• Journal of Korean Society of Water and Wastewater
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• v.34 no.2
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• pp.115-125
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• 2020

This study was aimed to examine inorganic fouling and fouling reduction method in direct contact membrane distillation(DCMD) process. Synthetic seawater of NaCl solution with CaCO₃ and CaSO₄ was used for this purpose. It was found in this study that both CaCO₃ and CaSO₄ precipitates formed at the membrane surface. More fouling was observed with CaSO₄(anhydrite) and CaSO₄·0.5H₂O(bassanite) than CaSO₄·2H₂O(gypsum). CaCO₃ and gypsum were detected at the membrane surface when concentrates of SWRO(seawater reverse osmosis) were treated by the DCMD process, while gypsum was found with MED(multi effect distillation) concentrates. Air backwash(inside to out) was found more effective in fouling reduction than air scouring.

• Korean Journal of Agricultural Science
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• v.37 no.2
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• pp.271-276
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• 2010

In this study, the light-frame wood shear walls according to the sheathing materials was carried out to investigate the shear load performance. Most common sheathing materials are the structural OSB and gypsum board used to consist wall of wood-frame house. Seven different type of specimens are composed of several sheathing materials and shear test was taken to evaluate shear performance by KS F 2154. As a result, shear walls(G12.5/G12.5 and G12.5/OSB) show that maximum shear strength and shear rigidity modulus are 7316N/mm${\cdot}$118.25 N/mm and 11129 N/mm${\cdot}$184.66 N/mm respectively. The shear wall using gypsum board 15mm improve maximum shear strength and shear rigidity modulus about 30%. The shear wall using 15mm gypsum board showed intermediate value in one side specimens. Different types of shear walls could be compared with the shear load performance. Also, nailed joint failure aspects are different to sheathing material and installing method.

• Environmental Engineering Research
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• v.24 no.2
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• pp.246-253
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• 2019

This study was conducted to explore the optimum proportion of zeolite and zeolite-kaolin as additives to cement clinker and gypsum samples, while maintaining the strength properties of produced environmentally sustainable cements. According to the British standard method, zeolite was added to cement clinker in proportions of 5-12% and 10-12% by weight, respectively, in the preparation of samples of zeolite-containing cement and zeolite-kaolin-based cement. Kaolin was used as a second additive as 10-20% of the total weight. The compressive strength tests were performed on base cement samples according to a standard procedure given in ASTM C109 Compressive Strength of Hydraulic Cement. These values were compared with those of the reference sample and the Omani allowable limits. The results indicated that the best compressive strength values were obtained with 88% cement clinker, 5% gypsum, and 7% zeolite for the zeolite-containing cement. Quantities of 70% cement clinker, 5% gypsum, 10% zeolite, and 15% kaolin gave the best results for zeolite-kaolin-based cement, resulting in a substitution of than 25% cement clinker. The study concluded that the partial cement clinker replacement using zeolite/kaolin combination may have a great influence on the reduction of $CO_2$ emission and energy saving in cement manufacturing.

• The Research Journal of the Costume Culture
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• v.7 no.2
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• pp.275-288
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• 1999

The purpose of this is providing a simple, relatively errorless body surface area calculation. Subjects were 10 married women and 10 singles women whose age was 20 to 29 years old. The Gypsum method has applied for the sampling of body surface. The Weight method has been used to measure body surface by means of transferring gypsum shape on uniform plane polypropylene films. In this study, compare analyzed errors between the traditional formulas for measuring body surface area and measuring data in this experiment. More than all, it has been to induce a regression equation for measuring body surface area, which is so simple to calculate with less errors, with variable factors as weight and height. The results of this experiment as follows : 1. In the traditional formulas, weight formula was shown high average error : Niya\`s height formula. which was modified K value as 0.62 in the height formula (S = KH) is shown lower average error than Lassabliere\`s Height formula. 2. In the weight-height formula (S=K √WH), it was shown high average error according to the increasing of K value. Kawanami\`s formula, which 5.378 as K value, was shown low average error both the singles and the married women. 3. Dubois weight-heingt formula (S=W/sup a/·H/sub b/·K) was shown low average error than the weight, height, weight-height (S=K√WH) formula. 4. The regression equations with variable factors as weight and height are 156.74W + 86.05H - 660.25 (Single women) and 136.02W + 90.57H - 6241.32 (Married women) the average error and absolute average error to the singles are 0.09%, 0.94% and resoectively -0.13%, 1.16% for the married women.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.389-394
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• 2017

The aim of the research is providing the application method of recycled materials to manufacture the low costed eco-friend block at currently operated concrete block plant. In this research, based on the previous research results on three types of slag cement with illite, desulfurized gypsum, and wasted refractory products, the actual block product was manufactured by the currently operated plant facility and evaluated their properties to suggest the optimal proportions. As an experimental results, in aspect of compressive strength, absorption ratio, freezing resistance, and pH, type III slag incorporating 5% desulfurized gypsum with 1% replaced illite as an aggregate could be suggested as am optimal proportion. In additionally, considering the high cost of the illite, it can be considered as an optimal proportion that type III slag incorporating 5% desulfurized gypsum for binder.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.1
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• pp.31-39
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• 2017

The effects of application of gypsum and fresh cattle manure on the yield of forage crop were investigated in Hwaong reclaimed land in Korea for 3 years from 2011 to 2013. This study was conducted to develop the practical application method of livestock manure as a fertilization source and a soil physico-chemical ameliorator for the cultivation of forage crop $Sorghum{\times}Sudangrass$ hybrid in newly reclaimed tidal land soil. Treatments with six applications were established with three replications; chemical fertilizer (CF), gypsum (G) $20Mg\;ha^{-1}$, G+fresh cattle manure (FCM) 100%, G+FCM 200%, G+FCM 300% and FCM 100% which referred to the application rate equivalent to the recommended amount of phosphate fertilization by soil test. The combined treatments of G+FCM increased soil organic matter, $Av.P_2O_5$ and exchangeable $Ca^{2+}$ contents while decreased exchangeable $Na^+$ and $Mg^{2+}$. The soil bulk density, soil hardness and soil aggregate formation were improved by G+FCM treatments. The dry matter yields of $Sorghum{\times}Sudangrass$ hybrid were significantly increased in proportion to the application rate of FCM. The phosphorus use efficiency showed the highest in the application level of G+FCM 100%, which seemed to be the results of reduced nutrient use efficiency by nutrient immobilization, leaching etc. when applied excessive amount of fresh animal manure.

• Journal of the Korean Ceramic Society
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• v.34 no.1
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• pp.70-78
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• 1997

3Y-TZP/SUS316 Functionally Graded Material (FGM) was fabricated by slip casting method. Alumina mold was used to overcome problems of gypsum mold in slip casting process, and the optimal dispersion con-ditions of 3Y-TZP/SUS316 binary slurries was determined using electrokinetic sonic amplitude and a viscometer, and observing sedimentation behavior. The properties of the specimens casted by gypsum mold and alumina mold were compared in terms of changes in shrinkage rate, drying and sintering conditions, and microstructure. It was found that the specimens obtaine from the alumina mold showed a clean surface, easier thickness control of each layer, and higher productivity. Especially, no degradation was observed in the SUS316 prepared using alumina mold. Thus it is desirable to use porous alumina mold rather than gyp-sum mold for the slip casting of 3Y-TZP/SUS316-FGM.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.384-387
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• 2006

Recently, the method of the apartment building design has been changed from wall type structures to moment structures. With like this reason, dry walls we used plentifully. Especially, the gypsum board was used from previously plentifully however the weak point of it is difficult to maintain because it weak strength. For the improvement of gypsum board, light weight concrete panel using cement board is used recently. As this study is the research of the series t on the development of non-bearing light weight concrete panel using bottom ash, the purpose of this study is to obtain basic data for application in the field. The results are that the structure 1 satisfies domestic standard concerned with sound insulation between households at the laboratory and field test.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.645-648
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• 2006

Recently, the method of the apartment building design has been changed from wall type structures to rahmen structures. With like this reason, dry walls are used plentifully. Especially, the gypsum board was used from previously plentifully however the weak point of it is difficult to maintain because it weak strength. For the improvement of gypsum board, light weight concrete panel using cement board is used recently. As this study is the research of the series t on the development of non-bearing light weight concrete panel using bottom ash, the purpose of this study is to obtain basic data for application in the field. The results are as follows. structure 1 satisfy domestic standard concerned with sound insulation between households at the laboratory and field test.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.273-274
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• 2010

This study investigated on the early hydration and physical characteristics of blast furnace slag through pH variation. The pH values applied to the experiments were, 12.0 and 13.0 which are the pH values of OPC, and type 3 of pH 14.0 which is a strong alkali condition. A paste and mortar method was used to test blast furnace slag and blast furnace slag containing 2wt% of gypsum. It was found that CAH and CSH phases were formed as key hydrates during the early hydration of blast furnace slag, and ettringites were produced extra during the early hydration of blast furnace slag containing 2wt% of gypsum.