• Food Science of Animal Resources
• /
• v.35 no.5
• /
• pp.703-706
• /
• 2015

The interaction of plasma with liquid generates nitrogen species including nitrite (NO⁻₂). Therefore, the color developing capacity of plasma-treated water (PTW) as a nitrite source for meat curing was investigated in this study. PTW, which is generated by surface dielectric barrier discharge in air, and the increase of plasma treatment time resulted in increase of nitrite concentration in PTW. The PTW used in this study contains 46 ppm nitrite after plasma treatment for 30 min. To evaluate the effect of PTW on the cured meat color, meat batters were prepared under three different conditions (control, non-cured meat batter; PTW, meat batter cured with PTW; Sodium nitrite, meat batter cured with sodium nitrite). The meat batters were vacuum-packaged and cooked in a water-bath at 80℃ for 30 min. The typical color of cured meat developed in cooked meat batter treated with sodium nitrite or PTW. The lightness (L*) and yellowness (b*) values were similar in all conditions, whereas, the redness (a*) values of cooked meat batter with PTW and sodium nitrite (p<0.05) were significantly higher than the control. These data indicate that PTW can be used as a nitrite source in the curing process of meat without addition of other nitrite sources.

• Food Science of Animal Resources
• /
• v.40 no.6
• /
• pp.990-1000
• /
• 2020

This study investigated the effects of Chinese cabbage powder as a natural replacement for sodium nitrite on the qualities of alternatively cured pork products. Chinese cabbages grown in Korea were collected and used for preparing hot air dried powder. Different levels of Chinese cabbage powder were added to pork products and evaluated by comparing these products to those with sodium nitrite or a commercially available celery juice powder. The experimental groups included control (100 ppm sodium nitrite added), treatment 1 (0.15% Chinese cabbage powder added), treatment 2 (0.25% Chinese cabbage powder added), treatment 3 (0.35% Chinese cabbage powder added), and treatment 4 (0.4% celery juice powder added). The cooking yields and pH values of treatments 1 to 3 were significantly lower (p<0.05) than the control. However, all of the alternatively cured products were redder (higher CIE a* values; p<0.05) than the control and this result was supported from higher nitrosyl hemochrome, total pigment, and curing efficiency. Furthermore, the inclusion of vegetable powders to these products resulted in considerably less residual nitrite content. However, Chinese cabbage powder (0.25% and 0.35%) was effective in producing alternatively cured meat products with a higher curing efficiency comparable to those of the traditionally cured control or the products with celery juice powder. Therefore, Chinese cabbage powder exhibited the efficacy for use as a natural replacer for alternatively cured meat products.

• Journal of the Korea Concrete Institute
• /
• v.25 no.4
• /
• pp.457-465
• /
• 2013

This study discussed the influence of mixtures and curing conditions on the development of strength and microstructure of RPC using ternary pozzolanic materials. Through pilot experiment, various RPC was manufactured by adding single or mixed ternary pozzolanic materials such as silica fume, blast furnace slag and fly ash by mass of cement, up to 0~65%, and cured by using 4 types of method which are water and air-dried curing at $20^{\circ}C$, steam and hot-water curing at $90^{\circ}C$. The results show that the use of ternary pozzolanic materials and a suitable curing method are an effective method for improving development of strength and microstructure of RPC. The unit volume of cement was greatly reduced in RPC with ternary pozzolanic materials and unlike hydration reaction in cement, the pozzolanic reaction noticeably contributes to a reduction in hydration heat and dry shrinkage. A considerable improvement was found in the flexural strength of RPC using ternary pozzolanic materials, and then the utilization of a structural member subjected to bending was expected. The X-ray diffractometer (XRD) analysis and Scanning Electronic Microscope (SEM) revealed that the microstructure of RPC was denser by using the ternary pozzolanic materials than the original RPC containing silica fume only.

• The Journal of Advanced Prosthodontics
• /
• v.5 no.2
• /
• pp.104-109
• /
• 2013

PURPOSE. Among the surface treatment methods suggested to enhance the adhesion of resin cement to fiberreinforced composite posts, conflicting results have been obtained with silanization. In this study, the effects of silanization, heat activation after silanization, on the bond strength between fiber-reinforced composite post and resin cement were determined. MATERIALS AND METHODS. Six groups (n=7) were established to evaluate two types of fiber post (FRC Postec Plus, D.T. Light Post) and three surface treatments (no treatment; air drying; drying at $38^{\circ}C$). Every specimen were bonded with dual-curing resin cement (Variolink N) and stored in distilled water for 24 hours at $37^{\circ}C$. Shear-bond strength (MPa) between the fiber post and the resin cement were measured using universal testing device. The data were analyzed with 1-way ANOVA and by multiple comparisons according to Tukey's HSD (${\alpha}$=0.05). The effect of surface treatment, fiber post type, and the interactions between these two factors were analyzed using 2-way ANOVA and independent sample T-tests. RESULTS. Silanization of the FRC Postec Plus significantly increased bond strength compared with the respective non-treated control, whereas no effect was determined for the D.T. Light Post. Heat drying the silane coupling agent on to the fiberreinforced post did not significantly improve bond strength compared to air-syringe drying. CONCLUSION. The bond strength between the fiber-reinforced post and the resin cement was significantly increased with silanization in regards to the FRC Postec Plus post. Bond strength was not significantly improved by heat activation of the silane coupling agent.

• Restorative Dentistry and Endodontics
• /
• v.22 no.1
• /
• pp.61-75
• /
• 1997

The bond strengths of composite resin to tooth dentin vary with the methods of cavity preparation and surface treatment. Recent developments in techniques of dentinal surface treatment have renewed interest in microabrasive as a means of tooth preparation, The purpose of this study was to determine the effects of a new method of cavity preparation on the bond of composite resin to dentin. Freshly extracted 144 healthy human third molars were used in this study. The dentin surfaces prepared with #600 SiC abrasive paper were divided into control and air abrasion groups according to the method of dentin surface preparation using different combinations of delivery pressure, time, and acid etching. The shear bond strengths were measured after the composite resin (Clearfil Photo Bright) was bonded to prepared dentin surfaces by light-curing using a dentin bonding system (All-bond 2), In addition, the average surface roughness was measured to investigate the effect of differently prepared dentin surfaces on the shear bond strengths. The surface changes of prepared dentin and the debonded dentin surfaces were observed with SEM (S-2300, Hitachi Co., Japan). The following results from this-study were obtained ; 1. There was no significant difference of shear bond strengths according to the changes of delivery pressure and time. 2. The shear bond strengths were lower than the control in the air abraded-only groups, but those of the additional acid-etched groups were higher than the control. 3. The shear bond strengths to all air-abraded surfaces were increased by acid etching. 4. The correlation between shear bond strengths and surface roughness was not certain, although the mean surface roughness of all air-abraded surfaces has increased evidently while it has slightly decreased for additional acid etching. 5. On SEM examination, the dentinal tubules were almost occluded in the air abraded-only groups, but those were opened in the additional acid-etched groups. 6. The debonded surfaces were showed adhesive failure mode in the air abraded- only groups, while those were showed mainly the mixed and cohesive failure mode in the additional acid-etched groups. These results suggest that the layer produced during cavity preparation or surface treatment with air abrasion must be removed for maximum bond strength of composite resin to dentin.

• Composites Research
• /
• v.30 no.2
• /
• pp.116-125
• /
• 2017

The purpose of this study is to develop silicon carbide fiber showing an excellent mechanical properties under highly oxidative conditions at high temperature. Polycarbosilane(PCS) as a preceramic precursor was used for making the SiC fiber. PCS fiber was taken by melt spinning method followed by melting the PCS at $300{\sim}350^{\circ}C$ in N2 gas. The Curing of PCS fiber was carried out in air oxygen chamber, prior to high temperature pyrolysis. Degree of cure was calculated by characteristic peak's ratio of Si-H to $Si-CH_3$ in FT-IR spectra before and after curing of PCS fiber. The properties of SiC fiber was affected greatly by the degree of cure. The SiC fiber produced by controlling fiber tension during heat treatment showed good properties. The SiC fiber exposed to $1000^{\circ}C$ at air from 1 min. up to maximum 50 hrs showed around 60% reduction in tensile strength. We found that large amount of carbon content on the fiber surface after long-term exposure has resulted in lower tensile strength.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.29 no.7 s.144
• /
• pp.997-1007
• /
• 2005

The textile finishing methods utilizing chitosan have been mostly focused on the applications in the improvement of the dyeing of cotton fabrics, or the improvement of hand of the cotton or wool fabrics. On the other hand, it Is difficult to find the application examples in the synthetic fiber fabrics including polyester and nylon fabrics. The aim of this study is to improve the stiffness and the poor wash fastness of the fabrics treated only with chitosan. We tried to improve the softness by employing chitosan and polyurethane mixture solution and to prevent the detachment of the chitosan from the fabric. The treatment was applied to cotton, polyester, and nylon fabrics. The change of the properties of the treated fabrics were investigated. The optimum finishing condition was sought by changing the mixture ratio of the chitosan/PU(polyurethane) solutions. The adjusted ratios of the chitosan/PU solutions were 1 : 0, 1 : 0.25, 1 : 0.5, and 1 : 2 during the mixture solution preparation. Using the KES(Kawabata Evaluation System), the physical and mechanical properties of the finished fabric specimens were analyzed, and hand values of the specimens were calculated through the use of translational formulas. According to the chemical composition of the fibers, chitosan solution or chitosan/PU mixture exhibited wide range of coating effect. Since the chitosan acid solution has high polarity, the bonding force with the cotton fibers is high. By the appropriate addition of PU in the chitosan treatment of cotton, KOSHI and HARI values of the fabric improved. The air permeability of the chitosan/PU treated cotton fabric specimen improved, resulting in the highest value at the mixture of chitosan : PU=1:0.25.

• Geomechanics and Engineering
• /
• v.8 no.5
• /
• pp.687-706
• /
• 2015

Methods commonly used to evaluate the improvement of lime-treated expansive soil include swelling characteristics and unconfined compressive strength. In the field, lime-treated expansive soils are in compacted unsaturated state. Soil water characteristic curves (SWCCs) represent a key parameter to interpret and describe the behavior of unsaturated expansive soil. This paper investigates the use of SWCC as a technique to evaluate improvements acquired by expansive soil after lime treatment. Three different lime contents were considered 2%, 4% and 6% by dry weight of clay. Series of tests were performed to determine the SWCC for the different lime content under curing periods of 7 and 28 day. Correlations between key features of the soil water characteristic curves of lime treated expansive soils and basic engineering behavior such as swelling characteristics and unconfined compression strength were established. Test results revealed that initial slope ($S_1$), saturated water content ($w_{sat}$), and air entry value (AEV) play an important role in reflecting improvement in engineering behavior achieved by lime treatment.

• Journal of the Korean Home Economics Association
• /
• v.43 no.2
• /
• pp.115-126
• /
• 2005

Environmentally and human compatible chitosan were pretreated on cotton fabrics which were then dyed with 100% persimmon juice. The chitosan concentration was 1% and the chitosan types were high molecular weight chitosan (1980cps), low molecular weight chitosan (18첸), chitosan oligomer and water soluble chitosan. The properties of the fabric surfaces, the dyeabilities, the color fastnesses, the antibacterial activities, the strengths, the elongations and the drape stiffnesses were evaluated. The properties of the chitosanpretreated, persimmon juice-dyed cotton fabrics (CLP) were compared to those of the untreated (CN), chitosan treated (CL) and persimmon juice-dyed fabrics (CP). The results were as follows. The fibers extruded from the surface of CN decreased on CP. The air between the fibers within CN were substituted by chitosan solution or persimmon juiceand decreased within CLP according to SEM observations. The effects of chitosan treatment, the chitosan molecular weights and the degrees of deacetylation of chitosan on the dyeabilities of the persimmon juice-dyed cotton fabric were not distinct. The curing after chitosan padding improved the dyeabilities of CLP compare to noncuring. The strengths of CP decreased and those of CL increased, compared to those of CN. The strengths of CLP were greater than those of CP. The elogations of CP and CL were greater than those of CN. The strengths and elongations of CLP were greater than those of CN. The chitosan treatments improved the strengths but not the elongations. The drape stiffnesses of CL, CP and CLP were greater than those of CN. The antibacterial activites of chitosan pretreated, persimmon juice-dyed cotton fabrics against Staphylococcus aureus were increased by more than 98% by persimmon juice.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.34 no.2
• /
• pp.204-214
• /
• 2007

The aim of this study was to investigate whether differences in surface treatment prior to repair influenced the seal of a resin fissure sealant placed on the occlusal surfaces of permanent molar teeth. One hundred and twenty extracted human molars were selected and a light curing sealant was placed on their occlusal surface following cleaning by prophylaxis and acid etching. The teeth were deliberately damaged, and then stored in artificial saliva for four weeks. Sixty teeth with the desired morphology of sealant failure were randomly divided into four groups where one group was treated with only etching agent, another by only air-abrasion, another by applying an etching agent followed by a bonding agent, and the last by air-abrasion followed by a bonding agent each. After sealant application, the samples were thermocycled and the degree of microleakage was determined. The results were as follows : 1. In the sealant/sealant interface group 2(0.22), 4(0.23) using air-abrasion showed a significantly lower microleakage score than group 1(0.38), 3(0.35) using an etching agent(p<0.05). There were no statistically significant differences(p>0.05) between groups 1, 2 and groups 3, 4. 2. In the sealant/tooth interface, group 3(0.20), 4(0.20) which used a bonding agent showed a significantly lower microleakage score than group 1(0.35), 2(0.40) (p<0.05). There were no statistically significant differences(p>0.05) between groups 1, 3 and groups 2, 4. 3. In SEM examination, while sealant surfaces treated with etching did not result in highly rough surfaces, those treated with air-abrasion did show rough surfaces.