Advanced Materials Research Vols. 343-344

Abstract: This paper shows that a new approach (i.e. cold-bonding technique) to recycle uncontaminated and innocuous lime sludge as coarse aggregates. The cold-bonding technique incorporates the principles of the cement chemistry and composite material to develop recycling coarse aggregates. Herein lime sludge was regarded as the main materials to produce recycling coarse aggregates, which meet the specifications of green building materials in Taiwan, using the cold-bonding technique instead of sintering method in light of the issues of reduction of waste, energy, and CO₂ footprint. The results show that the specific gravity (in the oven-dry state, OD) of recycling coarse aggregate is in the range of 1.20 to 1.23; the absorption capacity is in 40.0 to 44.6 %; the dry loose density (i.e. unit weight) is 811 to 837 kg/m³; the single particle compressive strength at 28-day is in the range of 17.8 to 20.4 MPa; the particle cylindrical crushing strength ranges from 27.9 to 33.8 MPa; other characteristics also satisfies ASTM C33. The developed recycling coarse aggregates could increase the reuse and recycling of lime sludge, reduce the energy consumption and CO₂ footprint, and diminish the impact on the environment and future generations.

Abstract: Air layer with irregular shape in sound absorbing structure is formed by different structure mode of materials. With building multiform interior space by materials and structure mode, it makes the shape of air layer between the facing and the structure of building to be irregular shape.According to related study of absorbing structure, it shows less information about the influence of air layer with irregular shape. The factors of sound absorption of absorbing structure were focused on absorbing structure which facing paralleled structure of building in past research. For searching the influence of sound absorption of absorbing structure caused by the air layer with irregular shape, the subject in this study is set as the air layer with irregular shape which facing tilts with single-axis. The factors of air layer with irregular shape are the angle between tilting facing and horizontal face, the length of span of tilting facing, and if the setting is that the air layer is divided into several parts not to be interlinked. By these factors the sound absorption characteristics of air layer with irregular shape are shown.In the other point of effects of absorption coefficient causing by setting of air cavity, both panel and perforated panel structure the influences are influenced mainly at low frequency, especially at 200 Hz. Whether the air cavity is set or not, the panel structure reveals less influences and the absorption coefficient reduces as increasing of span at low frequencies.

Abstract: The molecular dynamics simulations are performed with single-crystal copper thin films under uniaxial tensile and cyclic loading to investigate temperature effects on the mechanical responses. With the changes of sample temperatures in uniaxial extension, the variation characteristics of maximum stress, the Young’s modulus, the maximal potential energy, the atomic structure of the emerging dislocation, and activation volume and activation free energy at the maximum stress point make us identify and explain the critical temperature for the transition of deformation mechanism in a temperature range from 293 to 460 K. Under cyclic loading, with raising temperature, the number of cycles to failure of copper films increases under different manners in different temperature range, which can be explained by our constructing model based on the evolutionary features of dislocation. Thus, the mechanisms of the strange temperature dependence of tensile and cyclic deformation have been explained. When the temperature is above 370 K, the rate controlling mechanism is dislocation climbing during uniaxial loading, and the number of cycles to failure goes up quickly with temperature; when below 370 K, the mechanism of uniaxial tensility is mainly characterized by the overcoming of Peierls–Nabarro barrier and a few localized pinnings, the number of cycles rises slowly; and when about 370 K, the mechanism in single-axial tension is pipe diffusion, the number of cycles increases at middle speed.

Abstract: The combined process of Electrolyzed oxidizing water(EOW)and membrane bioreactor(MBR)was applied to treat the UDMH wastewater, and its treatment efficiency was compared with that by MBR alone．In the combined process, the treatment efficiency of UDMH wastewater is better than MBR alone. When the influent COD and UDMH are 800 to 1000 mg•L^-1 and 300 mg•L^-1, the effluent COD and UDMH are about 55 mg•L^-1 and 0.3 to 1.5 mg•L^-1 respectively, close the demand of the Discharge standard of water pollutants for space propellant．In the MBR process alone，the effluent COD and UDMH are about 90 mg•L^-1 and 45 mg•L^-1 respectively, which worse than the combined process EOW-MBR, especially the effluent UDMH far beyond the demand of the Discharge standard of water pollutants for space propellant．

Abstract: Phosphates are widely used as a substitute material for bones and teeth in medical sciences. It is known that phosphate and iron have a strong affinity for each other. In this study, process of formation of iron phosphate was closely monitored using scanning electron microscope equipped with backscatter electron image and energy dispersive X-ray imaging facilities. Different stages of formation of the iron-phosphate material in an environment rich in phosphate and iron were observed. Initial stage of absorbing iron on phosphate-rich substrate is the most important stage of the entire process. X-ray mapping provides strong visual evidence to track down the dispersion of major elements during this process.

Abstract: Incremental tendency method is used to discriminate master factors of regional environmental quality. In this article, incremental tendency method has been revised. Taken Tianjin sea area as an example, the collation of environmental quality master factors in 2006 has been listed. It is advanced that environmental quality master factors of Tianjin sea area are mainly inorganic nitrogen and petroleum substances, and pollution management should also be aimed at these types of substances. Finally the meaning of new model in application has been explained. It provided practical basis for sustainable development of Tianjin sea area.

Abstract: Cement industry is a one of the major sources of environmental pollution therefore the reduction of cement demand should be improved. Fly ash and silica fume is a by-product of industries and it should be reused to reduce the waste pollution. Thus, this study investigated the use of fly ash and silica fume as a cement replacement in binary and ternary blended cements on compressive strength and physical properties of mortar. Autoclaved curing at 130 °C and 20 psi of pressure for 9 h was used in this study. The results show that the compressive strength of binary blended cement mortar with FA tends to decrease with increased FA replacement and shows compressive strength lower than PC control. However, compressive strength of binary blended cement mortar with SF was improved and shows compressive strength higher than that of PC control. The compressive strength of ternary blended cement mortar was higher than binary blended cement at the same level replacement and it increases with increased SF replacement. Moreover, ternary blended cement mortar containing 10%SF by weight contribute in giving compressive strength higher than PC control. The incorporation of FA with SF can enhance workability of blended cement mortar containing only SF replacement.

Abstract: In this study limestone powders with different particle sizes of 5, 10 and 20 μm were used to replace a part of Portland cement in different replacement levels to produce Portland-limestone cement pastes. The percentages of limestone replacement are 0, 5, 7.5, 10, 12.5, 15 and 20% by weight. The effect of fineness and the amount of limestone powders on compressive strength and setting time are investigated. It has been established that limestone replacement causes reduce the compressive strength due to the dilution effect, but it can reduce energy consumption and CO₂ emission in cement manufacturing. The fineness of limestone powder used has influence on the observed compressive strength values. From the standard consistency results, it seems that limestone has no effect on water requirement compared to Portland cement. Moreover, the increase in level of fine particles would require much water. Both initial and final setting times were decreased with an increase in the amount of limestone. Furthermore, at the same level replacement, the cement pastes using 5 μm of limestone show lower setting time than those using 10 and 20 μm, respectively.

Abstract: This study proposed a new type of hydrocyclone. A rotating ring containing one pair of symmetric blades was attached to the overflow pipe. The momentum of the inlet fluid drove the ring/blades to rotate, and the rotating blades swept small-sized particles to the hydrocyclone wall to be discharged from underflow. This design can destroy circulation flow on hydrocyclone roof and make small-sized particles to be separated.

Abstract: The effects of Hg²⁺ on microbial community structures of aerobic activated sludge were investigated by nested PCR-DGGE techniques. The results showed that the microbial community of each group might have obvious change compared with the group without Hg²⁺ in the inflow, especially when the Hg²⁺ concentration was 46.87mg/L in the inflow, and the microbial community changed obviously with the extend of operation time. The variance of microbial species become obvious in each activated sludge group with the extend of operation time. Compared with the group without Hg²⁺ in the inflow, the dominant microbial species of each activated sludge group changed, and the dominant microbial species of the group whose concentration of Hg²⁺ increased gradually in the inflow had the biggest changes after 60 days. Hg²⁺ in the inflow may stimulate the growth of Actinomycetes after an operation period of 30 days.