• Transactions of Materials Processing
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• v.13 no.3
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• pp.262-267
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• 2004

Ultrasonic machining has been known as one of the conventional machining methods in the glass fabrication processes. In ultrasonic machining, typically, glass is removed by the impulse energy of the abrasive generated by the ultrasonic power. However, when the machining feature decrease under hundreds of micrometers, as conventional ultrasonic machining uses only the impulse energy of the abrasive, the speed of ultrasonic machining decreases significantly and the surface roughness becomes deteriorated. To overcome this size effect, the chemicals which can erode glasses, such as HF, XF, etc, are added to the slurry. The chemical-assisted ultrasonic machining method, so called, is another alternating effective way for micro machining of glasses. In previous work, we used the hydrofluoric acid (HF) as an additive chemical. But, as the HF solution is too poisonous to be used as a ultrasonic process additive, it is needed to be substituted by other safe chemicals. As results of the machinability comparison of several chemicals, the GST-500F was selected to replace the HF. The GST-500F (pH $4.0{\pm}1.0$) is non-volatile, odorless. During experimental works, it was shown that the machining rate increases 1.5 times faster than the conventional ultrasonic machining. The machining load also decreases. However, the enlargement of the hole diameter and significant tool wear are still the problems to be solved.

• Structural Engineering and Mechanics
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• v.40 no.5
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• pp.595-616
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• 2011

Impact experiments have been carried out on concrete slabs. The first group was traditionally manufactured, densely reinforced concrete targets, and the next were ordinary Portland and calcium aluminate cement based HPSFRC (High performance steel fiber reinforced concrete) and SIFCON (Slurry infiltrated concrete) targets. All specimens were hit by anti-armor tungsten projectiles at a muzzle velocity of over 4 Mach causing destructive perforation. In Part I of this article, production and experimental procedures are described. The first group of specimens were ordinary CEM I 42.5 R cement based targets including only dense reinforcement. In the second and third groups, specimens were produced using CEM I 42.5 R cement and Calcium Aluminate Cement (CAC40) with ordinary reinforcement and steel fibers 2 percent in volume. In the fourth group, SIFCON specimens including 12 percent of steel fibers without reinforcement were tested. A high-speed camera was used to capture impact and residual velocities of the projectile. Sample tests were performed to obtain mechanical properties of the materials. In the companion Part II of this study, numerical investigations and simulations performed will be presented. Few studies exist that examine high-velocity impact effects on CAC40 based HPSFRC targets, so this investigation gives an insight for comparison of their behavior with Portland cement based and SIFCON specimens.

• Journal of Animal Science and Technology
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• v.47 no.4
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• pp.537-546
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• 2005

An experiment was conducted to determine the effect of supplementation of chlortetracycline (CTC,110ppm), copper sulfate(Cu, 125ppm) and two levels of probiotics(Prob I, 0.04%, Prob II, 0.1%), Bacillus licheniformis and Bacillus subtilis) on growth performance, nutrient digestibility and manure characteristics in growing pigs. A total of 50 pigs that averaged 20.78$\pm$0.35kg BW and 50$\pm$2.3d age were allocated in a randomized block design with two pigs per pen and 5 pens per treatment. Pigs and feeders were weighed 10-days interval for the 40-d trials to determine ADG, ADFI and feed:gain ratio(F:G). Average daily gain, feed intake, feed/gain and nutrient digestibility were not improved(P>0.10) by the supplementation of CTC, Cu and two levels of probiotics. There were significant(P<0.05) Cu effects on digestibility of crude protein, and probiotics effects on digestibilities on organic matter, crude protein and energy between first 20 days and subsequent 20 days. Fecal concentrations of copper were highly increased(P<0.001) by the copper supplementation. Total bacteria and coliform counts were not altered by the supplementation of CTC, Cu and two levels of probiotics. Ammonia emission from slurry, measured during first 3 weeks, was reduced (P<0.001) in pigs fed diet with 125 ppm copper from copper sulfate. Results indicate that CTC, Cu and Probiotics supplementation had a little or not positive effect on grower pig performance under sound environmental conditions. Further studies may be warranted to investigate the effects of dietary copper-either reduced or in combination with dietary ammonia control agents-on the ammonia emission characteristics of swine manure.

• Journal of Animal Science and Technology
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• v.51 no.4
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• pp.337-342
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• 2009

The feasibility of reutilization of magnesium ammonium phosphate (MAP) or struvite slurry recovered from the process through microwave irradiation was studied in this experiment. For this purpose, 4 different operations were performed with or without Mg source addition and different levels of MAP recycled in a batch reactor. Dissolution rate of MAP, ${NH_4}^+$ elimination pattern and physicochemical changes of MAP during microwave irradiation were also studied. The result showed that only 33% orthophosphate ($PO_4-P$) and 27% $NH_4-N$ removal occurred without adding any external Mg source (run A), whereas 87% $PO_4-P$ and 40% $NH_4-N$ removed when 1.0 M ratio of $MgCl_2$ (run B) was added based on $PO_4-P$ in influent. Although the addition of 1.0 molar ratio of microwave irradiated MAP (Run C) removed lower $PO_4-P$ and $NH_4-N$ than 1.0 M $MgCl_2$ (run B), $PO_4-P$ removal was double when compared with no Mg addition (run A). Addition of half MAP and half $MgCl_2$ (run D) showed the similar removal efficiency (88% $PO_4-P$ and 35% $NH_4-N$) with sole $MgCl_2$ addition (run B). Based on these results, the reutilization of MAP irradiated by microwave would be a feasible way to enhance the removal efficiencies of N and P, as well as curtail the Mg chemical usage. Track study showed that $NH_4-N$ gradually increased at initial stage of microwave irradiation of MAP, and then started eliminating from liquor as temperature increased over $45^{\circ}C$. Dissolution rate of ${PO_4}^{-3}$ during microwave irradiation was proportional to the initial MAP concentration, having $0.0091x^{0.6373}$ mg/sec. It was found from the scanning electron microscope (SEM) study that physical structure of MAP crystal started breaking down into small cube granules within very short time by electromagnetic vibration force during microwave irradiation and then gradually melted down into solution.

• Journal of the Mineralogical Society of Korea
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• v.21 no.3
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• pp.313-320
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• 2008

Hectorite was synthesized under hydrothermal conditions and its physicochemical properties have been investigated in terms of temperature, pH, and organic agent to observe the change of doll basal spacing. The IR, CEC, MB, swelling volume and specific surface area of the hectorite were measured for the characterization. The solid/liquid ratio of hectorite to distilled water before mixing with other materials was also determined for its use as a multi-functional material. The $d_{001}$ basal spacing decreased from $12.63\;\AA$ at room temperature to $10.19\;\AA$ at $650^{\circ}C$ in the heating tests. As the pH of hectorite slurry increased. the $d_{001}$ basal spacing decreased. reaching the lowest value of $13.33\;\AA$ at pH 7 and afterward, increased. All the fool basal spacings of the hectorite increased when it was intercalated with the following solvents: $12.86\;\AA$ in diethyl ether, $13.31\;\AA$ in acetonitrile. $13.59\;\AA$ in methanol, $14.05\;\AA$ in ethanol, $15.69\;\AA$ in acetone, and $17.42\;\AA$ in ethylene glycol. Our IR analysis results were in good agreement with those of other researchers. The CEC, MB, swelling volume and specific surface area of hectorite were determined to be 105 cmol/kg, 80 cmol/kg, $68\sim74ml/2g$ and $213m^{2}/g$, respectively. Also, the hectorite to distilled water ratio of 2 to 100 was found to be most favorable for mixing with other materials such as the solvents mentioned above.

• Korean Journal of Food Science and Technology
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• v.50 no.4
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• pp.391-399
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• 2018

Bioconversion and fermentation of onion extract by lactic acid bacteria were carried out to enhance the bioavailability of quercetin through the increase of quercetin recovery and aglycone formation. Lactobacillus casei, L. plantarum, and Kluyveromyces lactis were selected as the optimum strains for bioconversion. The environmental conditions to maximize the conversion ratio between glycoconjugate and quercetin aglycone have been evaluated. The concentrations of quercetin after fermentation of onion slurry by K. lactis and L. casei increased to 260% and 318%, respectively; however, the quercetin concentrations decreased after 48 hours of fermentation. Additionally, the quercetin hexose concentration increased to almost 141%. Controlling the initial pH of the onion juice increased the lactic acid production by L. casei and L. plantarum by more than two-fold. Meanwhile, the concentration of quercetin hexose decreased rapidly with the increased production of aglycones. The scale-up experiments showed the same fermentation efficiency; however, thermal sterilization reduced the quercetin glycone concentrations drastically.

• Applied Biological Chemistry
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• v.34 no.2
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• pp.125-129
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• 1991

This experiment was carried out to examine the MBC adsorption on clay minerals by the slurry method. The adsorption of MBC on Kaolinite nearly reached equilibrium after shaking lot 2hrs. but on Bentonite and Zeolite, 10hrs., respectively. The adsorption amount was in the order of Zeolite>Bentonite>Kaolinite, and Na-saturated clay mineral adsorbed more MBC than Mg-saturated clay mineral did. The more the amount of clay minerals, the more MBC was adsorbed by clay minerals, whereas the amount of MBC adsorbed per unit gram of clay minerals reduced and Kd value cf MBC was greatest on the Na-Zeolite. The lower the pH of the water-clay system at each concentration, the more MBC was adsorbed by clay minerals. The pH dependence of the adsorption of MBC may be due to protonation of MBC in acid solution.

• Journal of Environmental Science International
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• v.10 no.5
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• pp.365-371
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• 2001

The optimum dosage of quicklime in producing organic fertilizer using livestock wastes vith a greater than 80% water content was analysed. After one day had elapsed to allow for the organic fentilizer to dry, the quicklime dosage and the composition of the organic fertilizer were analysed. Any from done to the organic fertilizer was also assessed. The amount of the quicklime required to stabilize livestock wastes was determined by water content of livestock wastes. For J farm(slurry style) of which livestock wastes have 94.6% of water concentration, less than 3% of total amount of livestock wastes, for H farm (scraper style) of which livestock wastes have 85% of water concentration, less then 4% of total livestock wastes and Y farm(traditional style) of which livestock wastes have 80% of water concentration, less then 5% of total livestock wastes. Generally, in order to pack the organic fertilizer, water containing quicklime0stabilized livestock wastes should be less than 35%. It takes 9 days to keep this water content for the wastes from H and Y farms(less than 85% in water content), and 12 days for the wastes from J (94.6% in water content). According to the classification standard for compost constitution by Higgins, the crude fertilizers from all 3 farms had high grade $K_2O$ and CaO, the middle grade T-N and middle or low grade $P_2O_5$. Stabilization by quicklime is known to inhibit bacterial decomposition of organic matter and the activity of pathogenic organisms. In this study, more then 99.99% of coliform group, fecal group and viable cell count were reduced. Our results indicate that livestock wastes of greater 80% water content could be used to produce organic fertilizer without the addition of a material for moisture control.

• Geomechanics and Engineering
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• v.12 no.3
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• pp.523-539
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• 2017

Clay soils are typical for their swelling properties upon absorption of water during rains and development of cracks during summer time owing to the profile desorption of water through the inter-connected soil pores by water vapour diffusion leading to evaporation. This type of unstable soil phenomenon by and large poses a serious threat to the strength and stability of structures when rest on such type of soils. Even as lime and cement are extensively used for stabilization of clay soils it has become imperative to find relatively cheaper alternative materials to bring out the desired properties within the clay soil domain. In the present era of catastrophic environmental degradation as a side effect to modernized manufacturing processes, industrialization and urbanization the creative idea would be treating the waste products in a beneficial way for reuse and recycling. Bottom ash and ecosand are construed as a waste product from cement industry. An optimal combination of bottom ash-eco sand can be thought of as a viable alternative to stabilize the clay soils by means of an effective dispersion dynamics associated with the inter connected network of pore spaces. A CATIA model was created and imported to ANSYS Fluent to study the dispersion dynamics. Ion migration from the bottom ash-ecosand pile was facilitated through natural formation of cracks in clay soil subjected to atmospheric conditions. Treated samples collected at different curing days from inner and outer zones at different depths were tested for, plasticity index, Unconfined Compressive Strength (UCS), free swell index, water content, Cation Exchange Capacity (CEC), pH and ion concentration to show the effectiveness of the method in improving the clay soil.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.6
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• pp.268-273
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• 2014

$Y_2O_3$ ceramic specimens were fabricated from the granular powder, obtained by spray drying process from the slurry. The slurry was prepared by mixing PVA binder, NaOH for Ph control, PEG and $Y_2O_3$ powder. The $Y_2O_3$ specimen was shaped in size of ${\phi}14mm$ and then sintered at $1650^{\circ}C$. The characteristics, microstructure, densities and plasma resistance of the $Y_2O_3$ specimens were investigated with the function of forming pressure and sintering time. $Y_2O_3$ specimens were exposed under the $CHF_3/O_2/Ar$ plasma, the dry etching treatment of specimens was carried out by the physical reaction etching of $Ar^+$ ion beam and the chemical reaction etching of $F^-$ ion decomposed from $CHF_3$. With increasing sintering time, $Y_2O_3$ specimens showed relatively high density and strong resistance in plasma etching test.