The purpose of this study is to create solidified cultivating soil with a low environmental load, which can be used as a planting base material or cultivating soil. The solidification method adopted was cementation technology using calcium carbonate, chosen for its low environmental impact. The main materials used were woody materials derived from waste, such as coir, sawdust, and bamboo powder. The physicochemical properties of the obtained solidified cultivating soil were analyzed and compared with existing products. The results showed that, in terms of physical properties, the solidified cultivating soil did not exhibit significant differences in permeability and water retention compared to existing products. This indicates that the physical properties measured in this study are comparable to those of existing products. In term of chemical properties, the solidified cultivating soil had higher values for pH, EC (electrical conductivity), total nitrogen, and ammonia nitrogen compared to existing products, while showing a lower C/N ratio. These results appear to be due to the effects of calcium carbonate and ammonia generated during the cementation process. The findings suggest that the previously disadvantageous ammonia generation could potentially be converted into benefits, such as serving as a nitrogen source for plants and contributing to the reduction of the C/N ratio.

A direct tensile strength test was developed to determine the tensile strength and tensile stress-strain relationship of polymer concrete. Referring to previous studies of direct tensile tests on cement concrete, the test method was developed by focusing on the method of transmitting tensile force from the testing machine to the specimen and the shape of the specimen. As a method of transmitting tensile force, a cylindrical specimen was inserted into a cylindrical jig and fixed by tightening a nut on the tightening ring with a torque wrench. Secondary bending was reduced by placing spherical seats at both ends of all threaded rods in the cylindrical jig. The specimen shape was a dog-bone-shaped cylindrical with a narrower diameter at the test section. It was confirmed that the fracture zone could be guided into the test section and that strain could be measured well in the test section. The tensile strength of the polymer concrete measured by the developed direct tensile test method was almost consistent with the split tensile strength.

It is known that the bending strength of polymer concrete decreases with increasing the water content due to water penetration. Therefore, the structural performance of the polymer concrete product like a manhole under service condition should be evaluated considering time-dependent change in mechanical properties of the polymer concrete according to water ingress. This study experimentally clarifies how the compressive, tensile, bending strengths and stress-strain relationship of the polymer concrete subjected to water penetration changes over time by means of the systematic acceleration laboratory test. It was found that the time-dependent change of the water content and associated strength and stress-strain relationship of the polymer concrete specimens and can be numerically simulated by water penetration analysis based on a diffusion mode and the assumption of the correlation between the local water content and the mechanical properties.

A highly visible non-destructive evaluation method to monitor the progress of steel corrosion in concrete is strongly required. The purpose of this study is to propose an evaluation method using the electromagnetic field response, aiming to visualize the corrosion in a perspective view. At first, the detection mechanism of electromagnetic field response of fundamental notched patterns on the steel surface was considered. Second, an inverse problem analysis was performed. In detail, a visualizing method in the reverse direction that transforms the electromagnetic field response into a combination of magnetic changes of elementary waveforms of square-wave shaped surface and a reproducing method of the corrosion shape on 2-Dimensions by combining the elementary waveforms were proposed. The position and width of the defects, as well as the ratio of the depth of each defect, were well visualized.

Tensile tests were conducted with millimeter specimens in overall length using various metallic materials, steel, aluminum, titanium and solder, to clarify the size effect on mechanical and physical properties, for the purpose of evaluating strength distribution in trial products and small material samples. As the results, it is obvious that tensile strength and Young’s modulus do not have the size effect; however, fracture elongation has the size effect in some cases. Crystal orientation analysis of high tensile steel plate specimens show that strain by external force induce heterogeneous of crystal orientation and orienting to [101] direction to the tensile axis as preferred orientation. These crystalline changes arise easily in smaller specimen and cause the growth of elongation, and the fracture elongations obtained by small specimen are estimated by Oliver’s formula. In addition, the difference in tensile strength and fracture elongation of locations in die-casted material have been found out.

Quenching is used to obtain beneficial properties of steel products, but it often causes quenching deformation. To suppress this problem, it is important to clarify the influence factors and mechanism of the quenching distortion. In this study, for high hardenability steel, the effects of hardenability on quenching deformation were investigated. Carburizing-quenching deformation of cylindrical specimens of three hardenability steels were examined by experiments and simulations. As hardenability became high, the volume and the diameter of the specimen increased due to quenching. However, the change of the length is not monotonic function of the hardenability, and it has a local maximum value. It is deduced that the non-monotonic dependence of the length change on hardenability resulted from a competition between the increase of elongation by bainitic transformation plasticity and the increase of compressive plastic strain and martensitic transformation plasticity according to the improvement of hardenability.

This paper describes the design of water-cooling type heat sink to be used for an electron beam converter using additive manufacturing of copper alloy, CuCrZr, for the purpose of producing molybdemum-99 and Technetium from molybdemum-100 in a superconductive accelerator facility. One main challenge of this heat sink design is that all the solid part in the electron beam scanning region becomes the heat source. Therefore, this study focused on the design of heat conduction paths considering the manufacturability to convey the heat from the outer case, where the maximum temperature was observed, to inner cooling plates. The temperature-dependent thermal properties were measured as well as the density and mechanical properties. The unsteady-state heat conduction analysis, partially considering the uncertainty in the heat transfer coefficient, revealed that the heat conduction paths worked well to reduce the maximum temperature, and that the higher thermal conductivity with the increase of the temperature contributed to convey the heat effectively. The designed heat sink was successfully manufactured by laser powder bed fusion additive manufacturing. Self-supported circular holes in curved vertical walls for the assemblability with the main structure were manufactured without distortion.