• Journal of Korea Foresty Energy
• /
• v.22 no.2
• /
• pp.26-35
• /
• 2003

Bamboo strand board (BSB) was made with Phyllostachys banbusoides growing in Damyang district. Physical and mechanical properties of this BSB were summarized as follows; The specific gravity of BSB was 0.63∼0.79. Specific gravity decreased slightly with the thickness and length of BSB. Moisture content of BSB manufactured was 5.8∼6.9%. The absorption ate of BSB (42∼48%) did not show any relationship with the thickness and length of BSB. The thickness swelling rate of BSB was 13.9∼17.0%, relatively higher than any other panel products. Thickness swelling rate increased with the thickness of BSB, showing the strand thickness influenced much more on the rate of thickness swelling of BSB than the length of strand. The 3-point bending strength of BSB was 98∼126kgf/$\textrm{cm}^2$. Bending strength of showed the tendency of increase with the increased length of BSB, but with the decreased thickness. In particular, the length of BSB showed more effect on the increase of bending strength of BSB than the thickness of BSB. The compression strength perpendicular to BSB surface was 411 ∼ 465 kgf/$\textrm{cm}^2$, and the optimal length of strand for the 1mm- and 2mm-thickness of strand was 40mm and 60mm, respectively. Compression strength paralleled to BSD was 160∼221kgf/$\textrm{cm}^2$ and the optimal length of strand for the 2mm-thickness of strand appeared to be 60mm. The present work showed that appearance, physical and mechanical strength of BSB appeared quite positive in terms of board qualities, suggesting that bamboo would be appropriate for the production of board materials. In addition, our work showed that the crucial factor for determining the mechanical characteristics of BSB was the dimension of strand.

• Journal of Korea Foresty Energy
• /
• v.25 no.1
• /
• pp.9-17
• /
• 2006

Properties of wood charcoal made from the domestic wood species at $300-900^{\circ}C$ have investigated to understand the correlation between carbonization temperature and chemical and physical characteristics of wood charcoal. In terms of charcoal yield at particular carbonization temperatures, it was drastically decreased until the temperature reaches up to $600^{\circ}C$ and the decrease ratio of yield was reduced at higher temperatures. As the carbonization temperature increased, pH of the wood charcoal increased so that it became basic at last. The wood charcoal prepared at $600{\sim}700^{\circ}C$ showed the highest caloric value and those of wood charcoals made at higher temperature became plateau at a little lower level than the peak. The caloric value of Japanese larch charcoal was a bit higher than that of Red oak charcoal. The carbon content in the wood charcoal was increased as the carbonization temperature increased, whereas the hydrogen content was decreased. Specific surface area of the wood charcoal became larger with increase in temperature up to $600^{\circ}C$ but it was decreased or reduced in the increasing ratio after, and then it rose again at higher temperature than $800^{\circ}C$. Absorption capacity of the wood charcoal against iodine and gaseous acetic acid became greater as the carbonization temperature increased. Japanese larch charcoal presented higher absorption capacity than Red oak charcoal. As the above results, it is revealed that carbonization temperature affects the chemical and physical properties of wood charcoal. Therefore, to use wood charcoal with maximum effect it should be prepared at optimum temperature for proper use.

• Korean Journal of Veterinary Research
• /
• v.24 no.2
• /
• pp.149-162
• /
• 1984

The research was conducted(1) to confirm the agent(s) responsible for the antimicrobial activity contained in the fermented tomato juice with L. acidophilus(2) to extract and purify the antimicrobial agent(s)(3) to find the biological, physical and chemical properties of the agent(s). The following results were obtained and summarized as followings; 1. The agent responsible for the inhibitory activity was confirmed by both well assay method using fermented tomato juice with L. acidophilus and turbidimetric technique using the cell-free filtrate or neutralized filtrate of tomato acidohilus culture and found exerted antimicrobial agent other than lactic acid. 2. The procedures of purification : The isolation and purification of antimicrobial agent from the lyophilized acidophilus tomato culture were carried out by (1) methanol extraction (2) acetone extraction, (3) Sephadex G-50 gel filtration (4) paper chromatography and (5) thin layer chromatography. 3. The biological, physical and chemical properties of antimicrobial agent: The biological, physical, chemical properties of the purified antimicrobial agent were: (1) The antimicrobial activity was strong against test organisms; Bacillus subtilis(ATCC 6633), Escheichia coli(ATCC 25922), Staphylococcus aureus(ATCC 167), Pseudomonas fluorescens(KFCC 32394), Proteus vulgaris and Shigella dysenteriae. (2) The pH value of the agent was 2.0 and the inhibitory activity was lost when it was neutralized at 7.0 of pH and the agent was heat stable at $121^{\circ}C$ for 60 minutes. (3) The ultraviolet light absorption spectra of methanol-acetone extract and TLC fraction exhibited a maximum absorption at 260nm and 224nm respectively. (4) The most purified agent from TLC plate increased about 130-fold in activity. (5) The agent isolated from TLC plate was free from $H_2O_2$ or lactic acid. 4. Bioautographic assy: By means of bioautography of the agent on silica gel of TLC plate a strong inhibitory activity against B. subtilis was demonstrated. 5. Mass spectrometry: The agent obtained from TLC plate was analyzed by mass spectrometry which show the parent peak at m/e 264 suggesting the molecular weight of the compound and molecular group such as [$C_2H{^+}_4$], [CO], [CH=NH], [$C_3{H^}4_7$], [$\begin{array}{rcl}O\\{\parallel}\\CH_3-C\\\end{array}$], [$C_6-H{^+}_{11}$], [$C_5H{^+}_{11}$], [$\begin{array}{rcl}O\\{\parallel}\\C_5H_7-C^+\\\end{array}$] were suggested.

• Food Science and Preservation
• /
• v.18 no.3
• /
• pp.271-278
• /
• 2011

Considering the importance of cassava as food crops in humid tropics, the effect of feed moisture (20, 25%) and barrel temperature (110, $130^{\circ}C$) on physical properties (piece density, expansion, mechanical properties, color, water solubility index, water absorption index) and pasting properties of extruded cassava starch was investigated. The feed moisture used during extrusion processing had a significant effect on extrudates SME input, specific length and piece density at (p<0.05) while effect on cross-sectional expansion index, apparent elastic modulus and breaking strength in bending shown significantly at p<0.1. Furthermore, the interaction effect of feed moisture and barrel temperature gave a significantly affected the SME input and piece density (p<0.1), specific length (p<0.05) and on redness (p<0.01). The increase in water injection rate led to increase in piece density, apparent elastic modulus, breaking strength in bending, cold peak viscosity, breakdown and final viscosity and decrease in cross-sectional expansion index and specific length. It was found that the extrusion cooking process did not affect the value of color L, color b, water solubility index and water absorption index. Thus, the results of this study can be useful to some extent in developing extruded cassava starch as human and animal feeds.

• Food Engineering Progress
• /
• v.23 no.4
• /
• pp.283-289
• /
• 2019

This study was performed to determine the effect of psyllium husk addition on the physical properties of rice extrudates. Rice-based formulations mixed with psyllium husk (0, 7, 14 and 21%) were extruded at a die temperature of 140℃, screw speed of 200 rpm, and moisture content of 20%. As the content of psyllium husk increased, expansion ratio decreased, while piece density and specific length increased. Apparent elastic modulus, breaking strength, adhesiveness, and hardness augmented with an elevation in psyllium husk content. Lightness declined as psyllium husk content furthered, while redness, yellowness, and color difference intensified. Water soluble index and water absorption index increased with an increased amount of psyllium husk. In conclusion, the addition of psyllium affected the expansion of extruded rice snack possessing hard texture, small cells, and sticky texture due to higher water absorption during hydration.

• Fibers and Polymers
• /
• v.7 no.4
• /
• pp.333-338
• /
• 2006

Silk fibroin (SF) fiber from the Antheraea pernyi silkworm was treated with a 1.23 N iodine-potassium iodide ($I_2-KI$) aqueous solution, and the structure and physical properties were investigated to clarify the effects of the iodine treatment. The noticeably high weight gain value of SF fiber, about 25 wt% was attributed to the absorption of polyiodide ions in the form of $I_3{^-}\;and\;I_5{^-}$. Fourier transform infrared spectroscopy and X-ray diffraction measurements suggested that polyiodide ions mainly entered the amorphous region. In addition, a new sharp reflection on the meridional direction, corresponding to a period of $7.0{\AA}$, was observed and indicated the possibility of the formation of mesophase structure of ${\beta}$-conformation chains. Dynamic viscoelastic measurements showed that the damping tan ${\delta}$ peak at $270^{\circ}C$ gradually shifted to lower temperature in the iodinated SF fibers, suggesting an enhancement of the molecular motion of the fibroin chains induced by the presence of polyiodide ions. With heating above $254^{\circ}C$, the iodine component introduced intermolecular cross-linking of SF, and the melt flow of the sample was inhibited. The thermal decomposition stability of fibroin molecules was greatly enhanced by iodine treatment.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2004.05a
• /
• pp.57-60
• /
• 2004

Recently. as the alternatives to preserve environment such as effective usage of wastes or unusable resources are drawing attentions, researches and measures for the two tasks, which are reuse of waste wood and development of eco-friendly materials, are being examined and established in various fields. However, they are still insufficient. Therefore, in this study, for the efficient application of waste woods and eco-friendly effects, mortar was produced using sawdust af the waste wood and mineral material cement for combination, in order to produce inorganic boards using waste woods, which were made when sawing. The present study purposed to analyze the physical and dynamic characteristics of woody cement boards, which were made by modifying water-cement ratio for each wood inclusion rate based on a hardening-accelerator inclusion rate set in previous studies and, based on the findings. to provide basic data about the physical properties of inorganic boards made of waste wood, in order to Produce woody cement boards using waste wood, which has problems in being used in the manufacturing of woody cement boards.

• Computers and Concrete
• /
• v.12 no.3
• /
• pp.319-335
• /
• 2013

In this paper, the properties of the cement mortar modified with styrene acrylic ester copolymer were investigated. Expanded vermiculite as lightweight aggregate was used for making the polymer modified mortar test specimens. To study the effect of polymer-cement ratio and vermiculite-cement ratio on various properties, specimens were prepared by varying the polymer-cement and vermiculite-cement ratios. Tests of physical properties such as density, water absorption, thermal conductivity, three-point flexure and compressive tests were made on the specimens. Furthermore, a coupled thermal-structural finite element model of an entire corner wall was modelled in order to study the best material configuration. The wall is composed by a total of 132 bricks of $120{\times}242{\times}54$ size, joined by means of a contact-bonded model. The use of advanced numerical methods allows us to obtain the optimum material properties. Finally, comparisons of polymer-cement and vermiculite-cement ratios on physical properties are given and the most important conclusions are exposed.

• Journal of the Korean Ceramic Society
• /
• v.46 no.1
• /
• pp.94-101
• /
• 2009

The physical properties of artificial aggregates made from clay and inorganic wastes with poor plasticity depends largely on forming method. The artificial aggregates composing of coal fly ash, stone sludge and clay were fabricated using 4 different forming methods and those physical properties were comparatively analyzed. The surface of aggregates made through the extrusion forming process was dense and smooth but was rough for the aggregates obtained by crushing a tile-shaped green body. The aggregates made by pelletizing process had a weak green strength and bumpy surface. The shell generated at surface during a high temperature sintering process induced the most aggregates to be bloated due to a dense shell. But the aggregates made through pelletizing process with dense surface layer showed no significant change in bulk density with sintering temperatures. The water absorption of aggregates decreased with sintering temperature, and that of pelletized specimen was standing $1.8{\sim}2.2$ times higher than that of made by other forming methods. It is concluded that the aggregates having various properties could be fabricated from one batch by using different forming methods.

• Tunnel and Underground Space
• /
• v.13 no.3
• /
• pp.215-224
• /
• 2003

Weathering in nature was simulated by freeze-thaw cyclic test which represents mechanical weathering. Measured physical properties were elastic wave velocities, absorption rate, volume change and weight change. Uniaxial compression tests were also conducted before and after the weathering tests. The change in weight and volume of the specimens were not clearly related to the weathering process, but P, S wave velocities, uniaxial compression strength and Young's modulus were clearly decreased as weathering progresses. Test result can be used for the assessment of long-term stability of rock slopes.