6-13
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• 2018

Utilizing the heat of cooling water discharge of coal-fired power plant, pipeline investment costs for businesses that supply heat to agricultural facilities near power plants increase in proportion to installation distance. On one hand, the distance from the power plant is a factor that brings difficulties to secure economic efficiency. On the other, if the installation distance is short, there is a problem of securing the heating demands, facility houses, which causes economical efficiency to suffer. In this study, the economic efficiency of 1km length of standard heat pipeline was evaluated. The sensitivity of the heat pipe to the new length variation was analyzed at the level of government subsidy, amount of heating demand and the incremental rate of pipeline with additional government subsidy. As a result of the analysis, it was estimated that NPV 131 million won and IRR 15.73%. The sensitivity analysis showed that NPV was negative when the length of heat pipe facility exceeded 2.6 km. If the government supports 50% of the initial investment, the efficiency is secured within the estimated length of 5.3 km, and if it supports 80%, the length increases within 11.4 km. If the heat demand is reduced to less than 62% at the new length of the standard heat pipe, it is expected economic efficiency is not obtained. If the ratio of government subsidies to initial investment increases, the elasticity of the new bloc will increase, and the fixed investment, which is the cost of capital investment for one unit of heating demand, will decrease. This would result in a reduction in the cost of production per unit, and it would be possible to supply heat at a cheaper price level to the facility farming. Government subsidies will result in the increased economic availability of hot plumbing facilities and additional efficiencies due to increased demand. The greater government subsidies to initial investment, the less farms cost due to the decrease in the price per unit. The results of the study are significant in terms of the economic evaluation of the effectiveness of the government subsidy for the thermal power plant heat utilization project. The implication can be applied to any related pilot to come.

• Journal of the Korean association of regional geographers
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• v.2 no.1
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• pp.51-67
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• 1996

There are three main rice-growing regions in the United States: the prairie region along the Mississippi River Valley in eastern Arkansas; the Gulf Coast prairie region in southwestern Louisiana and southeastern Texas; and the Central Valley of California. The Central Valley of California is producing about 23% of the US rice(Fig. 1). In California. most of the crop has been produced in the Colusa, Sutter, Butte, Glenn Counties of the Sacramento Valley since 1912, when rice was commercially grown for the first time in the state(Fig. 2). Roughly speaking, the average annual area sown to rice in California is about 300,000 acres to 400,000 acres during the last forty years(Fig. 3). California rice is grown under a Mediterranean climate characterized by warm, dry, clear days, and a long growing season favorable to high photosynthetic rates and high rice yields. The average rice yield per acre is probably higher in California than in any other rice-growing regions of the world(Fig. 4). A dependable supply of irrigation water must be available for a successful rice culture. Most of the irrigation water for California rice comes from the winter rain and snow-fed reservoir of the Sierra Nevada mountain ranges. Less than 10 percent of rice irrigation water is pumped from wells in areas where surface water is not sufficient. It is also essential to have good surface drainage if maximum yields are to be produced. Rice production in California is highly mechanized, requiring only about four hours of labor per acre. Mechanization of rice culture in California includes laser-leveler technology, large tractors, self-propelled combines for harvesting, and aircraft for seeding, pest control, and some fertilization. The principal varieties grown in California are medium-grain japonica types with origins from the cooler rice climates of the northern latitudes (Table 1). Long-grain varieties grown in the American South are not well adapted to California's cooler environment. Nearly all the rice grown recently in California are improved into semidwarf varieties. Choice of variety depends on environment, planting date, quality desired, marketing, and harvesting scheduling. The Rice Experiment Station at Biggs is owned, financed, and administered by the rice industry. The station was established in 1912, as a direct result of the foresight and effort of Charles Edward Chambliss of the United States Department of Agriculture. Now, The station's major effort is the development of improved rice varieties for California.