Global warming caused by excess emission of greenhouse gases such as carbon dioxide (CO₂)， methane (CH₄)， and dinitrogen monoxide (N₂O) induces severe climate change over the world． The ecology of animals and plants are significantly influenced by the climate change． According to International Union for Conservation of Nature and Natural Resources (IUCN)， more than 44000 kinds of animals and plants are endangered at the present stage． Various types of methods have been proposed to reduce greenhouse gas emission and to remove greenhouse gases contained in the atmosphere． One of effective methods is to use renewable energies instead of fossil fuels such as coal， fuel oil， and natural gas． There are seven types of renewable energy source: (1) solar power， (2) wind power， (3) hydroelectric power， (4) geothermal power， (5) solar thermal power， (6) heat from the atmosphere and other natural sources， and (7) biomass (organic matter derived from animals and plants)． The wind power mentioned in this review article is transformed into electrical energy by using wind turbines． Unfortunately， birds often collide at the wind turbine equipment． Current situation of this kind of bird collision is explained here in this review article in detail．

Shape memory alloy (SMA) heat engines work with low-grade heat such as hot water, thus they might be promising systems for energy harvesting. In this article, we review current state of SMA heat engines and subjects for their development.

Japanese agriculture faces challenges such as an aging population and an increase in abandoned farmland. Increasing agricultural income is necessary. To combat climate change, Japan will increase renewable energy to 38%. As a result, agricultural solar power generation is attracting attention. This article explains the installation and operation of agricultural solar power generation, technical research, social perspectives, and future prospects.

Currently, the food industry continues to see growth in liquid products containing ingredients. This is difficult to achieve in continuous production with conventional automatic liquid filling and packaging machines. Furthermore, the food manufacturing industry is strongly demanding labor-saving measures and high efficiency due to labor shortages. To resolve these issues, we will develop automatic filling packaging machines and related technologies.

The CO₂ facilitated transport membranes we are developing require virtually no energy compared to conventional CO₂ separation technologies and occupy a significantly smaller footprint (approximately one-tenth). In an effort to further increase the membrane area per unit volume beyond that of previously developed spiral-type modules, we explored the development of both hollow fiber modules and flat-membrane stack modules. Additionally, to reduce membrane production costs, the feasibility of adopting new substrate materials was investigated. As a result, although hollow fibers coated with a gel membrane on their outer surfaces exhibited membrane performance comparable to that of flat membranes, coating the inner surfaces proved to be technically unfeasible. Conversely, in the case of flat-membrane stack units, it was found that the flow configuration of the feed and sweep gases significantly influenced membrane performance, similar to heat exchangers. Among the tested configurations, the crossflow arrangement yielded the highest membrane performance. Furthermore, when the membrane substrate was replaced from PTFE to paper, all gas permeances decreased with increasing humidification, suggesting that the paper substrates responded differently to moisture compared to conventional PTFE substrates.

In order to reduce CO₂ emissions, the utilization of Al scrap is strongly required. Currently, Al scrap is mainly recycled into cast Al alloys. Because Si contents of wrought Al alloys are much lower than Al cast alloys, Si removal is desired for recycling Al scrap into wrought alloys. However, Si is difficult to remove by current pyrometallurgical processes once it dissolves in molten Al. This work proposed Si removal from molten Al-Mg alloy through the precipitation of Mg₂Si inter-metallic compound. Molten Al-Mg alloy was equilibrated with Mg₂Si at 823 and 873 K, and the reduction limit of Si concentration was thermodynamically discussed. The Si concentration of Al-Mg alloy varied from 0.14 to 1.3 mass% at 823 and 873 K. The precipitation of Mg₂Si was enhanced by increasing Mg concentration in the Al alloy due to the increase in the activity of Mg, although the activity coefficient of Si was decreased. The concentration dependency of the activity coefficient of Si was obtained as a function of temperature and mole fraction of Mg as follows: ln γ _{(l, in Al-Mg)} = ( – 0.459 x_Mg² – 2.22 x_Mg – 2.24)

In industrial manufacturing processes, there is an increasing demand for equipment that can clean precision surfaces using high-speed air jets. When cleaning film, unstable vibration caused by the jet can be a problem. In this study, we investigated a method for stabilizing film vibration by using a porous material as the wall surface around the jet nozzle, through experiments and numerical simulations. We created an experimental device with the same specifications as the actual device, varied the pressure applied to the porous material, and measured the film vibration with a laser displacement meter. As a result, we observed a tendency for the vibration displacement and amplitude to decrease with increasing airflow velocity from the porous material. Next, we conducted numerical simulations of the flow field near the film surface and the restoring force acting on the film using a jet with a higher velocity than that of the actual device. When the film was subjected to both uniform and localized displacements, we found that the porous material wall tended to have a greater restoring force against unstable vibration than a rigid wall. Although the airflow velocity from the porous material was only a few percent of that of the jet, we demonstrated the possibility of stabilizing film behavior.

Fine bubbles (FBs; <100 µm) were introduced into bio diesel fuel (BDF) and low-sulfur A heavy oil (LSA) to investigate their effects on combustion and emissions in a high speed diesel engine operating at 2000 rpm under partial load. FB addition led to injection delay due to partial consumption of injection energy by FB compression. However, improved fuel atomization and mixture formation were observed, especially under high-load conditions. As a result, the brake specific fuel consumption decreased by up to 6.3 % for BDF and 5.3 % for LSA, with load-weighted average reductions of 4.2 % and 4.2 %, respectively. Simultaneously, brake specific NOₓ emissions were reduced by maxima of 10.2 % for BDF and 18.1 % for LSA, with load-weighted average reductions of 7.6 % and 9.6 %. Heat release analysis showed a flatter profile for BDF-FB, indicating more complete late-stage combustion, whereas LSA-FB exhibited a sharper peak due to lower viscosity and more uniform FB size. These results suggest that FB application enhances combustion efficiency and reduces emissions, with fuel-specific mechanisms depending on physical properties such as viscosity and oxygen content. FB technology is thus a promising method for improving performance in existing diesel engines.