• KSBB Journal
• /
• v.17 no.3
• /
• pp.255-260
• /
• 2002

1,3-Propanediol as a bifunctional organic compound could be used in polymerization reactions producing polyesters and polyurethanes. Byproduct containing high concentration of glycerol from fat industry was used to produce 1,3-propanediol in lower production cost as well as waste treatment. In this study, various attempts were made to increase 1,3-propanediol production under different conditions using Klebsiella pneumoniae ATCC 15380. The conversion yield and byproduct formation were influenced significantly by the fermentation pH and temperature. The optimal glycerol and nitrogen concentration for 1,3-propanediol production were found to be 25 a/L and 1%(w/v), respectively. The formation of 1,3-propanediol was optimal at pH 6.0 and temperature $35^{\circ}C$. 1,3-Propanediol production from byproduct from 2.5% glycerol was lower than that of 2.5% commercial glycerol and amounted only to 9.84 a/L from byproduct, while to 12.13 a/L from commercial glycerol.

• Asian-Australasian Journal of Animal Sciences
• /
• v.24 no.9
• /
• pp.1217-1226
• /
• 2011

Finding alternative feeds, such as sesame hulls and Prosopis juliflora species can attenuate difficulties of feed shortage and reduce the cost of animal feed in arid and semi-arid countries. Thirty-two Black male kids with similar initial weights (BW = $16.7{\pm}0.80\;kg$) and $120{\pm}5\;d$ of age, were used to evaluate the effect of replacing barley grains and soybean meal with Prosopis juliflora pods (PJP) and sesame hulls (SH) on growth performance, digestibility and carcass and meat characteristics. Kids were equally divided into four dietary treatment groups for an 84-d fattening period. Treatment diets had similar crude protein (CP) and metabolizable energy (ME). The treatment groups were: (T1) no PJP nor SH, (T2) 10% PJP and 20% SH, (T3) 15% PJP and 15% SH, and (T4) 20% PJP and 10% SH. A tendency was detected (p<0.08) for dry matter (DM), crude protein (CP), organic matter (OM) and neutral detergent fiber (NDF) intakes that were greater for T2 than T3 and T4 while T1 was not different from all other treatment groups. Ether extract (EE) intake was the greatest (p<0.05) for T2 and the lowest for T1. Acid detergent fiber (ADF) intake was greater (p<0.05) for T2 than T1 while T3 and T4 were intermediate. Final live weight, average daily gain (ADG) and feed conversion ratio (FCR) were comparable among different treatment groups. Digestibility of DM, OM, CP, NDF and ADF were similar among all treatment groups, however, EE digestibility was the lowest (p<0.05) for T1 when compared to other treatments. In addition, nitrogen intake, nitrogen in urine and retained and retention percentages were similar among all treatment groups. However, N loss in feces was higher (p<0.05) for T2 than T3 and T4 while T1 was intermediate. No differences were observed among treatment groups with respect to fasting live weight, hot and cold carcass weights, dressing-out percentages, mesenteric fat, visceral organs, carcass cuts percentages and carcass linear dimensions. No differences were also observed for dissected loin, leg, rack and shoulder tissues except in the total bone % for loin cuts and in the meat to bone ratio for rack cuts. T3 has the greatest total bone % and the lowest meat to bone ratio when compared to all other treatment groups. No differences were observed between treatment groups in all quality characteristics of the longissimus muscle. The present study demonstrates the potential of using PJP and SH for growing kids without adverse effects on growth performance, carcass characteristics and meat quality.

• Korean Journal of Poultry Science
• /
• v.19 no.3
• /
• pp.125-136
• /
• 1992

This study was conducted to estimate the effect of dietary alfalfa meal on the contents of egg yolk cholesterol, the levels of egg yolk pigmentation and the performance of laying hens. Alfalfa meal which was alternated wheat bran was supplied 0, 3.5 and 7%, respectively. Total 192 brown laying pullets of 47 weeks old were randomly assigned to the wire cages from July 23 to October 7, 1991 for 10 weeks. The results obtained were summarized as follows ： 1. The egg production was highest at 3.5% alfalfa meal level during the entire period. But there was no significant difference among treatments. 2. Egg weight increased in treatments 3.5 and 7% alfalfa meal supplementation significantly. (P<0.01). 3. Even though there was no significant difference, the daily egg mass was the highest at 3.5% of alfalfa meal level. 4. Daily feed intake was the highest at 3.5% of alfalfa meal level. However, feed conversion rate was the lowest among treatments. 5. The feed cost per kg egg mass in the treatment of 3.5% alfalfa meal was significantly lower than the other treatments. (P<0.05). 6. Shell thickness and shell weight in terms of egg shell quality were increased as the levels of alfalfa meal were increased. But there was no significant difference among treatments. 7, The egg yolk Pigmentation was improved significantly as the level of alfalfa meal was increased (P<0.01). 8.899 yolk cholesterol contents were decreased in the treatments of 3.5 and 7% alfalfa meal supplementation compared with those in the treatment of wheat bran only(P >0.05). The results of this study indicate that 3.5% alfalfa meal level was most effective and economical in laying hen.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.11
• /
• pp.219-225
• /
• 2020

In this study, the prototype of a blower was designed and made to develop a long-life blower with a volume flow rate of 10,000 ㎥/min with a required total pressure efficiency of 83% or more. Five experimental impellers with various lengths of dust deflectors were manufactured and used for the erosion experiments. The erosion test was conducted by operating for 160 hours in a self-produced closed loop-type erosion test apparatus. A prototype of a model blower was designed, fabricated, and tested. The results revealed a total pressure, air volume flow rate, and efficiency of 690.6 mmAq, 16,243.6 ㎥/min, and 83.6%, respectively, as the result of conversion to a blower based on the measured value of the blower model. The prototype was designed and fabricated as the experimental erosion equipment of the blower. A blower with a dust deflector was developed by performing the erosion experiments under harsh conditions. The blower showed an improved effect of more than 190% based on the wear thickness of the impeller compared to a conventional blower without a dust deflector.

• Journal of Advanced Marine Engineering and Technology
• /
• v.39 no.3
• /
• pp.223-229
• /
• 2015

Surface modification is a technology to form a new surface layer and overcome the intrinsic properties of the base material by applying thermal energy or stress onto the surface of the material. The purpose of this technique is to achieve anti-corrosion, beautiful appearance, wear resistance, insulation and conductance for base materials. Surface modification techniques may include plating, chemical conversion treatment, painting, lining and surface hardening. Among which, a surface modification process using electrolytes has been investigated for a long time in connection with research on its industrial application. The technology is highly favoured by various fields because it provides not only high productivity and cost reduction opportunities, but also application availability for components with complex geometry. In this study, an electrochemical experiment was performed on the surface of 5083-O Al alloy to determine an optimal electrolyte temperature, which produces surface with excellent corrosion resistance under marine environment than the initial surface. The experiment result, the modified surface presented a significantly lower corrosion current density with increasing electrolyte temperature, except for $5^{\circ}C$ of electrolyte temperature at which premature pores was created.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.23 no.2
• /
• pp.171-181
• /
• 2011

Recently, many studies have been attempted to save the cost of production and to build the ocean energy power generating system. The low-reflection structure with the wall-typed curtain which has a wave power generation system of OWC is known as the most effective energy conversion system. A three-dimensional numerical model was used to understand the characteristics of velocity of flows about compressed air and to estimate the pressure acting on the low-reflection structure due to the short-period waves. The three-dimensional numerical wave flume which is the model for the immiscible two-phase flow was applied in interpretation for this. The numerical simulation showed well about the changes in velocity of compressed air and the characteristics of pressure according to the change in the wave height and depth of the curtain wall. Additionally, the results found that there was the point of the maximum velocity of the compressed air when the reflection coefficient is at its lowest point.

• The Journal of the Korea Contents Association
• /
• v.17 no.4
• /
• pp.1-11
• /
• 2017

Interest in all kinds of renewable energies has been highly increased while the micro-small-hydro power(MSHP) development has shown relatively slowly growth because of the negative public recognition about dam site development. It is, however, announced that the micro-SHP shows higher energy conversion efficiency compared to other renewable energies and does not emit any carbon dioxide. Thus, it is concerned about the development and application of micro-SHP as an alternative energy. In this study, the application for Android was exploited with Eclipse to visualize readily the potential realizable amount of hydropower by micro-SHP. With this application, we can select the region from the map, obtain the design discharge of the selected site was calculated with HEC-HMS, presented by U.S. Army of Corp. and perform the simply economic analysis in sequence. Yeongwol in Gangwon-do Province, Korea was chosen as the target area since historically abundant precipitation was found and it is possible to obtain fundamental data from WAMIS. Results from this study could be expanded the whole region of Korea. Also, the initial investment cost would be reduced if the location for micro-SHP would be determined properly, because this application can help us easily select and examine the potential micro-SHP sites without on-the-spot visit.

• Current Photovoltaic Research
• /
• v.4 no.2
• /
• pp.68-79
• /
• 2016

The power conversion efficiency of perovskite solar cells has remarkably increased from 3.81% to 22.1% in the past 6 years. Perovskite solar cells, which are based on the perovskite crystal structure, are fabricated using organic-inorganic hybrid materials. The advantages of these solar cells are their low cost and simple fabrication procedure. Also, they have a band gap of about 1.6 eV and effectively absorb light in the visible region. For the commercialization of perovskite solar cells in the field of photovoltaics, the issue of their long term stability cannot be overlooked. Although the development of perovskite solar cells is unprecedented, their main drawback is the degradation of the perovskite structure by moisture. This degradation is accelerated by exposure to UV light, temperature, and external bias. This paper reviews the aforesaid reasons for perovskite solar cell degradation. We also discuss the research directions that can lead to the development of perovskite solar cells with high stability.

• Journal of Microbiology and Biotechnology
• /
• v.24 no.12
• /
• pp.1664-1672
• /
• 2014

In this study, a fibrous bed bioreactor (FBB) was used for $\small{D}$-lactic acid ($\small{D}$-LA) production by Sporolactobacillus inulinus Y2-8. Corn flour hydrolyzed with ${\alpha}$-amylase and saccharifying enzyme was used as a cost-efficient and nutrient-rich substrate for $\small{D}$-LA production. A maximal starch conversion rate of 93.78% was obtained. The optimum pH for $\small{D}$-LA production was determined to be 6.5. Ammonia water was determined to be an ideal neutralizing agent, which improved the $\small{D}$-LA production and purification processes. Batch fermentation and fed-batch fermentation, with both free cells and immobilized cells, were compared to highlight the advantages of FBB fermentation. In batch mode, the $\small{D}$-LA production rate of FBB fermentation was 1.62 g/l/h, which was 37.29% higher than that of free-cell fermentation, and the $\small{D}$-LA optical purities of the two fermentation methods were above 99.00%. In fe$\small{D}$-batch mode, the maximum $\small{D}$-LA concentration attained by FBB fermentation was 218.8 g/l, which was 37.67% higher than that of free-cell fermentation. Repeate$\small{D}$-batch fermentation was performed to determine the long-term performance of the FBB system, and the data indicated that the average $\small{D}$-LA production rate was 1.62 g/l/h and the average yield was 0.98 g/g. Thus, hydrolyzed corn flour fermented by S. inulinus Y2-8 in a FBB may be used for improving $\small{D}$-LA fermentation by using ammonia water as the neutralizing agent.

• Journal of Digital Convergence
• /
• v.15 no.10
• /
• pp.429-436
• /
• 2017

A design thinking-based collaborative workshop in which various stakeholders in the milk processing industry circulation ecosystem participated shows a new problem innovation paradigm that encourages the spread of practical prototyping culture. in the expression of empathy and collective intelligence among members on facing issues, the conversion of collaboration and communication methods, the business handling of the organization based on the design work method as 'creativity mechanism'. In this workshop, which was promoted in three stages of 'approach to problems', 're-definition of problems', and 'experience-based future vision design', participants themselves redefine real problems in terms of the accuracy of feed orders between feed suppliers and livestock farmers, ordering of feeds on time, cost reduction of feed supply and present new alternatives and expanded business areas. The results suggested in this workshop suggest the usefulness of design thinking in business innovation in that they presented how to approach the problem and a creative thinking system to find its solution to direct and indirect stakeholders of the industry as well as the improvement of supply and demand rate of livestock feed and quality.