Abstract: Lotus-type porous iron was fabricated by continuous zone melting technique through thermal decomposition of chromium nitride(Cr1.18N). Nitrogen dissolves into the molten iron through thermal decomposition of Cr1.18N. When the molten iron is solidified in one direction, insoluble nitrogen forms the directional gas pores aligned along the solidification direction. The porosity increases with increasing transfer velocity. For most of lotus metals fabricated by pressurized gas method, the porosity does not change with the transfer velocity owing to constant gas solubility in liquid and solid phase. On the other hand, the porosity of lotus metal fabricated by thermal decomposition method depends on the transfer velocity. This difference is attributed to the decomposition behavior of gas compound dependent upon the heating rate.
Abstract: EPP(Expanded Polypropylene) media with a large surface area was developed to treat the first flush of storm water from motorway. A series of studies have been carried out concerning the main mechanism of physical characteristics with the filtration and adsorption of EPP media in EcoTank system in order to evaluate the performance risk for treating trace metals (Cd, Cr, Cu, Pb and Zn) under uncertainty. In view of quantitative and qualitative risk analysis, this study assesses the uncertainty analysis involved in predicting of treating heavy metals from road runoff using an EcoTank system. Results of treatment performance estimation after the treatment of trace metals using an uncertainty analysis were 50.0.% probability (class 3; moderate) for Cd, 52.0% probability (class 4; high) of Cr, 47.1% probability (class 3; moderate) for Cu, 44.4% probability (class 3; moderate) for Pb and 51.2% probability (class 4; high) for Zn, respectively. The performance risk values of all the heavy metals satisfied the acceptable criteria.
Abstract: In order to improve the combustion effects of pulverized coal and replacement ratio of coals, the combustion- supporting mechanism, development and applications are analyzed and industry experiment are carried out based on the research of combustion- supporting agent without alkalis on coals combustion with TG- DTG- DSC ways. The results show that there is an optimum addition percent for coals combustion with combustion- supporting agent. The coal ratio and coke ratio are improved obviously with 1.7%combustion- supporting agent in LongGang.
Abstract: The strain rate sensitivity of Oxygen plasma treated carbon nanotube sol-gel coating Basalt and concurrent microstructural evolution investigated. Both the materials are strain rate sensitive and the change in index parameter of strain rate sensitivity with strain reflects the change in micromechanisms of deformation and mode of fracture. From the SEM micrographs, an increase in surface roughness can observed and the degree of fibrillation decreased after helium and oxygen plasma treatment. Contact angle analysis showed the treated Basalt filament had lower contact angles than the untreated one. Based on FTIR results, the change of wettability and surface energy is attributable to polar groups on the fiber surface introduced by the treatments. Deformation processes in the Oxygen plasma treated carbon nano tube sol-gel coating Basalt involved craze-tearing and brittle mode of fracture, while plasma treated carbon nano tube in nano-composites filaments predominantly characterized by wedge, ridge tearing, fibrillation and brittle fracture. Depend yield stress of the Oxygen plasma treated carbon nanotube sol-gel coating Basalt with strain rate follows Eyring’s equation.
Abstract: In order to investigate the influence of vanadium on aging dynamics of Cu-Ni-Si alloy, the microstructure, hardness and electrical conductivity of the cold rolled Cu-Ni-Si alloys with varying V content were systematically studied. The results show that V can postpone the recovery and accelerate the precipitation with (NiV)2Si compound. Consequently, V can increase hardness obviously. However, because of the precipitation during the hot rolling procedure, V addtion has a little harmed to electrical conductivity.
Abstract: Urbanization together with increased population and industrialization has increased impermeable areas including asphalt and concrete pavement, leading to potential dangers of environmental disasters in urban area. While environmental pavements have been investigated to mitigate these problems in some countries such as Germany and Japan, little work has been done in Korea. Furthermore, most studies on environmental pavements have focused on permeable asphalt pavements.
This study was intended to develop new materials for water-absorbing pavement blocks to control pavement temperature and storm water runoff. Bottom ash, which is a coal combustion by-products, was used as a composing material for these blocks. A polymer with water absorption ratio of 76% was used as a water-retention material for the pavement blocks. The effect of block compositions on mechanical characteristics, compressive strength and porosity were examined as well as thermal characteristics. This water-absorbing polymer is likely to be suitable to be used with the bottom ash blocks. The time required to fill the pores of the blocks with the polymer ranged from 9 to 14 sec, indication that the polymer can be readily applied to the blocks. The final products with optimum compositions satisfied the Korean Standard for blocks and possessed an excellent water-retentive ability. Experiments are ongoing to measure the properties of the blocks for further application as a new construction material.
Abstract: Urban area may be warmer than surrounding regions due to asphalt and concrete for roads, buildings, and other artificial structures. Especially, pavements have become an important contributor to this effect by altering land-cover over significant portions of an urban area. Therefore, researchers have studied ways to reduce the heat island effect such as cooling pavement, porous pavements such as water-retentive or water absorbing pavements. Accordingly, this study aims at the development of water-retention asphalt pavement for urban areas in order to solve problems related to the distortion of water cycle and the heat island phenomena. Experimental results indicated that asphalt pavement using developed water retaining material was effective to decrease its surface temperature compare to other pavements. A correlation between air temperature and surface temperature of the pavement was obtained to estimate the efficiency of the developed pavement materials.
Abstract: This paper presents our concepts and initial investigation of a novel construction automation approach using a new layered fabrication process called Contour Crafting (CC). The process aims at automated construction of whole houses as well as sub-components. The potential of CC became evident from the initial investigations and experiments with various materials and geometries. Using this process, a single house or a colony of houses, each with possibly a different design, may be automatically constructed in a single run. CC uses computer control to take advantage of the superior surface forming capability of trowels to create large intricate structures with smooth and accurate surfaces.
Abstract: Wood I-joists is a kind of wood-based engineering material which was widely used in wood construction. As it is in fact, the property of I-joists are influenced not only by shear stress but also by a part of normal stress when they are taking into application. In this study, the effects of different factors were evaluated on the tensile property of the wood I-joists. The factors include the depth of the tanks on the flanges, the amount of glue spread and adhesive type. The method of orthogonal test was used in the process of the experiment design, and tensile test were taken during the experiment at the aim of testing the property of the I-joists using a universal mechanical testing machine. Ultimately, it has been discovered that the factor of adhesive type is the most influential one in the three factors which had been listed. So this paper offers the optimal fabrication technology of the I-joists to make it is possible for the increase of reliability when wood I-joists are taken into application.
Abstract: In this work it was determined the effect of fly ash (FA) as bonding material during the fabrication of low thermal expansion porous materials. SiC, fly ash, Vitrified Bonding Material (VBM), and LiAlSiO4 powders were used as raw materials. Porous materials were sintered at 850°C and 950°C after manual milling and mechanical milling in a planetary ball milling at 800 RPM. SEM micrographs showed the presence of porous materials, and it was observed that fly ash particles did not melt at 850°C. However if sintering temperature increases at 950°C, FA starts to melt and it is forming bridges between SiC particles. Thermal expansion values were around 3.0x10-6 K-1. According to these results, it seems that it is possible to have a favorable synergy between FA and VBM to fabricate SiC porous materials with low thermal expansion values.