Applied Mechanics and Materials Vols. 204-208

Abstract: Dielectric properties of sol–gel prepared Ni-doped calcium copper titanate Ceramics (CCNTO) are investigated. For the x of CaCu3NixTi4O12+x is 0, 0.1, 0.2, 0.3 respectively. The XRD pattern shows that crystal structure of the sample without Ni is basically single-phase. The dielectric properties of CCNTO were analyzed by Agilent 4294A. The experimental results show that the sample has a better dielectric properties when x=0.2. The maximum dielectric constants is found when x=0.2. The dielectric loss decreased with the increases of Ni in the low frequency region, the high frequency region is just the opposite, the sample has lower dielectric loss in the low frequency region when x=0.2.

Abstract: This article discusses the connotation of green building materials and basic characteristics, and analyzes the difference between green building materials and green products. Summarize the selection of green building materials, and to judge the development trend of green building materials in China. Finally, the author gives some countermeasures and suggestions on the healthy development of China's green building materials industry.

Abstract: In order to study the effects of slate powder on mineral admixtures in suppressing ASR of slate aggregate, refer to the following methods: accelerated mortar bar test in “Standard for Constructional Quality Acceptance of Railway Concrete Engineering” TB10424-2010 and “Durability Design of Railway Concrete Structures” TB10005-2010, as well as an improved steam curing method. The text has studied the expansion of the specimens that are made from slate aggregate with different powder contents and specimens using slate powder as admixtures. The results show : When powder content in aggregate is less than 20%, it dose not have adverse effects; ASR of high-activity slate aggregate can be suppressed by using 30% fly ash and 5% silica fume as mineral admixtures; when the mineral admixtures are effective, a certain amount of powder mixed with admixtures can contribute to suppression; the main mechanism that slate powder can suppress ASR is that alkali in concrete can be consumed and physically diluted by slate powder.

Abstract: Sol-gel method is used for the formation of Pb(Zr0.63Ti0.37)O3(PZT) thin films. The initial films were formed with spin coating sol solution on silicon wafer and drying coated wet sol film at 300°C for 5min. This process was repeated for 1-4 times to obtain 4 initial films with different thicknesses. 4 initial films were annealed at 500°C for 2h to obtain PZT ceramics films. The morphologies of the surface and cross-section of PZT films were observed with a scanning electronic microscope (SEM). The phase structures of PZT films were analyzed using an X-ray diffraction meter (XRD). Experimental results show that PZT film prepared by coating wet sol on silicon once can be high smooth and compact film.

Abstract: Using 1,4-bis(2-benzimidazolyl) benzene (BBIB) and 4,4'-difluorobenzophenone as the monomers, poly(N-arylenebenzimidazole ketone) (PNABIK) has been prepared via the aromatic nucleophilic displacement reaction. The chemical structure of PNABIK was confirmed by FT-IR, elemental analysis and 1H NMR. The results show a good agreement with the proposed structures. The polymer was obtained in quantitative yields with Mn value 12500 and Mw value 28600, respectively. DSC and TGA measurements show that the glass transition temperature (Tg) is 202 °C and 5% weight loss temperature is 550°C in nitrogen and 571 °C in air, respectively. In addition, the novel polymer exhibit good solubility.

Abstract: A solution method was developed to synthesized heteronanostructure of Ag nanoparticles on titanate nanowires, and then flexible photocatalytic Films were made by these nanowires. The nanowire is about 50 nm in diameter, several hundreds micrometers in length. The size of the Ag nanoparticle grafted on the nanowire is about 50 to 100 nm. The nanowire Film showed excellent photocatalytic activity to decompose the methamidophos and satisfactory antibacterial effect to kill Escherichia coli.

Abstract: This paper presents a biomass and natural gas combined cooling heating and power (BNGCCHP) system, which achieves energy cascade utilization and improves overall energy efficiency. The thermodynamic analysis of BNCCHP system is analyzed from the energy and exergy balance respectively. A case of BNCCHP system for a commercial building is studied.

Abstract: The heating source of a district heating (DH) system in Beijing was reformed from coal boilers to a groundwater heat pump (GWHP) system and a sewage source heat pump (SSHP) system. This study aims to evaluate the actual performance and benefits of two water-source heat pump systems. We found total energy savings and primary energy saving rate due to the retrofit to be 950 tons of standard coal equivalent (TCE) every year and 34.6%, respectively. Field test results indicated the necessity of system performance improvement. Appropriate approaches to improve the system performance were discussed.

Abstract: Drain water at 35°C was directly discharged into sewer in most of barbershop with Electric water heater. Heat utilization efficiency is lower, and energy grade match between input and output is not appropriate in most of barbershops. Two waste heat recovery systems were presented according to the heat utilization characteristics of barbershops and principle of cascade utilization of energy. One was the waste heat recovery system by water-to-water heat exchanger (WHR-HE), and the other is the waste heat recovery system by water-to-water heat exchanger and high-temperature heat pump (WHR-CHEHP). The two heat recovery systems were analyzed by the first and second Laws of thermodynamic. The analyzed results show that the energy consumption can be reduced about 75% for HR-HE, and about 98% for WHR-CHEHP. Both WHR-HE and WHR-CHEHP are with better energy-saving effect and economic benefits.

Abstract: Radiant floor heating as a new type of energy-saving heating method has more and more used in modern building heating project. According to the different heat source, radiant floor heating is divided into low temperature hot-water floor radiant heating and electrical floor radiant heating. This paper analyzes the heat transfer process of structure layer of the low temperature hot-water and electrical floor radiant heating system, establishes two dimensional steady heat transfer mathematic model, numerical calculation using Fluent software. Respectively simulated when floor materials is different, the heat transfer process of low temperature hot-water floor radiant heating and electrical floor radiant heating system, The analysis results show that: for low temperature hot-water floor radiant heating, when floor material is soft wood, the ground temperature distribution is more uniform; for electrical floor radiant heating, when floor materials is marble, the ground temperature distribution is more uniform; electrical floor radiant heating is more energy saving, and temperature distribution in the ground of floor using the constant heat flux electric heating mode is more uniform than which using the low temperature hot water heating mode.