In this paper we examine the product induced material flows through the product manufacturing system. Research strategies to reduce materials related environmental loads based upon this examination are suggested.
Fossil fuels (i.e., petroleum, natural gas and coal), which meet most of the world energy demand today, are being depleted fast. Also, their combustion products are causing the global problems, such as the greenhouse effect, ozone layer depletion, acid rains and pollution, which we are posing great danger for our environment and eventually for the life in our planet. Many engineers and scientists agree that the solution to these global problems would be to replace the existing fossil fuel system by the Hydrogen Energy System. Hydrogen is a very efficient and clean fuel. Its combustion will produce no greenhouse gases, no ozone layer depleting chemicals, little or no acid rain ingredients and pollution. Hydrogen, produced from renewable energy (e.g., solar) sources, would result in a permanent energy system, which we shall never have to change. However, there are other energy systems proposed for the post-petroleum era, such as a synthetic fossil fuel system. In this system, synthetic gasoline and synthetic natural gas will be produced using abundant deposits of coal. In a way, this will ensure the continuation of the present fossil fuel system. The two possible energy systems for the post-fossil fuel era (i.e., the solar hydrogen energy system and the synthetic fossil fuel system) are compared with the present fossil fuel system by taking into consideration production costs, environmental damages and utilization efficiencies. The results indicate that the solar hydrogen energy system is the best energy system to ascertain a sustainable future.
The development of sustainable products requires the consistent modelling of ecological, economic, and social aspects along the Life Cycle of the product A Life Cycle Sustainability methodology and database has been developed. It integrates the new Life Cycle Working Time approach for the most important work-related social issues like qualified working time, accidents, child work, working environment conditions, woman work etc. into the established Life Cycle Engineering methodology of IKP and the respective Software System GaBi. Focus of the approach is to provide reliable decision support while at the same time securing its applicability in practice through caring for data availability, international comparability, process-relatedness and other criteria. The methodology is presently applied in practice in an ongoing international project developing sustainable, biosource based foam products.
This paper described an estimation of inventory data of advanced composite materials. Inventory analysis, especially about energy consumption of production and recycling processes of carbon fiber reinforced plastics(CFRP) was mentioned. In production process, data of energy consumption in various molding processes were calculated and compared with the data of production of carbon fiber and prepreg. Amount of energy required in production of carbon fiber is much larger than other processes and it was proved that it is most important process for improvement. In recycling process, data of material recycling and thermal recycling were estimated. Since energy needed in material recycling is much smaller than that of production process, the validity of material recycling was shown.
New recycling process of chlorine component in polyvinyl chloride was proposed. Hydrogen chloride, evolved from polyvinyl chloride by heating at 533K, was conducted into metal oxides at 573K to form the corresponding metal chloride. The metal chlorides were then regenerated to metal oxides and chlorine gas by introducing oxygen gas at 673K. Among the metal oxides studied, cobalt oxide was the most effective both for the fixation and release of chlorine components. More than 60% of chlorine ions in PVC was recovered as chlorine gas even after 50 times of the iterative uses.
Crosslinked polyethylene (XLPE) is used for power supply electric wires and cables: its superior electrical characteristics and thermostability are fine. But, the XLPE has a tridimensional closslinked structure, which can hardly be delinked to be re-formable material. Round 40% of the waste XLPE is thermally recycled, but the remainder is burnt out or landfilled. We searched out appropriate conditions of heat and shear for XLPE, thereby turning waste XLPE to re-formable polyethylene. This recycled material displays desirable characteristics, namely, more or less 1% of gel content, melt mass-flow rate (MFR) 0.1-30g/10min at 190C. Notably, it turns out that the recycled material is slightly wider in molecular weight distribution than and the same in short chain branch as polyethylene.
The most common methods of processing natural fibers have been tested in the production of glass-fiber reinforced polymers. This can result in problems due to inadequately adapted process parameters. Therefore the effect of production and treatment of fibers and semi-finished products like hybrid nonwovens and the process parameters on the properties of the part produced were studied. The material technology is available for using natural fibers as reinforcing agents, however, only a few effective products exist. The fiber/matrix interface is of great significance for the quality of the composite material. It can be characterized by means of the IR-spectroscopy, the scanning electron microscopy and by the determination of the mechanical properties. The fiber/matrix interaction can be improved significantly if the natural fibers are purified and alkalized, coupling agents are applied and the manufacturing process of the system natural fiber/thermoplastics is optimized.
This study is concerned with the development and application of a specific asphalt mixture which can be reused by recycling as many times as requested by heating. This mixture is a joint material for road repair works used by impregnation. It comprises short cut and fine fiber, flake-shaped inorganic powder and rubber or resin together with asphalt at optimum ratios, carrying high initial strength and high impact strength, still keeping high fluidity at elevated temperatures. This report describes the properties of the mixture and its applications to road repair works.
The water vapor explosion (WVE) process that was developed in this study is used to separate wood materials into small wood elements. The WVE process was directly applied to the separation of Sugi (Cryptomeria Japonica) and Karamatsu (Laryx leptolepis) in the forms of sawn timbers and slabs. In this process, wood materials were exploded from within by the force of water vapor generated by compression under high pressure and temperature and evaporation of the internal moisture. For the WVE of wood materials, appropriate conditions (pressure, temperature, and time) were required. By WVE of Sugi and Karamatsu sawn timbers with the moisture content (MC) of air-dried (MC=10-20%) condition, mainly strands and chips were obtained. WVE of Sugi sawn timbers and slabs adjusted to 100-200% MC (water-soaked) also produced fiber bundles that were long, narrow, and flexible.
“The steam extraction of essential oil and compressive molding of woody resources by high-pressure steam” had been developed in our laboratory. Using this technique, we obtained essential oil and biomass boards from wood residue. In this paper, the mechanical properties of the boards fabricated under various steam conditions were investigated.
The compressive molding process using high-pressure saturated steam has been developed in our laboratory and is used to produce biomass boards without any adhesives. Through this compressive molding process, essential oil was attempted to obtain by the high-pressure steam distillation from woody resources. In this study, sawdust from western red cedar (Thuja plicata) was used as the raw material. The yields of essential oil were compared with different extraction methods. The yields of the essential oil were increased with steam pressure and were much higher than other extraction method. Each essential oil obtained from different steam conditions mainly contained thujic acid, β-thujaplicin, furfural, and 5-hydroxymethyl-2-furfural. Especially the tropolone group mainly including β-thujaplicin was isolated by chelating with copper ion.
The disposal of Municipal Solid Waste incineration residue (MSW ashes) is in very critical condition due to the tightness of landfill spaces in Japan. As relieves to this predicament, many technologies have been developed to prolong the lifetime of landfill spaces. Ecocement system and Ash rinsing system, typical of those technologies, were developed to utilize as a raw material of cement. Understanding the characteristics of MSW ashes is very important to maintain the quality of cement and to control the cement manufacturing process. In this study, a variety of MSW ashes were analyzed for the peurpos of promoting their utilization as an alternative cement raw material. These analyses were carried out for 237 samples of MSW ashes collected from 142 incineration facilities in Japan. As a result, although principal chemical compositions of MSW ashes vary due to which type of incineration process they came from, they can be used as a cement raw material in all cases. Fly ash with higher compressibility requires bridging prevention measures. Making a best use of these results, Ecocement system and Ash rinsing system were established and started operation.
Incinerated ashes of sewage treatment sludge contain significant amount of phosphorus. Phosphorus is a very important material, and studies on phosphorus recovering technology are going under way. However, the phosphorus recovered from this sludge is mainly composed of aluminum phosphate. To promote the utilization of aluminum phosphate, zeolite formation process was studied. On the run 1, phosphorus recovered from incinerated ash of sewage treatment sludge by using H2SO4 and NaHCO3 was treated with NaOH, which dissolves aluminum phosphate and extracted aluminum phosphate reacted with aqueous sodium silicate solution to form zeolite. In this reaction, zeolite was recovered by freezing treatment followed by recovering of Na3PO4 by vaporization. On the run 2, phosphorus recovered by using of sulfuric acid and calcium carbonate was treated with NaOH in the same way as run 1. Aluminum phosphate reacted with calcium sulfate by alkalization formed calcium phosphate. Phosphorus free aluminum reacted with sodium silicate to form zeolite, and Na2SO4. Recovered zeolite showed the methylene blue adsorption capacity of 90mg (methylene blue)/g.
Rubber is a useful material but used rubber has disposal problems and continues to accumulate all over the world. In particular, wiper blade rubber is high quality natural rubber. We investigated the use of recycled wiper blade rubber for vibration isolator and noise absorbing materials. Wiper blade rubbers were cut or crushed to small sizes and molded. Dynamic and static properties as well as the noise absorption coefficient of recycled materials were measured. We found which cut or crushed size is better for vibration isolator and noise absorbing materials. We developed a method of wiper blade rubber recycling.
Steel as one of the most traditional materials is the target of NIMS (National Institute for Materials Science, Japan) project. The usage of steel is various and abundant. Even a small amount of a decrease in environmental load related to steel service makes a significant progress in the global. Doubled strength and doubled service life are aimed at in the ULTRA STEEL project at NIMS. Materials design and methodology for these goals need new concepts in steel research and already five-year-attempts have been done with prominent results.
Continuously cast (CC) 0.1mass% C steels with or without P addition have been produced, and their microstructures have been characterized. The process to optimize the microstructure of the CC steels containing high impurities has been established through solidification and thermo-mechanical treatment. Although rapid solidification is effective in refining the γ grain structure and for dispersing the segregation of impurities finely, P addition changes the α grain structure dramatically and decreases the γ-grain size. Based on the mapped EPMA data for P and Mn, the local equilibrium calculation was made to discuss the γ grain growth behavior in the solidification path. Since phosphorus stabilizes the δ-ferrite and lowers the transformation temperature from δ to γ, the pinning effect of the δ-ferrite on the γ-grain boundary migration is expected in the temperature range of the rapid γ grain growth. The Mn segregation was also reduced with the P addition.
Phosphorus is an element that is highly effective for solid solution strengthening, but its content is kept at minimum in steel making, because an increase in the P content decreases the toughness, especially after quenching and tempering, such as the 50% Charpy absorbed energy transition temperature and the Charpy absorbed energy at low service temperatures. On the other hand, grain refinement improves the toughness of low carbon steels. In this study, an ultrafine grain structure is introduced to low carbon steels to suppress the detrimental effects by the high content of P. The addition of P increases the tensile strength even in an ultra-fine ferrite-cementite microstructure as well as in a ferrite-pearlite microstructure. The 0.1wt. % addition of P decreases the Charpy absorbed energy of the ferrite-pearlite (FLP) and the quench-and-tempered specimens considerably at 233K. On the other hand, the ultra-fine ferrite-cementite specimen with a 0.1wt. % P shows a value that is comparable to that of the F/P specimen without P. The 50% Charpy absorbed energy transition temperature is concurrently improved by the grain refinement.
The possibility of intelligent utilization of iron-aluminum scraps is discussed in this paper. Adding aluminum in the scraps to cast iron, the wear resistance, heat resistance and damping capacity of aluminum-alloyed cast iron were investigated. Superior properties were found in the cast irons with suitable aluminum concentrations. Iron-aluminum mixed scraps could be utilized as the raw material for high quality cast irons.
Environment-conscious life-cycle design (eco-life-cycle-design) is a comprehensive method to reduce the environmental load and improve materials efficiency in the total life cycle of closed loop of production, in service, demolition, recycle/reuse, reproduction of building materials, components and/or systems. Special attention is paid to the compatibility of long service life with environmental harmony (ecobalance performance). This paper proposes and discusses this eco-life-cycle-design for new external thermal insulation systems using new short-cut fiber reinforced cement composites (FRC) as exterior materials.
Development of materials database and evaluation system is needed to establish risk-base engineering and technology for risk-acceptable and safe society. This paper shows the outline of “Materials risk information platform” under development as a system which indicates most suitable solution and information for selection and application of materials.
The ultimate objective of the US Life Cycle Inventory (LCI) database project is to develop publicly available LCI databases for commonly used materials, products and processes. The purpose is to support public and private sector efforts to develop environmentally-oriented decision support systems and tools; to provide regional benchmark data for generating or assessing company, plant or new technology data; and to provide a firm foundation for subsequent life cycle assessment tasks such as characterization, normalization and impact assessment. The first phase of the project, funded by the US Department of Energy and the General Services Administration through the National Renewable Energy Laboratory (NREL), is being undertaken by the Canadian not-for-profit ATHENATM Sustainable Materials Institute in conjunction with two US consulting firms, Franklin Associates Ltd. and Sylvatica, and will be completed by the end of November.
Environmentally benign production requires besides production integrated environmental optimization, the consideration of the life cycle, as well as End-of-Pipe technologies. On the example of a refinery, which are in focus of the environmental discussion (e. g. fuel desulphurization, VOC-, SO2-, heavy metal carrying dust emissions), different technologies (electrostatic filter, wet scrubber) and peripheral system conditions (power plants, waste water treatment) to reduce dust and heavy metal emissions will be discussed. The environmental impacts are quantified, as the goal of reducing emissions on-site may be compensated due to additional emissions from operating the technologies (electricity demand, operating supplies, shifting emissions from air to water). It may be important to integrate the demand and impact of the installation of the technologies (e. g. steel work, concrete). Thus a multi-parameter trade-off situation may occur and not any End-of-pipe technology automatically leads to environmental benefit. Besides trade-off situation in operating the technologies, secondary side effects may occur (e. g. removing emissions besides the target emissions). The knowledge of the sensitive life-cycle parameters and a suitable database—and thus the possibility to quantify impacts—leads to sustainable decision making in process design and process optimization using LCA methods.
LCA as standardized methodology offers information which is very helpful besides the environmental analysis. The strategic management system in companies needs enormous amounts of different types of information to realize corporate risks and chances in very early stages. The following approach combines the approved methodology of LCA which mostly is used as an operative tool, with strategic economic models from the market perspective. The process of using LCA in strategic risk management starts with the identification of risks based on material and energy flows, the risk analysis and evaluation figures out the relevance of the substance flow risk for the product and the company. The risk management process leads to decisions to control the risk with respect to the product—market—strategy of the specific product. The combination of LCA from the environmental perspective on the one hand with native economic models like portfolio analysis on the other hand offers a completely new interdisciplinary approach. Interdisciplinary approaches will be the most relevant approaches for companies to handle the highly dynamic and extremely complex markets of the future.
The quantitative model for CO2 emission from passenger cars in Japan is proposed. Cars are scrapped from society according to their lifetime distribution. How much the improvement of fuel economy in order to achieve the goal by COP3 is estimated. Consequently, it turns out that it must be improved by 2.42 times of the fuel economy in 1995 by the year of 2010. Substitution scenarios to small sized cars from large sized cars are considered and it effects largely on the reduction of CO2 emission.
We investigate and analyze environmental impact evaluation methods utilized in 17 organizations in order to grope for a new useful estimation method. It is found that environmental impact evaluation methods are different at different organizations. For this paper, two types of equations are mainly adopted. One is E=a·s·p and the other is E=a·s, where E is the environmental impact evaluation value; a is an environmental impact field; s is the mass or volume of impact; and p is the probability of impact occurrence.
The status of LCA research in Korea is reviewed with an emphasis on the use of LCA for a new and improved, and in many instances, cleaner materials processing technology development. After reviewing the general status of LCA research in Korea, three case studies are presented where LCA has been used to assess the environmental impact of an alternative processing technology. The first case deals with electroplating process; the second, plasitic deformation process; and the third, production of aluminum foam from recycled aluminum scrap. In each case it is shown how LCA is used to assess quantitatively the environmental impact of an alternative process.
The “Establishment of a Sustainable Society Based on Material Recycle” can be regarded as issue urging a fundamental change in the values and social systems of the modern society and a challenge demanding a reform of the industrial structure from the conventional systems of individual optimization. This paper reports our view on LCA issues and on material selection, taking LCA of automobiles as an example, and challenges of Japanese steel industry on them.
Modern car concepts make use of more and more lightweight materials in order to reduce the fuel consumption during the car use. Thus, the environmental burdens during the production phase of the cars rise mostly, compared to the traditional materials. But the cars can be understood as rolling stocks of secondary resources. The recycling contributes to energy and resource conservation as well as emission reduction. The paper aims at demonstrating the use of Life Cycle Assessment, focusing on environmental benefits during recycling within the context of the whole car life cycle. The relations between the environmental profiles of virgin and secondary materials are resolved and the effects on the environmental sound material selection are presented.
A home appliance recycling system, called “thermal elutriation system (TES)” has the following advantages: saves time and problem for disassembly, utilizes melted plastics as energy, collects fine grade for non-shredding, and extracts all CFCs. In this study, the environmental impact of TES was compared to a general recycling system “shredding” sifting out the steel from shredded home appliance. The recycling processes of treated metals and plastics are included in the assessment as avoiding the production impact from virgin materials and energy. In steel recycling, it was assumed that dilution process with iron or fine ore was applied to make the steel quality of TES and the shredding system comparable (shredded steel contains more impurity). Steel from the shredding is recycled in an electric arc furnace with dilution of copper and steel from TES is recycled in an oxygen converter without dilution. TES showed less contribution in all impact categories since TES distracts all CFCs and takes out metals with lower impurity. Even though the shredding collects 90% CFC and 70% thermal insulating CFC, its GWP and ODP were still considerably higher. The dilution process made the big effect in all impact categories.
Teijin Limited developed highly advanced chemical recycling technology for products made mainly from polyester. The new technology allows recovery of DMT (dimethylterephthalate) and EG (ethylene glycol), the raw materials used in making polyester, from most types of polyester products, even those containing additives or processing substances. The recovered raw materials have a high purity comparable to that of materials produced from oil. Teijin's new recycling plant will be operational in 2002 at its Tokuyama facility with a capacity of 30, 000 tons of polyester per year, equaling close to one billion 500ml-size bottles.
Wooden cable drums are used for transporting and installing communication cables. They are used outdoors and are easily damaged by mishandling and use in harsh environments. Recently, plastic drums have been considered as a possible replacement for wooden drums. However, plastic products are made from oil, fossil fuel, and their environmental effects are much debated. We have conducted a field survey, and used it as a basis for models. We have also undertaken an inventory analysis and impact assessment. The results are sensitive to drum weight and the number of times the drum is reused. We also discuss a way to reduce the environmental impact of these plastic drums.
LCA of manufacturing processes and waste treatments of packages for drink is studied using published data. PET bottles, tin steel cans, aluminum cans, glass bottles and carton are selected as packages for drink. The waste treatments of landfill, incineration with and without electric power generation, “package to others” recycle and “package to package” recycle are compared. The inventory results are the following: Incineration of PET bottle is better than material recycle in reducing solid waste. In future, the use of PET bottles by raw material of in steel making will be the best option. Recycle of steel and aluminum cans are better than landfill. Ninety five percent of CO2 emission of collection and transportation of waste is from collection process. The CO2 emission of one-way-use glass bottle is much higher. Glass bottle should be used repetitively. The CO2 emission of carton was very little as compared with other package for drink because it is made from biomass. Recycle from carton to toilet tissue was the best option.
This study was conducted with the aim of assessing the impact of eco-friendly packaging (EFP) on consumer buying behaviour in India. The data were collected from the respondents selected randomly within the city of Mumbai. The views of the respondents belonging to different age groups, gender, income and education levels were analyzed. The findings of the study revealed that the product packaging was an important parameter for a majority of consumers while selecting a product. They knew that packaging was increasingly becoming a nuisance as it added to the solid waste. However, it was found that awareness level of consumers about EFP was not high. A significant correlation was observed among awareness of EFP, education and income levels. Consumers, in general, feel the need to have EFP but most of them were not willing to pay extra cost for the ‘greener products’ carrying it.
The amounts of new wood used for housing construction and wood wastes from demolished buildings were calculated using various scenarios of wood recycling. Increase in reuse rate was found to be effective to reduce the total amounts of final wastes and the use of new wood materials.
The Aquasolv®-Technology is a new process, using only water under special thermo-dynamical conditions, so called subcritical state, to receive natural raw materials and fine chemicals from plant-biomass, especially ligno-cellulose. The renunciation of additional chemicals causes different ecological and economical advantages in processing and quality of received raw materials, but also a great advantage in combination with the use of solar energy to generate thermal process-energy. Because of using only pure water as a solvent, the heating up of the solvent can be directly supported by thermal solar energy plants. So it is possible, to connect the reactor-system of the Aquasolv®-Process directly with solar energy technique, more or less without heat exchangers and thus without greater losses through limitation of the technical efficiencies. Additional, the ecological as well as economical side can be economized by using biological rests and residues, which are insufficient used in Central Europe or lead even to problems in waste-management. Reducing the business activities to regional concepts which means, small plant scales and minimized transportation, such industrial concepts could be of greater interest in future, while managing the internal industry to a path, more independent of crude oil.
The most serious problem in recycling of steel is surface hot shortness during hot deformation due to Cu mixed from scrap into steels. Tin accelerates the effect of Cu. Several methods have been researched to suppress this shortness. However, it is difficult to separate Cu and Sn from steel scrap using physical and chemical methods and to remove these elements from steels by current smelting process. Therefore, Cu and Sn accumulate in steels produced using steel scrap: such elements are called tramp elements. On the other hand, Cu has a potential to increase strengths and corrosion resistance of steels, which might decrease environmental load during the life cycle of steels. The surface hot shortness occurs through preferential oxidation of Fe atoms during heating for hot deformation and formation of liquid Cu-enriched phase at the steel/scale interface. Therefore, there exist tolerable contents of Cu and Sn in commercial steels. The amount of Cu in steel scrap is increasing in Japan year by year. Therefore, in the present research, the details of the mechanism of the surface hot shortness are examined in order to find the ways for the suppression of the shortness by controlling microstructures near the steel/scale interface through physical metallurgy. Controlling of microstructures can be performed by the optimization of contents of harmless alloying and impurity elements, heating temperature, heating atmosphere and deformation rate.
In recent years, the necessity of the promotion of steel recycling is increasing from the viewpoints of effective usage of resources and restraint of environmental problems. In case steel scrap is recycled, surface cracks occur during hot rolling process, which poses a serious problem. This phenomenon is attributed to Cu. Copper is mixed from steel scrap and Cu in steels is enriched at the steel/scale interface by selective oxidation of Fe. This copper-enriched phase liquefies over 1083°C and penetrates into austenite grain boundaries to cause surface cracking. This cracking is called surface hot shortness due to Cu. To suppress this shortness, addition of Ni is known effective. But removal of Ni is difficult in the current refining process. Therefore, other ways of the suppression are desired. In this research, in order to know the detail of the shortness effects of C and P on the surface hot shortness are investigated.
As a fundamental study related to the recycle of Ni-Fe-Co alloy, the distribution equilibrium of Fe, Co and Ni between MgO saturated FeOx-MgO-SiO2 slag and nickel alloy was investigated at 1773, 1823 and 1873K with controlled oxygen partial pressure between 10-4 to 102Pa. The results suggest that most of nickel and cobalt can remain in the alloy phase with lower oxygen partial pressure, and iron can be eliminated adequately from nickel alloys with higher oxygen partial pressure. However, the solubility of nickel and cobalt oxide in the slag also increases with increasing the oxygen partial pressure. Lower oxygen partial pressure and higher temperature are favorable for decreasing the loss of nickel and cobalt into slag. An oxygen partial pressure at which the separation coefficients show minimum was observed. The MgO solubility in the FeOx-MgO-SiO2 slag decreases when the NiO content exceeds about 25% at higher oxygen partial pressure.
In order to develop the steels bearing low environmental burdens as well as high performances, the present situation in Japan has been analyzed from several points of view. The issues related with steel production include 1) potentiality of the domestic contribution to reducing the global amount of CO2 emission and 2) possible recipes in practical process to lower the environmental load with high performance. A sector occupying a huge share in the industry field can reduce the CO2 emission effectively and the steel industry is such the sector. A sophisticated use of thermo-mechanical process in steel production can improve both the environmental and the service performance. By lowering the heating temperature in the thermo-mechanical process, the CO2 emission can be decreased and the yield strength can be increased by ultrafine-grain strengthening.
Method for lead removal from molten brass was investigated to reduce the concentration of lead in scrap brass. Granular Ca-Si compound was added to the molten brass to form large Ca-Pb-Si compounds. The Ca-Pb-Si compounds were then skimmed off from the molten brass. After casting into a metal mold, the brass ingot was characterized by EPMA and fluorescence X-ray analysis. The effects of grain size of Ca-Si compound, the method of adding Ca-Si compound, agitation time, holding time after agitation and compound removal temperature on the percentage of lead removal were discussed. It was confirmed based on the results that the compound method that uses granular Ca-Si compound to form Ca-Pb-Si compounds which are skimmed off from the molten metal enables the reduction of lead concentration.
From the viewpoint of ecomaterals, development of dezincification resistant Pb-less brass is required. In order to reveal the effects of microstructural factors and alloying elements on dezincification of (α+β) brass, the brasses with different β phase area ratio and mean grain size of α phase were prepared by melting pure Cu, Zn and alloying elements and then pouring into a metal mold with three different solidification rates. Dezincification corrosion of the casting brass was examined by means of galvanostatic anodic polarization test. The results show that the mean and maximum dezincification depths of Cu-Zn system decrease with the decrease of the mean grain size of α phase. However, reduction of the dezincification depth by only controlling the microstructural factors has a limitation. The dezincification can be retarded significantly by the addition of a small amount of P and the refinement of the mean grain size of α phase with controlling the solidification rate.
There have been attempts to reflect the site-dependency of the impacts of air emissions in life cycle impact assessment (LCIA). Recently, EXPEC (Exposure Per Emission Coefficient) has been proposed as a useful tool for assessing spatially differentiated potential impacts. In this study, EXPEC was applied to estimate the spatially differentiated potential impacts caused by direct emissions from gasoline vehicle (GV) and indirect emissions from electric vehicle (EV) during the usage (100, 000km) of vehicles in Tokyo Metropolitan area. We focused on NOx emissions as an example of pollutants. A simplified circle Gaussian plume model was used to calculate concentration of NOx around emission source. The total amount of NOx inhaled by the local population was calculated with the concentration and population densities around the emission sources, and traffic volume in Tokyo Metropolitan area. The total amounts of NOx inhaled by the local population caused by GV and EV during the usage (100, 000km) of vehicles were 8.7-9.6 10-3kg and 3.7 10-6kg, respectively. Significant difference between EV and GV was observed in the total amount of NOx inhaled by the local population. It is suggested that site-specific consideration is quite important to assess the actual impacts by vehicles.
Fuel cell vehicle (FCV), which is powered by hydrogen-fueled polymer electrolyte fuel cell (PEFC), has been developed and successfully demonstrated the operation. It is estimated that FCV will be introduced into the market in the near future. In this study, comparative assessments have been carried out for FCV and gasoline vehicle (GV) to evaluate the environmental impacts during the life cycle (LC) of these vehicles. This study consists of the following investigations: 1) Life cycle assessment (LCA) case study for PEFC, 2) Life cycle inventory (LCI) analysis for hydrogen, 3) LCA case studies for FCV and GV. It was found that the amount of LC-CO2, LC-NOx, and LC-HC of FCV were smaller than those of GV. It was suggested that introduction of FCV would have a large potential to reduce atmospheric emissions.
The general aim of this work was to investigate a solar thermal collector and the energetic and environmental impacts related to this renewable technology. It was realised an eco-profile of an exemplary equipment, calculating the Cumulative Energy Demand (CED) and the Cumulative Emissions related to the production and use of a collector and the energy (or emissions) saved employing the renewable technology.
Creep strength property of a full-annealed 0.1C-15Cr-1Mo-3W 0.2V-0.05Nb-0.07N-0.003B steel and the effects of tungsten and cobalt on that have been investigated. Contrary to a tempered martensite microstructure of the conventional ferritic creep resistant steels, microstructure of full-annealed 15Cr steel is mainly ferrite. Increases in creep strength at 923K with increase in tungsten content and addition of cobalt have been obviously observed, especially with a combination of increase in tungsten content and addition of cobalt. Higher Cr content of full-annealed 15Cr steel than those of the conventional ferritic creep resistant steels is desirable for better oxidation resistance. It has been concluded that full-annealed 15Cr ferritic creep resistant steel should be one of the candidate materials for a low emission power plant.
More than 90% of steel products used in Japan are recovered as obsolete scrap, and more than 40 million tons of steelmaking materials, about 40% of total steelmaking materials consumed in Japan, are provided by steel scrap. Because of its ease of separation and melting over other materials, steel is a material that is extremely suitable for recycling use. Meanwhile, steel is extensively used for frames, envelopes and other building components and thus is a major structural material alongside wood and concrete. This paper describes how steel can contribute to the construction of sustainable buildings through maximum use of its excellent performance—recyclability.
A PVC-substitute compound has been developed that uses neither flame-retarding agents containing halogens nor additives containing toxic heavy metals. A power cord has been fabricated using this compound and a comparison has been made with the conventional power cord based on PVC. The power cord using the new compound proved to be provided with characteristics equivalent to those of PVC power cords.
Halogen-free electric wires with superior heat resistance of 125°C and 150°C respectively have been developed, based on establishing proprietary technologies of flame retardance and an anti-aging agent system in addition to application of electron beam cross-linking. The halogen-free wires developed here proved to provide excellent mechanical properties and heat resistance, and were confirmed to meet the vertical flame retardance specifications of VW-1. The wires were subjected to chemical substance elution tests and combustion fumes analysis tests, and no toxic substances were detected with the wires.
To examine the effect of Mg content on extrudability in 7xxx aluminum alloys, hot extrusion experiments and then microstructure examination by XRD, SEM and EPMA have been performed. The finite element analysis has been also carried out for comparison of extrusion pressure in direct and indirect extrusion process. The total energy consumption from cradle to gate in Al extrusion process has been estimated after calculating the standard data of unit process in LCA inventory analysis. The extrudability and the tensile strength are equal to, or above that of conventional A 7003 alloy even the content of Mg varied from 1.1wt.% to 0.5wt.%. alloy. This means that minimizing the content of Mg in A7003 alloy can enhance recovery efficiency during Al scrap recycling. It has been found that energy consumption of unit process can be reduced when the indirect process is used. However, there are little differences in total energy consumption related with increasing Mg content or changing extrusion process at the range from cradle to gate. Thus, for LCA inventory in the extrusion process, a range within the process except mining and extraction has to be introduced.