Applied Mechanics and Materials Vols. 541-542

Abstract: Red mud foam lightweight thermal insulation material was prepared by red mud, fly ash, cement as main raw materials, adding a certain amount of adhesive, through ingredients, mixing, molding, foam, sintering process. The influence of the ratio of red mud and fly ash on the properties of materials was studied and the mechanism of influence was analyzed. The test results show that performances of the samples were best when the ratio of red mud and fly ash is 5:4 and its flexural strength is 0.44MPa, compressive strength is 1.23MPa, density is 481kg/m³.

Abstract: Autothermal reforming (ATR), which is the combination of endothermic steam reforming and exothermic partial oxidation, is an attractive process to produce hydrogen using for transportation fuel cell because of its moderate size. ATR is considered to be thermally self-sustaining that the external heat source is not required. In order to keep the adiabatic temperature of ATR reactor, the process control strategy needs in understanding the dynamic characteristics of the ATR system. Thus, the modeling and simulation of ATR process for hydrogen production fueled by ethanol is carried out in this work. The open loop responses of the feed and ATR temperatures are simulated by the dynamic models of ATR system. The simulation results showed the predominantly influence of the electrical power of preheater on the feed and ATR temperatures while the air flowrate has an inverse effect on the feed temperature and a direct effect on the ATR temperature. As a result, the match of control loop is very sensible for an effective control strategy in the development of control system design for maintaining the adiabatic temperature of ATR reactor for sustaining the effectiveness of hydrogen production.

Abstract: This paper uses molding process to prepare a new kind of pipe insulation material, called silicone rubber-vacuum insulation panel (SR-VIP), which consists of a silicone rubber layer, a VIP layer and silicone rubber layer, making the composite sandwich structure. The thermal consuctivity of the composite is as low as 0.005 W/m·K. The tensile strength, tear strength, compression strength and compression set of the composite are 7.8MPa, 22N/mm, 65Mpa, 25%, respectively. Compared with traditional foam insulation materials, the composite possesses superior thermal insulating properties and mechanical properties.

Abstract: This paper studies the formation dynamics of belite-calcium barium sulphoaluminate cement clinker with and without CaF₂. The results suggest that, under the condition of the experimental preparation process, the formation process of belite-calcium barium sulphoaluminate cement clinker is controlled by diffusion mechanism in the temperature range of 1250-1380¡æ and the formation dynamics fits nicely with D₄̍́˽̂ځ˿̃˽˸́˽ځ˹^2/3=kt. Apparent activation energy was calculated to be 250 kJ·mol^-1and 195 kJ·mol^-1 for sample clinker without and with 0.6% CaF₂ content. It is concluded that CaF₂ contributes a lot to the reduction in energy consumption during the process of sintering belite-calcium barium sulphoaluminate cement clinker.

Abstract: This paper study on the mortar strength, particle gradation and mortar fluidity of binary and ternary systems for cementitious materials with limestone powder or fly ash, analyze the influence of limestone powders with different specific surface areas and contents on the performance of cementitious materials; and research the performance of limestone powder in cementitious materials by means of micro analysis. The result shows that the limestone powder can not only work as the filling material, but also speed up the early hydration of cement in the cementitious material system.

Abstract: The saturated CO₂ loadings in monoethanolamine (MEA) aqueous solutions at normal temperature and pressure were measured. The calcium chloride (CaCl₂) aqueous solution was added into the CO₂ loaded MEA aqueous solution to converse the ionic form of CO₂ (CO₃^2-) to CaCO₃ precipitation. The influence of the addition of CaCl₂ on the CO₂ fixation was illustrated.

Abstract: The phosphobetaine amphoteric surfactant of N, N-dimethyl-tridecane hydroxyethyl ammonium phosphate (PBET-13), was synthesized by using epichlorohydrin, NaH₂PO₄ and dodecyl/tetradecyl dimethyl amine and cetyl/octadecyl dimethyl ammonium as raw materials. The scale inhibition, interfacial tension and foaming performance of PBET-13 were studied. The results show that the surfactant has higher scale inhibition efficiency to CaSO₄ than that of CaCO₃. PBET-13 solution with the appropriate concentration of NaCl could reach to the ultra-low value of interfacial tension, and PBET-13 shows good foam performance.

Abstract: Cement-based foam insulation board is a lightweight thermal insulation and have a characteristic of energy saving. The effects of material constitution on the properties of mechanical properties, dry densityand thermal conductivity for thermal insulation materials. The subject of fast hardening sulphoaluminate cement as cementitious materials, polystyrene particles as a lightweight thermal insulation material, adding a certain amount of water reducer, cellulose ethers, air entraining agent to make thermal insulation materials. The experimental results shows that the appropriate material constitution is following: the cement-bead ratio is 12, the ratio is 0.65, the water-cement ratio is 0.4, the content of water reducer is 0.5%, the content of cellulose ether is 0.4%, the content of the air entraining agent is 0.4% .This mix ratio test of mechanical properties are: flexural strength is 0.72MPa, compressive strength is 1.24MPa, dry density is 375kg/m³, water content is 2.3%, water absorption is 10.8%, softening coefficient is 0.95 and coefficient of thermal conductivity is 0.053 W/ (m K).

Abstract: Specimens were prepared by burning mixtures containing CaCO₃ and SiO₂ in 3:1 stoichiometric ratio along with dopants at different temperatures. Formation of C₃S doped with SO₃, BaO and MgO was studied. The results show that the temperature of beginning formation for C₃S is 1380°C in the system, and there exist both C₃S and C₂S. SO₃, BaO and MgO can effectively stabilize the M₁ and M₃ type alites through substitution and interstitial imperfection, and make f-CaO content 8.68 wt% at 1450°C. C₃S doped with minor elements appears in the shape of six-party plate with the mean size of 17~30μm.

Abstract: Zinc oxide (ZnO) is a low toxicity and environmentally friendly material, and it is applied on devices, sensors or actuators for trending towards green-life. A porous ZnO film deposited by a rapid process of aerosol deposition (AD) was employed as the gas-sensitive material in a CO gas sensor for reducing the manufacturing cost and time, further extending the AD application. A relative resistance change (R / R) of the ZnO gas sensor was used for CO gas measurement. The sensitivity of the fabricated ZnO gas sensors had a more outstanding performance about 49%, compared to the literature data reported by Joshi.