• Food Science of Animal Resources
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• v.37 no.2
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• pp.219-227
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• 2017

The objective of this study was to determine the physicochemical and sensory properties of cooked emulsion sausages containing different levels of lotus rhizome powder (0, 1, 2, and 3%, based on total weight). Lotus rhizome powder had no significant (p>0.05) impact on pH, moisture, protein, or ash content of sausage. However, fat content was slightly but significantly (p<0.05) decreased when the level of lotus rhizome powder was increased in the sausages. The addition of lotus rhizome powder to sausages at over 1% resulted in significantly (p<0.05) darker and less red color of cooked sausage compared to control. Increase in lotus rhizome level slightly improved the emulsion stability and apparent viscosity. Significant (p<0.05) reduction in cooking loss was observed when more than 1% of lotus rhizome powder was added to sausages. The textural properties of sausages were unaffected by the inclusion of lotus rhizome except for springiness and chewiness. On the manufacture day, control sausage had significantly (p<0.05) higher TBARS value than treatments. Regarding sensory characteristics, increased levels of lotus rhizome powder decreased (p<0.05) color and juiciness scores. However, cooked sausages exhibited similar overall acceptability regardless of the level of lotus rhizome powder added to sausages. Therefore, lotus rhizome powder, an antioxidant dietary fiber, could be used as an effective natural ingredient in meat products for the development of healthier and functional food.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.1028-1034
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• 1999

Poly(lactic acid) is expected to be one of the most promising biodegradable polymers. However, the high molecular weight polymer could be obtained by ring-opening polymerization process conventionally, which raises the production cost and decreases the final yield. In this study, linear and star-shaped poly(L-lactic acid)s were prepared by direct solution polycondensation method and their physical and thermal properties were examined. Tin compounds were found to be effective catalyst for the preparation of high molecular weight polymers. When 0.2g (0.5 wt % of monomer) of $SnCl_2$ and 100 mL of p-xylene were used, the polymer yield and molecular weight were relatively high. As a means to obtain higher molecular weight polymer easily in the direct polycondensation system, dipentaerythritol(dipet) or pentaerythritol(pet) was introduced as a multifunctional branching monomer to provide a star-shaped poly(lactic acid). Moderately high molecular weight polymers with the inherent viscosity values up to 1.14 dL/g(weight-average molecular weight of about 140000 by GPC) were obtained and could be cast strong and transparent films.

• Journal of the Korea Concrete Institute
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• v.14 no.5
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• pp.742-749
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• 2002

This study was performed to clarify the formation procedure of continuous voids in cellular concrete, and to examine the effect of a foaming agent on the manufacture of cellular concrete with continuous voids. By the experiments, it was determined that cellular concrete to be formed with continuous voids is influenced by temperature, viscosity and flowability of cement paste, and stability of air voids, and is formed in accordance with cohesion of air voids. It was also found that separate voids are formed at an added amount of air voids corresponding to 2 ％ or less of the amount of cement, whereas an antifoaming phenomenon occurs when the added amount of air voids exceeds 9 ％ of the amount of cement. In products with respective cement fineness of 3,000, 6,000, and 8,000㎠/g, a higher compressive strength was exhibited at a higher cement fineness. The continuous void ratio depending on a variation in fineness was 38 ％, 52 ％, and 22 ％ in those products, respectively. That is, a highest continuous void ratio was exhibited at a cement fineness of 6,000㎠/g. When the water-cement ratio was reduced from 45％ to 25％, the compressive strength of the cellular concrete was increased from 15 kgf/㎠ to 20 kgf/㎠ Thus, the reduction in water-cement ratio was effective in achieving an increase in strength without any variation in the specific gravity of the cellular concrete.

• Polymer(Korea)
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• v.31 no.4
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• pp.283-288
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• 2007

Polymer blends containing poly(acrylonitrile-butadiene-styrene) (ABS) and polycarbonate(PC) (70/30, wt%) with compatibilizer were prepared using twin screw extruder. Compatibilizers were prepared by reactive extrusion with the ABS, maleic anhydride(MAH) and dicumyl peroxide(DCP) using twin screw extruder In the ABS/PC (70/30) blends, tensile strength did not change significantly, but increased from 52.25 to 55.03 MPa when the ABS-g-MAH was added in the amount of 5 phr. From the results of rheological properties, storage modulus of the ABS/PC/ABS-g-MAH blends at low frequencies showed lager value than that of the ABS/PC(70/30) blend. From the results of the morphological properties of the ABS/PC(70/30) blend, it was observed that the drop size of the PC ranged from 1.2 to $1.5\;{\mu}m$ and did not change significantly with the addition of the ABS-g-MAH($1{\sim}10\;phr$). From the results of the storage modulus, complex viscosity, and tensile strength of the ABS/PC (70/30) blends, it is found that the ABS-g-MAH is an effective compatibilizer in the ABS/PC (70/30) blends when the ABS-g-MAH is added in the amount of 5 phr.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.245-252
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• 1998

The chitosanolytic capabilities of cellulases, glucosidases, proteases and commercial enzymes were evaluated, and effective chitosanolytic cellulases from T. viride, T. reesei and Celluclast, a commercial enzyme from T. reesei were characterized. The reaction of cellulase from T. viride, T. reesei and Celluclast was optimal at pH 5. 0 and $45{\sim}55^{\circ}C$. Max. chitosanolytic activities of cellulases from both T. viride and T. reesei were observed at the enzyme/chitosan ratio=0.1 and chitosan concentration=3.0%. For the possible application of commercial Celluclast to chitosan oligosaccharides production, 3%(w/v) chitosan was reacted with 1%(v/v) Celluclast at pH 5.0 and $55^{\circ}C$. The apparent viscosity decreased by 98% within 30 minutes reaction and Max. contents of 50% EtOH solubles were 70% at 15 hrs reaction. Total reducing sugars were also increased with reaction time and maintained approx. 13.5% after 2hrs reaction. In 15 hrs treated chitosan hydrolyzates, various kinds of chitosan oligosaccharides were produced and contents of chitosan hexamer, known for its antitumor activities, were about 8.0%, about 4 times higher values compared with acid hydrolysis method. The results suggested that chitosan oligosaccharides could be produced with low-cost cellulases from T. reesei.

• Journal of Conservation Science
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• v.25 no.4
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• pp.439-450
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• 2009

The purpose of this study is to find out characteristics of the fillers made by epoxy resin (L-30) and filling epoxy resin (L-50) with talc, quartz sand and wollastonite with different mixture ratio of 5%, 50%, 80%, 120%, and 150%. The viscometer and colorimeter were used to measure the viscosity and chromaticity of the fillers. Additionally, IC and SEM were used to reveal characteristics of the filler, and checked ultrasonic wave velocity, compressive strength and contact angle to estimate the stability between the filler and stones which are essential for conservation treatments. The filler mixed with the talc had the lowest value in the ultrasonic wave velocity analysis, and its compressive strength decreased as the mixing rate of talc increased. On the other hand, wollastonite had higher values than others in the ultrasonic wave velocity and the compressive strength regardless of epoxy resin type, also, these values increased as mixing rate increased. The properties of the filler, which include the granularity and shape, have influence on characteristics of the stone conservation adhesives. Thus, the filler type, characteristic, and mixture ratio must be considered for effective conservation treatment.

• Korean Journal of Food Science and Technology
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• v.47 no.5
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• pp.645-651
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• 2015

Sucrose in chiffon cakes was replaced with different levels of sorbitol (0, 30, 50, 70, and 100%), and the effects on the physical properties and storage stability of the cakes were measured. The specific gravity and viscosity of the batter, as well as the volume and moisture content of the cakes, decreased with increasing sorbitol content. The hardness of the cakes slightly decreased as the amount of sorbitol increased, whereas the lowest cohesiveness was observed in the cakes with equal amounts of sucrose and sorbitol. Storage for one day slightly increased the hardness of the cakes and decreased their cohesiveness. Although the amount of mold and total microbial count increased with increasing storage days at room temperature, the replacement of sucrose with 70 or 100% sorbitol was effective in suppressing microbial growth. In sensory tests, the formulation with 70% sorbitol substitution in the chiffon cakes was the most acceptable.

• Journal of Conservation Science
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• v.28 no.3
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• pp.265-276
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• 2012

Physicochemical properties of HBA epoxy resins were controlled by varying hardener mixture and reactive diluent to improve applicability for stone conservation. The epoxy risen comprises hydrogenated Bisphenol-A based epoxide (HBA), fast curing agent (FH), slow curing agent poly(propyleneglycol)bis(2- aminopropylether) (SH) and difunctional polyglycidyl epoxide (DPE). Talc was used as an inorganic additive. The changes in viscosity and temperature during curing reactions depending on the composition of the epoxy resins were investigated. Additionally, bending, tensile and adhesive strengths were measured to identify the effective mechanical strength in stone conservation. Finally various compositions of epoxy resin/inorganic additives were developed for stone conservation by controlling cure kinetics and mechanical properties.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.2
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• pp.15-29
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• 2020

The aims of this study is to improve physical properties of the sewage sludge and the process sludge generated in the leachate treatment by mixing the dry fuel, to develop the neutral solidifing agents that reduce oder, and to recycle the sewage and the process sludges as landfill cover materials. The mixing ratio (W/W) of sludges and dry fuel was appropriate at about 1:1, and the mixed materials were shown to be homogeneous at that ratio. We could know that when the sludges were mixed with dry fuel, moisture contents and viscosities are reduced, and air passages are formed between particles and particles. The various mixing tests and odor tests showed that the neutral solidifing agent was effective for the odor reduction. The main ingredient of the solidifing agent is the ash of sewage sludge, enabling it competitive in waste recycling and production costs. The landfill cover, using developed neutral solidification agent, improved physical properties to satisfy the quality standards and to increase the compressive strength. It also proved to reduce the value of complex oder and the usage of solidification agent to 1/3 (3,000 to 1,000) and to 1/8 (50% to 6%), respectively, from the comparative study with alkaline solidified landfill cover. Further research is under way to prove that this can be mixed with general soil to be used as a soil improvement agent for plant cultivation.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.720-726
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• 2009

Hydrodynamic similarity was investigated in pressurized three-phase slurry bubble columns by selecting the bubble holdup and pressure drop as objective functions, for the effective design and scale-up of it. In addition, effects of operating variables on the bubble holdup with variation of column diameter were also analyzed. Gas velocity($U_G$), viscosity(${\mu}_{SL,eff}$) and surface tension(${\rho}_{SL}$) of slurry phase, density difference between the slurry and gas phases(${\rho}_{SL}-{\rho}_G$) depending on the operating pressure, pressure drop per unit length(${\Delta}P/L$), column diameter(D) and gravitational acceleration(g) were chosen as governing parameters in determining the bubble holdup and pressure drop in the column. From the dimensional analysis, four kinds of dimensionless groups were derived from the 7 parameters and 4 fundamental dimensions. Effects of dimensionless groups such as Reynolds, Froude and Weber numbers on the bubble holdup in the column were discussed. The pressure drop and bubble holdup could be predicted from the correlation of dimensionless groups effectively, which could be used as useful information for the design and scale-up of pressurized slurry bubble columns.