• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.1
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• pp.110-115
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• 2016

The need for high-strength galvanized steel has recently increased because of the increased number of car consumers who want improved efficiency and exterior quality. High-strength galvanized steel with high corrosion resistance improves the durability of products and exterior quality. Furthermore, the gilt of zinc does not come off during machining because of the fine adhesive property of zinc. When these are welded, zinc has a lower melting temperature than iron, so zinc is more quickly vaporized than iron. Vaporized zinc can stick to electrodes, which increases spatter in welding transportation. Created spatter can enter the molten pool and develop into inner defects or blowholes and pits. Scattered spatter sticks to the product, which leads to the secondary cost of spatter removal. Therefore, in this study, comparisons of amounts of spatter generated are conducted according to the composition of shielding gas in the MIG and CMT processes to find optimal welding parameters.

• Corrosion Science and Technology
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• v.16 no.1
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• pp.38-47
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• 2017

Due to various types of Zn coatings for many decades for various applications, it is imperative to study and compare their corrosion resistance properties of some of these. Here, we introduce a systematic methodology for evaluation and validation of corrosion protection properties of metallic coatings. According to this methodology, samples are were exposed in an advanced cyclic corrosion test chamber according to ISO 14993, and removed at the end of each withdrawal for respective corrosion and electrochemical characterization to evaluate both barrier and galvanic protection properties. Corrosion protection properties of coatings were evaluated by visual examination according to ISO 10289, mass loss and subsequent corrosion rate measurements, electrochemical properties, and advanced electrochemical scanning techniques. In this study, corrosion protection properties of a commercial zinc rich coating (ZRC) on AISI 1020 mild steel substrates were evaluated and benchmarked against hot dip galvanized (HDG). Results were correlated, and corrosion protection capabilities of the two coatings were compared. The zinc rich coating performed better than hot dip galvanized coating in terms of overall corrosion protection properties, according to the exposure and experimental conditions used in this study. It proved to be a suitable candidate to replace hot dip galvanized coatings for desired applications.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2001.06a
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• pp.25-26
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• 2001

• Proceedings of the KWS Conference
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• 2000.10a
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• pp.243-246
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• 2000

• Proceedings of the KWS Conference
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• 2002.05a
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• pp.207-210
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• 2002

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.11a
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• pp.134-134
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• 2012

• Polymer(Korea)
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• v.38 no.5
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• pp.580-587
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• 2014

Composite films of zinc calcium alginate were prepared by a film maker from 7 wt% sodium alginate solution and then they solidified into 3, 5 wt% content $ZnCl_2$, $CaCl_2$ solution followed by washing and drying at room temperature. The characteristics were measured with several methods (antimicrobial activity, water solubility, swelling ratio and viscosity, SEM, EDS) and the film properties were investigated. Composite films of zinc calcium alginate showed an increase in the water resistance by increasing $ZnCl_2$ and $CaCl_2$ content and the antimicrobial test showed that the calcium alginate as well as zinc alginate films result in excellent antimicrobial activity in the two strains, Staphylococcus and Escherichia coli. The results show the possible improvement of the physical properties of composite films.

• Clean Technology
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• v.12 no.4
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• pp.232-237
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• 2006

The zinc-based desulfurization sorbents for a fluidized-bed system were prepared by a spray drying method and the effects of the pH and viscosity of the slurry on the attrition resistance of the prepared sorbents were investigated in this work. In order to improve the attrition resistance, alumina sol was used for an inorganic binder and pH of the slurry was changed for its better dispersion in slurry. The attrition resistance of the prepared sorbents decreased due to the phase transition of alumina sol to gel as the slurry pH increased to its basicity. The optimum pH condition for the good attrition resistance of the sorbents was about 6.0 in this study. It was confirmed that the attrition property of the sorbents were varied with the viscosity of the slurry. The attrition resistance of the sorbents prepared by the spray drying method increased as their bulk density increased, while it decreased as the surface area and porosity of the sorbents. The optimum viscosity for the high attrition was in the range 400-500 cP.

• Applied Chemistry for Engineering
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• v.28 no.6
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• pp.645-648
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• 2017

A catalyst for promoting the commercialization of N-phenylamleimide (PMI), a compound used to strengthen the heat resistance of ABS resins and also completely imported, was developed. N-phenylmaleamic acid (PMA) was first quantitatively obtained through the reaction of maleic anhydride and aniline. A catalyst was then investigated for obtaining PMI. Zinc acetate/$Et_3N$, composite catalyst, showed better performance than a single acid catalyst. By using the developed composite catalyst, PMI could be synthesized with the yield and purity of 90% and 99.3%, respectively without any further purification processes.

• Journal of Microbiology and Biotechnology
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• v.11 no.1
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• pp.50-55
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• 2001

Different polluted water samples were collected from a wastewater treatment plant, agricultural drainage canals, the River Nile, and irrigation canals. The samples were examined for the enumeration of Pseudomonas aeruginosa in the Sohag area, Egypt over a period of one year. A total of 240 isolates were collected and tested for their resistance to 12 common antibiotics and 6 heavy metals. The isolates were found to be less resistant to norfloxacin(1.7%), ofloxacin(4.6%), amikacin(9.6%), tobramycin (10.4), carbenicillin (15.4), and gentamycin (41.3%), yet more sensitive to rifampicin (75%), kanamycin (89.6%), ampicillin (90.8%), chloramphenicol (91.7%), streptomycin (92.9%), and tetracyclin(96.3%). In contrast, 7.1%, 12.9%, 25.4%, and 53.7% of the isolates were resistant to lead, cadmium, mercury, and zinc, respectively. None of the isolates had developed a resistance to silver or molybdenum. The high frequency of metal-antibiotic double resistance existed between lead and amikacin (56.5%), cadmium and ofloxacin (72.7%), zinc and norfloxacin (100%), and mercury and carbenicillin (94.6%). The high occurrence of antibiotic-resistant bacteria in natural water could be related to the widespread use of antibiotics, with possible public health hazard.