• International Journal of Industrial Entomology and Biomaterials
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• v.13 no.1
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• pp.45-50
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• 2006

Papers were prepared from cut cocoons and mulberry branches, which are byproducts from sericulture industry. The long filament of silk should be cut into appropriate length in order to prepare paper and this was achieved by chemical method. By a mixture of sodium hydroxide and sodium carbonate solution, the silk filaments were cut into short fibers (less than 1 mm in length). Since the short silk fibers (sSf) could not bind each other by itself, starch and poly(ethylene oxide)(PEO) were added as a bonding agent. When starch and PEO were used in a ratio of 3:7, the silk papers had optimum mechanical properties for paper. Fibers from the skin of mulberry branches (MBF) were added to sSf to enhance the mechanical properties of pure silk paper. Bleaching of MBF was performed with a mixture of hydrogen peroxide and sodium silicate. The mechanical properties were greatly enhanced and the optimum blend ratio of MBF and sSf were 7:3. The mulberry/silk paper has good absorption property against formaldehyde, and therefore, the paper could be applied as a wall paper for preventing the sick house syndrome.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.1
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• pp.29-36
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• 2017

The purpose of this study is to investigate experimentally the effect of types of alkali-activators and curing conditions on the compressive and tensile behavior of fiber-reinforced cementless composites. Two types of alkali-activators and two curing conditions were determined and density test, compressive strength test, and uniaxial tension test were performed. Test results showed that the cementless composite with sodium silicate showed higher performance in terms of strength, tensile strain capacity, and toughness than that with calcium hydroxide and sodium carbonate. The effect of curing conditions depends on the types of alkali-activators.

• Journal of the Korean Ceramic Society
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• v.42 no.5 s.276
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• pp.338-345
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• 2005

To prepare the complex gel of flux and pseudo-boehmite used in precursor of the flaky ${\alpha}-A1_2O_3$ crystal, aqueous solution of the mixture of sodium carbonate and sodium phosphate was added with stirring in aqueous solution of the mixture of sodium sulfate, potassium sulfate and titanium sulfate. The complex gel was dried at $110^{\circ}C$ and was crystallized above $1,050^{\circ}C$, and then the effect of the amount of titanium sulfate on size, morphology, thickness and crystal size distribution of the flaky ${\alpha}-A1_2O_3$ crystal was investigated. Addition of titanium sulfate was prevented the aggregation and generation of twin crystal, and had an effect on the crystal size and the thickness during crystal growth. When the amount of titanium sulfate was more than 6 g, particle size was decreased but was free from crystal twining and aggregation. On the other hand, when the amount of titanium sulfate was lower than 6 g, crystal size was increased but crystal twinning and aggregation were noticed.

• KSBB Journal
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• v.26 no.2
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• pp.143-150
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• 2011

The aim of the study was to optimize harvesting method for concentrating microalgae from microalgae mass culture. It is well known that the mass density of microalgae is usually very low and these are small size (5-20 ${\mu}m$) in the culture medium. It is essential that microalgae is harvested and concentrated economically for economical biodiesel production from microalgae. In this study, to determine optimized conditions for microalgae harvesting by chemical flocculation. Flocculation of three algae, Chlorella ellipsoidea, Dunaliella bardawil, and Dunaliella tertiolecta, was performed using various chemical flocculants, such as inorganic flocculants (aluminium sulfate, aluminium potassium sulfate, ferrous sulfate, ferric sulfate, ferric chloride, calcium hydroxide, sodium carbonate, sodium nitrite, and sodium aluminate), organic flocculant (polyacrylamide), and biopolymer flocculants (chitosan and starch). The results indicated that aluminium based inorganic flocculants is suitable for microalgae harvesting such as Chlorella ellipsoidea, Dunaliella bardawil, and Dunaliella tertiolecta. The results also recommended that flocculant doses, agitation speed, agitation time, sedimentation time for economical microalgae harvesting method using chemical flocculants.

• Carbon letters
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• v.24
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• pp.62-72
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• 2017

The aim of this work was to evaluate the dielectric properties of impregnated and activated palm kernel shells (PKSs) samples using two activating agents, potassium carbonate ($K_2CO_3$) and sodium hydroxide (NaOH), at three impregnation ratios. The materials were characterized by moisture content, carbon content, ash content, thermal profile and functional groups. The dielectric properties were examined using an open-ended coaxial probe method at various microwave frequencies (1-6 GHz) and temperatures (25, 35, and $45^{\circ}C$). The results show that the dielectric properties varied with frequency, temperature, moisture content, carbon content and mass ratio of the ionic solids. PKSK1.75 (PKS impregnated with $K_2CO_3$ at a mass ratio of 1.75) and PKSN1.5 (PKS impregnated with NaOH at a mass ratio of 1.5) exhibited a high loss tangent ($tan{\delta}$) indicating the effectiveness of these materials to be heated by microwaves. $K_2CO_3$ and NaOH can act as a microwave absorber to enhance the efficiency of microwave heating for low loss PKSs. Materials with a high moisture content exhibit a high loss tangent but low penetration depth. The interplay of multiple operating frequencies is suggested to promote better microwave heating by considering the changes in the materials characteristics.

• Textile Coloration and Finishing
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• v.29 no.4
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• pp.211-222
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• 2017

In this study, we investigated the dyeing properties of the ultra-fine nylon suede non-woven fabric with Sulphur black dye regarding to the effect of dye concentrations, reducing agent contents, sodium carbonate contents, antioxidant contents, immersion temperature and exposure time in air by pad-steam process. The optimal conditions of dyeing for the ultra-fine nylon suede non-woven fabric were determined with dye concentration of 30% o.w.f., reducing agent content of $9{\sim}13g/{\ell}$, sodium carbonate content of $1{\sim}4g/{\ell}$, antioxidant content of $1{\sim}5g/{\ell}$, immersion temperature of $70^{\circ}C$, exposure time of 20 minutes in air and immersion time of 1 minute, respectively. Meanwhile, the colorfastness to washing, the colorfastness to light, and the colorfastness to perspiration for dyed ultra-fine nylon suede non-woven fabric were achieved in the range of 4-5 grades. The formaldehyde and arylamine were not detected on the ultra-fine nylon suede non-woven fabric by KC tests.

• Journal of Bio-Environment Control
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• v.7 no.3
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• pp.214-218
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• 1998

This study was performed to stabilize the physical properties of Sodium Carbonate Decahydrate that was selected as a highly concentrative thermal energy storage medium. The addition of ARS(additives to prevent supercooling) showed to prevent the supercooling of Na$_{2}$CO$_{3}$.10H$_{2}$O, and the supercooling was decreased below $1.5^{\circ}C$ with ARS of 3 wt% and the addition of PSC(phase separation controller) of 1.5 wt% controlled the phase separation of Na$_{2}$CO$_{3}$ .10H$_{2}$O with the phase change cycles increased from 0 to 1,500, the phase change temperature and the latent heat has changed in the range of 30$\pm$1.$0^{\circ}C$ and 54$\pm$2.0Kcal.kg$^{-1}$ respectively.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.1
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• pp.75-82
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• 2013

The traditional Hanji-making was confronted with lots of industrial disadvantages and economic problems, due to the original hand-made process. Recently, the studies on the automation of overall Hanji manufacturing process is carried out by applying the commercial chemical pulping method in order to expand industrial application or efficiency of non-wood fibrous materials. However, the application of commercial pulping methods to the bast tissues of paper mulberry leads to the chemical and mechanical deterioration of cellulosic fibers. In this study, the optimal cooking method using the bast parts of paper mulberry produced by an auto-scraping device was applied to minimize the damage of fiber strength for the paper yarn manufacture. The pre-steaming treatment and alkaline pulping systems were evaluated in removal efficiency of lignin and pectin materials within the bast tissue of paper mulberry. With the application of pre-steaming treatment and 2 stage pulping system using potassium carbonate and then sodium hydroxide, kappa values were decreased two times more in lignin removal than the single stage of pulping method. It was also identified from SEM images and ATR-FTIR spectra that the pectin components within cellular structure of bast tissue were easily removed and the debarked bast parts by a auto-scraping device were easily defiberized by 2-stage pulping sequence using potassium carbonate/sodium hydroxide pulping system.

• Journal of the Korean Chemical Society
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• v.27 no.3
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• pp.178-182
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• 1983

The conductances of sodium, potassium, ammonium, tetramethylammonium, and tetraethylammonium iodides, picrates(Pic) of sodium and potassium, and tetrabutylammonium tetraphenyl-boride have been measured in ethylene carbonate-acetone mixtures at $25{\circ}C$. The limiting equivalent conductances of the electolytes were computed by Fuoss-Kraus equation and the order was $(C_4H_9)_4NB(ph)_4 at any composition of the mixtures. The dissociation constants of the salts showed that the mixtures are good ionizing solvents for the salts. The order of limiting ionic equivalent conductance, $Na^+, is consistent with exactly the reverse order found for solvation number. Effective solvated radii calibrated by the Nightingale method showed that picrate ion seems to be unsolvated and that iodide ion seems to be solvated to some extent in the mixtures.

• Journal of Sericultural and Entomological Science
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• v.13 no.1
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• pp.69-72
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• 1971

1. To study proper sample size in boiling-of test, we extracted samples in size of 200, 100, 50, 20, and 10 grams and tested them. In the result of this test we couldn't find a statistical significance among them, but it is seemed that the proper sample size is 100 gram to think about the errors of measurement and treatment when the sample size is either too little or too much in ordinary test. 2. We tested boil-of result by twisted sample skein (sizing skein) and untwisted sample. In this test to use sodium carbonate (Na$_2$CO$_3$) having powerful sericin dissolving power as a scouring agent, boil-off percents made no statistical significance between two kinds of sample skein. And to use marseilles soap having less powerful sericin dissolving power as a scouring agent, boil-off percents made a difference between twisted and untwisted sample skein. 3. We compared five kinds of scouring agent, for example sodium carbonate, monogen, synthetic detergent (HiTi), marseilles soap A (made in Japan) and marseilles soap B (made in Korea). Among them synthetic detergent and marseilles soap B showed no statistical significance compared with marseilles soap A which we used in ordinary boil-off test. So synthetic detergent and marseilles soap B can be substituted for marseilles soap A. 4. Generally the higher pH value of boil of solution, tile more sericin dissolution, showed and vice versa.