Search

The vibration performance of a simulation for a hidden-frame supported glass curtain wall (HFSGCW) was tested using a Laser Doppler Vibrometer (LDV) in this paper. The effect of silicon structural sealant on the first order inherent frequency of HFSGCW and the spectral characteristics per LDV on different points were studied. Meanwhile, the test results of LDV were verified using traditional sensors (DASP modal analysis system) in order to evaluate the feasibility of LDV used for safety state evaluation of HFSGCW. Results show that the first order inherent frequency obtained by LDV matches well with DASP modal analysis results. The first order inherent frequency decreases with an increase of sealant failure，and the first order frequency amplitude scale of structural sealant upper point increases significantly after the structural silicon sealant is destroyed. The safety state of HFSGCW is divided into three levels. Meanwhile, a safety state rapid evaluation model and key detection technologies of HFSGCW based on LDV is proposed.

This paper aims to calculate and analyze the spatial and temporal variations in the groundwater flow quantity in Nam Co Lake based on the water balance principle. The results show that a large amount of groundwater was gradually lost and that, groundwater loss decreased from 1.9 billion m3 to 1.5 billion m3 from the period of 1980&ndash, 1984 to 1995&ndash, 2009. The comparative analysis in the current study indicates that the decrease in the groundwater index has a strong linear relationship with the temperature of the ground surface on the Tibetan Plateau, with a correlation coefficient as high as 0.92. Moreover, environmental variations such as large-scale engineering construction projects and increases in water storage may have played dominant roles in the sudden changes in the water quantities of plateau lakes (e.g., Nam Co Lake) during the periods of 1990&ndash, 1995 and 2000&ndash, 2009. The increased water levels resulted in reduced groundwater losses, which may lead to the substantial expansion or gradual shrinkage of the Qinghai&ndash, Tibet Plateau lakes over short periods of time. The results of this study provide an important reference for studying the mechanisms of lake water level changes on the Qinghai&ndash, Tibet Plateau.

The two-dimensional Ti3C2(OH)2 nanosheets were synthesized by exfoliation of laminated Ti3AlC2 in HF and characterized by X-ray diffractometry, SEM, TEM, and HRTEM. The results indicated that the Ti3C2(OH)2 compounds had 2D layer-like structures with a thickness of 10–20 nm, and the fabrication process of Ti3C2(OH)2 nanosheets was discussed on the basis of the experimental facts. The tribological properties of Ti3C2(OH)2 nanosheets as additives in base oil were investigated using a UMT-2 ball-on-disc tribotester. Under the determinate conditions, the friction coefficient of the base oil containing Ti3C2(OH)2 nanosheets was lower than that of the base oil under 15 N load with 200 rpm, and decreased with increasing mass fraction of Ti3C2(OH)2 nanosheets when it was

A man–plant integration test was processed using the CELSS integration experiment platform in which 4 kinds of plants were grown (Lactuca sativa L var. Dasusheng, L. sativa L var. Youmaicai, Gynura bicolor and Cichorium endivia L) to exchange material with 2 persons in order to research the dynamic changing laws and balanced regulation of air and water between man and plant in an inclosed system. In the test the material flow was measured so that the dynamically changing laws and balanced regulation of air and water between man and plant in the closed system were mostly mastered. The material closure degree of air, water and food reached 100%, 90% and 13.9% respectively with the whole system closure degree up to 95.1%. Meanwhile, it was proved that a 13.5 m2 planting area could meet the demand of one person for O2 in the system, and the energy efficiency ratio of which reached 59.56 g/(kW m2 day). The material flow dynamic balance-regulating technology was initially mastered between man and plant through the test. The interaction was realized among man, plant and environment in the closed system, which is of great significance to the advancement of long-term manned environment control and life support technology for China.

Laser doppler vibrometer (LDV), which has measurement advantages such as being remote and non-contact, accurate, and having rapid dynamic response, is a useful assessment tool for the safety-state evaluation of hidden frame-supported glass curtain walls (HFSGCW). The engineering application influence factors of a LDV safety-state evaluation model for HFSGCW were analyzed and the vibration frequency for practical cases was tested in this paper. Results show that the first order peak frequency from a frequency spectrum obtained by LDV can be selected as the safety-state evaluation index for HFSGCW caused by structural sealant failure. A rubber hammer is an effective way to excite glass panels to obtain an accurate vibration frequency spectrum. The middle of glass panels is advisable to be selected as the measurement point to obtain an accurate dynamic frequency. The frequency spectrum of a glass panel edge point can be used to determine structural sealant failure position. Binoculars are suggested to be added in order to improve working efficiency of LDV for measurement distance greater than 10 m. Pasting reflective film is an effective way to increase LDV test signal accuracy. The glass panel safety-state of a commercial center building in Guangdong (China) is accurately evaluated by LDV, and those test results provide guidance for real-time monitoring and repair of HFSGCW.