The use of renewable energy is attracting attention due to global warming and energy problems. Power generation using marine renewable energy includes wave power generation and tidal current power generation. Practical use of both is desired. Therefore, an example of the demonstration test stage will be described. In addition, an example of development of about 1 kW, which is called pico power generation, is also described.

As the current depletion of fossil resources and global warming emerging, it is expected to establish sustainable production processes that circulate and utilize the resources available on the earth’s surface. In particular, there are expectations for the production of a value-added chemical from atmospheric carbon dioxide (CO₂), however it is necessary to require a large amount of reducing power and energy. In recent studies, electrochemically active bacteria (EAB), microbes can be able to interact with a conductive material via extracellular electron transfer pathway, receive attention from application to bioelectrochemical systems such as microbial electrosynthesis system (MES). Since it is estimated that a value-added chemical production process combing EAB and solar cells can achieve an energy conversion efficiency higher than that of photosynthesis. In this report, we first describe EAB and subsequently summarize one of the attractive microbes, autotrophic acidophile iron-oxidizing bacteria and laboratory studies that have been conducted to towards development for a sustainable bioprocess using MES. We also discuss possibilities of MES biotechnology to utilize that facilitate the development of eco-friendly future industry.

In this paper, the sailing mechanism of a sailing ship is explained in relation to sustainable development (SD). In relation to the UN SDGs, sailing is also being used by maritime transport with the gradual entry into force of MARPOL 73/78 conventions. On the other hand, in Japan, there is little interest in the motion mechanism of sailing ships. Therefore, the main equipment of the sailing ship, the fluid force involved in the movement, and the side slip prevention mechanism will be explained. Also, the rolling moment elimination mechanism is explained. Finally, the general content of SD is also outlined.

Technologies related to the passenger aircrafts equipped with turbofan engines and carbon fiber composite materials have made remarkable progress. Also, air passengers and freight have been steadily increased. However, due to the effects of the world economy, the number of passenger aircraft orders for aircraft manufacturers has been considerably fluctuated. Large fluctuations in orders make it difficult to manage the supply chain and formulate production plans, and to determine the timing of capital investment. To stabilize the management of aircraft manufacturers and suppliers, it is important to predict the number of passenger aircraft orders to some extent. In this study, by using the Fourier transform, the periodicity of the passenger aircraft ordering trends since 1960 were analyzed. As a result, it was found that the passenger aircraft ordering trends could be simulated, and the periods of the waveform of the ordering trends of passenger aircraft were approximately 8 to 10 years. Further, it was clarified that the waveforms were synchronized with the expansion and recession periods of United States economies.

Increasing energy efficiency and reducing CO₂ emissions in the manufacturing industry are pressing task for Japan as it aims for sustainable development. On the other hand, the manufacturing field requires not only processing to the intended dimensions but also value-added improvement. Value-adding is mainly performed in the surface treatment process using low-energy-efficient processing methods, which results in energy consumption and environmental impact. In this study, we investigated ways to improve the functionality of workpieces by using energy-efficient machining methods. We investigated the control of wettability using cutting marks produced by ball end milling. Seven types of cutting marks were created on brass by cutting with a φ10 mm ball end mill. The static contact angle with 1 μl of water was measured on the machined surfaces. Through the analysis of the contact angle and the cutting marks' shape, we clarified that the cutting marks influence wettability.

This paper presents the results of technological development research to safely and efficiently reduce substances contained in combustion emissions, which may impair the growth of crops and the health of workers, below the permissible limit. There are carbon monoxide and nitrogen oxides. Agricultural crop production factories, including greenhouses and glass greenhouses, may use the combustion emissions of hydrocarbon fuels as a carbon dioxide source to promote photosynthesis. In this study, the upper limit concentration of chemical substances permitted for emissions of the gas-fired water heater was calculated by model calculation, and it was set as the target purification. (1) A system using catalyst and air dilution was constructed, and it was shown that the target purification was satisfied. (2) The constructed combustion emissions purification system was verified under automatic cultivation operation of lettuce for eating raw. It was confirmed that the quality and yield of the fertilization method were equivalent to those of the vaporization type carbon dioxide fertilization method, and that the system exerted its effect stably.

Manufacturing is the primary greenhouse gas (GHG) emitter. Manufacturers are making a wide range of efforts to reduce greenhouse gas emissions. Selecting appropriate processing conditions is one way to do this. However, strategies to reduce GHG emissions may not contribute to lower economic costs or higher productivity. A comprehensive evaluation is necessary when making decisions, such as in production planning. In this study, we conducted drilling operations under multiple machining conditions and analyzed the effects of machining conditions on GHG emissions. The relationship between environmental impact, economic cost, and productivity was also clarified. Machining was performed using high-speed steel, cemented carbide twist drills, and cemented carbide insert drills. In addition, two machining speed patterns, high speed and low speed were examined for the cemented carbide tools. We used inventory analysis methods for quantitatively evaluating CO₂ emissions. We also evaluated and clarified the relationship between CO₂ emissions, economic cost, and productivity for manufacturing 1,000 parts under each machining condition.

This study aims to investigate wettability influence on the motion of a rolling circular cylinder entering water. The movement of the rolling cylinder after the water-entry was taken with a high-speed camera. As a result, the asymmetry was observed in the splash and the cavity caused by the hydrophobic cylinder entering water. In particular, an intriguing phenomenon visualized is the fact that the wettability can affect the movement direction of the rolling cylinder, i.e., the rolling cylinder having a hydrophobic surface moves to the opposite direction to the hydrophilic cylinder within the present experimental conditions. This study also formulated an equation of motion (EOM) of the rolling circular cylinder, assuming that the drag direction acting on the cylinder deviates from the moving direction due to the asymmetry of the splash and the cavity. The EOM formulated in this study can be found to deduce the movements of the hydrophobic and hydrophilic cylinders.

Many kinds of refining processes are used in the steelmaking industry. Molten metal contained in the bath of the processes is strongly agitated by gas injection. Meal droplets are carried up into the upper molten slag layer due to the gas-lift effect. Each metal droplet falls and finally returns to the lower metal layer although it is captured for a while at the metal-slag interface due to the interfacial effect. The behavior of molten metals near the interface is closely associated with the refining efficiency and metal loss. The residence time at the interface was investigated in this study. An analytical equation was derived for the residence time and a water model study was carried out to validate the equation. Water and silicone oil were used for the models of molten metal and slag, respectively.

The Japanese firefly Luciola cruciata (Japanese name: Gennjibotaru) is one of the most popular fireflies in Japan. Strong and fantastic flashing light of the male firefly in summer night has historically attracted deep interest of Japanese people. The firefly can be commonly found in poems and novels written in Japanese. Unfortunately, the population of the Japanese fireflies is gradually declining due to some reasons such as the greenhouse effect and crop-spraying. In order to preserve the fireflies and grow their population we set up a biotope consisting of a brook and a pond in Hita city, Oita prefecture, Japan. The biotope was designed to resemble the traditional Japanese landscape called Satoyama. Of course, live snails Semisulcospira libertina (Japanese name: Kawanina) were initially supplied to feed the larval stage of the fireflies. The quality of water flowing in the biotope was carefully controlled. A change in the population of the fireflies in the biotope over 10 years and related information are reported in this technical note.

In a piezoelectric element having interdigital transducers (IDT), strain distribution occurs depending on presence or absence of electrodes on the surface when a voltage is applied to the electrodes. Accordingly, it is important to understand the distribution and the mechanism of its generation. In this paper, a non-contact measurement method of the strain distribution by the Digital Image Correlation (DIC) using the IDT pattern is proposed, where speckle patterns are not necessary to be painted on its surface. The effectiveness of the proposed method is evaluated by comparing the strain obtained by the DIC to the strain measured by strain gauges and a finite element analysis (FEA) applying sinusoidal voltage to the electrodes. The results show that they are in good agreement in global strain over the element even though they are less than 100μ strain. The amplitude of the local strain on the electrodes are significantly different from those on the bare piezoelectric parts. The waveform of the DIC strain on the electrodes is asymmetric between applying the positive and the negative voltage and in antiphase to the bare piezoelectric parts. The reason of such a behavior is discussed by using the FEA result.

Manipulation of oil droplets in O/W emulsion flow in bifurcating channel by externally applied electric field is experimentally attempted. The oil droplets in the O/W emulsion are charged with positive electricity in advance by adding cationic surfactant. Positive and negative electrodes are installed in both sides of the channel just before the bifurcating region to generate an electric field in spanwise direction. In the region where electric field is applied, positively charged oil droplets flow toward the negative electrode located in right-hand side of the channel. Oil droplets finally tend to be directed to the right-hand side branch at the bifurcation. Rate of number of oil droplets directed to the right-hand side branch increases with increase of the concentration of the cationic surfactant as long as the concentration is less than critical micelle concentration (CMC) of the cationic surfactant. When the concentration exceeds CMC, the rate keeps almost constant. This may because the surface of the droplet is fully covered by the surfactant when the concentration exceeds CMC.