• Clean Technology
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• v.10 no.3
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• pp.159-168
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• 2004

Benzene adsorption experiment was carried out for activated carbon and zeolite 13X adsorbents. Single column and dual column packed with two adsorbents were used to investigate the dynamic adsorptive characteristics. Effect of feed flow rate on the breakthrough curve was not significant. Specific adsorption amount of benzene for activated carbon was larger than that for zeolite 13X. On the contrary, adsorption amount per column volume was larger for zeolite 13X column because the density of zeolite 13X was larger. In the dynamic experiment using dual adsorbents column, length of mass transfer zone was changed by the feed direction. Breakthrough time was longer and breakthrough curve was sharper when activated carbon was packed in feed inlet and zeolite 13X was packed in column outlet. Also breakthrough time and breakthrough curve slope were affected by the packing ratio of the two adsorbents.

• The Korean Journal of Community Living Science
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• v.16 no.4
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• pp.15-24
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• 2005

We investigated the changes of volatile flavor components from Codonopsis lanceolata, which were packed in woven polypropylene(WP) film or low density polyethylene(LDPE) film and stored for 15 and 30 days at refrigerated($2{\∼}4^{\circ}C$ ) or room($18{\∼}20^{\circ}C$) temperature. A hundred and sixty seven volatile flavor components in the fresh C. lanceolata were identified by GC/MS analysis. When determining the flavor components from C. lanceolata cultivated on a wild hill and stored at 4 conditions for 30days, six volatile components such as 1-hexadecene, 2,6-dimethyl-2-octanol, 2-methyl-2-dodecanol, $\alpha$-guaiene, $\delta$-cadinene and trans-2-hexen-1-ol were detected as common components of all stored samples, and The types of common flavor components of C. lanceolata were different according to storage conditions. The numbers were 16 from refrigerated, 7 from room temperature stored, and 10 components from WP or LDPE packed conditions, respectively. The total peak area ratio of the major 10 compounds were $52.0{\∼}86.8\%$, and the percentage of trans-2-hexen-1-ol, which was the only common compound among the major 10 components, was the highest as $26.4{\∼}68.1\%$ The major flavor profile, describe by highly trained panel, were green, aldehydic, earthy and camphoreous. As the result from sensory evaluation, the freshness of C. lanceolata was maintained better by controlling storage temperature rather than selection of package materials. The best condition for characteristic flavor of C. lanceolata was packing with LDPE and chilling.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.34.1-34.1
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• 2009

A great deal of attention has been focused on ZnO nanowires for various electronics and optoelectronics applications. in the pursuit of next generation nanodevices, it would be highly preferred if well-ordered ZnO nanowires of lower dimension could be fabricated on silicon. Before the growth of nanowires, silicon substrates were selectively etched using silicon nitride as masking layer. Vertical aligned ZnO nanowires were grown by metal organic chemical vapor deposition on patterned silicon substrate. The shape of nanostructures was greatly influenced by the micropatterned surface of the substrate. The aspect ratio, packing fraction and the number density of nanowires on top surface are around 10, 0.8 and $10^7\;per\;mm^2$, respectively, whereas the values are 20, 0.3 and $5\times10^7\;per\;mm^2$, respectively, towards the bottom of the cavity. XRD patterns suggest that the nanostructures have good crystallinity. High-resolution transmission electron microscopy confirmed the single crystalline growth of the ZnO nanowires along [0001] direction.

• Polymer(Korea)
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• v.33 no.4
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• pp.364-370
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• 2009

The curing kinetics and mechanical properties of siloxane-diaminodiphenylmethane (ETSO-DDM) on the two kinds of bisphenol (BPH) system which are DGEBA and DGEBF were investigated with the different contents of ETSO. To investigate the curing kinetics of the ETSO-DDM/BPH systems, differential scanning calorimeter (DSC) was used. The mechanical properties of ETSO-DDM/BPH systems were also examined by universal testing machine (UTM), tensile test and flexural test. From experimental results, the activation energies and mechanical properties of ETSO-DDM/BPH were improved with the decrease contents of ETSO. This was due to the high cross-linking density made from short length of ETSO-DDM, resulting in improving the mechanical inter-locking between ETSO-DDM and BPH in these systems.

• Polymer(Korea)
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• v.26 no.5
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• pp.551-558
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• 2002

It was observed that adsorption characteristics of sulfonated fabric ion-exchanger for separating nickel ion from electroplating rinse water. Swelling ratio was increased by increasing degree of sulfonation and polarity of solvent. Ion-exchange capacity was also increased by increasing degree of sulfonation and showed 3.38 meq/g at 16% sulfonated ion-exchanger. There was little effects of pH. Adsorption equilibrium was attained within 10 min, and adsorption rate was 7.5 mg/min. Adsorption capacity was not changed after 7 cycles of regeneration process. Regeneration adsorption capacity was slightly decreased to 2.01 meq/g. It confirmed that durability of sulfonated fabric ion-exchanger was suitable for adsorption process. Adsorption equilibrium time was linearly increased by increasing L/D and adsorption capacity showed the ion exchange capacity within the range of 2.71 ∼ 3.01 meq/g in continuous process. Design of adsorption column could be possible for L/D<2. Under constant L/D condition, there is no little pH effect when rinse water is acidic solution, and operation condition of adsorption process was optimized under pH 5.

• Journal of Korean Neurosurgical Society
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• v.53 no.6
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• pp.342-348
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• 2013

Objective : Several scales are currently used to assess occlusion rates of coiled cerebral aneurysms. This study compared these scales as predictors of recanalization. Methods : Clinical data of 827 patients harboring 901 aneurysms treated by coiling were retrospectively reviewed. Occlusion rates were assessed using angiographic grading scale (AGS), two-dimensional percent occlusion (2DPO), and volumetric packing density (vPD). Every scale had 3 categories. Followed patients were dichotomized into either presence or absence of recanalization. Kaplan-Meier analysis was conducted, and Cox proportional hazards analysis was performed to identify surviving probabilities of recanalization. Lastly, the predictive accuracies of three different scales were measured via Harrell's C index. Results : The cumulative risk of recanalization was 7% at 12-month, 10% at 24-month, and 13% at 36-month of postembolization, and significantly higher for the second and third categories of every scale (p<0.001). Multivariate-adjusted hazard ratios (HRs) of the second and third categories as compared with the first category of AGS (HR : 3.95 and 4.15, p=0.004 and 0.001) and 2DPO (HR : 4.87 and 3.12, p<0.001 and 0.01) were similar. For vPD, there was no association between occlusion rates and recanalization. The validated and optimism-adjusted C-indices were 0.50 [confidence (CI) : -1.09-2.09], 0.47 (CI : -1.10-2.09) and 0.44 (CI : -1.10-2.08) for AGS, 2DPO, and vPD, respectively. Conclusion : Total occlusion should be reasonably tried in coiling to maximize the benefit of the treatment. AGS may be the best to predict recanalization, whereas vPD should not be used alone.

• Korean Journal of Metals and Materials
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• v.48 no.7
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• pp.630-638
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• 2010

The present investigation has been performed on the mixing behavior and microstructural development during fabrication of Fe micro-nano powder feedstock for a micro-powder injection molding process. The mixing experiment using a screw type blender system was conducted to measure the variations of torque and temperature during mixing of Fe powder-binder feedstock with progressive powder loading for various nano-powder compositions up to 25%. It was found that the torque and the temperature required in the mixing of feedstock increased proportionally with increasing cumulative powder loading. Such an increment was larger in the feedstock containing higher content of nano-powder at the same powder loading condition. However, the maximum value was obtained at the nano-powder composition of not 25% but 10%. It was owing to the 'roller bearing effect' of agglomerate type nano-powder acting as lubricant during mixing, consequently leading to the rearrangement of micro-nano powder in the feedstock. It is concluded that the improvement of packing density by rearrangement of nano-powders into interstices of micro-powders is responsible for the maximum powder loading of about 71 vol.% in the nano-powder composition of 25%.

• Resources Recycling
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• v.28 no.2
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• pp.31-39
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• 2019

The pelletizing of printed circuit board (PCB) sludge was researched for copper recovery in pyrometallurgical process. This pelletizing was carried out by using self-manufactured compression-type apparatus after pre-treatments (drying, water scrubbing, size classification) were proceeded. The physical properties (compression strength and drop-breakage test) were tested with a change of sludge sizing and the number of compression. In the case of using the undersized sludge of #140, its properties were improved to 0.6 MPa and 9.3 times. Moreover, they increased to 0.82 MPa and 19.0 times by using the #140 ~ 325 sludge. These imply that the packing density increases due to the elimination of large-sized sludge (#140), and also the weight of required binder decreases by the removal of fine-sized sludge (#325).

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.12
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• pp.1903-1912
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• 2018

Objective: To evaluate the effect of lactic acid bacteria and storage temperature on the microbial, chemical and mycotoxin composition of corn silage. Methods: Corn was harvested at 32.8% dry matter, and chopped to 1 to 2 cm. The chopped material was subjected to three treatments: i) control (distilled water); ii) $1{\times}10^6$ colony forming units (cfu)/g of Lactobacillus plantarum; iii) $1{\times}10^6cfu/g$ of Pediococcus pentosaceus. Treatments in triplicate were ensiled for 55 d at $20^{\circ}C$, $28^{\circ}C$, and $37^{\circ}C$ in 1-L polythene jars following packing to a density of approximately $800kg/m^3$ of fresh matter, respectively. At silo opening, microbial populations, fermentation characteristics, nutritive value and mycotoxins of corn silage were determined. Results: L. plantarum significantly increased yeast number, water soluble carbohydrates, nitrate and deoxynivalenol content, and significantly decreased the ammonia N value in corn silage compared with the control (p<0.05). P. pentosaceus significantly increased lactic acid bacteria and yeast number and content of deoxynivalenol, nivalenol, T-2 toxin and zearalenone, while decreasing mold population and content of nitrate and 3-acetyl-deoxynivalneol in corn silage when stored at $20^{\circ}C$ compared to the control (p<0.05). Storage temperature had a significant effect on deoxynivalenol, nivalenol, ochratoxin A, and zearalenone level in corn silage (p<0.05). Conclusion: Lactobacillus plantarum and Pediococcus pentosaceus did not decrease the contents of mycotoxins or nitrate in corn silage stored at three temperatures.

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.549-555
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• 2023

Jacking force loss management inside the PSC Box girder of a common high-speed railway is a very important feature in girder performance, and requires detailed management during the maintenance of the girder. This study aimed to analyze the timing of re-tension prediction of PSC Box girder based on the reduction level of the packing force inside the girder and the results of the tension loss measured without the train load test. As a result of predicting the timing of re-tension according to the level of tension reduction of the PSC Box Girder, the Jacking Force Loss curve was gently analyzed before the structure reached 17 years after confirmed completion, and 17 years later, it was found that the jacking force loss curve progressed rapidly. The results confirmed that the tension of the structure decreases with the service life increase, but considerably decreases as the structure ages. Therefore, more data and research on tension loss of facilities over 20 years are much required.