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

• Resources Recycling
• /
• v.9 no.3
• /
• pp.37-45
• /
• 2000

This paper presents the experimental test results on moisture and freeze-thaw resistance of hot mix crumb rubber modified (CRM) asphalt concrete mixture. To compare the differences in mechanical properties of conventional and CRM asphalt concretes, various tests were conducted under different moisture conditions and freeze-thaw cycles. Marshall mix design was also performed to determine the optimum asphalt contents for the both asphalt concrete mixtures. Test results revealed that the moisture and freeze-thaw resistance of CRM asphalt mixture was superior to the conventional asphalt concrete. As a result, it is considered that the utilization of waste tires in asphalt pavements has the potential of minimizing the damage due to the moisture and freeze-thaw.

• Journal of the Korean Geotechnical Society
• /
• v.27 no.3
• /
• pp.19-26
• /
• 2011

Compaction tests have been performed to investigate the compaction characteristics of sands and clays with organic mixture. Weathered granite soil, kaolinite, and granulated carbon were used as the alternatives of sand, clay, and organics, respectively. The soapy water which is a kind of surfactant solutions was also used as water substitute to see the engineering properties changes of each soil. As seen when water was used, the optimum moisture contents increased and the maximum dry unit weight decreased for the soil with surfactants as the percentage of the organic contents increased. Surfactants slightly improved the compaction efficiency at low compactive energy level for the weathered granite soil with organics. As the organic contents increased for clays with surfactants, the optimum moisture contents decreased and the maximum dry unit weight increased. Surfactants slightly improved the compaction efficiency of clays with organics at all levels of compaction energy.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.19 no.1
• /
• pp.36-50
• /
• 1995

The purpose of this study was 1) to estimate the improvement of thermal storage/release and moisture transport properties of PEG-treated acrylic athletic socks and suggest the optimum add-on for PEG treatment, 2) to investigate wear performance of untreated cocks and two kinds of socks treated with PEG of minimum and optimum add-on respectively, and 3) to consider the effect of thermal storage/release and moisture transport properties of PEG- treated socks on the wear performance and the subjective comfort zone. Thermal activities of specimens treated by PDC were evaluated on a DSC by measuring the heat of fusion on heating and the heat of crystallization on cooling. Moisture regain, absorption speed, wickability, water retenti on value, and water-vapor permeability were measured. In the wear trials that the subjects performed a subsequent exercise protocol wearing three differently treated socks in a conditioned environment ($14\pm2^{\circ}C$, 65$\pm$2% R.H.), microclimate temperature and humidity, and subjective wear sensations including thermal sensation, wettedness, softness, fit, and overall comfort were obtained. PEC-treated specimens with more than 20% add-on showed thermal storage on heating and thermal release on cooling by a DSC and the heat contents of treated ones were generally proportional to the add-ons. Moisture transport properties were highly improved after PEG treatment and increased rapidly with increasing add-on. The tendencies were, however, relaxed above 50% add-on and the treated knits were much stiffer above that add-on. In the wear trials of untreated, PEG add-on 20%, and 50% acrylic socks, the changes of microclimate temperature of 50% socks were significantly less than that of 20% socks. PEG add-on 50% socks showed significantly less changes of microclimate humidity than other two kinds of socks. Three kinds of socks showed significant differences in overall comfort and add-on 50% socks were accepted more comfortable than other two kinds of socks. Comfort zone of foot was extended after PEG treatment on socks and it implied that the subjects wearing PEG- treated socks felt comfortable in wider ranges of microclimate temperature and humidity.

• Journal of Environmental Health Sciences
• /
• v.22 no.4
• /
• pp.82-90
• /
• 1996

This study was performed to find the optimum mixing ratio of paper waste in composting of mixture of swine feces and newspaper. Using the experimental setting of aeration rate which was found in the experiment carried out priorly, and moisture contents reported in other literature, just the initial C:N ratios were differentiated by mixing different amount of newspaper with the same amount of swine feces. This study was carried out by operating 4 experimental cornposting reactors of bench scale for 3 weeks. The followings are the conclusions that were derived from this study. 1. During composting reaction, the C:N ratio of each cornposter was decreased. Degree of decrease was in order of run 3, run 2, run 4, and run 1 of which initial C:N ratio was 30, 25, 35, and 20 respectively. All of the final composts were found to be completed composting reaction. 2. Ash contents of each reactor increased rapidly in order of run 3, run 2, run 4, and run 1. The absolute values of quadratic effect coefficients of each second order regression function was 0.059, 0.038, 0.032, and 0.030 respectively. Ash contents evolution trend had a linear correlation with the C:N ratio trend. (r=-0.96932, p<0.05) 3. The range of highest temperatures reached during composting was 47.2-53.5$\circ$C. Those were not significantly different from one another. Thermophilic temperatures were maintained in the range of 48-108 hours. 4. Contents of heavy metal detected in the final compost were lower than those of Korean and European standards. 5. Concentration range of Nitrogen in the final compost was 1.11-2.27%, and that of phosphorus was 8.40-10.70 mg/kg. 6. The optimum C:N ratio which has been proposed without the consideration of types of bulking agents should be re-examined. Biodegradabilities of each bulking agents was thought to be important factor when determining the optimum initial C:N ratio for cornposting.

• Geomechanics and Engineering
• /
• v.22 no.2
• /
• pp.143-152
• /
• 2020

In this research, soil samples of the Kerman sedimentary basin, Iran, were investigated through laboratory tests such as petrography (Scanning Electron Microscopy (SEM), X-Ray Fluorescence Spectroscopy (XRF) and X-Ray Diffraction (XRD)), physical and mechanical characteristics tests. The soil in this area is dominantly CL. The petrography results showed that the dominant clay mineral is Illite. This soil has made some problems in the earth dams due to the low shear strength. In this study, a set of samples were prepared by adding different amounts of lime. Next, the petrography and strength tests at the optimum moisture content were performed. The results of SEM analysis showed substantial changes in the soil structure after the addition of lime. The primary structure was porous and granular that was changed to a uniform and solid after the lime was added. According to XRD results, dominant mineral in none stabilized soil and stabilized soil are Illite and calcite, respectively. The pozzolanic reaction resulted in the reduction of clay minerals in the stabilized samples and calcite was known as the soil hardener material that led to an increase in soil strength. An increase in the hydrated lime leads to a decrease in their maximum dry unit weight and an increase in their optimum moisture content. Furthermore, increasing the hydrated lime content enhanced the Unconfined Compressive Strength (UCS) and soil's optimum moisture. An increase in the strength is significantly affected by the curing time and hydrated lime contents, as the maximum compressive strength is achieved at 7% hydrated lime. Moreover, the maximum increase in the California Bearing Ratio (CBR) achieved in clay soils mixed with 8% hydrated lime.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.13 no.3
• /
• pp.247-250
• /
• 1984

As a consecutive work on stability for the quality of ginseng products, the sorption properties of red ginseng (RG), red ginseng powder (RGP), and red ginseng powder tablet (RGPT) were studied in order to set the optimum moisture level for them. The levels of moisture at BET monolayer of RGP and RGPT ranged 5.97 to 7.27 % and 4.73 to 5.14 % in wet basis, respectively. Based on these values, the optimum moisture content for both of them would preferably be set at $6.7{\pm}0.7%$ and $4.9{\pm}0.2%$. From the results of storage study on microorganism growth under the maltreated condition, $40^{\circ}C$, and 75% RH, the optimum level of moisture for RG could be extended up to $14.0{\pm}0.5%$, which is much higher than the circulating values of 10.416%.

• Korean journal of food and cookery science
• /
• v.30 no.2
• /
• pp.119-128
• /
• 2014

The purpose of this study is to propose the optimum adding rate of freeze-drying beet leaf powder, which has antioxidant components, that have superior DPPH radical extinction effects, in the Sulgidduk, a representative of steamed rice cake, which improve its functionality. According to the measured results on moisture contents and pH levels of Sulgidduk, with added freeze-drying beet leaf powder, the moisture contents have been significantly declined with increasing rates of added beet leaf powder. The pH levels of sample groups are within the range of 6.26-6.13. From the chromatography of measured results, lightness and yellowness have declined and redness have increased along with increasing rates of added beat leaf powder. According to the texture of measured results, the hardness, and chewiness have declined by the increasing the rate of added beet leaf powder. For the storage period, hardness, and chewiness have been inclined, but cohesiveness declines, with increased the storage period, while there are no changes from elasticity. The DPPH contents of Sulgidduk, with added freeze-drying beet leaf powder, inclined by increasing the rates of added beet leaf powder. The sensory test results of color, aroma and fragrance incline with increasing rates of added beet leaf powder. From acceptance test results, the sample group added with 3% receive the highest appraisals.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.51 no.7
• /
• pp.632-638
• /
• 2006

Characteristics of sweet (sugary, su) and super sweet (shrunken-2, sh2) corn seeds shelled by different threshing methods at different moisture content status were studied. Hybrid seeds of a su (Early Sunglow ${\times}$ Golden Cross Bantam 70, GCB 70) and a sh2 (Xtrasweet 82 ${\times}$Fortune) were dried to moisture content of 12, 15, 18, and 21%. Hand shelling did not give any mechanical damages to seeds, while an electrical corn thresher gave some visible mechanical damages. The emergence rate of hand shelled seeds was higher than that of machine shelled seeds by $6{\sim}14%$ for a su and by $9{\sim}18%$ for a sh2 hybrid depending on seed moisture contents in cold test. The optimum seed moisture content to reduce mechanical threshing damages and to improve seed quality was 15% for su and 12% for sh2 hybrid seeds. At the optimum seed moisture contents, germination rate at $25^{\circ}C$, emergence rate in the cold test and ${\alpha}-amylase$ activity were highest, while the percentage of damaged seeds and leakage of total sugars and electrolytes in soaking water were minimized.

• International Journal of Highway Engineering
• /
• v.13 no.2
• /
• pp.139-145
• /
• 2011

The practice of asphalt pavement recycling has grown rapidly over the decade, one of which is the cold in-place recycling with the foamed asphalt (CIR-foam) or the emulsified asphalt (CIR-emulsion). Particularly, in Iowa, the CIR has been widely used in rehabilitating the rural highways because it significantly increases the service life of the existing pavement. The CIR layer is typically overlaid by the hot mix asphalt (HMA) to protect it from water ingress and traffic load and obtain the required pavement structure and texture. Most public agencies have different curing requirements based on the number of curing days or the maximum moisture contents for the CIR before placing the overlay. The main objective of this study is to develop a moisture loss index that the public agency can use to monitor the moisture content of CIR layers in preparation for a timely placement of the wearing surface. First, the moisture contents were measured in the field using a portable time domain reflectometry (TDR) device. Second, the weather information in terms of rain fall, air temperature, humidity and wind speed was collected from the same location. Finally, a moisture loss index was developed as a function of initial moisture content, air temperature, humidity and wind speed. The developed moisture loss index based on the field measurements would help the public agency to determine an optimum timing of an overlay placement without continually measuring moisture conditions in the field.