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Liu Y.,Peking University | Feng H.,Peking University | Bao Y.,China Building Material Test and Certification Group Co. | Qiu Y.,China Building Material Test and Certification Group Co. | And 2 more authors.
Journal of the European Ceramic Society | Year: 2010

Alumina and zirconia (Y-TZP) based bilayer ceramic dental composites with core to veneer thickness ratio (R-value) of 1:1 and 2:1 were fabricated through an established dental laboratory multi-steps-firing procedure. Their flexural strengths were determined by three-point bending test. A combinational approach of numerical simulations by finite element analysis associated with direct fractography investigation was applied to elucidate the origins of fracture and interfacial delamination and the influence of physical properties mismatch between core ceramic and veneer porcelain. A newly developed argon ion beam cross-section polishing technique was used to conduct fine polishing required for close investigating of the core-veneer interface under scanning electron microscope. For the same core ceramic no significant difference was observed in determined flexural strength of two groups of bilayer composites. The flexural strength of the bilayer composites is ∼55% and ∼35% of the core ceramics and achieved ∼90% and 70-77% of the predicated value respectively in case of Y-TZP and alumina based composites. Numerical simulations by finite element analysis indicate that the often observed interfacial delamination in Y-TZP based bilayer composites has a clear origin of the severe physical properties mismatch between veneer porcelain and core ceramics, particularly the flexural strength, which may be prevented by increasing the flexural strength of veneer porcelain to above 300 MPa. The observation of the formation of microcracks in alumina core immediately one grain-thick under the veneer-core interface warns the possible thermal damages initiated during the veneering operation. © 2009 Elsevier Ltd. All rights reserved.

Zhang L.,South China University of Technology | Yao X.,South China University of Technology | Zang S.,China Building Material Test and Certification Group Co. | Han Q.,South China University of Technology
Materials and Design | Year: 2015

During airplane related accidents, the transparent polyurethane interlayer is finding new applications in the aircraft protection as an interlayer of windshield to enhance structural survivability under impact loading. Using dynamic mechanical analysis, Instron testing system and low impedance Split Hopkinson Tension Bar (SHTB), dynamic tensile response of a transparent polyurethane interlayer is studied experimentally under wide ranges of strain rates and temperatures. Based on the constitutive theory and the experimental data, thermal-viscoelastic Zhu-Wang-Tang (ZWT) constitutive model is employed to describe the tensile response of the polyurethane interlayer. The experimental results also reveal the time-temperature equivalence relation for the polyurethane interlayer. Strain rate and temperature are put together to a unified parameter by introducing a dimensionless parameter, and a unified curve reflecting the time-temperature equivalence relation is obtained. © 2014 Elsevier Ltd.

Liu Z.,China Building Material Test and Certification Group Co. | Bao Y.,China Academy of Building Research
Advanced Materials Research | Year: 2011

Building-integrated photovoltaics (BIPV) is a relatively recent new application of photovoltaic (PV) energy technologies whose energy output is affected by many design-related factors including PV module technologies, installation orientation, tilt and shadow range of solar panels. The shading analysis of a residential house's PV roof in Beijing was conducted by using building analysis program Autodesk Ecotect 2010. Analysis result shows that there is no shadow on the PV roof from 9a.m to 4p.m in winter solstice when the solar altitude angle reaches minimum, which ensures almost no shading losses for the PV modules over the year. The differences in monthly energy output were compared in the case of different installation tilt of solar panels and PV module technologies. Finally, the contribution to the building energy of the PV roof was discussed. The results show that appropriate design and selection of PV modules can compensate for the energy requirements for building heating and cooling to some extent. © (2011) Trans Tech Publications, Switzerland.

Yuan X.,China Building Material Test and Certification Group Co.
Key Engineering Materials | Year: 2012

Through collecting and analyzing thermal data from on-site testing of more than 30 cement plants, combining with design indicators of production line and control parameters in practical operation, the paper has summarized 4 first level, 5 second level and 133 third level energy efficiency evaluation indicators of cement enterprises after an in-depth study on the main factors influencing coal and power consumption of cement plants. On this basis, an energy efficiency evaluation system of new suspension preheater cement enterprise is to be established in China. It is expected to provide cement enterprise the basis of mastering the level of energy management and checking questions of energy utilization, to play guiding functions in settlement of energy-saving measures, development of energy-saving potential and reduction of energy consumption. © (2012) Trans Tech Publications.

Zeng C.,China Building Material Test and Certification Group Co. | Huang Z.,University of Science and Technology of China
Key Engineering Materials | Year: 2014

The total bauxite reserves of China are about 3.7 billion tons, however the principal and the first-class bauxite reserves account for only about 20%. A large number of coal gangue was accumulated on the surface of earth, which not only encroaches land but also pollutes the environment. In this study, low-grade bauxite with alumina content of 53.18 wt.% originating from Shanxi Yangquan and coal gangue with alumina content of 38.07 wt.% originating from Shanxi Datong were used to synthesize mullite materials. Bauxite and gangue were mixed by the ratio of 1 to 1. The ingredients were prepared according to the alumina content of 45.63 wt.% and 70 wt.%, by adding a certain amount of industrial alumina, respectively. The samples were sintered at 1350°C to 1600°C after being milled, dried and formed. The influence of alumina content and sintering temperature on the phase, microscopic morphology and properties of samples were discussed. The results show that, the main phases of the sample with the alumina content of 70 wt.% were mullite (more than 60 %) and corundum after being sintered for 4h at 1600 °C. The phenomenon of columnar mullite and granular corundum staggering had been observed. The bulk density and the bending strength of sample is 3.21 g/cm3 and 220.73 MPa respectively. © (2014) Trans Tech Publications, Switzerland.

Peng C.,China Building Material Test and Certification Group Co. | Yang W.,China Building Material Test and Certification Group Co.
Key Engineering Materials | Year: 2016

In order to improve the properties of MgO-Cr2O3 refractory, the effect of ZrO2 addition in MgO-Cr2O3 refractory physical properties and RH degasser slag corrosion resistance was investigated. The results show that the presence of ZrO2 additive increase the density of MgO-Cr2O3 samples largely due to promotion of grain boundary activities and ultimately direct bond formation. Simultaneously, the high temperature mechanical properties and corrosion resistance are improved in this test. The results also indicate that in the RH degasser slag system with a high ratio of calcia to silica, the slag resistance behavior of MgO-Cr2O3 composite with ZrO2 added could be described as follows: the ZrO2 reacts with CaO to form the CaZrO3 compound, this kind of compound could increase the corrosion resistance performance by blinding pore and the reaction could also thick the viscosity of slag, it is expected to be the major reason that the corrosion resistance of MgO-Cr2O3 refractory is improved by the addition of ZrO2. © 2016 Trans Tech Publications, Switzerland.

Liu Z.,China Building Material Test and Certification Group Co.
Advanced Materials Research | Year: 2011

For achieving the maximum energy efficiency of Building-integrated Photovoltaics (BIPV) buildings, the Solar Heat Gain (SHG) through the BIPV modules should be measured accurately. A solar calorimetry hot box was designed to test the SHG through the BIPV modules in this paper, which could measure the incoming solar and long-wave radiation various BIPV module configurations. Combined with the electric energy production, a new concept of ratio of solar heat gain to power energy generation efficiency was presented in this paper, which can be characterized as the design indicator of BIPV module's energy efficiency level for BIPV buildings cooling in hot summer. The influence of indoor climate environment parameters on the electric energy output efficiencies of BIPV modules can be conducted by the solar calorimetry hot box. © 2011 Trans Tech Publications, Switzerland.

Yan Y.Q.,North China Institute of Science and Technology | Wen Y.G.,China Building Material Test and Certification Group Co.
Applied Mechanics and Materials | Year: 2014

In this communication, Ag0.9Na0.1 (NbyTa1-y)O3 (y=0.5,0.6,0.7,0.9)(ANNT) mixed oxide powder was synthesized by citrate wet chemical method. TG-DTA, XRD and TEM analyses showed that the reaction temperature was 800°C, the calcining time was three hours, and the product was pure ANNT in well-dispersed grain structure (45nm in average). © (2014) Trans Tech Publications, Switzerland.

Wei C.,Xi'an Technological University | Liu Z.,China Building Material Test and Certification Group Co. | Deng X.,Xi'an Technological University
Advanced Materials Research | Year: 2011

In recent years, Building Integrated Photovoltaic (BIPV) system has been becoming one of most important application of solar energy. Heat is the key of the BIPV design. If the temperature of photovoltaic modules is too high, it will affect the efficiency of solar cells, the structure performance of the components and service life. This paper present a photoelectric-thermoelectric (PV-TV) model which can collect heat from the solar panels so that to reduce its surface temperature, and then to generate electricity by using of temperature difference technology and devices. The model presented in this paper provides designers a new concept in BIPV design. © (2011) Trans Tech Publications, Switzerland.

Zhang R.,China Building Material Test and Certification Group Co.
Key Engineering Materials | Year: 2016

A new method of using ion chromatograph (IC) to test chloridion content in the cement was introduced in this paper. Compared with existing methods, in the experimental processing, IC method can avoid tedious pretreatment processing steps and highly toxic reagents. After 6 times of parallel experiments, IC method showed lower standard deviation and repeatability limit than Ammonium thiocyanate titration method and distillation and titration method. The repeatability limit of IC method is about 0.0006 %. From the parallel experiments, we can find, IC method showed high reproducibility and instrument stability. © 2016 Trans Tech Publications, Switzerland.

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