Hideyuki Kanematsu

Evaluation of Various Metallic Coatings on Steel to Mitigate Biofilm Formation

In marine environments and water systems, it is easy for many structures to form biofilms on their surfaces and to be deteriorated due to the corrosion caused by biofilm formation by bacteria. The authors have investigated the antibacterial effects of metallic elements in practical steels so far to solve food-related problems, using Escherichia coli and Staphylococcus aureus. However, from the viewpoint of material deterioration caused by bacteria and their antifouling measures, we should consider the biofilm behavior as aggregate rather than individual bacterium. Therefore, we picked up Pseudomonas aeruginosa and Pseudoalteromonas carageenovara in this study, since they easily form biofilms in estuarine and marine environments. We investigated what kind of metallic elements could inhibit the biofilm formation at first and then discussed how the thin films of those inhibitory elements on steels could affect biofilm formation. The information would lead to the establishment of effective antifouling measures against corrosion in estuarine and marine environments.

Multilingual discussion in metaverse among students from the USA, Korea and Japan

E-learning continues to be used as an educational tool all over the world. However, the typical e-learning systems are sometimes not enough for students to feel a close connection with others. Now engineering education needs to be carried out from a global viewpoint, since there are lots of opportunities for international collaboration in higher education organizations. In this study, we investigated multilingual discussion in Metaverse and its possibility to enhance the skills for international discussion and international characteristics. Students from Edwards-Knox high school in the USA, graduate students from Yonsei University, Korea, and Nagaoka University of Technology (NUT), Japan, participated in this discussion held on the virtual island (owned by NUT) of Second Life. A language grid system was incorporated into the Metaverse system. This made it possible for the discussion to be carried out with and without the translation system. These sessions were carried out and compared with each other. Also the effectiveness of the international discussion project in Metaverse (with the language grid system) was discussed.

US Students Carry out Nuclear Safety Project in a Virtual Environment

Abstract A project about nuclear safety was carried out through e-learning. It was a problem based learning (PBL) activity that took place in Second Life (SL), an online three-dimensional community. The virtual classroom was built on an island owned by Nagaoka University of Technology, Japan. Three students from a high school near Clarkson University participated in this project. A teacher gave them a short lesson about nuclear energy safety and then proposed the problem. The students understood the contents very well and solved the problem through voice chat interactions in SL. They engaged in active discussions and displayed high interest for the safe use of nuclear energy throughout this successful project. The results clearly indicate that this type of PBL class is possible for actual e-learning about nuclear safety and for engineering education.

Nuclear Energy Safety Project in Metaverse

This project for learning nuclear energy safety was carried out through e-learning. Problem Based Learning (PBL) was selected as the educational tool and Metaverse as the class environment. The virtual classroom was built on a virtual island of Second Life owned by Nagaoka University of Technology. Three students from two National Technical Colleges in Japan joined the project. A teacher gave the students a short lecture and proposed the problem. Students understood the contents very well and solved the problem through chat-based discussions in Metaverse. Students’ clear and precise understanding, their high activeness of discussion and high interest for the safety of nuclear energy was apparent throughout this successful PBL class project. The results indicate very clearly that this kind of PBL class was obviously possible for actual e-learning in nuclear engineering and engineering education.

Electrochemical stability of hot dip galvanised steel in an acid environment containing Thiobacillus Ferrooxidans

Abstract Hot dip and non-hot dip galvanised steel specimens were immersed in a 9K medium containing Thiobacillus ferrooxidans and the weight change and variation in potential with time measured. After this period, the surfaces of the specimens were observed using a scanning electron microscope and analysed by energy dispersive analysis by X-rays (SEM-EDX). Both specimens showed increased weight changes after immersion in the 9K medium with T. ferrooxidans, but did not show any significant difference in potential in the solution with T. ferrooxidans and that without the microorganisms. However, SEM-EDX analysis of the specimens immersed in the microbially infected solution showed the presence of dark areas that exhibited high concentrations of phosphorous and sulphur. This suggests the existence of biofilm on the specimen surface, which is implicated in microbially influenced corrosion (MIC) of the steel surface.

Composite coating to control biofilm formation and effect of alternate electro-magnetic field

Abstract Three kinds of composite coating (the common matrix was silane oligomer and titanium organic, tin organic and nickel organic compounds were dispersed in the matrices) specimens on glasses were immersed in a unique Laboratory Biofilm Reacter (LBR) for 12 days. In the LBR, the water was circulated, incorporating ambient germs into the system and biofilm was formed on the specimen set in the LBR. In the LBR, clean water was circulated and the weak alternative electromagnetic field was applied to the water phase. For the biofilm resistant coating (organic titanium or tin composite coating based on silane oligomer), the effect of the applied alternative electromagnetic field was remarkable.

Problem Based Learning for US and Japan Students in a Virtual Environment

Problem Based Learning (PBL) is important for engineering education and has been a tool for creative engineering design. It can enhance creativity and has been used to successfully carry out many experiments in the real world. Researchers in the US and Japan (the authors) are pursuing studies to determine the effectiveness of its use in a virtual environment, one with cutting-edge technology and opportunities for complementary activities between face to face learning and electronic learning. Here students can work from anywhere in the world, at any time, and at their own pace. For this project, student teams from the US and Japan were asked to solve problems in a virtual community. Each team worked independently on a different project. The US team designed and built a car for the future, while the Japan team focused on designing a safe way for using nuclear energy. A discussion about the US team’s successful project is provided.

Application of bacterial 16S rRNA gene analysis to a comparison of the degree of biofilm formation on the surface of metal coated glasses

Abstract The contaminated surfaces of materials are generally covered with a biofilm that consists of microorganisms and extracellular polysaccharides. The Gram stain method, which is used to visualise bacteria, allows biofilms to be semiquantitatively analysed. Although this method can be used to compare the amount of bacteria in a biofilm, we cannot identify kinds of bacteria. In the present study, 16S rRNA gene analysis was performed to measure and determine the bacterial population in biofilms formed on organic nickel coated glass and uncoated glass. The amount of 16S rRNA was markedly higher on organic nickel coated glass than on uncoated glass. 16S rRNA sequencing revealed that the majority of bacteria on uncoated glass and organic nickel coated glass were Proteobacteria, especially Sphingomonadales and Methylophilales; however, a marked difference was observed in the amount of Sphingomonadales on these glasses.

Virtual STEM Class for Nuclear Safety Education in Metaverse

Abstract The blend education of e-learning and hands-on activity was carried out, using Metaverse. The topic was picked up, relating to radioactivity, nuclear safety education and STEM education. The students were six 5 th and 6 th graders in an elementary school. The lecture was given to them through the virtual class in Metaverse (Second Life). And then, the hands-on experiments relating to radioactivity were carried out in real life, lead and guided by the teacher in Second Life synchronistically and supported by the teacher in real life sometimes. The questionnaire given to each of students after the hands-on experiments showed very clearly that the project satisfied with the original goals very well, from both viewpoints of STEM education and nuclear safety education at early stage (pre secondary) levels. We concluded that the blend education worked well for STEM education to much extent.

Corrosion and biofilm for a composite coated iron observed by FTIR-ATR and Raman spectroscopy

Corrosion of metallic materials occurs in various ways. Recently, many researchers have pointed out that biofilm formed by a biofouling process may be a main cause for the initial stage of corrosion. From this viewpoint, the control of biofilm would help lead to corrosion prevention. In this paper, the authors studied the composite film of silane compounds with dispersed organometallic compounds that showed anti-fouling effect on pure iron substrates. The specimens were immersed in a laboratory biofilm reactor for 7 days to form biofilms on them. The surfaces of the specimens were observed by optical and scanning electron microscopy, Raman spectroscopy and FTIR-ATR spectroscopy. Finally, the effect of the composite coating on biofilm formation and corrosion characteristics was studied and shown to inhibit both.