This paper develops a theoretical model of material flow analysis (MFA) within the framework of the Waste Input–Output model (WIO) (Nakamura and Kondo). The model is developed based on two fundamental ingredients: yield ratios and the degree of fabrication. In manufacturing process, multiplication of physical inputs by the yield ratios gives the portion that enters physical outputs, with the rest being discarded as process waste without entering outputs. In input–output analysis, the degree of fabrication can be visualized as triangularity of the input coefficients matrix (goods of lower degree of fabrication can enter those of higher fabrication, but the reverse does not hold), which is known to emerge through an appropriate reordering of sectors. Application to the Japanese IO data indicates that the model can provide accurate estimates of the weight as well as the composition of metals (Fe, Cu, Pb, Zn, and Al) used in a passenger car. The model is also used to estimate the major final use categories (household consumption, public consumption, capital investment, inventory investment, and export) of metals.

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One of the gravest environmental problems facing us today is how to manage materials we use and produce as a result of the industrial development in the 20th century. The concept of ecomaterials was proposed with their full life-cycle taken into consideration in 1991 and has widely developed now. There have been many governmental activities for the creation of sustainable society in Japan such as enactments of environmental laws and regulations. Many Japanese enterprises have been also engaged in a lot of activities for environmental protection. Owing to their endeavour, ecomaterials in Japan have been developed and their number has increased yearly. The research was made on how ecomaterials are currently used in Japan. All the information was obtained from the Web-sites 2004 year version environmental reports of the organizations concerned. In this paper, ecomaterials produced by two hundred and sixty six listed companies on the stock market were researched and classified into six categories. About 3900 ecomaterials were found in the 2004 year version environmental reports of 266 companies researched, whereas the number of ecomaterials researched in the year 2001 was only 1898 in 286 companies and in the year 2003 about 3700 in 281 companies. This means the number of ecomaterials in Japan in the year 2003 nearly doubled compared to that of 2001 and increased further in 2004. It also indicates the realization on the part of Japanese companies of the importance of ecomaterials resulting in the advancement of related research activities. Higher materials efficiency products of user friendly, energy saving and high performance type, which are the results of years of engineering research and development are being promoted as newly improved and efficient products. It seems that the time is approaching when it is necessary to consider as a part of environmental problems the limited availability of natural resources and to promote a sustainable society from a broader perspective.

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In order to verify the effectiveness of the “Ecological Rucksack” as an indicator on resource utilization for electrical and electronic equipments, the Ecological Rucksack of 36-inch high-definition TVs produced in 1993 and 2003 has been estimated in cooperation with the Wuppertal Institute in Germany. The Ecological Rucksack (abiotic material) of the 1993 product was 19 tons (product mass 91.0 kg) and that of the 2003 product was 7.7 tons (product mass 79.5 kg), therefore, an approximate 11 tons or 60% reduction. The breakdown of the Ecological Rucksack (abiotic material) of the 1993 product indicated that the values associated with the print circuit board mounted inc. electronic components (hereafter called PC board) represented approximately 50% of the total, followed by power consumption during use at 40%. The PC board represented less than 10% of the product mass but occupied approx 50% of the Ecological Rucksack (abiotic material). The smaller and lighter PC boards employed in the later product substantially contributed to the reduction of Ecological Rucksack. As evident in the example of the PC board, the consideration of Ecological Rucksack reveals the hidden material flow and presents a new approach to resource utilization.
However as for the materials used over the life cycle of a high-definition TV set, the factors obtainable from the MI factors table represented only 25% of the product mass. By applying the MI factors of materials with equivalent properties, the rate of MI factors increased to 99% of the product mass, thereby enabling an estimation of the Ecological Rucksack for a TV set. The estimation made this time around underlined the fact that further examination of the data was required for the PC board, because it would strongly affect the evaluation results for determining the Ecological Rucksack of a high-definition TV set. Further enhancement of the database is therefore required for enabling applications to electric and electronic equipment.

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Super environment-conscious intelligent composite materials incorporated with life-cycle program of self-repair during in service and self-collapse after designed service life are proposed. One example is carbon short-cut fiber reinforced composites (CFRC) incorporated into matrix mortar with numerous two kinds of micro capsules imbedded with two smaller capsules containing nanometer-size reacting particle (calcium oxide (CaO) or cement) and initiating one (highly water-containing resin particle). These double capsules are incorporated during mixing mortar and fiber as chemical admixture, but they are stably dispersed, not breaking during in service of composites. By triggering these double capsules by external electromagnetic wave having two different frequencies, these capsules are broken, and chemical reaction occurs. As the results, self-repair is made to occur in the crack part during in service by the rather mild hydration reaction of cement, and self-collapse after designed service life by the rapid expansive hydration reaction of CaO. These cement composites are intelligent due to the appropriate response to the controlled external electromagnetic trigger, and environment-friendly due to the elongation of service life by self-repair, and the easiness of demolition and recycling by self-collapse. The same concept is also applied to carbon continuous fiber reinforced plastic reinforced concrete (CFRPRC). Other than double microcapsules, glass optical fibers are also imbedded into matrix resin of FRP. By detecting the change of electric resistance of CFRP, we can predict the collapse. By triggering the embedded double capsules, self-repair and self-collapse are made to occur. These pseudo-biological functions of self-repair and self-collapse are also incorporated into base concrete. These CFRPRC are enough to become intelligent and environment-friendly. By using well designed these super environment-conscious intelligent composites, I try to realize environment-conscious interior planning in which non-adhesive, but joint or set-in type interior construction are considered.

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Using fine metal powders, we were able to fabricate dense P/M (powder metallurgy) products by a three-dimensional inkjet printing system. We used carbonyl nickel powder with a mean particle size of 5 μm as a raw material and examined two binder supply methods: (i) supplying a binder directly from the inkjet head (DB method), and (ii) coating the powder with a water-soluble polymer and then supplying thin polymer-dissolved water from the inkjet head (CB method). The layered green product was sintered in a hydrogen atmosphere at a temperature in the range of 1073–1623 K. Sintered samples fabricated by the CB method had non-uniform microstructure due to agglomeration of the coated powder. In samples made by the DB method, the macroscopic shape was retained after high-temperature sintering at 1623 K, and a high density of over 90% was achieved, which was attributed to uniform powder cohesion in the laminating process.

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Model experiments were performed for fabricating composite materials using Al scrap and waste glasses. Significance of the fabrication using the waste matters was discussed from an environmental point of view. Al alloy having composition of the Al scrap was melted and infiltrated into a soda-lime glass beads’ bed by a vacuum process. Reaction layer was formed at the interface between the glass beads and the molten Al alloy. The layer thickness of 50 microns was obtained after 1 h reaction. The composite materials showed a strong bonding between the filler (the glass particles) and the matrix. Variation of the layer thickness was measured at various conditions of the reaction time and temperature.
Distribution of the metal elements in the microstructure of the composite material was analyzed with SEM/EDX. It was shown that not only Si but also some elements were removed from the glass to the Al alloy matrix. Behaviors of the other elements were discussed, considering the thermodynamics. Compression test of the composite materials was performed. They fractured in a brittle manner once, however, after the fracture, they were not broken into pieces, but followed by the ductile deformation.

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Innovative reuse process of rice husks (RH), being one of the representative agricultural wastes, has been developed to fabricate magnesium composites by solid-state reaction to form magnesium silicide (Mg₂Si) reinforcements, having high hardness and Young’s modulus. From a view point of the biomass energy, rice husks, including about 70 mass% organics, could be effectively used as environmentally benign fuels to supply electric power or biomass ethanol. Considering that the most of the rice husk wastes after absorbing organics is SiO₂, the solid-state synthesis of Mg₂Si compounds by reaction of SiO₂ with magnesium was suggested in this study. First of all, the effect of the acid washing treatment to remove organics of rice husks on the crystallization of amorphous SiO₂ was evaluated by TG-DTA and XRD analysis. The carbon content of 0.05% in the wastes was drastically reduced by using acid-washed rice husks, compared to that of non acid-washed ones (0.19%). When employing the wastes with and without the acid washing treatment, the crystallization temperature is about 1273 and 1073 K, respectively. The latter showed the lower crystallization temperature because the reaction of the alkaline contents, such as K, P, and Ca, with SiO₂ during heating caused to decrease the SiO₂ melting point. Rice husk wastes burned at 1273 K after the acid treatment was mixed with AZ31 magnesium alloy powder to fabricate the magnesium composites including Mg₂Si dispersoids. Microscope observation and XRD analysis indicated that the amorphous SiO₂ included the wastes was more effective to promote Mg₂Si formation.

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Solid-state recycling for runner scraps of Mg–Al–Ca alloy was carried out by extrusion at 673 K and mechanical properties of the recycled Mg alloy were investigated by tensile tests. At room temperature, the recycled specimen showed a good combination of high ultimate tensile strength (348 MPa), high 0.2% proof stress (305 MPa) and large elongation (9%). Additionally, the recycled specimen exhibited superplastic behavior at 573 and 673 K. The excellent mechanical properties of the recycled specimen result most likely from fine dispersion of precipitates which is attained by hot extrusion.

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In this work, the mechanical properties of roll-cast recycled aluminum alloy were investigated. Fe was added to 6111 aluminum alloy to simulate recycled aluminum alloy. The Fe content was varied between 0.14 and 1.02 mass%. A high-speed twin roll caster was used because it exhibits better cooling characteristics than the conventional twin roll casters. The strip was cast at a speed of 60 m/min and the resulting strip microstructure was not columnar, but equiaxed or globular. When the Fe content was 0.4 mass%, the Fe content does not appear to exert any influence on the tension test results after T6 heat treatment, and after a 180-degree bending test no cracks occurred on the outer surface.

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Thin strips of the 6063 aluminum alloy and the alloys with increased nominal Fe contents (0.7–6 mass%Fe) were fabricated directly from the molten alloys using a vertical-type high speed twin-roll strip caster equipped with a pair of water-cooled pure copper rolls. The estimated cooling rates from the DAS measurement were about 4500 and 100°C/s at the near the surface region and the mid-thickness region of the strip respectively. Refinement of Al–Fe–Si intermetallic compound particles was also successfully achieved, however, segregated coarse particles were also observed at the mid-thickness region. The cast strips were cold-rolled and heat-treated to form 0.5 mm-thick thin sheets. They were either naturally aged at room temperature (T4) or artificially aged (T6), and then subjected to bending, tensile and hardness tests. No detrimental effect of Fe was appeared concerning the bendability even in the alloy containing 3 mass%Fe. No cracking took place even in the 180° bending (hemming) test. The reduction of age-hardenability was evident for the alloy with 1 mass%Fe and more. The alloy sheet containing 0.7 mass%Fe exhibited not only a good bendability in the T4 condition but also the larger proof stress and UTS than those of the master alloy in the T6 condition. This means that the capacity of Fe impurity in a 6063 alloy (0.35 mass% according to JIS) can be doubled by using the present roll caster. Strip casting at a high cooling rate using the present roll caster is considered to be a promising method for reducing the detrimental effect of impurity iron from the scrap melt.

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Although the cascade of material flow is presently suitable for the aluminum recycling, a better utilization of secondary alloys is required. In order to establish an upgradeable recycling design for developing wrought products from secondary aluminum alloys, a fine distribution of the primary phases in hyper-eutectic Al–Si–Fe–Mn cast materials has been achieved. Two novel processes were adopted. One was repeated thermomechanical treatment (RTMT), which involves a repetition of a multi-step cold-working followed by heat treatment. The other was rapid solidification by high-speed twin-roll casting to develop a fine solidification structure in a thin sheet. By applying these processes, refined microstructures were successfully obtained. Microstructural refinement by RTMT resulted in the avoidance of early fracture that was detected in the cast material by a tensile test. The RTMT imparted good ductility; therefore, it was possible to allow greater flexibility in the cold working of Al–Si–Fe–Mn cast materials.

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Tensile and high-cycle fatigue behavior of thermomechanical treated hyper-eutectic Al–Si–(Fe,Mn,Cu) materials were studied. Through the repeated thermomechanical treatment (RTMT) which is a repeat of the multi steps cold-working followed by heat treatment, Si crystals and/or intermetallic compounds were broken into some fragments and dispersed in the aluminum matrix. Fine dispersion of the second phase particles exhibited good ductility, since early fracture was overcome. A few large Si crystals or aggregates of compounds, however, gave an origin of fatigue crack generation. Since microcrack linkage generates a larger fetal crack, not only refinement but also random distribution of second particles may be required to improve fatigue strength at and below room temperature. At higher temperature, on the other hand, dynamic recovery may cause apparent strain rate dependence on flow curves.

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Porous aluminum with a porosity of 78% and pore size of 850–1000 μm was fabricated under various sintering pressure, sintering time and raw Al powder size conditions by the spacer method consisting of spark plasma sintering (SPS) and sodium chloride (NaCl) dissolution. The effects of the fabrication conditions on compressive properties of the porous Al were investigated. The sintering pressure of 20 MPa and sintering time of 10 min were needed to fabricate robust porous Al under the sintering temperature of 843 K and raw Al powder size of 3 μm. Also, the porous Al specimen fabricated from Al powder of 300 μm exhibited much lower flow stress than those fabricated from Al powder of 3 and 20 μm when employing the temperature of 843 K, the pressure of 20 MPa and the duration time of 10 min. This indicates that the raw Al powder size is needed to be much smaller than the spacer size. This is because the Al particle cannot touch with adjacent Al particles when the Al powder size is comparable to the spacer size.

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The catalytic activities of propylene oxidation on different aluminum silicates with the mayenite structure [Ca₁₂Al_14−xSi_xO_33+0.5x (x=0,4)] formed at 500, 800 and 1000°C were investigated. The aluminum silicates were prepared by the hydrothermal and solid-state reactions of a stoichiometric mixture of calcium oxide, alumina sol and silica. The XRD results of the aluminum silicates obtained by the solid-state reaction showed that the peak intensities of the mayenite phases became larger as the calcination temperature increased. The aluminum silicates included two kinds of active oxygen species (O₂²⁻, O₂⁻) related to Raman shifts around 887 and 1092 cm⁻¹, respectively. As a result, the aluminum silicates exhibited oxidation activities based on the easily reducible active oxygen species. Notably, the Ca₁₂Al₁₀Si₄O₃₅ calcined at 1000°C without the hydrothermal treatment showed the highest activity of all catalysts, indicating that the crystal structures play an important role in determining the catalytic activity.

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The crushing behaviour and energy absorption of foam filled aluminium tubular structures were investigated using the quasi-static compressive tests. The crushing behaviour of the tubular structures changed due to foam filling. The energy absorption of the foam filled tubular structures was improved significantly. Foam filling caused an interaction effect between the tube and the foam during progressive crushing, leading to an increase in the mean crushing load compared to that of the foam or tube itself. This interaction effect might be affected by several parameters such as the density of the foam, the properties of both the foam material and tube material, and the thickness and outer diameter of the tube. In particular, the interaction effect essentially depended on the ratio of the mean crushing force of the foam to that of the tube.

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Deformation mechanism of the recycled aluminum alloy by solid state recycling at elevated temperature was investigated. Elongation of the recycled specimen did not decrease when deformation mechanism was other than grain boundary sliding. Harmful effect of contaminations is negligible when deformation mechanism is related to dislocation activity in grains.

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It is important to develop an effective sorting system of aluminum to reduce the cascade recycling of aluminum scraps by instead returning the scraps to wrought aluminum. A feasibility study has been conducted to develop a new sorting process of aluminum scraps. In this study, irradiation of an aluminum surface by pulsed Nd:YAG laser and an automatic sorting method by a pattern-matching method were tested to identify the alloy number of aluminum scraps. For sorting test samples, seven aluminum alloys (1050, 2024, 3003, 4343, 5052, 6063, 7075) were selected from seven wrought aluminum alloy series. The surface of the aluminum irradiated and melted by a YAG laser beam. The surface morphology, including the molten area, brightness profile and change in color, was observed after irradiation. There was a difference in the surface morphology among the aluminum alloys after irradiation. The effect of laser irradiation conditions such as the defocus distance, input energy and laser irradiation angle on the surface morphology after irradiation was investigated to establish the appropriate conditions of laser irradiation for sorting aluminum alloys. It was clear that the surface morphology of aluminum seems to depend on physical properties such as thermal conductivity and liquidus temperature. Therefore, it seems possible to establish an automated aluminum sorting method by using the pattern matching method on irradiated aluminum samples.

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The dispersion and fluidity of aqueous platelet γ-alumina slurries were enhanced by addition of ammonium polyacrylate (PAA) as a dispersant at pH 10. Magnesia powder was mixed with the slurries using a planetary mixer for 150 s after ball milling of the slurries for 24 h. Magnesia was eluted gradually into the aqueous media by formation of a chelate with PAA. The slurries were solidified by PAA deficiency because of reduction of the electrostatic repulsive force between the alumina particles. The degree of shrinkage of the green body on drying was very small, and this was therefore regarded as a near-net-shaping process. A porosity of about 60% and strength of 45 MPa were obtained in bodies fired at 1300°C and the mean pore diameter was 0.6 μm.

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The effects of seeding on synthesis of MCM-22 (MWW) have been studied by the dry gel conversion (DGC) method. Highly reproducible crystalline MWW zeolite could be obtained by DGC method, using seeds of calcined sodium MWW with SiO₂/Al₂O₃=31. Crystallization of MWW phase was completed in the presence of seeds (2 mass% against SiO₂) at 150°C within two days. The small amount of seed (0.25 mass% against SiO₂) was sufficient for the required phase formation of MWW. The MWW with SiO₂/Al₂O₃ ratio from 35 to 66 was obtained as pure phase; however, the crystallinity of MWW decreased with further increase in the ratio: products were contaminated with impurities.
The catalytic properties of MWW were examined in the skeleton isomerization and the cracking of hexane, and compared to zeolites such as BEA, MFI, and MOR. The catalytic activities were in the order: MFI>BEA>MWW>>MOR; however, the selectivity for the isomerization were in the order: BEA>MWW>MFI. These catalytic properties were due to the differences of structures and acid strength of zeolites.

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Zincoaluminophosphates, ZnAPO-5 and ZnAPO-36 with AFI and ATS topologies, were successfully synthesized by dry-gel conversion (DGC) method: vapor-phase transport (VPT) and steam-assisted conversion (SAC) methods. ZnAPO-5 was synthesized successfully at 175°C by VPT and SAC methods using Et₃N as structure directing agent (SDA). ZnAPO-36 was also obtained by VPT and SAC methods using Pr₃N as SDA. The heating protocol was a key factor for the crystallization in the synthesis of ZnAPO-36: the best result was obtained by heating at 140°C for 1 d after aging of the gel at 105°C for 2 d. Calcination procedure is important to get microporous molecular sieves. ZnAPO-5 by VPT method calcined at 550°C gave clear XRD with high microporosity. Highly microporous ZnAPO-36 by VPT method was obtained by careful calcination. Characterization of these zincoaluminophosphates was performed by XRD, NH₃-TPD, TG, SEM, N₂ adsorption, and ICP analysis. ZnAPO-5 and ZnAPO-36 have the Brønsted acidic characters by the substitution of a part of aluminum with zinc.
The isopropylation of biphenyl (BP) over these molecular sieves gave different level of the selectivities for 4,4′-DIPB: 60–75% for ZnAPO-5 and 35–45% for ZnAPO-36: these selectivities are in the similar level to corresponding magnesioaluminophosphates corresponding magnesioaluminophosphates. These differences of ZnAPO-5 and ZnAPO-36 in the selectivity are due to the pore structure: ZnAPO-5 has one-dimensional straight channel; however, ZnAPO-36 has one-dimensional channel with side pocket. The steric restriction by ZnAPO-5 effectively controls the transition state to differentiate the slim isomers from others; however, pores of ZnAPO-36 cannot differentiate effectively the isomers because of their side pockets.

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Poly(L-lactic acid) (PLLA) was blended with poly(ε-caprolactone) (PCL) using a single-screw extruder in order to modify poor characteristic of these polymers. When the polymer was blended, the block copolymer that is synthesized by methyl acrylate (MA) and ε-caprolactone (ε-CL) via an atom transfer radical polymerization was used as a novel compatibilizer. The structure of the synthesized compatibilizer is determined by ¹H or ¹³C NMR. From this result, it was found that the ring-opening polymerization of the ε-CL was taken place in the hydroxyl end group of MA. Moreover, the morphologies of the PLLA/PCL solvent-cast blend films were observed by the optical microscope and SEM. From the optical microscopic observation, the morphologies of the solvent-cast blend films with the synthes