• International Journal of Highway Engineering
• /
• v.18 no.3
• /
• pp.21-32
• /
• 2016

PURPOSES : In this paper, the analytical solutions suggested to simulate the behavior of rheological fluids were rigorously re-derived and investigated for fixed conditions to evaluate the applicability for the solutions on a mini-cone slump test of cement paste. The selected solutions with proper boundary conditions can be used as reference solutions to evaluate the performance of numerical simulation approaches, such as the discrete element method. METHODS : The slump, height, and spread radius for the given boundary and yield stress conditions that are determined by five different analytical solutions are compared. RESULTS : The analytical solution based on fluid mechanics for pure shear flow shows similar results to that for intermediate flow at low yield stresses. The fluid mechanics-based analytical solution resulted in a very similar trend to the geometry-based analytical solution. However, it showed a higher slump at high yield stress and lower slump at low yield stress ranges than the geometry-based analytical model. The analytical solution based on the mini-cone geometry was not significantly affected by the yield criteria, such as von Mises and Tresca. CONCLUSIONS : Even though differences among the analytical solutions in terms of slump and spread radius existed, the difference can be considered insignificant when the solutions were used as reference to evaluate the appropriateness of numerical approaches, such as the discrete element method.

• Korean Chemical Engineering Research
• /
• v.45 no.4
• /
• pp.356-363
• /
• 2007

The stability of paste solutions for electroluminescence display(ELD) device was found to be greatly affected by kind and dosage of a stabilizer used. The stabilizer Disperbyk-180 showed the best stability performance against phosphor paste solutions among the stabilizers used during this study. The phosphor paste solutions remained stable over 90 days with a wide range of added amounts of Disperbyk-180. Based on the above results, screen printing test was performed. The addition of Disperbyk-180 into phosphor and dielectric paste solutions produced improved qualities such as no phase separation, no bubble generation and no significant viscosity change during printing process. Especially for the phosphor paste solution, both uniformity and brightness were significantly improved and the excellent adhesion onto the ITO film was found. The ELD device fabricated using the above same paste solutions showed brightness of $57.6cd/m^2$ at 100V and 400 Hz. The half lifetime of ELD device was measured as 1,250 hours and almost the same value observed with imported commercial paste solutions.

• The Korean Journal of Food And Nutrition
• /
• v.25 no.3
• /
• pp.460-482
• /
• 2012

On the basis of the cookbooks and Data Base of the Korean Classics(http://db.itkc.or.kr/itkcdb/mainIndexIframe.jsp), this paper analyzed the fermented soybean listed in the general documents of the Chosun Dynasty(1392~1897) and the Goryeo Dynasty(918~1392). In the Goryeo Dynasty, there are 15 kinds of Jang(soybean paste or solution), among which are Jang (soybean paste fermented by mold)(6 documents), Yeomgjang, Yeomshi(2), and Gaejang(1). However, the cookbook at that time is defunct. The Goryeo Court relieved the famine-stricken people by proving them with Jang. In the Chosun Dynasty, 111 kinds of Jang were listed in the general documents, and 153 kinds in cookbooks. There were 55 kinds of general Jang, such as Jang(204), Yeomjang(63), Chojang, Goojang(7), and Gaejang(6), are listed in the general documents, and in the cookbooks, there are 55 kinds of Jang, such as Sookwhangjang(9 cookbooks), Daemaekjang(8), Myeonjang(8), Saengwhangjang (8), and Yooinjang(8), and among them, 13 kinds belong to the Chinese origin. A total of 9 Kinds of Ganjang(soybean solution fermented by mold), such as Soojang(30), Cheongjang(23), Gamjang(8), and Ganjang(3) are found in the general documents. In the cookbooks, 12 kinds of Jang, as Cheongjang(10), Cheonrijang(4), Ganjang(3), and etc., are listed. There were 9 kinds of Gochoojang(red pepper-soybean paste), such as Chojang(12), Gochojang(3), and etc., are listed in the general documents, and 9 kinds as Gochojang(7), Manchojang(7), rapid Manchojang(4), and etc., are in the cookbooks. In addition, 16 Kinds of Yookjang(fermented soybean-meat paste) as Haejang(15), Hyejang(11), Yookjang(11), and etc., are found in the documents, and 22 kinds as Nanjang(9), Gejang(6), Yookjang(5), Shoigogijang(4), and etc., are in the cookbooks. Eighteen Kinds of Shi(soybean paste fermented by bacteria) as Yeomshi(40), Shi(35), Shijang(6), and etc., are recorded in the documents, and 19 kinds as Jeonkookjang(6), Shi(4), Sooshijang(4), and etc., are in the cookbooks, and among them 11 kinds belong to the Chinese origin. Six kinds of Jipjang(aqueous soybean paste) as Jipjang(7), Uoopjang(4), Pojang (2), Jangzoop(2) are recorded in the documents, and 15 kinds as Jipjang(9), Zoopjeo(7), and Hajeoljipjang(5) are in the cookbooks. Soybean paste, or solution for relieving hunger is not recorded in the documents. However, the Chosun court, for the purpose of relieving famine-stricken people, used general Jang. Such 21 Jang to relieve the famine-stricken people as Pojang(7), rapid Jang(6), and Sasamgilgyeongjang(4) are listed in the cookbook. Geonjang(dried soybean paste), Nanjang (egg-soybean paste), Doojang(soybean paste), Maljang(random soybean paste), Myeonjang(wheate-soybean paste), Sodoojang (red bean-soybean paste), Yookjang(soybean-meat paste) and Jang(soybean paste) are recorded in the documents, as well as in the cookbooks. Chinese-original Jang and Shi are recorded in the cookbooks, with no list in the general documents. Therefore, it seems that it didn't pass down to the general public.

• Journal of the Korean Ceramic Society
• /
• v.24 no.4
• /
• pp.329-334
• /
• 1987

Diffusion of SO4-- ion in hardened cement paste with slag and siliceous powders such as silica fume and white carbon was investigated. Ca(OH)2 from hardenend cement paste was dissolved by sea-water and then gypsum was formed from the reaction of Ca++ in hardenend cement paste and SO4-- ions in MgSO4 solution. A part of the gypsum by reaction with calcium aluminate hydrates formed ettringite. Amounts of SO4-- ions passed through hardened cement paste was less than that of Cl- ions(Dcl-) in hardened cement paste were 0.1∼0.6${\times}$10-11$\textrm{cm}^2$/sec and 1∼4${\times}$10-8$\textrm{cm}^2$/sec respectively.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2022.04a
• /
• pp.95-96
• /
• 2022

Carbon nanotubes has a positive effect on the mechanical properties, functionality, and durability of cement-based materials. In this study, carbon nanotube solutions mixed with two different types of superplasticizers were dispersed by high-pressure homogenizer, and used for preparation of cement paste. The 7and 28day compressive strength were evaluated.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2021.05a
• /
• pp.201-202
• /
• 2021

Currently, the domestic construction industry is trying to expand the range of building materials due to overload of growth. In particular, several studies are being conducted to make up for the weakness of building materials by solving problems such as reduction of tensile strength and brittle behavior of concrete. Among them, efforts to maximize the use of carbon nanotubes (CNT) that has excellent mechanical and electrical conductivity properties are continuing. However, CNT is hydrophobic and have a strong Van der Waals force between particles, making it difficult to obtain an effective dispersion state. Therefore, in this study, various kinds of surfactants like DOC (Sodium Deoxycholate), PVP (Polyvinylpyrrolidone), and PCE (Polycarboxylate ester) were added to improve the dispersibility of CNT, and analyzed the changes in the properties of the cement paste mixed with them.

• Journal of Nutrition and Health
• /
• v.7 no.1
• /
• pp.37-43
• /
• 1974

The L-ascorbic acid, when various kinds of flavoring and spices were added to it's solution individually or in combination, was determined by the 2,4-Dinitrophenylhydrazine method. The remaining rate of it in the solution, to which such spices and flavoring as vinegar, sugar, salt, glutamic acid-Na, welshonion, garlic, sesame, rice jelly, soy, pimento, hotbean paste, pepper, ginger and cinnamon were added individually, was higher than in the solution of itself alone. In the case of pinenuts, sesame oil and, bean paste, however, the remained total ascorbic acid was of little quantity, The rate of it's autooxidation in the solution added with fennel, cinnamon, ginger, pepper, bean paste, pinenuts, curry in individual were found high, but relatively low in garlic, sesame oil, glutamicacid-Na, sugar, honey, salt, pickled shrimps, hot bean paste, and soy. When combined spices and flavoring were added, the content of ascorbic acid showed high values in all cases, indicating that particularly high in soy-bean sprout namul, chinese radish namul, and muchim, seasoned with the most frequently used flavoring, No. 7,8,9,10 while low values in the combination of mustard muchim.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.10
• /
• pp.2457-2460
• /
• 2009

• Journal of the Korea Institute of Building Construction
• /
• v.19 no.2
• /
• pp.113-121
• /
• 2019

Single walled carbon nanotube (SWCNT) has been used as a material for reinforcing various advanced materials because it has superior mechanical properties. However, pure SWCNT that does not have any functional group has a hydrophobic character, and exists as bundles due to the strong Van der Waals attraction between each SWCNT. Due to these reasons, it is very difficult to disperse SWCNTs in the water. In this work, in order to use SWCNT for production of cementitious composites, SWCNT was first dispersed in water to make an aqueous solution. Sodium deoxycholate (DOC) and Sodium dodecyl sulfate (SDS) were chosen as surfactants, and the dosage of DOC and SDS were 2wt% and 1wt%, respectively. Sonication and ultracentrifugation were applied to separate each SWCNT and impurities. Using such processed SWCNT solutions, cement paste was prepared and its shear stress vs. strain rate relationship was studied. The yield stress and plastic viscosity of cement paste were obtained using Bingham model. According to the results in this work, cement pastes made with DOC and SDS showed similar rheological behavior to that of air entrained cement paste. While cement paste made with DOC 2 wt.% SWCNT solution showed similar rheological behavior to that of plain cement paste, cement paste made with SDS 1 wt.% SWCNT solution showed different rheological behavior showing much less yield stress than plain cement paste.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2000.01a
• /
• pp.177-179
• /
• 2000

Barrier rib for the plasma display panel (PDP) was made by photolithographic process utilizing photosensitive barrier rib paste. The barrier rib paste was prepared by first dissolving poly(MMA-co-MAA) binder polymer in butyl carbitol(BC) solvent at 15 wt% concentration. To this solution were added a mixture of functional monomers , Irgacure 651 photoinitiator, and barrier rib power and then the whole mixture was dispersed in the three roll mill for 2 hour. The effect of component and concentration of photosensitive barrier rib paste was studied. After optimization of the paste formulation and photolithographic process, barrier rib could be obtained with good resolution up to 110-120 ${\mu}m$ height and 80-90 ${\mu}m$ width.