• 방사성폐기물학회지
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• 제14권1호
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• pp.11-19
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• 2016

This paper focuses on the estimation of durability and service-life of reinforced concrete structures in Wolsong Low- and intermediate-level wastes Disposal Center (WLDC) in Korea. There are six disposal silos located in the saturated environment. The silo concrete is degraded due to reactions with groundwater and chemical attacks, and finally it will lose its properties as a transport barrier. The infiltration of sulfate and magnesium, leaching of potassium hydroxide, and chlorine induced corrosion are the most significant factors for degradation of reinforced concrete structure in underground environment. From the result of evaluation of the degradation time for each factor, the degradation rate of the reinforced concrete due to sulfate and magnesium is $1.308{\times}10^{-3}cm/yr$, and it is estimated to take 48,000 years for full degradation while potassium hydroxide is leached in depth of less than 1.5 cm at 1,000 years after the initiation of degradation. In case of chlorine induced corrosion, it takes 1,648 years to initiate corrosion in the main reinforced bar and 2,288 years to reach the lifetime limit of the structural integrity, and thus it is evaluated as the most significant factor.

• 한국초지조사료학회지
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• 제7권3호
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• pp.157-161
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• 1987

In order to utilize the tuber of Jerusalem artichoke (Jerusalem tuberosus L.) which has been considered one of the most economical resources for bioenergy, the tubers of the plant were processed into silage in 11 lab-silo with three levels of mixture of concentrates i.e. 10, 20, 30%. The silage was stored for 20 to 40 days before analyses. The quality of silage was compared with those of the tube-only silage without concentrates. Aproximate composition, pH, ammonium nitrogen, total nitrogen, and organic acids were analyzed. The results obtained are summarized ; 1. With the mixture of concentrates, the water content of the silage was able to be adjusted to 70 percent and NDF significantly increased (P<0.05) while ADF significantly decreased. 2. The content of water-soluble carbohydrate (WSC) was significantly decreased in silages of the mixture of concentrate and the tuber (P<0.05), while total nitrogen and ammonium nitrogen increased. 3. Tube-only silage gave satisfaction in fermentation, particularly organic-acid fermentation. As the storage period extended, Flieg's score of the silage was improved. Conclusively, the tuber of Jerusalem artichoke found to satisfy the requirements of good silage and to be recommended as a good resource for all-inane silage provided the tuber was ensilaged with 20 to 30 percent concentrate.

• 펄프종이기술
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• 제32권3호
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• pp.25-31
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• 2000

It is required to use substantial amount of wet strength resin for producing multi-functional mulch papers since these paper products shold maintain its strength properties when they exposed to outdoor weather for several months. While producing mulch papers it is usual to observe significant amount of foam at white water silo. Thus it is imperative to use defoaming or antifoaming agents. In this study diverse defoaming and antifoaming agents have been tested for their effective-ness in eliminating foams that produced. It was shown that combined use of a silicone type defoamer and a fatty acid type anti-foaming agent was msot effective in eliminating foams. These chemicals were used in trial production of mulch papers and their influence on paper-making wet end system was examined including one pass retention cationic demand con-ductivity pH etc. It was found that the defoaming agents were very effective for removing foams in trial production. Tensile strengths of the mulch papers produced were significantly greater than commericial mulch papers produced in Japan.

• 한국초지조사료학회지
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• 제10권1호
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• pp.48-54
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• 1990

In order to investigate effects of starch addition on the fermentative quality and dry matter digestibility (DMD) of Kudzu, Puerarie thunbergii Bentham plants were ensiled by the conventional method in small experimental plastic silo of 7.5 liter with different levels of starch addition. The fermentative quality, neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) of silage were determined by chemical analysis, and in vitro dry matter digestibility (DMD) by pepsin-cellulase technique. Total digestibile nutrients (TDN), digestible energy (DE) and metabolizable energy (ME) were calculated with DMD. The results obtained were as follows; 1. Acetate, butyrate, PH, NDF, ADF, and ADL of Kudzu silage were reduced with increasing of starch addition but the contents of lactate and total acid were increased. 2. The DMD was marked 47.5, 49.5, 51.2, 57.9 and 62.0 % under starch addition with a rate of 0, 2, 4, 6 and 8 %, respectively. 3. TDN, DF and ME were increased with high rate of starch addition. 4. The regression equation and correlation of Kudzu silage between level of starch (X) and DMD (Y) were Y= 41.6 + 1.86 X (I= 0.96, P < 0.01), of silage between Flieg's score (X) and DMD (Y) were Y= 41.6 + 0.23 X (I= 0.96, P < 0.01) and of silage between level of starch (X) and Flieg's score (Y) were Y= 21.3 + 7.97 X (I= 0.97, P < 0.01), respectively.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.711-722
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• 2008

A projectile when passes through a moving shock wave, experiences drastic changes in the aerodynamic forces as it moves from a high-pressure region to a low pressure region. These sudden changes in the forces are attributed to the wave structures produced by the projectile-flow field interaction, and are responsible for destabilizing the trajectory of the projectile. These flow fields are usually encountered in the vicinity of the launch tube exit of a ballistic range facility, thrusters, retro-rocket firings, silo injections, missile firing ballistics, etc. In earlier works, projectile was assumed in a steady flow field when the computations start and the blast wave maintains a constant strength. However, in real situations, the projectile produces transient effects in the flow field which have a deterministic effect on the overtaking process. In the present work, the overtaking problem encountered in the near-field of muzzle guns is investigated for several projectile Mach numbers. Computations have been carried out using a chimera mesh scheme. The results show that, the unsteady wave structures are completely different from that of the steady flow field where the blast wave maintains a constant strength, and the supersonic and subsonic overtaking conditions cannot be distinguished by identifying the projectile bow shock wave only.

• Advances in concrete construction
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• 제13권3호
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• pp.243-254
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• 2022

Reinforced concrete (RC) deep beams are critical structural elements used in offshore pile caps, rectangular cross-section water tanks, silo structures, transfer beams in high-rise buildings, and bent caps. As a result of the low shear span ratio to effective depth (a/d) in deep beams, arch action occurs, which leads to shear failure. Several studies have been carried out to improve the shear resistance of RC deep beams and avoid brittle fracture behavior in recent years. This study was performed to investigate the behavior of RC deep beams numerically and experimentally with different reinforcement arrangements. Deep beams with four different reinforcement arrangements were produced and tested under monotonic static loading in the study's scope. The horizontal and vertical shear reinforcement members were changed in the test specimens to obtain the effects of different reinforcement arrangements. However, the rebars used for tension and the vertical shear reinforcement ratio were constant. In addition, the behavior of each deep beam was obtained numerically with commercial finite element analysis (FEA) software ABAQUS, and the findings were compared with the experimental results. The results showed that the reinforcements placed diagonally significantly increased the load-carrying and energy absorption capacities of RC deep beams. Moreover, an apparent plastic plateau was seen in the load-displacement curves of these test specimens in question (DE-2 and DE-3). This finding also indicated that diagonally located reinforcements improve displacement ductility. Also, the numerical results showed that the FEM method could be used to accurately predict RC deep beams'behavior with different reinforcement arrangements.

• Asian-Australasian Journal of Animal Sciences
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• 제11권5호
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• pp.522-529
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• 1998

This experiment was conducted to study the effects of lactic acid bacteria (LAB) inoculation either alone or in combination with cell wall degrading enzymes on the fermentation characteristics and chemical compositions of Rhodesgrass silage. Over to 1 kg of fresh Rhodesgrass sample a treatment of inoculant LAB with or without addition of an enzyme of Acremoniumcellulase (A) or Meicelase (M) or a mixture of both enzymes (AM) was applied. The treatments were control untreated, LAB-treated (application rate $1.0{\times}10^5cfu/g$ fresh sample), LAB+A 0.005%, LAB+A 0.01%, LAB+A 0.02%, LAB+M 0.005%, LAB+M 0.01%, LAB+M 0.02 %, LAB+AM 0.005%, LAB+AM 0.01%, and LAB+AM 0.02%. The sample was ensiled into 2-L vinyl bottle silo, with 9 silages of each treatment were made. Three silages of each treatment were incubated at 20, 30 and $40^{\circ}C$ for 2-months of storage period. All silages were well preserved with their fermentation quality has low pH values (3.91-4.26) and high lactic acid concentrations (4.11-9.89 %DM). No differences were found in fermentation quality and chemical composition of the control untreated silage as compared to the LAB-treated silage. Combined treatment of LAB+cellulases improved the fermentation quality of silages measured in terms of lower (p < 0.01) pH values and higher (p < 0.05) lactic concentrations than those of LAB-treated silages. Increasing amount of cellulase addition resulted in decrease (p < 0.05) of pH value and increase (p < 0.05) of lactic acid concentration. LAB + cellulase treatments (all cellulase types) reduced (p < 0.01) NDF, ADF and in vitro dry matter digestibility of silages compared with the control untreated silages. The fermentation quality and the rate of cell wall reduction were higher (p < 0.01) in the silages treated with LAB + cellulase A than in the silages treated with either LAB+cellulase M or LAB + cellulase AM. Incubation temperature of $40^{\circ}C$ was likely to be more appropriate environment for stimulating the fermentation of Rhodesgrass silages than those of 20 and $30^{\circ}C$.

• Asian-Australasian Journal of Animal Sciences
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• 제14권7호
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• pp.947-950
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• 2001

To improve the low content of crude protein and low quality fermentation of napiergrass silage, ensiling with phasey bean was examined. Napiergrasses, (Pennisetum purpureum cv. Merkeron), hybrid napiergrass (Pennisetum purpureum${\times}$ Pennisetum typhoides) and phasey bean (Macroptilium lathyroides cv. Murray) were cultivated in Fukuoka, Japan. The first growth of napiergrasses and phasey bean were harvested at 90 days of age and chopped into about 1 cm lengths. The mixing levels of phasey bean with napiergrasses were 0, 25, 50 and 75; 700 g of plant materials were ensiled into a laboratory silo (1.0 litre. polyethylene container) and incubated for 30 days. After opening silos, pH, total nitrogen (TN), volatile basic nitrogen (VBN) and organic acids (lactic acid: LA, acetic acid: AA, butyric acid: BA) were determined. The experiment was a factorial design of $2{\times}4$ with 3 replicates. The data were analyzed statistically by two-way analysis of variance. Without inclusion of phasey bean, lower quality was observed for hybrid silage than for Merkeron silage. The inclusion of phasey bean at the rate of 25% increased DM and TN, and decreased pH value, VBN/TN, AA and BA in both Merkeron and hybrid napiergrass silages. The value of pH, TN, VBN/TN, AA and BA were not significantly different among 25, 50 and 75% mixing levels of phasey bean. LA production increased significantly with the increase in phasey bean mixing level in both hybrid and Merkeron silages. At all mixing levels of phasey bean, LA production did not show significant differences between Merkeron and hybrid silages.

• 한국초지조사료학회지
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• 제38권2호
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• pp.99-105
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• 2018

This study was carried out to estimate the effect of selected inoculants on chemical compositions and fermentation characteristics of rye silage. Rye was harvested at dough stage and divided into 5 treatments, following: No additives (CON); L. plantarum R48-27 (LP27); L. buchneri R4-26 (LB26); Mixture of LP27 and LB26 at 1:1 ratio (MIX); and L. buchneri (LB). The rye forage was ensiled into 10 L bucket silo for 100 days. The contents of NDF and ADF were lowest (P<0.05) in LB26. The pH in LB26, MIX, and LB were lower (P<0.05) than CON and LP27. Lactate content in LB was higher (P<0.05) than the others, while acetate content in LB26 and LB were higher (P<0.05) than that in CON and LP27. Lactate to acetate ratio was highest (P<0.05) in LB, but lowest in LB26. Lactic acid bacteria (LAB) count in LB was higher (P<0.05) than that in CON, while yeast count in CON was lower than in all silages applied inoculants. In conclusion, silages inoculated with LB26 could improve potentially the aerobic stability caused by increases of acetate and propionate concentrations.

• 펄프종이기술
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• 제30권4호
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• pp.18-27
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• 1998

Biopulping is defined as the treatment of wood chips with lignin-degrading fungi prior to pulping. Fungal pretreatment prior to mechanical pulping reduces electrical energy requirements during refining or increases mill throughput, improves paper strength, reduces the pitch content, and reduces the environmental impact of pulping. Our recent work involved scaling up the biopulping process towards the industrial level, investigating both the engineering and economic feasibility. We envision the process to be done in either a chip-pile or silo-based system for which several factors need to be considered: the degree of decontamination, a hospitable environment for the fungus, and the overall process economics. Currently, treatment of the chips with low-pressure steam is sufficient for decontamination and a simple, forced ventilation system maintains the proper temperature, humidity, and moisture conditions, thus promoting uniform growth of the fungus. The pilot-scale trial resulted in the successful treatment of 4 tons of wood chips (dry weight basis) with results comparable to those on a laboratory. Larger, 40-ton trials were also successful, with energy savings and paper properties comparable with the laboratory scale. The overall economics of the process also look very favorable and can result in significant annual savings to the mill. Although the current research has focused on biopulping for mechanical pulping, it is also beneficial for sulfite chemical pulping and some applications to recycled fiber have been investigated.