2016년 7월~2018년 2월까지 해운회사의 상선에서 위탁실습을 다녀온 4학년 학생을 대상으로 위탁실습생의 근로실태 및 실 습만족도에 대하여 설문조사를 실시하였다. 평균 근로시간은 10시간, 최소 휴식시간은 4시간 미만이 가장 많은 것으로 조사되었다. 실습 만족도에 대하여 만족 또는 보통 수준을 보였으며, 벌크선과 컨테이너선에서 실습한 학생들의 만족도가 다소 낮게 나왔다. 라면 끓이기, 휴식 중 작업, 야식 준비 등 실습 목적 외 부당한 지시를 받는 사례가 다수 있었다. 실습생은 선원법 상 선원이 아닌 자로 분류 되어 있다. 이로 인해 근로시간 또는 휴식시간 등에 대해 보호를 받지 못하고 있는 것이 현실이다. 또한 일부 해운회사에서는 실습교 육을 가장한 실질적 근로(노동) 인력으로 활용하고 있는 사례가 있어 이에 대한 대책 마련이 시급하다.

Membranes techniques used to convert chemical energy into electrical energy from energy sources such as hydrogen, salt water, and water. Membrane materials have transport property of desire molecular and barrier property for satisfy to requirement of cell performance. Typically, PFSA polymer is used to fabricate membrane. Each material has different characteristics depending on the membrane formation conditions. Macroscopic characteristics are difficult to correlation with molecular motion, mobility, and transport within membrane matrices. NMR spectroscopy can analysis about these characteristics by observing the molecule level. In this study, NMR spectroscopy can provide fundamental information of PFSA ionomers and correlation with macroscopic characteristics.

One of the key components to determine polymer electrolyte membrane fuel cell (PEMFC) performances is a polymer electrolyte membrane (PEM), the representative PEM material is perfluorinated sulfonic acid (PFSA) ionomers. PFSA ionomers such as Nafion®and 3M® ionomers have been widely used as PEM materials for fuel cells owing to their excellent chemical inertness and high proton conductivity. Generally, polymeric materials are highly influenced by the membrane fabrication histories including casting solvents, thermal annealing temperature and time, when they are converted in the membrane forming process. In this study, 3M PFSA ionomer membranes were systematically prepared under different fabrication histories. Their morphological contribution on fundamental characteristics, transport behavior, and electrochemical performances were disclosed.

Chlor-alkali (CA) membrane process is a commercially useful process to produce valued chemicals such as chlorine, sodium hydroxide and hydrogen via salined water electrolysis using sodium ion (Na+)-selective membranes. The most important issue in CA process is to reduce high energy consumption. A plausible solution is to obtain highly Na+-conductive membranes. The representative membrane materials are chemically stable perfluorinated sulfonic acid (PFSA) ionomers such as Nafion® and Aciplex®. PFSA membranes, but it is necessary to develop alternatives to PFSA membranes. In this study, a sulfonated poly(arylene ether sulfone) copolymer membrane is radiation-grafted with a highly sulfonated poly(styrene) used as a side chain material.

The anion exchange membrane (AEM) has a structure having a group of positively charged ions inside, and selectively permeates the anion of the electrolyte. In addition, excellent ion conductivity and chemical durability, and highly reliable electrochemical performance are required. However, commercially available AEMs have a hydrocarbon-based backbone. It is difficult to make the thin film because of low solubility. As a result, it has low ionic conductivity and high area resistivity and shows limitations in electrochemical applications. In this study, a perfluorinated ionomer-based anion exchange membrane with excellent chemical stability is prepared and shows enhanced anion conductivity in electrochemical applications.

Sulfonated poly(arylene ether sulfone) (SPAES) random copolymers have been perceived as alternatives to perfluorinated sulfonic acid (PFSA) ionomers owing to their cheap production cost and low hydrogen permeability. In spite of their advantages, there are some issues to overcome such as membrane durability and relatively low proton conductivity in the low humidity range. An approach to solve these problems is to fill SPAES copolymers into porous support films (e.g., poly(tetra fluoro ethylene), PTFE). However, it is difficult to make defect-free pore-filling membranes. In this study, SPAES nanodispersion in a water-alcohol mixture is made under a modified supercritical condition and used to make highly proton conductive and chemical durable SPAES-PTFE pore-filling membranes.

Saline water electrolysis is a representative electrochemical conversion to produce chlorine gas and sodium hydroxide as major products by applying electric power. Perfluorinated sulfonic acid (PFSA) ionomers have been usually used as polymer electrolyte membrane materials owing to high sodium ion selectivity and strong resistance to acidic compounds (e.g., Cl2, HCl and so on) produced in anode. However, PFSA ionomers have been suffering from chemical degradation occurring when exposed under harsh basic condition in cathode. In this study, double layered chlor-alkali membranes were prepared by anchoring crosslinked hydrocarbon ionomer via radical polymerization technique in water channels located in a surface layer of PFSA ionomer membranes and electrochemically evaluated.

Perfluorinated sulfonic acid (PFSA) ionomers have been widely used as representative polymer electrolyte membrane (PEM) materials for water electrolysis to generate hydrogen and oxygen gases with a high purity (e.g., 99.999%) simultaneously. PEM should satisfy high selectivity of proton to water and act as gas barrier to hydrogen and oxygen in order to improve current efficiency which is a barometer to determine how effectively the electric energy is used for water electrolysis. In this study, PFSA ionomers with different chemical architectures and equivalent weights were used to make PEM materials for water electrolysis. The structure-property-performance relationship was systematically investigated.

This study was investigating the anti-obesity effects of diets with a mixture of cheese, red ginseng and fermented mature fruit of Rubus coreanus Miquel. We fed the experimental diets (SC5, SC10) supplemented with 5% or 10% cheese containing of fermented mixture, then orally administered the extract of fermented mixture (RB100, RB300) at a concentration of 100 or 300 mg/kg body weight to SD rats with high fat diet (HFD). The results were as follows: Sample cheese groups decreased visceral fat mass and adipocyte size of stomach compared to that of HFD group. Additionally, lipid droplets of liver in sample cheese groups were smaller than that in HFD group. The serum triglyceride (TG), total cholesterol (tChol), glucose, leptin, and insulin levels in sample cheese group were lower than that in HFD group. But, the serum adiponectin and HDL-cholesterol (cHDL) levels were higher than that in HFD group. These results suggest that fermentation of red ginseng and Rubus coreanus mixed with cheese might be helpful in preventing obesity in high fat diet-fed rats.

세계풍력발전협회(GWEC) 2017년도 Global Wind Report에 따르면 전세계 풍력에 의한 발전용량은 2001년도 23,900MW에서 2016년도 486,790MW로 비약적으로 발전하고 있다. 반면 국내 발전원별 총발전량 비중에서 풍력에 의한 발전은 0.2% 불과하다. 국내외 발전원별 정산단가가 풍력으로 전기를 생산하는 데 드는 발전원가가 석유 등 화석연료 발전원가와 같아지는 Grid Parity에 이미 도달하여 풍력발전에 의한 전기의 생산은 더욱 확대될 것이다. 본 연구에서는 전 세계 해상풍력설비의 88%가 위치하고 있는 유럽의 주요 해상풍력발전단지의 선박통항 규정과 어로활동에 대한 기준을 분석하여 향후 국내 해상풍력발전단지 설치 시 선박통항 및 어로활동 기준 설정 시 고려되어야 할 사항을 제시하였다.

The present experiment was designed to investigate the effects of extruded linseed supplementation on methane production in Holstein steers. Four Holstein steers fitted with permanent cannulas were assigned to two dietary treatments in a duplicated 2 × 2 Latin square design: a control diet consisting of tall fescue straw (65%) and concentrate (35%), and a treatment diet supplemented with 3.8% extruded linseed by replacing a part of ingredients in the concentrate of the control diet. The concentrates of the control and the treatment diet were isoenergetic and isonitrogenous. Extruded linseed supplementation did not affect dry matter intake but significantly (P<0.05) increased the intake of lipid. Rumen pH was significantly (P<0.05) lower for control than for treatment. Although there was no significant difference between treatments, the concentration of total VFA in control was 21% higher than in treatment. The concentrations of acetic acid, propionic acid and butyric acid were not different between treatments. Extruded linseed supplementation significantly (P<0.05) reduced methane output(g/d) and emission factor. Methane conversion rate was lower for treatment than for control but no significant difference was found. The results of the present study showed that extruded linseed supplementation in the diet of Holstein steers could reduce methane output.

This study was conducted with two ruminally cannulated Holstein steers to examine the effect of micronized and steam flaked corn on ruminal fermentation characteristics. The in situ dry matter degradability after 48 h incubation was the highest (P<0.05) at micronized corn (2.5 mm thickness) compared with steam flaked corn treatments. The steam flacked corn (3.3 mm thickness) was degraded lower (P<0.05) than the 2.9 and 3.1 mm thickness of steam flacked corn. Effective dry matter degradability and the rate of constant were the highest (P<0.05) at micronized corn (2.5 mm thickness) compared with steam flaked corns as well. The in vitro dry matter degradability after 48 h incubation was tended to higher (P=0.088) at micronized corn (2.5 mm thickness) than steam flaked corns, whereas there is no significantly difference between steam flaked corn treatments. Total volatile fatty acid concentration was higher at steam flaked corn (2.9 mm thickness) than micronized corn (2.5 mm thickness) and steam flaked corn (3.1 and 3.3 mm thickness). The acetate : propionate ratio was the highest (P=0.008) at steam flaked corn (2.9 mm thickness) and the lowest (P=0.008) at micronized corn (2.5 mm thickness). Total gas and methane production after 48h ruminal incubation was the highest (P=0.001) at micronized corn (2.5 mm thickness) compared with steam flaked corns. According to these results, the thickness of steam flaked corn as resulted corn processing is believed to do not affect methane production. However, further study is needed to better understand the present results to verify the correlation between corn processing method and their thickness on methane production using the same thickness corns by difference processing methods.