• Asian-Australasian Journal of Animal Sciences
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• v.21 no.2
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• pp.198-203
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• 2008

This study was conducted to compare the effects of feeding high protein and low energy milk replacer (HPR; CP 25%, ME 3.6 Mcal/kg DM) with low protein and high energy milk replacer (HPR; CP 21%, ME 4.2 Mcal/kg DM) on feed consumption, body weight (BW) gain, health and selected blood metabolites in Holstein calves during the pre-weaning period. At each feeding, each milk replacer (MR) was prepared by mixing 0.125 kg of dry MR in 1L of warm ($60^{\circ}C$) water. The calves were fed either HPR (n = 10) or HER (n = 10) using mobile plastic bottles fitted with soft rubber nipples. All calves received 1.8L diluted MR at each feeding 3 times daily during the first 4 weeks of age; feeding frequency was reduced to 2 times daily for the next 2 weeks of age and then to once daily during the last week of the experiment. Jugular blood was sampled in calves at day 7, 14, 21, 35 and 49 of age to enumerate selected metabolites. Daily MR, starter and hay intake during the pre-weaning period were similar in calves fed HPR and HER. Consumption of starter, MGH and total DM steadily increased with the age of calves. Final BW, daily BW gain and feed efficiency of calves were not affected by treatments. Serum glucose, cholesterol, creatinine were decreased (p<0.05) and blood urea N was increased (p<0.05) in calves fed HER or HPR as they grew older. Serum glucose, total protein and albumin concentrations in calves were not affected by treatments. Serum GPT and GOT concentrations were higher (p<0.05) in calves on HPR than on HER. Scouring score, days scoured, respiratory score, rectal temperature and general appearance were similar in calves fed HPR and HER. Poor general appearance (dullness and droopy ears) of calves fed either HPR or HER reflected nutritional insufficiency and stress. In conclusion, energy and protein concentrations in MR did not affect feed intake and BW gain in Holstein calves during the pre-weaning period. Poor general appearance and lower BW gain of calves compared to those reported in the literature for milk fed calves prompt a demand for further research to improve the daily nutrient supply to MR-fed calves.

• Analytical Science and Technology
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• v.35 no.5
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• pp.205-211
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• 2022

Deuterium (D) is an isotope with one more neutron number than hydrogen (H). Heavy elements rarely change their chemical properties with little effect even if the number of neutrons increases, but low-mass elements change their vibration energy, diffusion rate, and reaction rate because the effect cannot be ignored, which is called an isotope effect. Recently, in the semiconductor and display industries, there is a trend to replace hydrogen gas (H₂) with deuterium gas (D₂) in order to improve process stability and product quality by using the isotope effect. In addition, as the demand for D₂ in industries increases, domestic gas producers are making efforts to produce and supply D₂ on their own. In the case of high purity D₂, most of them are produced by electrolysis of heavy water (D₂O), and among D₂, hydrogen deuteride (HD) molecules are present as isotope impurities. Therefore, in order to maximize the isotope effect of hydrogen in the electronic industry, HD, which is an isotope impurity of D₂ used in the process, should be small amount. To this end, purity analysis of D₂ for industrial processing is essential. In this study, HD quantitative analysis of D₂ for high purity D₂ purity analysis was established and hydrogen isotope RM (Reference material) was developed. Since hydrogen isotopes are difficult to analyze with general gas analysis instrument, they were analyzed using a high-precision mass spectrometer (Gas/MS, Finnigan MAT271). High purity HD gas was injected into Gas/MS, sensitivity was determined by a signal according to pressure, and HD concentrations in two bottles of D₂ were quantified using the corresponding sensitivity. The amount fraction of HD in each D₂ was (4518 ± 275) μmol/mol, (2282 ± 144) μmol/mol. D₂, which quantifies HD amount using the developed quantitative analysis method, will be manufactured with hydrogen isotope RM and distributed for quality management and maintenance of electronic industries and gas producers in the future.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.5
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• pp.551-561
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• 2024

Underground utility tunnels are spaces densely packed with various infrastructure facilities, such as power, telecommunications, and water supply and drainage systems, making internal environment management crucial. An investigation into accident cases and on-site demands in these tunnels revealed that while fires and floods are the most common types of incidents, the demand for real-time condensation prevention and response is frequent according to on-site managers. Condensation occurs due to the difference in humidity and temperature between the inside and outside of the tunnel. Frequent or prolonged condensation can lead to metal pipe corrosion, electrical failures, and reduced equipment lifespan. Therefore, this study developed a control algorithm and monitoring system to prevent condensation in underground utility tunnels. The proposed control algorithm estimates the likelihood of condensation in real-time based on the measured temperature and humidity and suggests appropriate responses for each stage to the managers. Finally, a practical condensation prevention monitoring system was built based on the developed algorithm, verifying the feasibility and applicability of this technology in the field.

• 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.

• Journal of Navigation and Port Research
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• v.28 no.3
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• pp.269-276
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• 2004

The reclaimed land has peculiar characteristic of nature environment unlike midtown or inland and also, in comparison with inland, has bad weather condition, such as low temperature, strong wind, excessive sunshine, and moisture involved in a salt. Therefore the case of developing water front needs understanding characteristic of weather environment mused by reclamation in detail and proper development and organized maintenance. If development which doesn't investigate topographic and climate characteristic sufficiently is drove ahead, a rise of expense for energy and maintenance is going to be mused by deteriorating weather environmental, occurring a flaw of facility and calculating inaccurate capacity of facility. We looked into the weather state and drew up the standard weather data of the newport area in Busan which is reclaiming and developing now. In this research at the base qf the standard weather data, we calculate the dynamic peak loads for commerce, business and residence and then we utilize the results of the load calculation as basic information to determine facility capacity in the rear city of the newport area.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.261-268
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• 2018

The use of electric cable was limited due to the installation time and large space as the increase of power demand and load quantity in side line. In order to solve these problems, the application of busway system which can supply the large current was increasing. But it was lack of methods of performance tests to evaluate the reliability and results of test for busway system. In this paper, we presented items to evaluate the reliability test for epoxy coated busway system with reference to IEC 61349-6. In addition, we proposed items to evaluate the reliability and long term life cycle test for the epoxy coated busway system. The combined acceleration deterioration test that reflects actual conditions of the survey as much as possible was conducted considering both thermal and electrical stresses. The deterioration condition was selected to satisfy fifty years life expectation and the insulation performance verification test of the busway system confirmed the long term life prediction. Furthermore, as test items for reliability assessment of compliance with the environment for the use of temperature, humidity and load current where busway system was installed, thermal overload test, water immersion test, cold shock temperature test and thermal cycle test were performed. And we examined changes in characteristics and abnormality after tests. From results, the test items presented to evaluate performance and reliability of the epoxy insulated busway system were confirmed to be appropriate in this paper, and the performance of the product was also confirmed to be excellent for reliability tests.

• Journal of the Korean Society of Food Culture
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• v.5 no.4
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• pp.463-472
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• 1990

This research was carried out as a basic survey to provide more effective and improved food service for the soliders of the Armed Forces who are serving to defend the Republic of Korea subjects were selected randomly who were serving in the army for a short-term. Following is the result of a survey regarding the situation of their meals, dietary life, and their food preference of 190 kinds of foodstuffs. As a result of surveying the dietary life of the soldiers, they indicated that there was dissatisfaction in the current Food Service because it lacked tasted and the same kind of meals were being served too frequently with regard to this, many subjects expressed that they were eating out because of the quality of they get from the regular meal service the meals, that is they were eating in restaurants to resolve their dissatisfaction over the quality of the meals. It was also surveyed that in the current meals there is a need to diversify ways in preparing food, increase the number of dishes, and improve the tasts of the food by using improved cooking method. It seemed that the soldiers were satisfied in the quantitative level of the current food service but that there is a need to improve the meals in quality. Following is the result of a survey on the preference of foodstuffs. In case of rice as the stationary food, mixture of five-grain plain white cooked rice showed a higher propensity compared to plain whte boiled rice. This shows that soliders prefer various cereals in their rice. Soliders liked soup made from meat better than vegetable soup or soup made from fish. Especially there was a high performance for beef soup. Soliders liked One-dish meals such as fried rice or boiled rice with asserted mixtures, noodled, and dumplings on the whole-soliders generally liked vegetables and they liked uncooked vegetables better than cooked vegetables. Generally everyone liked beverages and there was a high preference for dessert. Among various rice cakes soliders liked songpyon(rice cake steamed on a layer of pine needles) and injolmi (cake made from glutinous rice). On the other hand, soliders did not like food prepared with fish, biscuits and candy very much. In the way of preparing food, soliders liked food that were fried in deep far rather than food cooked in water. Also they liked pot stem better than soup. As examined in the survey, those surveyed wanted improvement in the quality and diversity of the food rather than increase the number of food and quality. Therefore there is a need for diversified supply and demand of quality of meal service.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.90-90
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• 2022

Nicaragua is located in Central America, climatic conditions are considered tropical dry forest. Statistics reflex that in Nicaragua exits 24,000 rice farmers. National rice production only covers 73% of the national consumption. It exists two sowing system: irrigation and rainfed. Varieties used in both systems are mid-late maturity (120-135 days), there are 14 released varieties for irrigation, eight for rainfed, and eight landraces used in rainfed. The current breeding system (introduction of lines from Colombia) has increased the national production, however, has some limitation due to the lack of enough variability, reducing the proability of finding good genotypes and therefore the possibility of satisfying 100% of the demand. The purpose of this study was to analyze the problems that must be resolved in the short and long term to improve rice productivity in Nicaragua. In this paper we explain some proposal for an improvement plan. The selection of varieties with high adaptability to various cultivation environmental conditions it is necessary, also to thoroughly manage seed purity to supply certified seeds. In rice cultivation technology, it needs to improve seedling standing and weeding effect by improving soil leveling and water-saving cultivation technology. Also, proper fertilization and planting density must be established in irrigated and rain-fed areas. Furthermore, capacity must be strengthened by collecting and training with the most recent agricultural technology information, as well as by revitalizing the union rather than the individual farmer. It is necessary to develop varieties highly adaptable to the Nicaraguan cultivation environment, as well as to expand irrigation facilities and cultivation technology suitable for weather conditions in rain-fed areas. Last, it is necessary to maintain the consistency of agricultural policy for continuous and stable rice production in response to climate change events such as drought or intermittent heavy rain.

• The Southeast Asian review
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• v.28 no.1
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• pp.219-261
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• 2018

The conflicts among nations surrounding international rivers are intensifying as worldwide water shortage is getting worse. The Mekong River is a representative trans-boundary river in Southeast Asia shared by six countries, China, Myanmar, Thailand, Laos, Cambodia, and Vietnam. As the economy grows, hydroelectric power has become a major power supply source to meet the increasing power demand of the these countries. However, the construction of dams on the Mekong River is controversial because hydroelectric power in the river upstream has a negative impact not only on the whole river ecosystem but also on residents' life around downstream, in particular. In order to understand the controversy arising from international rivers, it is necessary to take into account different positions of countries sharing it. However, studies on the position of a specific country to Mekong hydropower have been conducted mainly focusing on China and Laos. Therefore, this study tried to study the position of Cambodian government which is located downstream of the Mekong River and is likely to bear costs rather than to gain benefits from hydroelectric power generation. What is the attitude of the Cambodian government to the hydroelectric development of the upper Mekong and what is the reason for that? The study confirmed the Cambodian government's support for dam construction on the Mekong River. It also figured out influential factors on the formation of such a position as follows: 1) economic asymmetry with China, 2) power dependency and geographical asymmetry in Laos, and 3) importance of hydroelectric power in Cambodia.

• Nuclear Engineering and Technology
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• v.25 no.2
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• pp.276-284
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• 1993

The ABB-CE System-80 reactor power cutback system(RPCS) is designed to enable continuous operation of the reactor without trip in the events of the loss of one of the two main feedwater pumps and loss of load, and thus improves plant availability in a cost effective manner. In this study expansion of RPCS has been investigated for continuous reactor operation without trip in the event of an inward control element assembly(CEA) deviation including a single rod drop. Under the expanded function of RPCS the control system will provide a rapid core power reduction on demand by releasing CEAs to drop into the core and reduce the turbine power, if necessary, to follow the reactor power variation. This design feature which is included as the new design features to be incorporated in the ABB-CE System-80+ meets the EPRI advanced light water reactor(ALWR) requirements. For this study core analysis models of System-80+ have been developed to simulate the nuclear steam supply system(NSSS) response as well as the RPCS initiation of rapid CEA insertion. The results of this study demonstrate that the reactor trip can be avoided in the event of inward CEA deviation including a single rod drop by the RPCS initiation and thus the plant availability and capacity factor would be increased.