• Korean Journal of Environmental Agriculture
• /
• v.16 no.4
• /
• pp.382-389
• /
• 1997

To study the optimum conditions of composing with sewage sludge, the variations of temperature and $CO_2$ generation amount during composting periods were investigated. The conditions were that sewage sludge added to bulking agents such as sawdust and rice hull were used and differently treated with microorganism seeding or not, initial C/N ratio, air flow rate and initial moisture contents. The results were summarized as follows : Seeding of 5% microorganism was higher temperature than not seeding. And using rice hull as bulking agents, and adjusting 21${\sim}$22 of initial C/N ratio, $200ml/l\;{\cdot}\;min$. of air flow rate and 64${\sim}$65% of initial moisture contents were higher temperature than any other conditions. Seeding of 5% microorganism was more $CO_2$ generation amount than not seeding. And using saw dust was more $CO_2$ generation amount than using rice hull as bulking agents. In the case of initial C/N ratio, adjusting 21${\sim}$42 was also more $CO_2$ generation amount than adjusting 12${\sim}$14. Judging from the result, it should be considered that the optimum conditions of composting with sewage sludges were seeding of 5% microorganism and adjusting 21${\sim}$22 of initial C/N ratio, $200ml/l\;{\cdot}\;min$. of air flow rate and 64${\sim}$65% of initial moisture contents.

• Journal of environmental and Sanitary engineering
• /
• v.15 no.3
• /
• pp.23-23
• /
• 2000

In this study, to determine the optimum fermentation process for the feed production of food wastes and estimate the practical value of fermented feed using kudzu creeper and sawdust as bulking agent. This study considered initial C/N ratio control as the fermentation process variables. The results are summarized as follows. Minimum water contents of byproducts in the fermentation feed production showed 3994(kudzu), 37%( sawdust) at the C/N ratio 25 and 45%(kudzu, sawdust) at the C/N ratio 35. Temperature variations in the fermentation feed production at the C/n ratio 25 indicated 68'C(kudzu), 70'C (sawdust).Optimum condition of consists of fermentation process of water content, C/N ratio and permeability (porous structure of the mixture). For optimum fermentation of gravitationally, dewatered garbage, the proper mixing ratios of kudzu(moisture contents : 17.3%) and sawdust(moisture contents : 13.2%) were 41% and 39%, respectively Major biological reaction in the aerobic fermentation feed production occurred during 12~14hrs

• Journal of the Korean Society of Combustion
• /
• v.14 no.3
• /
• pp.16-23
• /
• 2009

It is strongly desired for coal-fired power plants to utilize not only low-rank coals with high moisture contents, but also lowering cost with diversifying fuel sources. In this study, combustion characteristics of low rank coal with high moisture, and standard pulverized coals are experimentally investigated using TGA (Thermogravimetric Analysis) and DTF (drop tube furnace). The coals tested are three kinds of coal with moisture content ranging from 8.32 to 26.82%. The results show that under the air combustion condition, the burn-out time at TGA rises as moisture content increases, and standard pulverized coal with 8.32% moisture content showed the lowest activation energy of 55.73 kJ/mol. In case of the high amount of moisture, the combustion efficiency decreases due to evaporation heat loss, and unburned carbon in ash produced at combustion process in DTF increased. Aslo, initial deformation temperature of slag attached in alumina tube of DTF decreased with lowering the crytallinity of anorthite and augite. To improve the combustion reactivity and efficiency, it is effective to upgrade through drying the high moisture coal to moisture level (less than 10%) of standard pulverized coal.

• Fisheries and Aquatic Sciences
• /
• v.14 no.2
• /
• pp.105-110
• /
• 2011

This study determined the effects of the dietary moisture level and feeding rate on the growth and gastric evacuation of young olive flounder. Four experimental diets with different moisture levels (9%, 21%, 30%, and 40%) were prepared through the addition of water to the commercial extruded pellet. Three replicate groups of fish (initial weight: $106{\pm}1.4\;g$) were fed diets containing 9%, 21%, 30%, and 40% moisture to satiation or a moisture level of 9% and 30% at a restricted feeding rate (95% of satiation) for 15 weeks. The mean water temperature was $22{\pm}1.6^{\circ}C$ during the feeding trial. Gastric evacuation rates were determined post-feeding. The dietary moisture levels did not significantly affect weight gain, but the weight of the fish receiving 9% and 30% moisture diets to 95% satiation were significantly lower than those of the fish fed 9-40% moisture diets to 100% satiation (P<0.05). The feed efficiency, protein efficiency ratio, viscerosomatic index, and survival were not significantly affected by the dietary moisture levels and feeding rates. The daily feed intake of the fish fed to 100% satiation did not significantly differ among the treatment groups. The stomach contents that peaked within 3 h of feeding gradually decreased, and the stomachs of fish were completely evacuated within 18 h. The contents of the intestine peaked at 3-12 h post-feeding, and then declined with the intestine being mostly evacuated at 30 h. The moisture of the stomach contents reached approximately 70% within 3 h post-feeding and gradually increased to approximately 75% within 12 h. No considerable differences were observed in the gastric evacuation and moisture levels of the stomach contents in the fish fed the different diets. The results of this study suggest that the gastric evacuation of olive flounder was not affected by the dietary moisture level and that the addition of water into the diet displayed no beneficial effects on the growth of young olive flounder.

• Proceedings of the KSME Conference
• /
• 2000.04b
• /
• pp.220-227
• /
• 2000

The purpose of this study is to develop the non-gravity fluidized dryer. In this non-gravity fluidized dryer the fluidized zone is produced by two paddles in mixer, which maximizes the surface area of materials and then heated air through the guiding panels dehumidify them. This can conduct the drying process quickly and control moisture contents to lower limits. The ventilation system is closed loop system, which can be changeable to open system, and can be used as a multi-purposed dryer in which mixing, drying, granulating and cooling process is conducted. In order to develop non-gravity fluidized dryer, in the first the fundamental experiments performed to mixing accuracy and then the other parts of dryer and control system were examined to check whether they were designed properly and operated harmoniously with mixer. Also the preparatory experiments were fulfilled to examine the efficiency and reliability of dryer. Lastly, on the basis of preparatory experiments in case the initial moisture contents, desired moisture contents, heated air velocity and heating temperature were vary, performance test for the non-gravity fluidized dryer carried out.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.10a
• /
• pp.312-312
• /
• 2017

• Food Science and Preservation
• /
• v.2 no.2
• /
• pp.285-291
• /
• 1995

This study was performed to investigate the optimum moisture content and the best packaging method of dried persimmons for long term storage at room temperature. The package material to be used were 0.05mm polyethylene film, Wrap film, 0.08mm LDPE film exchanged nitrogen gas, and non package for untreated control. Before the storage, the initial moisture contents of dried persimmons were treated with 40%, 35% and 30%, respectively; 40% as traditional dryness, 35% as extending dry period one more week, and 30% as for two more weeks. The best package method was 0.08mm LDPE film exchanged nitrogen gas, and the optimum moisture control was 35%

• Journal of Industrial Technology
• /
• v.13
• /
• pp.3-17
• /
• 1993

The composting process is a suitable to dispose the livestock manure in terms of resources recovery. However the performence of composting process is greatly affected by the environmental conditions such as characteristics of manure, type of the bulking agent, initial moisture contents, temperature, recycle and so on. The purpose of this study is to evaluate the optimum environmental conditions of composting process for livestock manures. The analytical results indicated that no bulking agent was necessary for the cow manure because of the proper C/N ratio. However the pig manure required a bulking agent since the pig manure had not only low in C/N ration but poor ventilation characteristics. In addtion, the initial miosture content for optimum composting appeared to be about 60%. The temperature control was also an essential factor to enhance the activity of thermophilic microorganisms in the laboratory composting unit. It was further found that the recycle of composts may contributed the completion of composting precess as well as C/N ratio reduction and moisture control.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.8 no.2
• /
• pp.1193-1199
• /
• 1966

More stable and higher yields in rice paddy depend mainly upon an adequately balanced supply of water for higher yield. Rice paddy is supplied naturally by rainfall but inevitably requires artificial supplenental irrigation for higher yields. Even though it may be true that the water requirement of rice plants is generally higher than those of other crops, the submerged condition is not necessarily required for rice. The moisture requirements of rice vary according to its growing stages and it is possible to increse the irrigation efficiency by means of lessening the loss due to percolation and evapolation in the field. This experiment was conducted on the effect of the various amount of water supply and different irrigation periods for yield and yield components, and was carried out to find out the most suitable irrigation method and to increase the irrigation efficiency for higher yields in rice paddy. Randomized block design with 3 replications was employed where the 3 levels of the amount of irrigation water; (120% moisture contents), unirrigated (90~100%) and more un irrigated candition (80~90% moisture content), and levels of the various irrigation periods; usual, initial, intermediate and final periods, being treated. The results obtained in this experiment are as follows: 1. As for the physical and chemical and soil properfies, and other characteristics, there are no differences among the treatments enough to be effective for the growth of rice plants. 2. Culm length was measured after harvest as shown in table 2. 3. Difference of the amount of irrigation water did not change the culm length and ear length, however it also indicated more apparent increase in final treatment plots thatn that of usual. 3. No difference in the number of ears and number of ears pers per hill was founded treatments both in the difference of water supply and in the various irrigation periods. 4. There is no difference in the maturing rate and 1000 grains weight. 5. The number of panicles and grains and more increased in 80~100% moisture contents soil than those of 120%. and it shows in un irrigated plots, more irrigated plots and control plots in turn. Other wise according to the period\ulcorner of irrigation the trend is appeared in turn initial, usual, final and intermediate treatments.6. Yield as shown in table 7. 8 was more increased in unirrigated plots(90~IOO% moisture content) than the control plots (120% moisture content) by up to 8.2% and also 3. 2% in more unirrigated plots than that of control by periods is shown: usual plots final, initial, inter mediate treatment plots in turn. 7. The above resutts lead to the conclusion that no remarkable, differences in yields and soil properties are made by the unirrigation. However, it is apparent that this treatment has .some advantages in the points that one could spare the amount of water supply for irrigation with more increase in yield. In addition, a higher temperature and a brisk oxygen supply would be possible throug h this treatments. Accordingly, these treatment would be a more reasonable and economical cultivation method of rice for the better harvest.

• Geomechanics and Engineering
• /
• v.11 no.3
• /
• pp.361-372
• /
• 2016

The soil-concrete interface shear strength, although has been extensively studied, is still difficult to predict as a result of the dependence on many factors such as normal stresses, surface roughness, particle sizes, moisture contents, dilation angles of soils, etc. In this study, a well-known rigorous statistical learning approach, namely the least squares support vector machine (LS-SVM) realized in a ubiquitous spreadsheet platform is firstly used in estimating the soil-structure interface shear strength. Instead of studying the complicated mechanism, LS-SVM enables to explore the possible link between the fundamental factors and the interface shear strengths, via a sophisticated statistic approach. As a preliminary investigation, the authors study the expansive soils that are found extensively in most countries. To reduce the complexity, three major influential factors, e.g., initial moisture contents, initial dry densities and normal stresses of soils are taken into account in developing the LS-SVM models for the soil-concrete interface shear strengths. The predicted results by LS-SVM show reasonably good agreement with experimental data from direct shear tests.