• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.4
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• pp.509-520
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• 1996

Ultrafine calcim carbonate powders with the size of $0.05~0.1\;{\mu}m$ and the calcite phase were synthesized by the nozzle spouting method, which could be only obtained when high calcium ion concentration within slurry was maintained at the beginning of the reaction. But, in the regions of low ${Ca(OH)}_2$ concentration (0.5~1.0 wt%) or high ${Ca(OH)}_2$ concentration (<3.0 wt%), synthesized calcium carbonate powder was shown the large particle size with agglomeration. To obtain ultrafine calcium carbonate powder in this region, the methods of slurry circuation and $CO_{2}$ gas supply were changed during reaction. Resultly, it was possible to synthesize ultrafine particles (${\approx}0.05{\mu}\textrm{m}$)in the regions of low ${Ca(OH)}_2$ concentration (${\approx}0.5wt%$) and high ${Ca(OH)}_2$ concentration (${\approx}0.5wt%$), which can not be obtained the fine calcium carbonate powder still now.

• Korean journal of food and cookery science
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• v.26 no.2
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• pp.188-197
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• 2010

In this study, the quality characteristics and storage properties of gat kimchi added with oyster shell powder and Salicornia herbacea powder were investigated during a storage time of 80 days at $5^{\circ}C$. After storage for 80 days, the average calcium contents were significantly higher in the kimchi containing the oyster shell powder and Salicornia herbacea powder than the control. In addition, the average hardness value was significantly higher in the OS4 group(oyster shell powder at 4% and Salicornia herbacea powder at 2%) than the control group, as well as the OS10 group(oyster shell powder at 10% and Salicornia herbacea powder at 2%) during storage for 80 days. The hunter b value of the OS4 group was significantly lower than the control group. During fermentation, gat kimchi containing the oyster shell powder and Salicornia herbacea powder had a higher pH and a lower acidity value than the control group. In terms of sensory evaluation, there were no significant differences between the control and calcium-added kimchi during fermentation. After 40 days of storage, the OS4 group showed a lower total viable count, as well as lower lactic acid bacteria, yeast and E. coli, as compared with the control and OS10 groups. Based on the microbial load, the gat kimchi containing the oyster shell powder showed limitations in terms of shelf life.

• Applied Chemistry for Engineering
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• v.28 no.3
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• pp.360-368
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• 2017

In order to investigate the durability of high performance polymer concrete composites, polymer concrete specimens were prepared using the ortho-type unsaturated polyester resin (UPR) and iso-type UPR as a polymer binder and the calcium carbonate and silica fine powder as a filler. The durability of polymer concrete specimens was measured by hot water resistance, chemical resistance, pore analysis and SEM observation. The compressive strength of the specimen using the iso-type UPR was higher than that of using the ortho-type UPR, and the compressive strength of the specimen using the silica fine powder was higher than that of using the calcium carbonate filler. From hot water resistance results, it was found that the specimen using the iso-type UPR was superior to that of using the ortho-type UPR and the specimen using the calcium carbonate filler was superior to that of using the silica fine powder. The compressive strength reduction rate was measured after the chemical resistance test and the sodium hydroxide solution showed the highest reduction rate, followed by sulfuric acid, hydrochloric acid and calcium chloride solutions. When using the alkaline solution of sodium hydroxide, the weight reduction rate of the specimen using calcium carbonate was lower than that of using silica fine powder, while for the acidic solutions of sulfuric acid and hydrochloric acid, the weight reduction rate of the specimen using the silica fine powder was lower than that of using calcium carbonate.

• Korean journal of food and cookery science
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• v.16 no.4
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• pp.311-315
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• 2000

Mulberry leaves Julpyun(a traditional Korean rice cake) was prepared by adding Mulberry leaves powder in the ratio of 0%, 3%, 6% and 9% of rice flour, and tested for inorganic nature, physical function, chromaticity, and rheological properties. As the ratio of mulberry leaves powder increased, both the amounts of major inorganic ingredients, calcium, magnesium, and sodium, and the amounts of minor inorganic ingredients, iron, copper, and zinc, were increased proportionally. Thus, one way to increase the amounts of inorganic ingredients appeared to add mulberry leaves powder. In physical function test, control cake(0% mulberry leaves) showed the highest value in appearance and the value decreased as the amounts of mulberry leaves increased. In color, 3%-mulberry leaves-Julpyun gave the highest value followed by 0%, 6%, and 9%-Julpyun in order. The values of texture and moisture were decreased as the ratio of mulberry leaves powder increased. In rheometer test, 9%-mulberry leaves Julpyun showed the high values in hardness, cohesiveness, and brittleness. Therefore, as the amounts of mulberry leaves powder increased, the amounts of inorganic ingredients increased, but the value of physical function test decreased. 9% mulberry leaves Julpyun has the highest value of rheometer test.

• Computers and Concrete
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• v.23 no.3
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• pp.189-201
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• 2019

Recent advances in the concrete technology are aiding in minimizing the use of conventional materials by substituting by-products of various industries and energy sources. A large amount of stone waste i.e., dust and slurry form both are being originated during natural stone processing and causing deadily effects on the environment. The disposal problem of stone waste can be resolved effectively by using waste in construction industries. In present work, Kota stone slurry powder, as a substitution of cement was used along with accelerators namely calcium nitrate and triethanolamine as additives, to study their impact on various properties of the concrete mixtures. Kota stone slurry powder (7.5%), calcium nitrate (1%) and triethanolamine (0.05%) were used separately as well in combination in different concrete mixtures. Mechanical Strength, modulus of elasticity and electrical resistivity of concrete specimens of different mix proportions under water curing were studied experimentally. The durability properties in terms of strength and electrical resistivity against sulphate and chloride solution attack at various curing ages were also studied experimentally. Results showed that accelerators and Kota stone slurry powder separately enhanced the mechanical strength and electrical resistivity; but, their combination decreased strength at all curing ages. The durability of concrete specimens was also affected under the exposure to chemical attack too. Kota stone slurry powder found to be the most effective material among all materials. Material characterization was also done to study the microstructural properties.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.06a
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• pp.99-105
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• 2000

Greases composed of base oil and thickener are widely used in the purpose of lubrication and anti-corrosion of machinery. However, greases are sometimes oxidized and decomposed by heat of friction, and produced organic acid. And the greases leaked out ordinary spot make the concrete structures weaken. In this study, the chemical effects of the greases with the concrete structures were investigated through oxidation reaction under pressure and oxygen, and evaluated by the analysis of TAN, Ca content, FT-IR and XRD of grease and cement powder after the oxidation reaction. As the results, TAN value decreased with the increase of the content of cement because of neutralization of organic acid produced by the oxidation of grease with calcium contained in the cement. The content of calcium linearly increased with the increase of cement due to calcium salt by neutralization of acid. Also, according to XRD results of the cement powder oxidized at 99 $^{\circ}C$, the diffraction peak due to calcium hydroxide decreased in comparison with that at room temperature because of the reaction of calcium and organic acid.

• Journal of Powder Materials
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• v.31 no.2
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• pp.126-131
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• 2024

The aim of this study was to improve the chemical stability of cycloserine containing organic and inorganic compounds. Composite particles were manufactured with a 1:1 weight ratio of organic/inorganic compounds and cycloserine. The influence of organic/inorganic compounds on the stability of cycloserine was investigated under accelerated stress conditions at 60℃/75% RH for 24 hours. In addition, the properties of the composite particles were evaluated using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and the dissolution of the drug was assessed by preparing it as a hard capsule. Among the organic and inorganic compounds investigated, calcium hydroxide most improved the stability of cycloserine under accelerated stress conditions (53.3 ± 2.2% vs 1.7 ± 0.2%). DSC results confirmed the compatibility between calcium hydroxide and the cycloserine, and SEM results confirmed that it was evenly distributed around the cycloserine. Calcium hydroxide also showed more than 90% cycloserine dissolution within 15 minutes. Therefore, the calcium hydroxide and cycloserine composite particles may be candidates for cycloserine oral pharmaceuticals with enhanced drug stability.

• Journal of the Korea Institute of Building Construction
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• v.14 no.3
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• pp.230-236
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• 2014

This study was carried out to investigate the manufacturability of artificial lightweight aggregate as a way to recycle basalt powder sludge, which is a waste produced during the manufacturing process of basalt in Jeju. Powdered waste glasses and calcium carbonate are used to improve the characteristics of manufactured artificial lightweight aggregate. Especially, considering the complex factors of basalt powder sludge, powdered waste glasses, and sintering method, the amount of calcium carbonate is appropriate at the 9 wt.% in order to improve the intumescent of lightweight aggregate. Also, the amount of powdered waste glasses is effective with using less than 50 wt.% and applying the direct sintering method at the same time on decreasing the absorption of lightweight aggregate. Furthermore, in order to manufacture artificial lightweight aggregate of high quality with a low specific gravity and low water absorption, it is considered to be more effective to apply the direct sintering method after the surface of artificial lightweight aggregate is covered with powdered waste glasses.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.4
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• pp.436-444
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• 2016

Clamshells, which comprise more than 50% of a clam’s weight, are a major byproduct of the clam industry and are mainly composed of insoluble calcium carbonate. This study investigates the use of clamshells as a natural calcium resource. Highly soluble powdered calcium lactate (LCCL) was prepared from the calcined powdered shells of littleneck clams (LCCP) using response surface methodology (RSM) to predict optimum conditions. These conditions, as derived from pH, solubility, and yield of 11 LCCLs manufactured according to the RSM model, were 1.80 M lactic acid and 1.13 M LCCP. The actual values of pH (6.98), solubility (93.99%), and yield (351.23%) under the optimized conditions were as predicted. The derived LCCL exhibited a strong buffering capacity in the range of pH 2.78-3.90 when combined with less than 2 mL of 1 N HCl. The ranges of calcium content and solubility of LCCL were 7.7-17.5 g/100 g and 96.6-98.9%, respectively. Fourier transform infrared spectroscopy (FT-IR) of the LCCL identified it as calcium lactate pentahydrate, and field emission scanning electron microscopy (FESEM) revealed an irregular and rod-like microstructure. These results confirm the potential use of clamshells, converted to highly soluble organic acid calcium, as an additive to enhance calcium content in food ingredients.

• Food Science and Preservation
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• v.23 no.4
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• pp.488-494
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• 2016

Cheonggukjang was prepared by addition of peanut (Arachis hypogaea L.) powder in order to improve its quality and functional properties. The physicochemical and sensory properties of Cheonggukjang added peanut powder were investigated, after adding the peanut powder with the amount of 5, 15 and 25% (w/w). The proximate composition of peanut powder was as follows: moisture, 1.80%; crude protein, 24.9%; crude lipid, 48.3%; crude ash, 2.90%; and carbohydrates, 22.1%. Crude protein and lipid content of Cheonggukjang increased with increaes in the amounts of peanut powder, while the moisture content decreased. Calcium and amino acid contents showed disparity depending on the increasing addition of peanut powder. Cheonggukjang containing 15% (w/v) peanut powder was found to be highest calcium contents. The major amino acids of Cheonggukjang were glutamic acid, aspartic acid, lysine, leucine, arginine and proline. Depending on increasing amounts of peanut powder, the L and b values (measured using Hunter's color values) were decreased, while the a value was increased. In addition, pH was decreased as the amount of peanut powder was increased. Sensory scores of Cheonggukjang containing 15% (w/v) peanut powder were best when considering both quality characteristics and sensory evaluation. This study suggested that peanut powder could enhance the quality and functionality of Cheonggukjang further.