• Journal of the Korean Wood Science and Technology
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• v.45 no.4
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• pp.382-398
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• 2017

This study was conducted to identify the potential of Quercus mongolica (QUM), Pinus densiflora (PID) and Pinus rigida (PIR) as a raw material for pellet production. Larix kaempferi (LAK), which has mostly been used for pellet production in Korea, was also used as a control. All specimens contained very minimal amounts of sulfur and chlorine. Ash content of LAK was the lowest, followed by PID, PIR and QUM. For the size distribution, the mass fraction between 0.42 mm and 0.25 mm was the highest in PIR. Most fuel characteristics of the produced wood pellets improved with the use of 12% moisture content (MC) particles and the increase of the ratio of length to diameter of a hole in flat-die (L/D ratio). When the MC, bulk density and durability of QUM, PID, PIR and LAK pellets was compared with the standards of the KFRI and ISO, the use of wood particles of 12% MC and flat-die with an L/D ratio of 5.00 for PID particles are suitable for high-quality pellets in the aspects of all fuel characteristics. For PIR and QUM, further work is needed to seek the optimum conditions for the production of high-quality and durable pellets.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.4
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• pp.109-119
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• 1998

Recently pipe-framed greenhouses are widely constructed on domestic farm area. These greenhouses are extremely light-weighted structures and so are easily damaged under strong wind due to the lack of uplift resistance of foundation piles. This experiment was carried out by laboratory soil tank to investigate the displacement be haviors of cylindrical pile foundations according to the uplift loads. Tested soils were sampled from two different greenhouse areas. The treatment for each soil type are consisted of 3 different soil moisture conditions, 2 different soil depths, and 3 different soil compaction ratios. Each test was designed to be repeated 2 times and additional tests were carried out when needed. The results are summarized as follows : 1. When the soil moisture content are low and/or pile foundations are buried relatively shallow, ultimate uplift capacity of foundation soil was generated just after begining of uplift displacement. But under the high moisture conditions and/or deeply buried depth, ultimate up-lift capacity of foundation soil was generated before the begining of uplift displacement. 2. For the case of soil S$_1$, the ultimate uplift capacity of piles depending on moisture contents was found to be highest in optimum moisture condition and in the order of air dryed and saturated moisture contents. But for the case of soil S$_2$, the ultimate uplift capacity was found to be highest in optimum moisture condition and in the order of saturated and air dryed moisture contents. 3. Ultimate uplift capacities are varied depending on the pile foundation soil moisture conditions. Under the conditions of optimum soil moisture contents with 60cm soil depth, the ultimate uplift capacity of pile foundation in compaction ratio of 80%, 85%, and 90% for soil 51 are 76kg, 115kg, and 155kg, respectively, and for soil S$_2$are 36kg, 60kg, and 92kg, respectively. But considering that typical greenhouse uplift failure be occurred under saturnted soil moisture content which prevails during high wind storm accompanying heavy rain, pile foundation is required to be designed under the soil condition of saturated moisture content. 4. Approximated safe wind velosities estimated for soil sample S$_1$and S$_2$are 32.92m/s and 26.58m/s respectively under the optimum soil condition of 90% compaction ratio and optimum moisture content. But considering the uplift failure pattern under saturated moisture contents which are typical situations of high wind accompanying heavy rain, the safe wind velosities for soil sample S$_1$and S$_2$are not any higher than 20.33m/s and 22.69m/s respectively.

• Food Science of Animal Resources
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• v.28 no.3
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• pp.263-268
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• 2008

This study was carried out to investigate the quality characteristics of various honeys originating from different sources, and to identify factors potentially useful for distinguishing the honey sources. The sugar composition, moisture content and total acidity of twenty six honey samples were analyzed. The moisture contents were lowest in honeys from Acacia and were not greatly different with regard to honey sources. Fructose content was highest, followed by glucose, sucrose and maltose in all kinds of honey. Sugar composition did not show any reliable criterion useful for identifying the sources of honey samples. The fructose/glucose ratio did not differ among samples, however the ratios in honeys from Acacia and Chestnut were higher than honey from poly floral sources. The total acidity of honeys ranged 10.30-12.45 meq/kg regard-less of the source, thus acidity is not a useful criterion for identifying the honey source.

• Preventive Nutrition and Food Science
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• v.5 no.1
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• pp.25-31
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• 2000

Extrusion conditions for production of rice extrudate were studied. The optimal production conditions of rice extrudate were determined by the relationship between dependent variables such as expansion ratio, shear strength and color change and independent variables such as moisture content of raw material, screw speed, and die tem-perature of extruder. The textural quality of rice exturdate was significantly affected by the moisture content of raw material (x1), screw speed (x2), and die temperature (x3) of extruder. The expansion ratio of rice extrudate showed the highest value at the moisture content of 18% of raw material, and the lowest at 24%, and whose regression equation was Y=34.8967 - 3.219X1 - (0.623$\times$10-2)X2 + 0.136X3 + (0.648$\times$10-1)X12 + (0.138$\times$10-3)X1X2 + (0.456$\times$10-4)X22 + (0.719$\times$10-3)X1X3 -(0.515$\times$10-3)X2X3- (0.552$\times$10-3)X32. The most desirable texture of rice extrudate determined by shear test and sensory evaluation was obtained at the following conditions : mois-ture content of 18% of raw material, screw speed of 210 rpm and die temperature of 11$0^{\circ}C$. The rice extrudate prepared under the above conditions showed the lowest shear force of 954g at which the highest sensory score was obtained.

• Magazine of the Korean Society of Agricultural Engineers
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• v.28 no.3
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• pp.99-106
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• 1986

This study was carried out to investigate the effects of moisture content, temperature, C/N ratio and pH of the sewage sludge mixed with hulle and sawdusts for making compost under aerobic condition and to improve the defect of the structure of experimental equipment heat lose and handling method. and obtained results were as follows 1.The temperature was reached 73$^{\circ}$ C around 50 hours fermentation in the condition of 0.8 L/min. of air and 60.4% of moisture content. and favorable moisture content of initial condition ranged from 50 to 65% 2.The temperature near bottom of the batch composter was decreased due to evaporate water vapor and lose the heat produced during aeration. and it is required to be improved. 3.The temperature in the batch composter from the center to the inside wall surface was gradually decreased. the temperatures of the points located in r=9cm and the wall surface were 4$^{\circ}$ C and 6$^{\circ}$ C respectively. and therefore it is required to be insulated. 4. The maximum C02 production was obtained as 7.3% per volume in the temperature of 63$^{\circ}$C at the moisture content of 60% 5.The temperature range of active microbes growth was found to be as 20$^{\circ}$C to 40$^{\circ}$C in the case of mesophiles and 50$^{\circ}$C to 65$^{\circ}$C in the case of thermophiles due to increase and decrease C02 production. 6.C/N ratio after decomposition was 1.3 to 2.6 smaller than that of initial one due to increase the amount of nitrogen. The more C/N ratio increased. the less the reaction velocity decresed. The optimum of it as found to be 30. 7.pH values after decomposition were slightly increased than that of initial ones. The reaction velocity was decreased at acid and alkall condition. Therefore it is neseseary to neutralize the medium to improve the reaction.

• Journal of the Korean Wood Science and Technology
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• v.26 no.4
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• pp.43-49
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• 1998

The availability of large quantities of waste woods provides an impetus for investigating woody biomass potential uses. Polyurethane (PU) foams are prepared with reacting isocyanates and polyols, and are used. in various industry fields. Thus, lignocellulosic waste raw-materials are proposed as replacement for synthetic polyol to PU foam formulation. In this study PU foams were manufactured from liquefied woods, methanediisocyanate(MDI), catalyst, foaming stabilizer, and viscosity aids. The polyol content, isocyanate.hydroxyl group (NCO/OH) ratio, and water content were varied to evaluate their effects on the foaming and water absorption of the PU foams. Less than 400 Molecular weight. of polyethylene glycol(PEG) and 1 to 3 solvent to woody raw-material ratio were desirable for liquefying woody materials. Liquefying rate was increased with more than 3 % addition of inorganic and organic catalysts and raising reaction temperature more than $150^{\circ}C$. Addition of starch enhanced liquefying of woody materials. Fourty percents of starch resulted in about 90% liquefying rates. Foaming rates were increased with increasing moisture contents of liquefied wood. Moisture contents of 0.6% resulted in 5 time-foaming rates, and seven percents of moisture contents more than 30 time-foaming rates. But, an increase in water content may result in a decrease in cross-links between wood polyol and isocyanate, because the NCO/OH ratio is constant. Increasing moisture contents have significantly decreased density of PU foams. The optimum water content should be about 2.5% or less in this adopted condition.

• Journal of Biosystems Engineering
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• v.11 no.2
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• pp.14-22
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• 1986

This study was carried out to find a method which can be used to measure the soil moisture content of the soil bin exactly and quickly. And gypsum block is used as an instrument in measuring soil moisture content in the field of green house farming, etc.. However the characteristics of gypsum block, or the guide line of making gypsum block is not well introduced in Korea. So the information about gypsum block such as the density of gypsum, type of electrode, dimension of electrode, distance between electrodes, density of surrounding soil were included in this study and their effects on the relationship between soil moisture content and electrical resistance were investigated. The results of this study are as follows; 1. The grid type electrode was quicker in accessing the equilibrium condition and showed more sensitive response to the change of soil moisture content than the plate type electrode. 2. The longer the distance between the electrodes, the larger the electrical resistance, and the distance of 3 to 5 mm was recommended. 3. The larger the width of the electrode, the smaller the electrical resistance. However, there was no significance between the levels designed in this study. Considering the size of the gypsum block itself, the adaptible range of width may be 4 to 8 mm. 4. The higher the density of gypsum, the smaller the electrical resistance. And the block of lower density was broken down in the soil of higy moisture content. The optimum ratio of gypsum to water was 7:5. 5. The measuring system used in this study allowed simultaneous, multi-data acquisition. So this system using A/D converter can be applied to the measurement of soil moisture content of soil bin.

• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.463-469
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• 1988

The effects of moisture content and particle size of rice flour on the physical properties of the extrudate were examined by using a autogeneous single screw extruder. The moisture contents tested were in the range of 17-28% and the particle sizes were 18-60mesh and 60-120mesh. Samples were taken at different temperatures from the start-up period to the steady state operation. The expansion ratio increased and bulk density decreased as the moisture content and particle size of the flour decreased. The cutting force decreased and the air cell size became uniform as the moisture content and particle size of the flour decreased. As the moisture content increased, the yellowness of the extrudate powder decreased, while the lightness increased, the apparent viscosity increased and the water soluble index decreased. Gelatinization and partial dextrinization were apparent during the extrusion process, and the degree of dextrinization was appeared to be influenced by the levels of moisture content and particle size of rice flour.

• Carbon letters
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• v.24
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• pp.62-72
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• 2017

The aim of this work was to evaluate the dielectric properties of impregnated and activated palm kernel shells (PKSs) samples using two activating agents, potassium carbonate ($K_2CO_3$) and sodium hydroxide (NaOH), at three impregnation ratios. The materials were characterized by moisture content, carbon content, ash content, thermal profile and functional groups. The dielectric properties were examined using an open-ended coaxial probe method at various microwave frequencies (1-6 GHz) and temperatures (25, 35, and $45^{\circ}C$). The results show that the dielectric properties varied with frequency, temperature, moisture content, carbon content and mass ratio of the ionic solids. PKSK1.75 (PKS impregnated with $K_2CO_3$ at a mass ratio of 1.75) and PKSN1.5 (PKS impregnated with NaOH at a mass ratio of 1.5) exhibited a high loss tangent ($tan{\delta}$) indicating the effectiveness of these materials to be heated by microwaves. $K_2CO_3$ and NaOH can act as a microwave absorber to enhance the efficiency of microwave heating for low loss PKSs. Materials with a high moisture content exhibit a high loss tangent but low penetration depth. The interplay of multiple operating frequencies is suggested to promote better microwave heating by considering the changes in the materials characteristics.

• Journal of the Korea Institute of Building Construction
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• v.5 no.2 s.16
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• pp.153-159
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• 2005

This study is to choose the optimal mixture and to analyze the sensibility properties of High strength concrete and mass concrete to apply the high rising building. The main experimental variables were water/binder ratio $39\%,\;33\%,\;35\%\;and\;37\%$, replacement ratio of fly ash $5\%,\;10\%\;and\;15\%$, in the high strength concrete and water/binder ratio $39\%,\;41\%\;and\;43\%$, replacement ratio of fly ash $10\%,\;20\%\;and\;30\%$, in the man concrete. According to the test results, the principal conclusions are summarized as follows. 1) The slump(or slump flow) and air content of fresh concrete were found to be the highest in the elapsed time 30 minutes. 2) The optimal mixture conditions are W/B $40\%$, FA $25\%$ in the mass concrete and W/B $33.4\%$, FA $15\%$ in the high strength concrete. 3) The ranges of sensibility are satisfied in the moisture content ${\pm}l\%\;and\;S/a\;{\pm}2\%$.