The effect of fine sand of blast-furnace slag (SBFS) on freeze-thaw resistance, sulfate resistance, and sulfuric acid resistance in mortar whose aggregate is replaced in part or in full with blast furnace slag (SBFS) was investigated. Evaluation carried out on small test specimens confirmed that freeze-thaw resistance, sulfate resistance, and sulfuric acid resistance all improve as the SBFS substitution rate increases. However, increased porosity with a larger proportion of pores sized 50 nm or larger was also observed. In the case of the use of molten slag from municipal solid waste (SMSW), no improvement in freeze-thaw resistance was observed with increases in SBFS substitution rate.
The flow through annuli is encountered in drilling operation, in which drilling mud flows between the borehole wall and the drilling pipe. Some drilling muds, depending on their prepared materials, exhibit nonNewtonian characteristics and in many cases may be regarded as pseudoplastic fluids. This study examines the dimensionless flow rate defined by Fredrickson and Bird (Fredrickson and Bird, 1958) on pseudoplastic fluid laminar flow in concentric annuli. A new approximation function is derived to evaluate the viscosity factor, also easy to use without numerical procedures. The function is more precise than the one, which was previously shown by the authors (Masuyama and Hatakeyama, 2003). Further, a new scheme is proposed to evaluate the characterizing coefficients, such as the pseudoplastic viscosity and the rheology constant using flow data. Furthermore, generalized formulas of the Reynolds number and the pipe friction coefficient for pseudoplastic fluid are shown for concentric annuli in order to calculate the pressure drop. They are extendable in the case of circular pipes, also parallel plates.
Cu electrolysis was performed using low-grade copper anode with purity 78.7 mass% at a anode current density of 200 A・m-2 in an unagitated sulfate solution containing 0.596 mol・dm-3 of Ni2+ ions as impurity at 60 ℃, and the structure of anode slime before and after passivation was analyzed. The highly-concentrated Sb, Pb and Ag were dispersed in copper anode before electrolysis. The passivation occurred at short time of 17.7 hours in the case of low-grade copper anode, and it occurred at shorter time of 11.4 hours in the solution containing Ni2+ ions as impurity. At normal dissolution of copper anode, copper parent phase dissolved in the form of dendrite and the framework of anode slime was composed of remained Cu-Ni-Sb-Sn-As compound. Cu2S and single phase of Ag and Pb were observed around this framework. At passivation, Cu, Ni and Sn dissolved from the slime framework composed of Cu-Ni-Sb-Sn-As compound, resulting in formation of Sb condensed phase. These Cu-Ni-Sb-Sn-As compound, Sb condensed phase, Cu2S compound around the slime framework, Ag and needle-shaped PbO dotted in the whole slime suppressed the diffusion of Cu2+ ions, as a result, CuSO4 was formed at interface between the slime and copper substrate. The passivation occurred at slime thickness of approximately 500μm in Ni2+-free solution, while it occurred at slime thickness of approximately 300μm in solution containing Ni2+ ions. This indicates that the passivation do not depend on only the thickness of slime. The thickness of CuSO4 formed at passivation in Ni2+-free solution was almost identical with that from the solution containing Ni2+ ions. In solution containing Ni2+ ions, the passivation occurred at less thickness of slime, showing that CuSO4 is easy to be formed in the vicinity of copper substrate due to decrease in solubility of CuSO4 and diffusion coefficient of Cu2+ ions.
Peat from highly organic soil is abundant in Northern Hokkaido, Japan. In the past, peat was used in various applications in Japan, such as an artificial culture of soil, as a fertilizer for gardening, and as an energy resource. However, peat is not used by the modern energy and manufacturing sectors in Japan because it has a high moisture content and low calorific value, which lowers its value as a resource considering its material characteristics and handling difficulties. Furthermore, large amounts of peat are generated at the construction sites in this area, and they are difficult to be reused at their generation sites because peat is a very soft soil and not suitable for construction work. Recently, many Japanese research institutions have been carrying out research and development on renewable energy resources including biomass energy. In Hokkaido, there are many biogas plants for methanizing biomass derived from livestock excrement or food waste. Thus, peat which is high in organic matter could potentially be used as an energy resource. In this study, we investigated the potential of utilizing peat as an energy resource for biogenic methane production in regional cities of Northern Hokkaido, while considering both its material characteristics and resource circulation. Batch tests using a hydrogen peroxide solution were performed on peat and silty soil to estimate the quantity of low-molecular-weight organic acids and the producing potential for biogenic methane gas. The oxidative decomposition of the peat produced a high yield of low-molecular-weight organic acids that were used as substrates for methanogenic microorganisms. In addition, a novel resource circulation method was proposed for peat in order to use it as an energy resource. Moreover, the energy resources problem in Northern Hokkaido was discussed in association with geographical parameters and the construction recycling system in Japan.