• Tribology and Lubricants
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• v.35 no.3
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• pp.169-175
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• 2019

In lithium-ion batteries (LIBs), the stress induced by the volume change of an electrode during charge-discharge processes may often cause the mechanical integrity of the electrode to degrade. Polymer binders with enhanced mechanical properties are preferred for improved mechanical integrity and cycling stability of the electrode. In addition, given that sliding and shearing between the polymer binder and components in the electrode may readily occur, frictional and adhesion characteristics of the polymer binder may play a critical role in the mechanical integrity of the electrode. In this study, frictional and adhesion characteristics of polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) were investigated using a colloidal probe atomic force microscope. Friction loops were obtained under various normal forces ranging from 0 to 159 nN in air and electrolyte and then the interfacial shear strengths of PAN and PVDF in air were calculated to be $1.4{\pm}0.5$ and $1.3{\pm}0.3MPa$, respectively. The results show that in electrolyte, interfacial shear strength of PAN decreased slightly ($1.2{\pm}0.2MPa$), whereas that of PVDF decreased drastically ($0.06{\pm}0.01MPa$). Decreases in mechanical properties and adhesion in electrolyte may be responsible for the decrease in interfacial shear strength in electrolyte. The findings from this study may be helpful in developing polymer binders to improve the mechanical integrity of electrodes in LIBs.

• Korean Journal of Agricultural Science
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• v.10 no.1
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• pp.129-134
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• 1983

Importance has been increased on farming mechanization in harvesting, handling and processing of forage in Korea. Small grasslands are most spread and popular in Korea in comparison with those of Europe and America. Therefore shearing characteristics of some major forage crops should be studied to be contributed to the basic data to develop a moderate size forage harvester being suitable to the small grassland. They were studied on six kinds of forage crops - reed canarygrass, alfalfa, red clover, orchardgrass, meadow fescue and birdsfoot trefoil-in regarding with moisture content levels and shearing angles. The results were as follows; 1. The increase rate of the linear density in relation to the diameter was greater in red clover than other kinds, and order of increase rate in greatness was reed canarygrass, alfalfa and meadow fescue. 2. The increase rates of the maximum shear forces were high in relation to their cross - sectional area in alfalfa and birdsfoot trefoil with hard stems, and the shear energy were comparatively large in orchardgrass and meadow fescue with soft stems, also reed canarygrass and red clover had high values in both the maximum shear force and the shear energy. 3. The shear energy per unit area or shear strength in relation to moisture content showed concave curves with the minimum values at about 70%w. b. which was in the beginning stage of drying in meadow fescue and orchardgrass, nevertheless reed canarygrass and red clover had convex curves with the maximum values at about 40%w.b. 4. The shear force in relation to the shear angle decreased generally with decrease of shear angle from $90^{\circ}$ to $70^{\circ}$ or $50^{\circ}$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.6
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• pp.586-593
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• 2012

To identify the food component characteristics of seven oysters(four cultured oysters and two wild oysters Crassostrea gigas and one dendely lamellated oyster Ostrea denselamellos Korean name beotgul) in Korea, the proximate, fatty/amino acid, mineral compositions, texture, color, chemical and taste compounds were investigated. The proximate compositions were not significantly different between cultured and wild oysters, whereas beotgul had lower levels of crude protein, ash and lipid content, and a higher carbohydrate content. The amino nitrogen contents of the three main types were 232.8-258.2, 160.5-213.9, and 218.5 mg/100 g, respectively, and the salinities were 1.5-1.7, 1.5-1.8, and 0.9%, respectively. Regarding the muscle texture, the shearing forces were 95-114, 105-132, and 170 g, respectively. Amounts of total amino acids of cultured, wild oysters and beotgul were 9,004-10,198, 8,165-8,942, and 7,767 mg/100 g, respectively. The major amino acids were aspartic acid (Asx), glutamic acid (Glx), proline, alanine, leucine, phenylalanine, lysine and arginine. Regarding inorganic ions, beotgul had much lower Fe and S contents than the cultured and wild oysters. The major fatty acids of cultured and wild oysters were 16:0, 18:0, 16:1n-9, 18:1n-9, 22:1n-9, 16:4n-3, 20:5n-3, and 22:6n-3, and there was little difference between the two. Beotgul had a higher polyenes ratio, i.e., 20:5n-3, and a lower monoenes ratio than the cultured and wild oysters. The free amino acid contents of cultured, wild oysters and beotgul extracts were 1,444-1,620, 1,017-1,277, and 1,144 mg/100 g, respectively, and the major free amino acids were taurine, glutamic acid, glycine, alanine, tryptophan, ornithine, and lysine. There was a little difference in the glycine, tryptophan, ornithine, and arginine contents.

• Journal of Soil and Groundwater Environment
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• v.11 no.6
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• pp.61-68
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• 2006

Soil washing techniques coupled with high pressure air jet were applied for diesel-contaminated soils sampled by an underground oil reservoir of which the initial total petroleum hydrocarbon (TPH) ($2,828{\pm}206\;mg/kg$) exceeded 5 times of current standard level (500 mg/kg) regulated by the Soil-Environment Conservation Law. Through several tests, we found that the position of impeller has a critical impact for washing efficiencies. The highest washing efficiency was obtained at an oblique angle (30 degree) for the impeller and optimized mixing speed (300 rpm) that could have high shearing forces. Considered economical and feasible aspects, the optimum mixing time was 10 min. Rate constants of TPH removal derived from the first-order equation were not linearly increased as mixing speed increased, indicating that mechanical mixing has some limits to enhance the washing efficiencies. Application of high-pressure air jet in washing process increased the washing efficiency. This increase might be caused by the fact that the surface of micro-air bubbles strongly attached hydrophobic matters of soil particles. As the pressure of air jet increased, the separation efficiencies of TPH-contaminated soil particles increased. In the combined process of high-pressure air jet and mixing by impeller, the optimum mixing speed and air flow-rate were determined to be 60 rpm and $2\;kg/cm^2$, respectively. Consequently, the washing technique coupled with high-pressure air jet could be considered as a feasible application for remediating petroleum-contaminated soils.

• Journal of the Korean Geotechnical Society
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• v.34 no.6
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• pp.49-59
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• 2018

When a tracked vehicle travels off-road, shearing action and ground sinkage occur on the soil-track interface and severely affect tractive performance of the tracked vehicle. Especially, the ground sinkage, which is induced by vehicle's weight (hereinafter referred to as static sinkage) and longitudinal forces in the direction of travel producing slip (hereinafter referred to as slip sinkage), develops soil resistance, directly restricting the tractive performance of an off-road tracked vehicle. Thus, to assess the tractive performance of an off-road tracked vehicle, it is imperative to take both of static sinkage and slip sinkage into consideration. In this research, a series of model track experiments was conducted to investigate the slip sinkage which has not been clarified. Experiment results showed that the slip sinkage increased with increasing the slip ratio, but the increasing rate gradually decreased. Also, the slip sinkage was found to increase as relative density of soil decreased and imposed vertical load increased. From the experiment results, the normalized slip sinkage defined as slip sinkage to static sinkage calculated in the identical condition was investigated, and an empirical equation for the slip sinkage was developed in terms of slip ratio, which allows vehicle operators to predict the slip sinkage in a given soil and operating conditions.

• Culinary science and hospitality research
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• v.19 no.5
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• pp.196-205
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• 2013

This study showed the chemico-physical characteristics and sensory evaluation of beef loin and ribs with various kinds of cooking apparatus and methods like pan heating, boiling, grilling, steaming, cooking heating, charcoal heating and double layer pan heating. Double layer pan filled with Phase Change Materials(PCM) heating was also tested. Heating time of beef loin and ribs by oven heating was the longest as 55.5 and 25.7 min. Cooking loss of beef loin and ribs were 40.49%, 27.98% each and showed biggest in charcoal heating(p<0.05). In the chemical analysis, grilling resulted in the highest protein contents of 29.3% in the loin and double layer pan heating had 28.6% in the ribs. In the loin, 20.3% of crude fat was the highest in the double layer pan heating, and 21.9% of crude fat of ribs in the PCM heating(p<0.05). In the test of shearing forces, double layer pan heating had the lowest result of $9.14kg/cm^2$ in the loin and $7.03kg/cm^2$ in the ribs. In the 9 point-scale sensory evaluation, PCM treatment showed the best result of 7.67 in the juiciness of loin and single layer pan heating and grilling treatment had the highest score of 7.00 in the ribs. Loin in the PCM heating had 7.11 and ribs in the grilling had 7.13, showing the best in overall acceptability. With this experiments, we could find the chemico-physical and sensory characteristics of beef loin and ribs were affected by various cooking methods.