Hydrogen evolution on a steel surface and subsequent hydrogen diffusion into the steel matrix are evaluated using an electrochemical permeation test with no applied cathodic current on the hydrogen charging side. In particular, cyclic operation in the permeation test is also conducted to clarify the corrosion-induced hydrogen evolution behavior. In contrast to the conventional perception that the cathodic reduction reaction on the steel in neutral aqueous environments is an oxygen reduction reaction, this study demonstrates that atomic hydrogen may be generated on the steel surface by the corrosion reaction, even in a neutral environment. Although a much lower permeation current density and significant slower diffusion kinetics of hydrogen are observed compared to the results measured in acidic environments, they contribute to the increase in the embrittlement index. This study suggests that the research on hydrogen embrittlement in ultra-strong steels should be approached from the viewpoint of corrosion reactions on the steel surface and subsequent hydrogen evolution/diffusion behavior.

Hot-press forming(HPF) steel can be applied successfully to auto parts because of its superior mechanical properties. However, its resistances to aqueous corrosion and the subsequent hydrogen embrittlement(HE) decrease significantly when the steel is exposed to corrosive environments. Considering that the resistances are greatly dependent on the properties of coating materials formed on the steel surface, the characteristics of the corrosion and hydrogen diffusion behaviors regarding the types of coating material should be clearly understood. Electrochemical polarization and impedance measurements reveal a higher corrosion potential and polarization resistance and a lower corrosion current of the Al-coating compared with Zn-coating. Furthermore, it was expected that the diffusion kinetics of the hydrogen atoms would be much slower in the Al-coating, and this would be due mainly to the much lower diffusion coefficient of hydrogen in the Al-coating with a face-centered cubic structure. The superior surface inhibiting effect of the Al-coating, however, is degraded by the formation of local cracks in the coated layer under severe stress conditions, and therefore further study will be necessary to gain a clearer understanding of the effect of cracks formed on the coated layer on the subsequent corrosion and hydrogen diffusion behaviors.

Boron nitride nanotubes (BNNTs) are receiving great attention because of their unusual material properties, such as high thermal conductivity, mechanical strength, and electrical resistance. However, high-throughput and highefficiency synthesis of BNNTs has been hindered due to the high boiling point of boron (~ 4000℃) and weak interaction between boron and nitrogen. Although, hydrogen-catalyzed plasma synthesis has shown potential for scalable synthesis of BNNTs, the direct use of H2 gas as a precursor material is not strongly recommended, as it is extremely flammable. In the present study, BNNTs have been synthesized using radio-frequency inductively coupled thermal plasma (RF-ITP) catalyzed by solid-state ammonium chloride (NH4Cl), a safe catalyst materials for BNNT synthesis. Similar to BNNTs synthesized from h-BN (hexagonal boron nitride) + H2, successful fabrication of BNNTs synthesized from h-BN+NH4Cl is confirmed by their sheet-like properties, FE-SEM images, and XRD analysis. In addition, improved dispersion properties in aqueous solution are found in BNNTs synthesized from h-BN +NH4Cl.

Pollution of chloride ion-reinforced concrete can trigger active corrosion processes that reduce the useful life of structures. Multifunctional materials used as a counter-electrode by electrochemical techniques have been used to rehabilitate contaminated concrete. Cement-based pastes added to carbonaceous material, fibers or dust, have been used as an anode in the non-destructive Electrochemical Chloride Extraction (ECE) technique. We studied the performance of the addition of Carbon Fiber (CF) in a cement-graphite powder base paste used as an anode in ECE of concretes contaminated with chlorides from the preparation of the mixture. The experimental parameters were: 2.3% of free chlorides, 21 days of ECE application, a Carbon Fiber Volume Fraction (CFVF) of 0.1, 0.3, 0.6, 0.9%, a lithium borate alkaline electrolyte, a current density of 4.0 A / m2 and a cement/graphite ratio of 1.0 for the paste. The efficiency of the ECE in the traditional technique using metal mesh as an anode was 77.6% and for CFVF of 0.9% it was 90.4%, with a tendency to increase to higher percentages of the CFVF in the conductive cement-graphite paste, keeping the pH stable and achieving a homogeneous ECE in the mass of the concrete contaminated with chlorides.

In vitro maturation (IVM) systems have become indispensable for the production of large numbers of competent oocytes in domestic species. The quality of in vitro matured oocyte is one of the important factors determining the success of assisted reproductive technologies (ARTs) including intracytoplasmic sperm injection (ICSI), in vitro fertilization (IVF), and somatic cell nuclear transfer (SCNT) in human and livestock. Incomplete cytoplasmic maturation of oocytes can lead not only to a failure of fertilization but also to a developmental arrest after ARTs. Thus, establishment of a stable IVM system to produce a large number of high quality oocytes, especially in domestic animals, is essential for improvement of ARTs efficiency by producing high quality embryos. The morphological characteristics are commonly used to predict the developmental potential of oocytes and embryos. Usually, normal oocytes shrink when exposed to a hypertonic medium, and recover their morphology when returned to an isotonic medium. During this process, oocytes show various morphologic changes, such as shrinkage in spherical (SSP) or irregular shapes (SIR). In the first study, we investigated whether the shrinkage pattern of oocytes that was observed after hyperosmotic treatment could be used as a morphologic characteristic to predict the quality of IVM oocytes in pigs. We found that SSP oocytes showed improved developmental competence after PA and SCNT. This improved embryonic development was most likely because of the more advanced nuclear and cytoplasmic maturation in SSP oocytes compared with SIR oocytes. Pig oocytes shows a wide variation in the size of perivitelline space (PVS) after IVM. Based on this finding, we examined in the second study whether or not there was any correlation between the PVS size of IVM oocytes and their developmental competence after PA and SCNT. Our results demonstrated that in vitro developmental competence to the blastocyst stage positively correlated with the size of the PVS of oocytes after IVM. In addition, we observed that mature oocytes with a larger PVS showed higher levels of intracellular GSH content and transcription factor expression. Furthermore, enlargement of the PVS by culturing in reduced NaCl medium improves the embryonic development after PA and SCNT. In the third study, we investigated the effects of a hypotonic medium with reduced NaCl (61.6 mM) compared with an isotonic medium (108.0 mM NaCl) on oocyte maturation and embryonic development after PA and SCNT. In addition, we attempted to optimize our IVM system using a hypotonic maturation medium by examining the effects of hypotonic medium during various stages of IVM on oocyte maturation and subsequent embryonic development. Our results demonstrated that maturation of pig oocytes in hypotonic medium with reduced NaCl during the last 11 hr of IVM increased the developmental competence of oocytes after PA and SCNT. These beneficial effects was also shown in a commercial medium (a minimum essential medium; aMEM) in which the NaCl concentration was reduced to 61.6 mM. In addition, IVM of oocytes in medium with reduced NaCl increases the proportion of SSP oocytes in pigs. In summary, our results demonstrate that IVM of pig oocytes in a hypotonic medium with low-NaCl is better able to support embryonic development after PA and SCNT, most likely by improving the cytoplasmic maturation via increased intraoocyte GSH content and widened PVS. Based on these results, the newly developed IVM system using a hypotonic medium with reduced NaCl can produce high quality oocytes and be considered a new strategy for improving ARTs efficiency in pigs.

NNK (4-(methylnitrosamino)―1-(3-pyridyl)-1-butanone) is a major form of nitrosamine abundant in cigarette smoke and is a powerful carcinogen. Mercury is a major component of the amalgam that is widely used as dental filling material. Concurrent exposure to these two agents may result in their interaction and alter their carcinogenic potential. The present study used an immortalized human epithelial cell system that allows continuous exposure to potential carcinogens, in an attempt to elaborate the carcinogenic potential of mercury and NNK in humans. Cytotoxicity of mercury chloride and NNK was measured by an MTT assay. Parameters of neoplastic cellular transformation such as cell saturation density, soft-agar colony formation, and cell aggregation were analyzed to examine the carcinogenic potential of mercury chloride and NNK. The study showed that exposure to mercury chloride with NNK resulted in increased soft agar colony formation and cell aggregation. ROS generation by mercury chloride was further enhanced by treatment with NNK. The apoptosis that was observed following mercury chloride exposure was further increased upon co-treatment with NNK. The interaction between these two agents was also observed in cytokine mRNA induction. In the present study, mercury alone did not seem to pose a significant threat as a carcinogen, but it may have potential to enhance the carcinogenic potential of a known carcinogen from cigarette smoke. The present study provides valuable data regarding the evaluation of potential carcinogenic risk of mercury chloride and NNK on concurrent exposure.

살모넬라증과 부루셀라증은 가축 및 사람에 심각한 피해를 유발하는 질병으로, 축산업과 식품산업에 많은 경제적 손실을 초래하고 있다. 본 연구에서는, 자몽종자추출물, 구연산, 사과산 그리고 염화벤잘코늄을 주성분으로 하는 스프레이형 소독제의 Salmonella Typhimurium과 Brucella ovis에 대한 효력시험을 수행하였다. 살균효력시험은 배지희석법에 따라 수행하였으며, 스프레이형 소독제와 시험 세균들을 처리조건에 따라 경수와 유기물로 희석하여 반응을 시켰다. 유기물 조건에서, Salmonella Typhimurium과 Brucella ovis에 대한 스프레이형 소독제의 살균력은 경수조건에서의 살균력과 비교하여 낮게 나타났는데, 이는 유기물들에 의한 소독제의 살균 유효성분에 대한 저해작용에 따른 것으로 사료된다. 스프레이형 소독제는 Salmonella Typhimurium과 Brucella ovis와 같은 인수공통전염병 유발 병원균들에 대해 살균효과를 나타내어, 살모넬라증과 브루셀라증과 같은 세균성 질병의 확산을 제어하는데 효과적으로 이용될 수 있을 것으로 사료된다.

In this work, recent progress on graphene/metal oxide composites as advanced materials for HgCl2 and CO2 capture was investigated. Density Functional Theory calculations were used to understand the effects of temperature on the adsorption ability of HgCl2 and water vapor on CO2 adsorption on CaO (001) with reinforced carbon-based nanostructures using B3LYP functional. Understanding the mechanism by which mercury and CO2 adsorb on graphene/CaO (g-CaO) is crucial to the design and fabrication of effective capture technologies. The results obtained from the optimized geometries and frequencies of the proposed cluster site structures predicted that with respect to molecular binding the system possesses unusually large HgCl2 (0.1- 0.4 HgCl2 g/g sorbent) and CO2 (0.2-0.6 CO2 g/g sorbent) uptake capacities. The HgCl2 and CO2 were found to be stable on the surface as a result of the topology and a strong interaction with the g-CaO system; these results strongly suggest the potential of CaO-doped carbon materials for HgCl2 and CO2 capture applications, the functional gives reliable answers compared to available experimental data.

The industrialization and urbanization forced to increase the density of pipelines such as water supply, sewers, and gas pipelines. The materials used for the existing pipe lines are mostly composed of concretes and steels, but it is true that the development for more durable and efficient materials has been continued performed to produce long lasting pipe lines. Recently, underground pipes serve in diverse applications such as sewer lines, drain lines, water mains, gas lines, telephone and electrical conduits, culverts, oil lines, etc. In this paper, we present the result of investigation pertaining to the structural behavior of unplasticized polyvinyl chloride (PVC-U) flexible pipes buried underground. In the investigation of structural behavior such as a ring deflection, pipe stiffness, 4-point bending test, experimental and analytical studies are conducted. In addition, pipe stiffness is determined by the parallel plate loading tests and the finite element analysis. The difference between test and analysis is about 8% although there are significant variations in the mechanical properties of the pipe material. In addition, it was found by the 4-point bending test there is no problem in the connection between the pipes by coupler.

Cellulose acetate (CA) has been used for microfiltration/ultrafiltration applications because of its good solubility in common solvents. However, it is sensitive to chemical and physical degradation. Therefore, in this study, cellulose acetate was crosslinked with terephthaloyl chloride (TPC) in dimethylacetamide (DMAc) solution to complement these weakness. Cross-linking was confirmed by increasing in dope solution viscosity and FT-IR. To indicate the chemical resistance, weight loss was observed after the cross-linked CA membranes were immersed in ethanol, hexane, acetone and DMAc solvent for 24h. The physical properties were evaluated by the tensile strength. In the result of experience, effect of the degree of cross-linking by increasing of the concentration of TPC improved the chemical and physical properties of CA.

음이온 교환막의 치환체 특성을 파악하기 위하여 탄화수소의 분자구조가 다른 세 종류의 음이온 교환기를 vinyl benzyl chloride (VBC) base 막에 도입하였다. 지방족계로 trimethylamine (TMA), 고리형계로 N-methylpiperidine (MP), 방향족계로 pyridine (Py)은 아민화 반응을 통하여 도입되었다. 각각의 반응속도는 막저항(MER)과 이온교환능력(IEC) 변화의 관측으로부터 Py < MP < TMA의 순서로 반응하고 있음을 보여주었다. 한편 SEM image에서는 Py 치환체 막이 가장 균일하고 치밀한 구조를 보여주었으며, 전기화학적 특성에서도 Py이 상용막(AMX)과 비슷한 막저항(5.0 Ω·cm2 >, in 0.5 mol/L NaCl)을 나타내었다. 이 모든 결과로부터 치환체의 공명구조는 균질한 이온교환막의 제조에 기여하고 있음을 알 수 있었다.

Porcine epidemic diarrhea virus (PEDV) causes porcine epidemic diarrhea (PED) and a considerable economic loss in the swine industry. In this study, the virucidal efficacy of a disinfectant composed of citric acid, benzalkonium chloride and phosphoric acid against PEDV was investigated. Virucidal efficacy was assessed as the infectivity of PEDV toward Vero cells after exposure of the virus to the disinfectant. PEDV was exposed to the disinfectant in the presence of either hard water (HW) or an organic matter suspension (OM). In HW condition, PEDV was inactivated by 600-fold dilutions of the disinfectant. In the presence of OM, the disinfectant showed virucidal activity after a 200-fold dilution. As the disinfectant possesses virucidal activity against PEDV, it should be an effective reagent to use to limit the spread of animal viral diseases.