• Transactions of the Korean hydrogen and new energy society
• /
• v.24 no.2
• /
• pp.99-106
• /
• 2013

The variations of performance and metabolites at an early stage were investigated for the successful start-up technology in continuous fermentative hydrogen production. Unsuccessful start-up was observed when the operation mode was changed from batch to continuous mode after the yield was reached to 0.5 mol $H_2$/mol $hexose_{added}$ by batch mode. $H_2$ production continued till 12 hours accompanied by butyrate production, but did not last with propionate production increase. It was suspected that the failure was due to the regrowth of propionic acid bacteria during batch mode which were inhibited by heat-shock but not completely killed. Thus, successful start-up was tried by early switchover from batch to continuous operation; continuous operation was started after the $H_2$ yield was reached to 0.2 mol $H_2$/mol $hexose_{added}$ by batch mode. Although $H_2$ production rate decreased at an early stage, stable $H_2$ yield of 0.8 mol $H_2$/mol $hexose_{added}$ was achieved after 10 days by lowering down propionate production. And it was also concluded that the reason for $H_2$ production decrease at an early stage was due to alcohol production by self detoxification mechanism against VFAs accumulation.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.11 no.1
• /
• pp.17-21
• /
• 1991

A field experiment was carried out to determine the effects of nitrogen(N) fertilization levels(0, 30, 60, 90 and 120 kg/ha) in early spring on the growth, dry matter(DM) yield, seasonal distribution of production and nutritive value of grasses. Additional N after the first, second and third harvest were applied as 60, 60 and 30 kg/ha, equally in 1989. Grass growth and DM yield were significantly increased(p$NO_3$-N concentration was not affected by N level of early spring. It is suggested that, therefore, N application in early spring is essential, and 60 to 90 kg/ha of N application may be desirable in early spring.

• Asian-Australasian Journal of Animal Sciences
• /
• v.24 no.4
• /
• pp.479-484
• /
• 2011

The study was conducted on 20 Holstein X Sahiwal cross bred dairy cows, with an average milk production of $2,752{\pm}113.79$ liters in $284{\pm}5.75$ days during a single lactation, that were divided in to two groups of 10 animals. We investigated the oxidative stress and antioxidant status during the transition period in dairy cows. In this study, plasma level of MDA was considered as an indicator of lipid peroxidation and SOD, catalase, GSH and GSHPx as antioxidants. The lipid peroxidation was significantly (p<0.001) higher in cows during early lactation as compared to the cows in advanced pregnancy. A significant positive correlation (r = +0.831, p<0.01) was determined between MDA and catalase in early lactating cows. In early lactating cows, blood glutathione was significantly lower than in advanced pregnant cows. However, early lactating cows showed non-significant negative correlation for all antioxidant enzymes with lipid peroxidation. In conclusion, dairy cows seemed to have more oxidative stress and low antioxidant defense during early lactation or just after parturition than advanced pregnant cows, and this appears to be the reason for their increased susceptibility to production diseases (e.g. mastitis, metritis, retention of fetal membranes etc.) and other health problems.

• Asian-Australasian Journal of Animal Sciences
• /
• v.15 no.8
• /
• pp.1110-1114
• /
• 2002

The animal production sector in Jordan is characterized by shortages of locally produced feedstuffs derived from rangeland, forage plants or from human food crops as by products. This is exacerbated by insufficient rainfall, overgrazing, early grazing and high stocking rate. Thus, subject to these constraints, other technological improvements are highly desirable to meet the needs of crop growth and animal production. Alternative adapted technologies are also desirable in order to meet the increased demand for red meat in relation to population growth along with the changes in the price subsidy for feedstuff. The technologies are those, which have been introduced to the animal production sector, obtained in agricultural research stations besides on-farm demonstrations. They include technologies suited for increasing birth and twining rates, synchronizing the mating period, introducing the early weaning method, and animal feed and sheep production. Economic assessments conducted in this study demonstrate promising results of hormonal and nutritional practices in improving production efficiency of Awassi sheep in Jordan. Jordanian published data between 1991 and 1998 were used. The examined practices were: 1) use of PMSG in estrus synchronization in ewes, 2) introduction of early lamb weaning program, 3) supplementation with $AD_3E$ for ewes and 4) the use of agro-industrial feed block as a feed supplement for grazing lambs. Production data were then subjected to partial budgeting for economical evaluation. The use of PMSG outperformed the control groups in fertility and net returns per ewe by US$ 8.36/ewe. The early weaning of lambs increased the net returns by US$ 3.90/lamb. The injection with vitamin $AD_3E$ showed an average additional net return of US$ 5.66/ewe. Feeding agriculture by-product blocks improved weight gain in the feed block groups and resulted in additional net returns of US$ 3.5/lamb. The economic viability and reproductive performance indicators demonstrate that efforts should be undertaken to disseminate these new practices in the development program.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.19 no.2
• /
• pp.71-81
• /
• 2016

This text was experimented and investigated the optimum production time and germination characteristics of seed that collect in Korean Chungnam, in order to offer the basic informations for slope restoration and revegetation using Poaceae plant. Optimum time of seed production was mid-late October of Miscanthus sinensis, Pennisetum alopecuroides, early November to late October of Themeda triandra var. japonica and M. sacchariflorus, and mid November of Phragmites communis. Epiphytic amount of seed full ripe was the most times in mid October of M. sinensis, P. alopecuroides and M. sacchariflorus, early November of T. triandra var. japonica, and mid November of P. communis. Seed rate of maturity was the highest times in early November of M. sinensis, P. alopecuroides and M. sacchariflorus, and mid November of T. triandra var. japonica and P. communis. Germination rate by seed collection time was the highest times in early October of M. sacchariflorus, mid October of T. triandra var. japonica, early November of M. sinensis and mid November of P. communis. Germination days by seed production time was the shortest times in early November of M. sinensis and M. sacchariflorus, mid November of T. triandra var. japonica and P. communis. Optimum temperature of germination was $20{\sim}25^{\circ}C$ in M. sinensis and P. alopecuroides, $25^{\circ}C$ in T. triandra var. japonica, and $25{\sim}30^{\circ}C$ in P. communis.

• Journal of the Society of Naval Architects of Korea
• /
• v.54 no.1
• /
• pp.57-62
• /
• 2017

These days, shipbuilding companies are making an effort to adopt the IT technology in order to improve the production efficiency. One such effort is to utilize a planning and scheduling system to predict the production cost in advance. In this system, assessing the welding material quantity is an important factor. Unfortunately, obtaining the welding material quantity in the early design stage is extremely difficult because the detailed production information, which is essential in deriving the cost associated with welding, is normally available at a later stage. This paper aims at developing a computerized program that produces an index to estimate the welding material quantity in the early design stage. By using only three-dimensional geometric information, the program analyzes the production process and estimates the welding material quantity at any design or production stage when no production information is available. The results can be used for the planning and scheduling system.

• Journal of the Korea Concrete Institute
• /
• v.12 no.6
• /
• pp.51-56
• /
• 2000

Fly ash used as a cement replacement material increases the long term strength and also improves the durability of concrete and mortar. However, the use of fly ash is a little in spite of great benefit. In order to increase the consumption of fly ash, it has to be used as a cement replacement materials in the production of mortar and concrete, and the reduction of early strength development due to the use of fly ash also has to be diminished. In this study, many chemical compounds which accelerate the early strength was investigated. The $Na_2$$SO_4$, $K_2$$SO_4$, Triethanolamine were selected and applied to the production of mortar. It was found that they enhance the early strength development of mortar(1, 3day) and decrease the amount of $Ca(OH)_2$, and also increase the production of ettringite. According to the results of mercury instruction test, the pores ranged from 0.01 $\mu\textrm{m}$ to 5$\mu\textrm{m}$ were decreased and it was also found in the analysis of X ray and SEM that fly ash increases the amount of ettringite at early ages.

• Asian-Australasian Journal of Animal Sciences
• /
• v.19 no.7
• /
• pp.970-977
• /
• 2006

Forage oat (Avena sativa L.) is grown extensively in a double-cropping system on dairy farms. Four oat varieties ('Swan', 'Targa', 'Foothill', and 'Nugene') were evaluated for forage production and forage quality during two growing seasons (spring and autumn) at two locations (central and southern region) in South Korea. The heading stage of four oat varieties was observed during spring, but the autumn season did not produce heading until harvest time except for the 'Swan' variety (early-maturing variety). The heading stage of 'Swan' in both locations was earlier compared to other varieties. The four varieties were resistant to both foliar disease and insects. Lodging resistance was higher during autumn except in 2002 at the central region, and late-maturing varieties ('Foothill' and 'Nugene') have lower lodging resistance. Dry matter (DM) content was significantly different between varieties (p<0.001). Comparing different varieties, 'Swan', an early-maturing variety, was highest in DM content. In DM, total digestible nutrients (TDN) and crude protein (CP) yield, the yield of oat varieties in the southern region was higher than in the central region, and forage yield of the oat varieties in the spring season was higher than during the autumn season. The DM and TDN yield showed significant differences between oat varieties. The CP content of oats grown in the central region (Cheonan) was lower than oats grown in the southern region (Daegu), and the spring season produced oats with lower CP compared to the autumn season. Among the four oat varieties, the CP content of late-maturing varieties was higher than the Swan variety (early-maturing variety). The acid detergent fiber (ADF) and neutral detergent fiber (NDF) contents were higher for the varieties grown in Cheonan and during the spring season. The ADF and NDF contents of late-maturing varieties were lower than the early-maturing variety. TDN and relative feed value (RFV) were higher for the varieties grown in Daegu and during the autumn season. Late-maturing variety had higher TDN and RFV than early-maturing variety. Our study showed differences in forage production and forage quality of oats grown in different locations, seasons and varieties. Forage quality as well as forage production was better in the southern region than in the central region. Forage quality was better during autumn, but forage production was better during spring. Late-maturing variety had better forage quality than the early-maturing variety. Therefore, late-maturing varieties are more suitable for use in the southern region.

• Korean Journal of Heritage: History & Science
• /
• v.56 no.3
• /
• pp.22-44
• /
• 2023

The subsistence economics of the early Bronze Age has focused on explaining the intensity of agricultural practices without sufficiently taking into account the diversity of production methods that may arise from cultural types or environmental factors. The problem appears to stem from paying insufficient attention to the question whether we should understand the transition from the Neolithic Age to the Bronze Age as continuous or discrete. This has hitherto blocked an avenue to investigate the gradual changes in subsistence resource production methods. Taking as its premise that changes in the production methods of subsistence resources in the Bronze Age have been continuous and gradual, this paper seeks to restore the production patterns of subsistence resources according to the variety of factors that may have influenced the early Bronze Age production method. With diverse cultural patterns and ecological spaces of the early Bronze Age being confirmed, the work of restoring the production methods of subsistence resources in a specific period is difficult to achieve with one or two stand-alone analyses. A more appropriate method would involve separating a number of different aspects related to the production of subsistence resources, analyzing and interpreting each, and in the final stage, synthesizing the analyses. The specific research method employed in this paper checked for compositional differences in stone production tools, functionally categorized according to a variety of factors that have a close relationship with the production of subsistence resources: cultural-environmental factors and cultural patterns, geographical and topographical factors, soil productivity, and size of settlement. The results of the analysis are as follows: for the early Bronze Age production pattern of subsistence resources in the Seoul and Gyeonggi regions, while no substantive differences were observed with respect to cultural type, geographical and topographical location, the results show statistically significant differences in the composition of production tools according to settlement size and soil productivity. Also, with an increasing ratio of settlement size and total production soil, increases in hunting and armoring tools, woodworking tools, and harvesting tools were observed; on the other hand, when it came to the ratio of fishing tools, the opposite relationship was observed. While a correlation between settlement size or crop cultivation productivity and dependence on hunting or farming was expected, the results of the regression analysis show that settlement size and soil productivity ratios do not have mutually significant relationships. The results thus illustrate that patterns of production differ according to a variety of factors, and no single factor is decisive in the adoption of subsistence resource production methods by a specific settlement. Therefore, the paper emphasizes the need to investigate the production patterns of subsistence resources according to the variety of cultural and environmental factors that make up settlements in early Bronze Age society.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2014.11a
• /
• pp.71-72
• /
• 2014

Green Frame is a building frame system to construct a column-beam structure using composite precast concrete members. To reduce the cost of producing precast concrete, in-situ production of members is required. However, when the structural members are produced on site, it needs a large space for production. So, "Just-In-Time" production method should be adopted. For Just-In-Time to be realized, the early strength of members should be ensured for them to be transported. Thus, steam curing to secure the early strength is applied in Green Frame. Yet, a large-scale steam curing system is not possible for in-situ production of precast concrete. A smaller steam curing system is needed. In this regard, the study is aimed to develop a new steam curing method applicable to the in-situ production of precast concrete.