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Xing Xu,Rui Cheng,Pu Yang,Ruiqi Liu 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.6
Concrete-fi lled U-shaped steel (CFUS) beam and concrete-fi lled steel tube (CFST) column are recently developed because of the quick construction and economical saving. This paper aims to investigate the seismic performance of a composite connection system connecting CFUS beam to square CFST columns. In the joint system, the grooved cuts on the square tube allowed the U-shaped steel beam passing through the joint core completely, which developed a through beam connection. To verify the seismic behavior of the beam-column connection, three specimens designed according to the strong column-weak beam and strong joint-weak member seismic concept were tested under combined constant axial compression and cyclic loading. For the test parameters, the diff erent connection details and the axial load on the CFST column were considered. The test results showed that the specimens exhibited good load-carrying, deformation, and energy dissipation capacities. The maximum story drift ratio of all the three specimens was 5%, satisfying the minimum requirement of special moment frames. The primary failure mode of the specimens was local buckling of the webs and the fracture of the bottom fl anges of the CFUS beam near the column tube. In addition, the joint shear strength of the specimens was evaluated based on ASCE design guidelines.
Microbial composition and diversity of the long term application of organic material in upland soil
NAN-HEE AN,Jong-Ho Park,Eun-Jung Han,Sung-Jun Hong,Yong-Ki Kim,Hyeong-Jin Jee 한국유기농업학회 2011 韓國有機農業學會誌 Vol.19 No.S
Organic and chemical fertilizer amendments are an important agricultural practice for increasing crop yields. In order to maintain the soil sustainability, it is important to monitor the effects of fertilizer applications on the shift of soil microorganism, which control the cycling of many nutrients in the soils. Here, culture-dependent and cultureindependent approaches were used to analyze the soil microorganism and community structure under six fertilization treatments, including green manure, rice straw compost, rapeseed cake, pig mature compost, NPK +pig mature compost, NPK and control. Both organic and chemical fertilizers caused a shift of the cultural microorganism CFUs after treatments. Bacterial CFUs of the organic fertilization treatments were significantly higher than that of chemical fertilization treatments. The DGGE profiles of the bacterial communities of the samples showed that the green manure treatment was a distinct difference in bacterial community, with a greater complexity of the band pattern than other treatments. Cluster analyses based on the DGGE profile showed that rice straw compost and pig mature compost had a similar banding pattern and clustered together firstly. Rapeseed cake, NPK, NPK + pig manure compost and control clustered together in other sub-cluster and clearly distinguished from green manure.
Microbial composition and diversity of the long term application of organic material in upland soil
An, Nan-Hee,Park, Jong-Ho,Han, Eun-Jung,Hong, Sung-Jun,Kim, Yong-Ki,Jee, Hyeong-Jin Korean Association of Organic Agriculture 2011 韓國有機農業學會誌 Vol.19 No.S
Organic and chemical fertilizer amendments are an important agricultural practice for increasing crop yields. In order to maintain the soil sustainability, it is important to monitor the effects of fertilizer applications on the shift of soil microorganism, which control the cycling of many nutrients in the soils. Here, culture-dependent and culture-independent approaches were used to analyze the soil microorganism and community structure under six fertilization treatments, including green manure, rice straw compost, rapeseed cake, pig mature compost, NPK +pig mature compost, NPK and control. Both organic and chemical fertilizers caused a shift of the cultural microorganism CFUs after treatments. Bacterial CFUs of the organic fertilization treatments were significantly higher than that of chemical fertilization treatments. The DGGE profiles of the bacterial communities of the samples showed that the green manure treatment was a distinct difference in bacterial community, with a greater complexity of the band pattern than other treatments. Cluster analyses based on the DGGE profile showed that rice straw compost and pig mature compost had a similar banding pattern and clustered together firstly. Rapeseed cake, NPK, NPK +pig manure compost and control clustered together in other sub-cluster and clearly distinguished from green manure.
Assessment of indoor air micro-flora in selected schools
Katiyar, Vinita Techno-Press 2013 Advances in environmental research Vol.2 No.1
Quantification of viable forms of microbial community (bacteria and fungi) using culture-dependent methods was done in order to characterize the indoor air quality (IAQ). Role of those factors, which may influence the concentration of viable counts of bacteria and fungi, like ventilation, occupancy, outdoor concentration and environmental parameters (temperature and relative humidity) were also determined. Volumetric-infiltration sampling technique was employed to collect air samples both inside and outside the schools. As regard of measurements of airborne viable culturable microflora of schools during one academic year, the level of TVMCs in school buildings was ranged between 803-5368 cfu/$m^3$. Viable counts of bacteria (VBCs) were constituted 63.7% of the mean total viable microbial counts where as viable counts of fungi (VFCs) formed 36.3% of the total. Mean a total viable microbial count (TVMCs) in three schools was 2491 cfu/$m^3$. Outdoor level of TVMCs was varied from 736-5855 cfu/$m^3$. Maximum and minimum VBCs were 3678-286 cfu/m3 respectively. Culturable fungal counts were ranged from 268-2089 cfu/$m^3$ in three schools. Significant positive correlation (p < 0.01) was indicated that indoor concentration of viable community reliant upon outdoor concentration. Temperature seemed to have a large effect (p < 0.05, p < 0.01) on the concentration of viable culturable microbial community rather than relative humidity. Consistent with the analysis and findings, the concentration of viable cultural counts of bacteria and fungi found indoors, were of several orders of magnitude, depending upon the potential of local, spatial and temporal factors, IO ratio appeared as a crucial indicator to identify the source of microbial contaminants.