• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.1
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• pp.8-15
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• 2021

TiO2 has been used in various fields such as solar cells, dental implants, and photocatalysis, because it has high physical and chemical stability and is harmless to the body. TiO2 nanofibers which have a large specific surface area also show a good reactivity in bio-friendly products and excellent photocatalysis in air and water purification. To fabricate TiO2 nanofibers, an electrospinning method was used. To observe the diameter of TiO2 nanofibers with fabrication variables, the fabrication variables was divided into precursor composition variables and process variables and microstructure was analyzed. The concentrations of PVP (Polyvinylpyrrolidone) and TTIP (Titanium(IV) isopropoxide) were selected as precursor composition variables, and inflow velocity and voltage were also selected as process variables. Microstructure and crystal structure of TiO2 nanofibers were analyzed using FE-SEM (Field emission scanning electron microscope) and XRD (X-ray diffraction), respectively. As-spun TiO2 nanofibers with an average diameter of about 0.27 ㎛ to 1.31 ㎛ were transformed to anatase TiO2 nanofibers with an average diameter of about 0.22 ㎛ to 0.78 ㎛ after heat treatment of 3 hours at 450℃. Anatase TiO2 nanofibers with an average diameter of 0.22 ㎛ can be expected to improve the photocatalytic properties by increasing the specific surface area. To change the average diameter of TiO2 nanofibers, the control of precursor composition variables such as concentrations of PVP and TTIP is more efficient than the control of electrospinning process variables such as inflow velocity and voltage.

• Journal of IKEEE
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• v.27 no.1
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• pp.122-126
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• 2023

In this paper, a control system for a complex microbial incubator was proposed. The proposed control system consists of a control unit, a communication unit, a power supply unit, and a control system of the complex microbial incubator. The controller of the complex microbial incubator is designed and manufactured to convert analog signals and digital signals, and control signals of sensors such as displays using LCD panels, water level sensors, temperature sensors, and pH concentration sensors. The water level sensor used is designed and manufactured to enable accurate water level measurement by using the IR laser method with excellent linearity in order to solve the problem that existing water level sensors are difficult to measure due to foreign substances such as bubbles. The temperature sensor is designed and used so that it has high accuracy and no cumulative resistance error by measuring using the thermal resistance principle. The communication unit consists of two LAN ports and one RS-232 port, and is designed and manufactured to transmit signals such as LCD panel, PCT panel, and load cell controller used in the complex microbial incubator to the control unit. The power supply unit is designed and manufactured to supply power by configuring it with three voltage supply terminals such as 24V, 12V and 5V so that the control unit and communication unit can operate smoothly. The control system of the complex microbial incubator uses PLC to control sensor values such as pH concentration sensor, temperature sensor, and water level sensor, and the operation of circulation pump, circulation valve, rotary pump, and inverter load cell used for cultivation. In order to evaluate the performance of the control system of the proposed complex microbial incubator, the result of the experiment conducted by the accredited certification body showed that the range of water level measurement sensitivity was -0.41mm~1.59mm, and the range of change in water temperature was ±0.41℃, which is currently commercially available. It was confirmed that the product operates with better performance than the performance of the products. Therefore, the effectiveness of the control system of the complex microbial incubator proposed in this paper was demonstrated.

• Journal of Animal Science and Technology
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• v.46 no.2
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• pp.261-272
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• 2004

This study was conducted to investigate indices affecting composts maturity for swine manure compost produced in a commercial composting facility with air-forced from the bottom. The composting was made of swine manure mixed with puffing rice hull(6: 4) and turned by escalating agitator twice a day. Composting samples were collected periodically during a 45-d composting cycle at that system, showing that indices of Ammonium-N to Nitrate-N ratio were sensitive indicators of composting quality. Pile temperature maintained more than 62$^{\circ}C$ and water contents decreased about 20% for 25days of composting. A great variety and high numbers of aerobic thermophilic heterotropic microbes playing critical roles in stability of composts have been examined in the final composts, sbowing that they were detected $10^8$ to $10^{10}$ $CFUg^{-1}$ in mesophilic bacteria, $10^3$ - $10^4$ in fungi and $10^6$ - $10^8$ in actinomycetes, respectively. The results of this study for detennining a factor affecting compost stability evaluations based on composting steps were as follows; 1. Ammonium-N concentrations were highest at the beginning of composting, reaching approximately 421mg/kg. However Ammonium-N concentrations were lower during curing, reaching approximately l04mg/kg just after 45 day. The ratio between $NH_4-N$ and $NO_3-N$ was above II at the beginning of composting and less than 2 at the final step(45 day). 2. Seed germination Index was dependent upon the compost phytotoxicity and its nutrition. The phytotocity caused the GI to low during the period of active composting(till 25 days of composting time) depending on the value of the undiluted. After 25 days of composting time, the GI was dependent upon compost nutrition. The Gennination index of the final step was calculated at over 80 without regard to treatments. 3. E4: E6 ratio in humic acid of composts was correlatively decreased from 8.86 to 6.76 during the period of active composting. After 25 days of composting time, the E4: E6 was consistently decreased from 6.76 to 4.67($r^2$ of total composting period was 0.95). 4. Water soluble carbon had a tendency to increase from 0.54% to 0.78%during the period of active composting. After 25 days of composting time, it was consistently decreased from 0.78% to 0.42%. Water soluble nitrogen increased from 0.22% to 0.32% during the period of 15 days after initial composting while decreased from 0.32% to 0.21% after 15days of composting. In consequence, the correlation coefficient($r^2$) between water soluble carbon and water soluble nitrogen was 0.12 during the period of active composting mule was 0.50 after 25 days of composting time

• Journal of Bio-Environment Control
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• v.27 no.2
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• pp.166-172
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• 2018

This study set out to conduct a field survey with smart greenhouse-based farms in seven types to figure out the actual state of smart greenhouses distributed across the nation before selecting a system to implement an optimal greenhouse environment and doing a research on higher productivity based on data related to crop growth, development, and environment. The findings show that the farms were close to an intelligent or advanced smart farm, given the main purposes of leading cases across the smart farm types found in the field. As for the age of farmers, those who were in their forties and sixties accounted for the biggest percentage, but those who were in their fifties or younger ran 21 farms that accounted for approximately 70.0%. The biggest number of farmers had a cultivation career of ten years or less. As for the greenhouse type, the 1-2W type accounted for 50.0%, and the multispan type accounted for 80.0% at 24 farms. As for crops they cultivated, only three farms cultivated flowers with the remaining farms growing only fruit vegetables, of which the tomato and paprika accounted for approximately 63.6%. As for control systems, approximately 77.4% (24 farms) used a domestic control system. As for the control method of a control system, three farms regulated temperature and humidity only with a control panel with the remaining farms adopting a digital control method to combine a panel with a computer. There were total nine environmental factors to measure and control including temperature. While all the surveyed farms measured temperature, the number of farms installing a ventilation or air flow fan or measuring the concentration of carbon dioxide was relatively small. As for a heating system, 46.7% of the farms used an electric boiler. In addition, hot water boilers, heat pumps, and lamp oil boilers were used. As for investment into a control system, there was a difference in the investment scale among the farms from 10 million won to 100 million won. As for difficulties with greenhouse management, the farmers complained about difficulties with using a smart phone and digital control system due to their old age and the utter absence of education and materials about smart greenhouse management. Those difficulties were followed by high fees paid to a consultant and system malfunction in the order.

• Horticultural Science & Technology
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• v.29 no.5
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• pp.389-406
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• 2011

As part of a feasibility study for introducing carbon labeling of fruit products in Korea, we explore the use of carbon footprints for Korean kiwifruit from Gyeongnam region as a case study. In Korea, the Korean Environmental Industry and Technology Institute (KEITI) is responsible for the carbon footprint labeling certification, and has two types of certification programs: one program focuses on climate change response (carbon footprint labeling analysis) and the other on low-carbon products (reduction of carbon footprints analysis). Currently agricultural products have not yet been included in the program. Carbon labeling could soon be a prerequisite for the international trading of agricultural products. In general the carbon footprints of various agricultural products from New Zealand followed the methodology described in the ISO standards and conformed to the PAS 2050. The carbon footprint assessment focuses on a supply chain, and considers the foreground and the background systems. The basic scheme consists of four phases, which are the 'goal', 'scope', 'inventory analysis', and 'interpretation' phases. In the case of the carbon footprint of New Zealand kiwifruit the study tried to understand each phase's contribution to total GHG emissions. According to the results, shipping, orchard, and coolstore operation are the main life cycle stages that contribute to the carbon footprint of the kiwifruit supply chain stretching from the orchard in New Zealand to the consumer in the UK. The carbon emission of long-distance transportation such as shipping can be a hot-spot of GHG emissions, but can be balanced out by minimizing the carbon footprint of other life cycle phases. For this reason it is important that orchard and coolstore operations reduce the GHG-intensive inputs such as fuel or electricity to minimize GHG emissions and consequently facilitate the industry to compete in international markets. The carbon footprint labeling guided by international standards should be introduced for fruit products in Korea as soon as possible. The already established LCA methodology of NZ kiwifruit can be applied for fruit products as a case study.

• The Korean Journal of Mycology
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• v.16 no.4
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• pp.220-225
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• 1988

This study was carried out to investigate the effect on the system of crop rotation of sesame(Sesamum indicum L). The results of infected plant percentage and yield of sesame wilting disease, fluctuation of density of Fusarium oxysporum and Actinomycetes, and their pathogenicity test on Fusarium spp isolated from sesame cultural soil were investigated. Density of F. oxysporum was the highest in a sesame continuous cropping soil but that of Actinomycetes was the lowest in that soil. And that of F. oxysporum and Actinomycetes according to investigation date was the highest at June. 30 and July. 30, respectively. Their pathogenicity of F. oxysporum and F. solani isolated from sesame cultural soil to sesame, peanut and green gram were recognized to all isolates except one isolate among F. oxysporum 8 isolates and one isolate to sesame, 2 isolates to peanut and all isolates to green gram among F. solani 4 isolates. F. oxysporum density and infected plant of wilting disease were increased as a result of replanted cultivation of sesame, and yield of that was prominantly reduced. Relation between density of F. oxysporum in cultural soil and infected plant percentage showed positive correlation and yield index highly negative. There was little difference between sesame-upland rice and sesame-peanut in the system of crop rotation.

• Journal of Food Hygiene and Safety
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• v.27 no.2
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• pp.146-151
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• 2012

In this study, effective gene extraction methods were compared to identify raw materials of processed meat products through molecular biological methods. Species specific primers were used to identify ingredients of processed foods and, as a sample, 13 kinds of processed meat products including beef, pork and chicken. According to the type of sample, 13 kinds of samples were classified into liquid type, source type and powder type. The samples were pre-treated (centrifugation) and (or) performed Whole Gene Amplification (WGA) kit for amplification of the extracted DNA. As a result, it was possible to identify the raw material of products through the centrifugation of sample 1 ml for liquid type of processed meat products. For source type of products after gene extraction, it was required to perform WGA for the identification of ingredients. For powder type products did not required any further pre-treatment and WGA. In this study, it was an opportunity to confirm the possibility of identification of raw material from the gene extraction of processed meat products and this method could be used to examine the authenticity of raw material of products.

• Korean Journal of Poultry Science
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• v.47 no.3
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• pp.143-151
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• 2020

This study investigated the effects of the addition of commercial enzyme products to broiler feed with reduced levels of metabolizable energy and crude protein on the growth performance, blood profiles, and cecal microflora. A total of 750 seven-day-old male Ross 308 broiler chicks were randomly allotted to five treatment groups with six replicates (25 birds/replicate) for 28 days. A corn-wheat-soybean meal-based diet was formulated to meet or exceed the nutrient recommendations and used as the control diet. Experimental diets with metabolizable energy reduced by 100 kcal/kg and crude protein by 1% were formulated containing four different commercial enzyme products. Feed intake and weight gain were not affected by the dietary treatments; however, feed conversion ratios were significantly lower (P<0.01) in the control group than in the other treatment groups during the entire experimental period. There were no significant differences in the blood profiles and cecal microflora between the dietary treatments. However, the viscosity of jejunal contents in chicks fed a diet with enzyme B was significantly lower than that in the other groups. The tentative marketing age was unaffected by any of the dietary treatments, and ranged from 26.39 d to 26.84 d. Collectively, the use of commercial enzymes contributed to a similar weight gain as that in chicks fed diets with reduced energy and crude protein levels; however, it failed to maintain the feed conversion ratio.

• Korean Journal of Agricultural Science
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• v.12 no.1
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• pp.75-85
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• 1985

This study is intended to find out the influence of Lignosulfonic Acid Type Admixture on compressive, tensile, flexural strength and dispersing action of mortar, and fixation of by-product of pulp industry. 1. The more Pozzolith-84 is added, the larger flow value is. The admixture of lignosulfonic acid type adhere to cement particles and the surface potential of particles is generated. On account of the repulsion among the cement particles, they are dispersed and the mortar get workable, so the production cost of precast product is curtailed and the amount of cement is reduced in a certain workability of mortar. 2. The strength of mortar is greater than plain mortar when P/C added is 0.2 and 0.4%. As time passed the potential energy is reduced and the distance of particles which lignosulfonic acid adhered to get near according as the amount of adhesion is increased. The setting and hardening reaction of morter is occurred in close state, so the strength of mortar is increased a little. The strength of mortar is less than plain mortar when amount P/C added is 0.8%. Pozzolith-84 is mainly composed of lignosulfonic acid and lignin does not influence the hardening of mortar, therefore the remained $SO_3$, $SO_3H$ are the reason of decrease of strength. 3. There is high significance between specific gravity and compressive strength. The larger specific gravity is, the more compressive strength is increased. There is high significance between 7 day's strength and 28 day's strength. The larger compressive strength is, the more tensile and flexural strength are increased. 4. Since Pozzolith-84 is a by-product of pulp industry, by using the Pozzolith-84 admixture the concreate quality is improved. The water pollusion is reduced according to fix by-products in concrete structure.

• Journal of Bio-Environment Control
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• v.27 no.3
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• pp.253-259
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• 2018

This study set out to select a system to realize an optimal environment for strawberry cultivation greenhouses based on data about the growth and development of strawberry and its environment and to provide basic data for the research of its improved productivity. For these purposes, the investigator conducted a field survey with greenhouses for strawberry cultivation in western Gyeongnam. The findings show that farmers in their fifties and sixties accounted for the biggest part in the age groups of strawberry farmers. While those who were under 50 were accounted for approximately 67.5%, those who were 60 or older accounted for 32.5%. As for cultivation experiences, the majority of the farmers had ten years of cultivation experiences or less with some having 30 years of cultivation experiences or more. All the farmers built an arch type single span greenhouse. Those who used nutrient solutions were about 75.0%, being more than those who used soil. All of the farmers that used a nutrient solution adopted an elevated hydroponic system. The single span greenhouses were in the range of 7.5~8.5m, 1.3~1.8m and 2.5~3.5m for width, eaves, and ridge height, respectively, regardless of survey areas. The rafters interval was about 0.7~0.8m. In elevated hydroponic cultivation, the width, height, and interval of the beds were about 0.25m, 1.2m and 1.0m, respectively. As for the strawberry varieties, the domestic ones accounted for approximately 97.5% with Seolhyang being the most favorite one at about 65.0%. As for the internal environment factors of greenhouses, 38 farmers measured only temperature and relatively humidity. As for hydroponics, the farmers used a hydroponics control system. Except for the farmers that introduced a smart farm system for temperature and humidity control, approximately 85.0% controlled temperature and humidity only with a control panel for side windows and ventilation fans. As for heating and heat insulation, all of the farmers were using water curtains with many farmers using an oil or electric boiler, radiating lamp or non-woven fabric, as well, when necessary.