• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2003.10a
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• pp.165-169
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• 2003

Current volume reduction methods for wasted expandable polystyrene (EPS) foam are summarized and compared each other. Wasted EPS foam has not been recycled effectively because of its large volume to weight ratio. This has prevented from its proper recycling because of high cost of transportation to recycling plant. Successful recycling of wasted EPS foam results directly from successful, i.e. economically and environmentally, volume reduction of wasted EPS foam. This paper deals with various methods for volume reduction methods of wasted EPS foam. Five typical methods of volume reduction are introduced and they are compared each other in terms of expected PS properties after volume reduction, cost effectiveness of each process, possible effects on environment caused by the volume reduction process, and possible recycled products. The methods include thermal, solvent, far infrared and mechanical compaction. Comparison in this paper is made mostly in qualitative manner. The focus in this study is concentrated on summarizing and comparing existing methods of volume reduction for wasted EPS foam.

• Advanced Composite Materials
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• v.16 no.1
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• pp.11-30
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• 2007

Since delamination often propagates at the interfacial layer between a surface skin and a foam core, a crack arrester is proposed for the suppression of the delamination. The arrester has a semi-cylindrical shape and is arranged in the foam core and is attached to the surface skin. Here, energy release rates and complex stress intensity factors are calculated using finite element analysis. Effects of the arrester size and its elastic moduli on the crack suppressing capability are investigated. Considerable reductions of the energy release rates at the crack tip are achieved as the crack tip approached the leading edge of the crack arrester. Thus, this new concept of a crack arrester may become a promising device to suppress crack initiation and propagation of the foam core sandwich panels.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.141.2-141.2
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• 2003

Subendothelial accumulation of foam cells plays a key role in the initiation of atherosclerosis. These foam cells accumulate in fatty streaks that evolve to more complex fibrofatty or atheromatous plaques. Oxidized LDL may also be involved in atherogenesis by inducing smooth muscle cell proliferation and smooth muscle foam cell generation. (omitted)

• Korean journal of food and cookery science
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• v.9 no.4
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• pp.278-283
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• 1993

This study was attempted to investigate the effects of enzymatic modification of milk protein with protease on functional properties. The selected functional properties were solubility, emulsifying activity (EA), emulsion stability(ES), foam expansion(FE), and foam stability(FS). These properties were measu-red from pH 3.0 to pH 8.0. The proteases used in this study were iaolated from Meju(fermemted soybean) and had specific activity of 250 units/㎎ protein at pH 7.0, 1600 units of pretense was used for 1gr. of skim milk protein. Skim milk showed 30.5％ degree of hydrolysis for 1 hr. and 36.4% degree of hydrolysis for 3.5 hrs. of protease treatment at pH 7.0. Solubility of native skim milk, control, 1 hr. and 3.5 hrs. groups were 3.37, 3.64, 10.21, 14.34％o at pH 4.0 respcetively. The emulsifying activity of native skim milk, control, 1 hr. and 3.5 hrs. groups were 38.8,42.0,43.0,46.7ft at pH 4.0, respectively. Enzymatic modification resulted in the increase of solubility and emulsifying activity at pH 4.0. However at pH 5.0 emulsifying activity of 1 hr. and 3.5 hr. group were lower than native skim milk and control groups. 1 hr. protease treatment was found to be most effective way of increasing foam expansion at pH 4.0 to 6.0. It was supported that, protease treated skim milk can be used to improve solubility, emulsifying activity, foam expansion at acid pH. meju protease. skim milk, solubility, emulsion, foam.

• Steel and Composite Structures
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• v.33 no.6
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• pp.837-847
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• 2019

A type of hybrid core made up of thin-walled square carbon fiber reinforced polymer (CFRP) honeycomb and Polymethacrylimide (PMI) foam fillers was proposed and prepared. Numerical model of the core under quasi static compression was established and validated by corresponding experimental results. The compressive properties of the core with different configurations were analyzed through numerical simulations. The effect of the geometrical parameters and foam fillers on the compressive response and energy absorption of the core were analyzed. The results show that the PMI foam fillers can significantly improve the compressive strength and energy absorption capacity of the square CFRP honeycomb. The geometrical parameters have marked effects on the compressive properties of the core. The research can give a reference for the application of PMI foam materials in energy absorbing structures and guide the design and optimization of lightweight and energy efficient cores of sandwiches.

• Journal of Welding and Joining
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• v.21 no.5
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• pp.525-533
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• 2003

The dimensional accuracy and global roughness between successive layers of VLM-s, which is a new rapid prototyping process using hotwire cutter and EPS foam, depend significantly on the operating parameters of hotwire cutter. In the present study, the effect of cutting angle on the kerf width and edge shape in hotwire cutting of EPS foam for the case of single-sloped cutting with one cutting angle was investigated. Through single-sloped cutting tests, the modified relationship between kerf width and effective heat input, considering the effect of the cutting angle, and the relationship between the melted area and the cutting angle were obtained. In order to investigate the effect of cutting angles on the thermal field in EPS foam, transient heat transfer analyses using single-sloped volumetric heat flux model and locally-conformed mesh were performed. Through the comparison between experimental and numerical results, it was shown that the proposed analysis model is needed to estimate the three-dimensional temperature distribution of the EPS foam for the case of single-sloped hotwire cutting.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.1
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• pp.29-35
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• 2016

It is important to uniformly supply the fuel gas into the reaction activity area in polymer electrolyte membrane fuel cell (PEMFC). Recent studies have shown that the cell performance can be significantly improved by employing metal foam gas distributor as compared with the conventional bipolar plate types. The metal foam gas distributor has been reported to be more efficient to fuel transport. In this study, three-dimensional computational fluid dynamics (CFD) simulations have been performed to examine the effects of metal foam flow field design on the fuel supply to the reaction site. Darcy's law is used for the flow in the porous media. By solving additional advection equation for fluid particle trajectory, the gas transport has been visualized and examined for various geometrical configuration of metal foam gas distributor.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.648-653
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• 1998

This study examines the effects of cell size and structure on the oil adsorption by polyurethane (PU) foam. A series of oil-adsorptive PU foam has been prepared, using various molecular weight of polyether polyol (GP-1000, GP-3000, GP-4000, GP-5000), together with TDI-80, water and additives. It was found that the cell size of PU foam decreased with increasing the agitation speed and surfactant content. Oil-adsotption of PU foam increased over 2000% with the increase of molecular weight of polyol and with the decrease of cell size. Increase in the surfactant content and the viscosity of adsorbed oil also give a remarkable decrease in oil adsorption.

• Korean Journal of Materials Research
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• v.32 no.2
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• pp.85-93
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• 2022

Porous mullite-corundum ceramics were prepared using organic foam impregnation method with alumina and silica as raw materials. The influence of alkaline treatment and surfactant modification on polyurethane foam were studied. Effects of sintering process and material composition on porous mullite-corundum ceramics were investigated. The results show that the hang-pulp quantity of polyurethane foam increases with alkaline treatment. After treatment with 3 wt% SDS solution, the hang-pulp quantity of polyurethane foam further improved. Open porosity of sample decreased with elevation of sintering temperature and holding time, and compressive strength of sample showed a trend opposite to the change of porosity. The open porosity of the sample was enhanced by the increase of m(Al₂O₃/SiO₂); the compressive strength decreased with increase of m(Al₂O₃/SiO₂). However, when m(Al₂O₃/SiO₂) was 2.5, the compressive strength of the sample reached 6.23 MPa, and the open porosity of the sample was 80.7 %.

• Journal of the Korean Applied Science and Technology
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• v.35 no.3
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• pp.905-913
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• 2018

The purpose of this study is to investigate the difference of muscle activity according to application of a foam roller during pilates. The 8 male subjects were selected and quadruped position, bridge, and core control movement of pilates were randomly assigned to 9 movements on a static mat motion, static foam-roller motion, and dynamic foam-roller actions. This program was conducted once at intervals of 1 week. The muscle activity of erector spinae, rectus abdominis, external oblique, gluteus medius, rectus femoris, and biceps femoris were measured and the collected data was analyzed by one-way ANOVA. First, in the quadruped, the rectus abdominis and external oblique, rectus femoris of the dynamic foam-roller actions showed higher muscle activity than the static mat motion and the static foam-roller motion(p <.001), gluteus medius muscle activity was also significantly higher (p <.05). biceps femoris were significantly higher in static foam-roller motions than in static mat-motion and dynamic foam-roller actions(p <.05). Second, biceps femoris muscle activity was highest in dynamic foam-roller actions than static mat-motion and static foam-roller motions during bridge(p <.001). Third, in the sitting core control, the rectus abdominis and gluteus medius of the dynamic foam-roller actions showed higher muscle activity than the static mat motion and the static foam-roller motion(p <.001). and activity of erector spinae muscle was also significantly higher (p <.01). external oblique were significantly higher in static mat-motion than in static foam-roller motions and dynamic foam-roller actions(p <.05). Considering the muscle activity during pilates exercise, it would be more effective to apply the method and difficulty.