• Fibers and Polymers
• /
• v.5 no.4
• /
• pp.280-288
• /
• 2004

Split-type nylon/polyester microfiber and polyester microfiber fabrics possess drapeability, softness, bulkiness, and smoothness, so that they can be applied in various industrial fields. In particular, these fabrics are able to absorb various organic solvents, and can be used as clean room materials. To investigate the chemical affinity between solvents and the compositional materials of these fabrics, the contact angle of thermally pressed film fabrics was measured with different solvents. The thermally pressed nylon/polyester fabric films showed a chemical attraction to formamide. The sorption properties of the microfiber fabrics were investigated using a real time testing device, and these tests showed that the sorption behavior was more influenced by the structure of the fibrous assembly than by any chemical attraction. The effect of the fabric density, specific weight, and sample structure on the sorption capacity and rate was examined for various organic solvents. The sorption capacity was influenced by the density and the specific weight of the fibrous assembly, and knitted fabric showed a higher sorption capacity than woven fabric. However, the sorption rate was less affected in lower viscosity solvents. On applying Poiseuille's Law, the lower viscosity solvents showed higher initial sorption rates, and more easily penetrated into the fibrous assembly.

• Proceedings of the KIEE Conference
• /
• 2006.07c
• /
• pp.1305-1306
• /
• 2006

A monolayer assembly of anthracene-viologen linked thiol ($AMVC_{8}SH$) was fabricated on a gold electrode by self-assembly method. Structural property of the self-assembled monolayers (SAMs) was carried out by optical and electrochemical method. Firstly, we investigated PL spectrum and UV/visible absorption for the optical properties in solution state. Secondly, we determined the characteristics of charge transfer in different electrolyte solutions by electrochemical quartz crystal microbalance (EQCM). From the data, the PL spectrum and UV/visible absorption were observed and the well-defined shape peaks were nearly equal charges during redox reactions and existed to an excellent linear relationship between the scan rates and existed to currents. The mass change was determined during redox reaction. The mass change behavior of SAMs was not only governed by the mobility of the ion in the viologen but the valence of the ion in the electrolyte solution.

• Journal of Pharmaceutical Investigation
• /
• v.21 no.2
• /
• pp.73-78
• /
• 1991

The influence of different suppository bases on the rectal absorption and the dissolution rate of propranolol was investigated. The bioavailability of propranolol in rectal suppository was determined by comparing the area under the concentration-time curves(AUC) for oral administration with rectal suppositories in rabbits. The dissolution $rates(D_{20min})$ were higher in such order as tween (TWE), witepsol H-15(WIT), polyethylene glycol(PEG) suppository. The maximum blood concentrations $(C_{max})$ were 803.9 ng/ml for TWE suppository, 770.2 ng/ml for WIT suppository, 281.2 ng/ml for PEG suppository and 177.1 ng/ml for oral administration. The relative bioavailabilities were 233.5% for TWE suppository, 218.1% for TWE suppository, 191.3% for PEG suppository. The correlation between $D_{20min}$ and AUC, the time for dissolution in 75% and $C_{max}$, the mean dissolution time and the mean residence time showed significant linear relationship respectively.

• Textile Coloration and Finishing
• /
• v.12 no.6
• /
• pp.344-352
• /
• 2000

Two kinds of nylon 6 fabrics with different fiber denier, such as ultramicro fiber(UMF) nonwoven fabric(monodenier 0.05d) and regular fabric(monodenier 2.92d) are dyed with C.I. Acid Red 18(leveling type) and C.I. Acid Blue 113(milling type). Dyeing rates and adsorption isotherms are measured at $60^\circ{C}$, pH 5.0 and at liquor ratio of 1 : 250. To investigate the effect of fixing agents (Matexil FA-SNX, Monorex-RD and Tinofix-ECO) on UMF nylon 6 nonwoven fabric, dyeing is carried out at 3~10% owf with 1 : 2 metal-complex acid dyes, such as Kayalax Navy R(unsulphonated type), Lanasyn Blue S-BL(monosulphonated type) and Kayakalan Black BGL(disulphonated type). The dyeing rate of UMF nylon 6 is faster than that of regular nylon 6. From the results of absorption isotherms, the regular nylon 6 has higher saturation value of Acid Red 18 compared with UMF nylon 6, whereas UMF nylon 6 has higher saturation value of the acid Blue 113. From the absorption isotherms of both acid dyes, the regular nylon 6 has higher saturation value of Acid Red 18, whereas UMF nylon 6 has higher saturation value of the acid Blue 113. The wash fastnesses of UMF nylon 6 increases in the order of metal-complek dye containing nonsulphonated group > monosulphonated group>disulphonated group. Aftertreatment of UMF nylon 6 dyed with unsulponated and monosulphonated dyes improves wash fastness upto grade 1.5, where as that of UMF nylon 6 dyes with disulphonated dye does not improve wash fastness.

• Korean Journal of Environmental Agriculture
• /
• v.29 no.1
• /
• pp.33-38
• /
• 2010

To improve the existing nitrogen recommendation method based on chemical properties of soils and to establish new recommendation rates of nitrogen fertilizer due to different types of soils, the application rates of nitrogen fertilizer were examined in different soils of 12 experimental rice paddy fields. The application rates of nitrogen fertilizer estimated by soil-testing were higher than the rates of nitrogen standard recommendation that has been used. The application rates for minimum rice productivity ranged from a low of 168 kg/10a in sandy soil to a high of 315 kg/10a in saline soil. Amounts of nitrogen absorption in rice were proportional to the application amounts of nitrogen fertilizer in soils. Nitrogen use efficiency was the highest, 36.7%, in immatured paddy field and it was inversely proportional to the application amounts of nitrogen. the rice tasty value was the highest in the soils without nitrogen application, and also it was the lowest in the saline soils with or without nitrogen application. As comparing with the nitrogen application rates obtained by the existing nitrogen recommendation method, optimal nitrogen application rates estimated by the standardization of nitrogen application efficiency rate, environmental index, and rice quality were 1.0 fold in the well adapted soil and sandy soil fields, 0.92 fold in the immatured soil field, and 0.83 fold in the saline soil field.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.11 no.1
• /
• pp.48-55
• /
• 2001

The purpose of this study was to evaluate the analytical accuracy and precision of microwave oven digestion/atomi absorption spectrophotometry (AAS) for analyzing airborne chromium collected on mixed cellulose ester membrane (M filter from the work environment, and to compare the accuracy and the precision with those of the National Institute for Occupational Safety and Health (NIOSH) Method #7024 hot plate digestion/AAS method. For this study, field air sample pairs were collected from a electroplating process, and spiked samples in a laboratory were prepared and using these samples. Two digestion methods were comp; and evaluated in terms of recovery rate and bias as indices of accuracy and coefficient of variation as a index of precision. The results and conclusions are as follows. In spiked samples, the accuracies (% mean recoveries) of hot plate/AAS and microwave oven/AAS method were 97.19%, 97.1%, respectively, and the precisions (pooled respectively, and the precisions (pooled coefficient of variance, $CV_{pooled}$) 6.93% and 3.88%, respectively. The biases of hot plate ani microwave oven methods were 4.56 - 14.7% and 2.22 - 7.42% respectively. There was no statistically significant difference between hot plate and microwave oven methods recovery rates of spiked samples (p>0,05). Also, no statistically significant difference was shown among the concentrations of air samples determined by two method (p>0.05). In conclusion, microwave oven/AAS method h excellent accuracy and precision, and advantages such as time-saving and simple procedure in comparison with the classical NIOSH method. Therefore, this method can be use widely to analyze airborne chromium collected on MCE filter from the work environments.

• Composites Research
• /
• v.24 no.3
• /
• pp.31-38
• /
• 2011

In this paper, a novel hybrid composite shield to protect space structures from hypervelocity impact of micrometeoroid and space debris is proposed. The finite element model of the proposed shield was constructed and finite element analysis was conducted to approximate the energy absorption rate. Before the final model analysis, analysis of each component including the aluminum plate, PMMA plate, and intermediate layer of fabric was performed, verifying the finite element model of each component. The material properties used in the analyses were predicted material property values for high strain rates. The analysis results showed that, other than the fabric, the energy absorption rate of each component was in agreement. Afterwards, the finite element model of the hybrid composite shield was constructed, where it was analyzed for the restrained and unrestrained fabric boundary condition cases. Through the finite element analysis, the fiber pullout mechanism was realized for the hybrid shield with free boundary inserted fabric, and it was observed that this mechanism led to energy absorption increase.

• Proceedings of the SAREK Conference
• /
• 2008.06a
• /
• pp.109-114
• /
• 2008

A dynamic model has been developed to simulate dynamic operation of a real double-effect absorption chiller. Dynamic behavior of working fluids in main components was modeled in first-order nonlinear differential equations based on heat and mass balances. Mass transport mechanisms among the main components were modeled by valve throttling, 'U' tube overflow and solution sub-cooling. The nonlinear dynamic equations coupled with the subroutines to calculate thermodynamic properties of working fluids were solved by a numerical method. The dynamic performance of the model was compared with the test data of a commercial medium chiller. The model showed a good agreement with the test data except for the first 5,000 seconds during which different flow rates of the weak solution caused some discrepancy. It was found that the chiller dynamics is governed by the inlet temperatures of the cooling water and the chilled water when the heat input to the chiller is relatively constant.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.20 no.12
• /
• pp.781-788
• /
• 2008

A dynamic model has been developed to simulate dynamic operation of a real double-effect absorption chiller. Dynamic behavior of working fluids in main components was modeled in first-order nonlinear differential equations based on heat and mass balances. Mass transport mechanisms among the main components were modeled by valve throttling, 'U' tube overflow and solution sub-cooling. The nonlinear dynamic equations coupled with the subroutines to calculate thermodynamic properties of working fluids were solved by a numerical method. The dynamic performance of the model was compared with the test data of a commercial medium chiller. The model showed a good agreement with the test data except for the first 5,000 seconds during which different flow rates of the weak solution caused some discrepancy. It was found that the chiller dynamics is governed by the inlet temperatures of the cooling water and the chilled water when the heat input to the chiller is relatively constant.

• Asian-Australasian Journal of Animal Sciences
• /
• v.29 no.3
• /
• pp.444-454
• /
• 2016

This study was designed to examine the characteristics of sawdust and cocopeat bedding materials, including physicochemical properties (Exp. I) and on-farm trial (Exp. II). In Exp. I, the proportion of particle size was in the order of sawdust>cocopeat India>cocopeat Vietnam (p<0.05), and cocopeat contained higher proportion of small particles ($250{\mu}m$+below $250{\mu}m$) than sawdust, causing a dust production problem. Bulk density was cocopeat India>cocopeat Vietnam>sawdust (p<0.05), thus cocopeat treatments showed 4.4 times higher bedding cost than sawdust. The water absorption rates were 702.0% in cocopeat India, 678.3% in cocopeat Vietnam, and 444.0% in sawdust, showing cocopeat had approximately 1.5 times higher water absorption rate than sawdust. Moisture evaporation rates after 12 h of air blowing (2.00 m/s) were higher (p<0.05) in cocopeat Vietnam (80.4%) than sawdust (71.2%) and cocopeat India (72.8%). In vitro ammonia emissions were higher (p<0.05) in sawdust ($2.71mg/m^2/h$) than cocopeat India ($1.59mg/m^2/h$) and Vietnam ($1.22mg/m^2/h$), and total ammonia emissions were higher (p<0.05) in sawdust ($37.02mg/m^2$) than cocopeat India ($22.51mg/m^2$) and Vietnam ($13.60mg/m^2$). In Exp. II, an on-farm trial was conducted with 48 Hanwoo cattle in 16 pens using the same bedding materials as in Exp. I, with fan (blowing 2.00 m/s) and no fan treatments, and feed bunk side (FB) and water supply side (WS) within a pen (4.5 m, $width{\times}9.0m$, length). Beddings were replaced with fresh bedding materials when moisture concentrations were over 65%. No interactions among treatments were detected for moisture concentration and increment rates, and ammonia concentrations, but a significant effect was observed (p<0.01) for each of the treatments. Both concentrations and increment rate of moisture were higher (p<0.01) in the beddings without fan than with fan. Moisture concentrations and increment rate within a pen were also higher (p<0.01) in FB than WS. Thus, the whole no-fan-FB and sawdust-fan-FB were replaced with fresh bedding material between 4 to 5 experimental weeks. The ammonia concentrations and pH of beddings were not significantly different among treatments. Therefore, using cocopeat bedding with a blowing fan can extend twice the bedding utilization period, and WS within a pen showed twice the bedding-life compared to FB. Despite the outstanding characteristics of cocopeat compared with sawdust, using cocopeat as an alternative for sawdust bedding is not recommended for cattle management, considering it has 4.4 times higher bedding cost and a dust production problem.