In this exposition, climate change is discussed from the environmental point of view. Definition of climate change and variation, climate change in earth's history, possible mechanism of the change and recent studies of theoretical approaches are introduced. More precise observation and identification of related values and information, for example, solar constants, albedo and material circulations, are quite important factors for the future studies on the climate change as complicated natural phenomena.
Climate variations significantly affect agriculture through complicated mechanisms. Therefore, agriculture is expected to be especially vulnerable to climate changes. The impacts of climatic warming on agriculture productions are: (1) the direct effects of increased atmospheric CO2 concentration on crop and weed, (2) the indirect effects of climate change on crop, weed, and pests, and (3) the effects of sea level rise on farmland at a low altitude. Thus, in agriculture sector, there are many complex interactions among the related factors. Experimental results, detailed modeling of basic processes, and knowledge of physical and biological processes provide a basic understanding of the direct and indirect effects of climate warming on agricultural production. Experimental results in growth chamber and temperature gradient tunnel are (1) grain yield of rice is generally promoted by high CO2, (2) yields increase 30% or more with doubled CO2 in the absence of other limiting factors, and (3) rice spikelets have the highest sensitivity to high temperature at anthesis (flowering), and are liable to be sterile due to a failure in pollination, when the flowering temperature is approximately 35°C. Crop models with climate change scenarios projected by general circulation models predicted the yield changes of crops: (1) rice yield is expected to increase in northern Japan, but decrease in western Japan, (2) the yield variability would decreases in northern and north-central Japan, but increase in south-central and south-western Japan, (3) maize yield is expected to increase in Hokkaido, but change little in central Japan, and decrease in southwestern Japan, and (4) wheat yield would decrease at all sites.
Hydrogen absorbing alloys have a number of useful functions, such as an energy conversion. As an application to refrigeration, a new MH-refrigeration system for a freezing compartment by using a hydrogen absorbing alloy has been developed. The MH-refrigeration system is able to attain the temperature of the freezing compartment below -30°C. And as an application to separation and purification of hydrogen, MH-hydrogen purification system for generator cooling has been developed. MH-hydrogen purification system is expected to decrease the generator's windage loss, resulting higher generator efficiency.
Battery development for EV application is quite different from that of consumer battery. In particular, temperature conditions affect battery performances like a cycle life or an energy efficiency remarkably in accordance with a heat generation due to batteries themselves. Accordingly, heat management technologies including the development of battery materials, the structural design of battery module or pack, and the installing system are strongly demanded. The heat behavior of Ni-MH batteries during charge and discharge processes was analyzed and discussed. Heat elements were basically divided to four types of factors corresponding to a battery reaction heat: Qr, a polarization heat: Qp, a sub reaction heat: Qs and a joule heat: Qj. To minimize the Qs by introducing an undercharge or a minimum overcharge is effective in order to reduce a heat generation and to increase an energy efficiency during a charge process. And a control technology of oxygen generation from positive electrodes due to a sub reaction of water decomposition is imperative. As an internal resistance of battery dominates a heat generation relating a joule heat and a polarization heat at charge and discharge processes. Eventually, both the material development and the control technology like a charge algorithm should be considered to suppress the total heat generation.
The minimization of environmental load as well as the most efficient use of energy and other resources are necessary for sustainable development, because the capacity of earth is finite. “Ecomaterials” was proposed as a key concept for material technology which would harmonize with the environment or minimize environmental load. This paper describes the concept and present research activities of the “ecomaterials”.
The progress of science and technology(S & T) is inducing tremendous changes in our perception to values. This is yielding new issues which may never been solved with conventional way of S & T. This fact should seriously be taken into account in educational and research institutes. This paper discusses the paradigm shift of S & T, and points out the necessity of the incorporation of uncertain factors like sense of values of people into the S & T paradigm. A new concept, ECO (Environment Conscious) TECHNOLOGY towards the global and human securities is suggested.