• Geomechanics and Engineering
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• v.15 no.6
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• pp.1135-1141
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• 2018

Volume changes of soils induced by inorganic acids cause severe foundation and superstructure failures in industrial buildings. This study aimed to assess the potential of fly ash to control volume changes in soils under acidic environment. Two soils such as black cotton soil predominant with montmorillonite and kaolin clay predominant with kaolinite were used for the present investigation. Both soils exhibited an increase in swelling subjected to phosphoric acid contamination. Ion exchange reactions and mineralogical transformations lead to an increase in swelling and a decrease in compressibility in black cotton soil, whereas phosphate adsorption and mineral dissolution lead to an increase in swelling and compressibility in case of kaolin clay. Different percentages of Class F fly ash obtained from Ramagundam national thermal power station were used for soil treatment. Fly ash treatment leads to significant reduction in swelling and compressibility, which is attributed to the formation of aluminum phosphate cements in the presence of phosphoric acid.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.4
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• pp.607-617
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• 1993

Three experiments were carried out in which lactating Hereford ${\times}$ Friesian cattle walked up to ten kilometers a day for three periods of five days with two non-walking days between each walking period and in which the animals were fed different diets. Measurements were made of milk yield, milk constituent yields and concentrations and blood metabolite concentrations. Exercise caused significant reductions in milk yield and in the yields of lactose and milk protein. Milk fat yield was not reduced when animals were exercised. During exercise the concentrations of ${\beta}-OH$ butyrate and free fatty acids increased, whereas the concentrations of glucose, magnesium and inorganic phosphorus decreased. Diet influenced the effect of exercise on some blood metabolite concentrations.

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.8
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• pp.1060-1068
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• 1998

The effects of various catalysts and softners on the anti-crease finish of ramie with glyoxal were investigated. A number of metal salts commonly used as Lewis acid catalysts in DP finishing of cotton with formaldehyde and N-methylol agents were screened for glyoxal treatment of ramie fabric. Various organic and inorganic acids were mixed with Lewis acid catalyst as co-catalysts to improve catalytic activity. As a result, the combination of aluminum sulfate and citric acid was proven highly effective in catalyzing the crosslinking of ramie cellulose by glyoxal under lower curing temperature. With a mixed catalyst, performance properties, such as whiteness and tearing strength as well as wrinkle recovery of treated ramie fabric were improved as compared with that treated with aluminum sulfate alone. Additional improvement of tearing strength and wrinkle recovery was achieved by applying silicons softner in the treatment bath.

• Biomolecules & Therapeutics
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• v.1 no.1
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• pp.103-108
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• 1993

The synthesis and physicochemical properties of a novel cephalosporin, DWC-751 are described. DWC -751, (6R , 7R)-7-[ (Z)-2-(2-aminothiazol-4-yl)-2- methoxyiminoacetamido]-3-[(1-methylbenzotriazol-3-ium) methyl]-ceph-3-em-4-carboxylate monosulfate($IV_{\alpha}$) was conveniently obtained by the conversion of compound (IV) into the crystalline monosulfate. Adjusting pH 4.8-5.2 in aqeous solution of the crude crystalline, compound(IV) in the form of a crystalline pentahydrate was prepared with a high degree of purity. The influence of the various organic and inorganic acids on the solubility of compoud(IV) and its salts, was examined. Particularly, the solubility of DWC-751 was 92 mg/mι at pH 1.7 and 233 mg/mι at pH 3.0. DWC-751 showed a broad antimicrobial spectrum against gram-positive and negative bacteria.

• Environmental Engineering Research
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• v.24 no.2
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• pp.271-278
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• 2019

Mass cultivation of microalgae is necessary to achieve economically feasible production of microalgal biodiesel. However, the high cost of nutrients is a major limitation. In this study, corncob extract (CCE) was used as an inorganic and organic nutrient source for the mass cultivation of Chlorella vulgaris (C. vulgaris). Chemical composition analysis of CCE revealed that it contained sufficient nutrients for mixotrophic cultivation of C. vulgaris. The highest specific grow rate of C. vulgaris was obtained at pH of 7-8, temperature of $25-30^{\circ}C$, and CCE amount of 5 g/L. In the analysis using various growth models, Luong model was found to be the most suitable empirical formula for mass cultivation of C. vulgaris using CCE. Analysis of biomass and production of triacyglycerol showed that microalgae grown in CCE medium produced more than 17.23% and 3% more unsaturated fatty acids than cells cultured in Jaworski's Medium. These results suggest that growing microalgae in CCE-supplemented medium can increase lipid production. Therefore, CCE, agricultural byproduct, has potential use for mass cultivation of microalgae.

• Journal of the Korean Society of Food Science and Nutrition
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• v.11 no.3
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• pp.67-74
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• 1982

The effect of various pH levels, temperatures. organic acids, inorganic salts, metal ions on the stability of the anthocyanins pigment (pH 3.7) from the juice of raspberries were investigated. Initial absorption of total anthocyanin was decreased as pH increased from 1.0 to 7.0. Total amount of anthocyanin reached the highest at pH 3.7 and least at pH 7.0. The total anthocyanin content decreased rapidly with the increasing temperature. Many organic acids were found to enrich and stabilize the color density at 520nm in anthocyanin solution (pH 3.7). The hyperchromic effect of saturated n-carboxylic acid increased in the following order; formic acid> acetic acid>n-butyric acid>propionic acid. On the polycarboxylic acid, especially, malic acid showed 550$\sim$930% higher than control group. On the inorganic salts (0.5M), sodium perchlorate had the most hyperchromic effect and followed by sodium sulfate>sodium chloride>sodium phosphate, monobasic. Among the metal ions, both aluminium ion and cupric ion much more accelerated the anthocyanins degradation as compared with other metal ions.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.306-312
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• 1998

Free sugar, organic acid, naringin, hesperidin and inorganic elements change of six varities of Cheju citrus fruits; Citrus natsudaidai, C. grandis, C. platymamma., C. sudachi, C. aurantiun and C. unshiu Marc. var. miyagawa by harvest date were investigated. Changes in free sugar of citrus fruits on the different harvesting stages and varieties showed a little differencies. The content of sucrose, glucose and maltose in citrus juice were $44.9{\sim}66.0%,\;15.7{\sim}25.7%\;and\;17.5{\sim}30.1%$, respectively. As the fruits were matured, free sugar was increased, but organic acid was decreased gradually. The major organic acids from the fruit juice were citric acid, malic acid and oxalic acid. Citric acid content exceeded 90%, oxalic acid ranged less than 3.58% and malic acid ranged $0.98{\sim}9.45%$ in total organic acids. Both naringin and hesperidin content showed markedly high in immature fruits, and in rind compare to fruit juice. Naringin and hesperidin content decreased as peel coloration progressed. It was estimated that fully matured fruits would be useful for making processed products, which lead to less turbity and less bitterness.

• Korean Journal of Agricultural Science
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• v.42 no.3
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• pp.191-199
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• 2015

We conducted this research to observe the changes of surface morphology and composition of clay minerals influenced by various concentrations of fluoric acid. Hydrofluoric acid (HA), a solution of hydrogen fluoride (HF) in water, is a colourless solution that is highly corrosive, capable of dissolving many materials, especially oxides. To do this, we treated several concentrations of HA on the ground soil samples collected from the agricultural experimental station located at Chungnam National University to observe the influence of fluoric acid on the changes of surface structures and elemental composition of clay particles. Generally, microscopic examination showed that the HA can not only attack an edge of clay particles but also start at any point where structural defects and weaknesses predisposed sites to acid. The orderly flake arrangement of clay minerals may reflect certain crystal symmetry elements. The ESEM-EDS results of element composition of clay particles influenced by HA indicated the changes of structures of clay minerals. It is also clear from the formation of etch figures and element composition of clay particles that the product layer at least partially dissolved or disintegrated in the presence of acid. Conclusively, the clay structures can be strongly influenced by concentrations of HA, resulting in changes of physical and chemical properties that can determine the behavior of solute transport as well as mobility of ions in soils.

• Journal of Microbiology and Biotechnology
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• v.21 no.10
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• pp.1073-1080
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• 2011

In order to investigate and generalize the effects of carbon and nitrogen sources on the growth of and lipid production in Chlorella sp. 227, several nutritional combinations consisting of different carbon and nitrogen sources and concentrations were given to the media for cultivation of Chlorella sp. 227, respectively. The growth rate and lipid content were affected largely by concentration rather than by sources. The maximum specific growth was negatively affected by low concentrations of carbon and nitrogen. There is a maximum allowable inorganic carbon concentration (less than 500~1,000 mM bicarbonate) in autotrophic culture, but the maximum lipid content per gram dry cell weight (g DCW) was little affected by the concentration of inorganic carbon within the concentration. The lipid content per g DCW was increased when the microalga was cultured with the addition of glucose and bicarbonate (mixotrophic) at a fixed nitrogen concentration and with the lowest nitrogen concentration (0.2 mM), relatively. Considering that lipid contents per g DCW increased in those conditions, it suggests that a high ratio of carbon to nitrogen in culture media promotes lipid accumulation in the cells. Interestingly, a significant increase of the oleic acid amount to total fatty acids was observed in those conditions. These results showed the possibility to induce lipid production of high quality and content per g DCW by modifying the cultivation conditions.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.2
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• pp.95-103
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• 2009

In order to improve the electrochemical, mechanical and electrocatalytic characteristics, engineering plastic of polyether ether ketone (PEEK) as polymer matrix was sulfonated (SPEEK) and the organic-inorganic blend composite membranes has been prepared by loading heteropoly acids (HPAs), including tungstophosphoric acid (TPA), molybdophosphoric acid (MoPA), and tungstosilicic acid (TSiA). And then these were covalently cross-linked (CL-SPEEK/HPA) as the electrolyte and MEA of polymer electrolyte membrane electrolysis (PEME). As a result, the optimum reaction conditions of CL-SPEEK/HPA was established and the electrochemical characteristics such as ion conductivity ($\sigma$) were in the order of magnitude: CL-SPEEK /TPA30 (${\sigma}=0.128\;S/cm^{-1}$) < /MoPA40 (${\sigma}=0.14\;S/cm^{-1})$ < /TSiA30 (${\sigma}=0.22\;S/cm^{-1}$) at $80^{\circ}C$, and mechanical characteristics such as tensile strength: CL-SPEEK /TSiA30 $\fallingdotseq$ /MoPA40 < /TPA30. Consequently, in regards of above characterisitics and oxidation durability, the CL-SPEEK/TPA30 exhibited a better performance in PEME than the others, but CL-SPEEK/MoPA40 showed the best electrocatalytic activity of cell voltage 1.71 V among the composite membranes. The dual effect of higher proton conductivity and electrocatalytic activity with the addition of HPAs, causes a synergy effect.