Nonlinear Numerical Analysis and Restoring force Model of Composite Joints with Steel Reinforced Recycled Concrete Columns and Steel Beams

Cyclic loading tests were conducted for eight composite joints (five interior joints and three exterior joints) with steel reinforced recycled concrete (SRRC) columns and steel beams under cyclic loading. The axial compression ratio and recycled coarse aggregate (RCA) replacement percentage were considered as the main design parameters for the above composite joints. The seismic behavior of the composite frame joints with (SRRC) columns and steel beams were studied by numerical simulation and the constitutive models of recycled aggregate concrete (RAC), steel and reinforcement were given to the corresponding elements. The experimental results were used to validate the finite element (FE) model. The results indicated that the FE model can accurately predict the deformation and stress load-strain curves of the composite joints. Then, a FE parameter analysis was carried out on the seismic behavior of the composite joints. The RAC strength, steel strength and column steel web thickness were considered as the main parameters. Results pinpointed that the increase in RAC strength and steel web thickness of the columns significantly affected the horizontal bearing capacity of the composite joints. However, with the increase in RAC and steel strength, the deformation ability and ductility of composite joints were almost unaffected. The reasonable increase in column steel web thickness can improve the seismic ductility of composite joints, evidently. On this basis, considering the stress characteristics of joint specimens, a four broken line restoring force model for steel reinforced recycled concrete column steel beam composite frame joints was established. This model includes the skeleton curve model, the stiffness degradation pattern and hysteresis rules. The calculation curve was in good agreement with experimental curves, which can well reflect the hysteretic behavior of joints subjected to low cyclic repeated loading. The above results can be used as a reference for the seismic design of composite frame joints

Adaptive Observer Based Fault Tolerant Control for Sensor and Actuator Faults in Wind Turbines

The installed wind energy generation capacity has been increasing dramatically all over the world. However, most wind turbines are installed in hostile environments, where regular operation needs to be ensured by effective fault tolerant control methods. An adaptive observer-based fault tolerant control scheme is proposed in this article to address the sensor and actuator faults that usually occur on the core subsystems of wind turbines. The fast adaptive fault estimation (FAFE) algorithm is adopted in the adaptive observers to accurately and rapidly located the faults. Based on the states and faults estimated by the adaptive observers, the state feedback fault tolerant controllers are designed to stabilize the system and compensate for the faults. The gain matrices of the controllers are calculated by the pole placement method. Simulation results illustrate that the proposed fault tolerant control scheme with the FAFE algorithm stabilizes the faulty system effectively and performs better than the baseline on the benchmark model of wind turbines

Determination of Three Typical Metabolites of Pyrethroid Pesticides in Tea Using a Modified QuEChERS Sample Preparation by Ultra-High Performance Liquid Chromatography Tandem Mass Spectrometry

Pyrethroid pesticides are widely used on tea plants, and their residues of high frequency and concentration have received great attention. Until recently, the residues of typical metabolites of pyrethroid pesticides in tea were unknown. Herein, a modified “quick, easy, cheap, effective, rugged and safe” (QuEChERS) method for the determination of three typical metabolites of pyrethroid pesticides in tea, using ultra performance liquid chromatography tandem mass spectrometry, was developed. The mixture of florisil, octadecylsilane, and graphite carbon black was employed as modified QuEChERS adsorbents. A Kinetex C18 column achieved good separation and chromatographic peaks of all analytes. The calibration curves of 3-phenoxybenzoic acid (3-PBA) and 4-fluoro-3-phenoxybenzoic acid (4-F-3-PBA) were linear in the range of 0.1–50 ng mL−1 (determination coefficient R2 higher than 0.999), and that of cis-3-(2-chloro-3,3,3-trifluoroprop-1-en-1-yl)-2,2-dimethylcyclopropanecarboxylic acid (TFA) was in the range of 1–100 ng mL−1 (R2 higher than 0.998). The method was validated and recoveries ranged from 83.0% to 117.3%. Intra- and inter-day precisions were lower than or equal to 13.2%. The limits of quantification of 3-PBA, 4-F-3-PBA, and TFA were 5, 2, and 10 μg kg−1, respectively. A total of 22 tea samples were monitored using this method, and 3-PBA and TFA were found in two green tea samples

Active Methanotrophs and Their Response to Temperature in Marine Environments: An Experimental Study

Aerobic methane (CH4) oxidation plays a significant role in marine CH4 consumption. Temperature changes resulting from, for example, global warming, have been suggested to be able to influence methanotrophic communities and their CH4 oxidation capacity. However, exact knowledge regarding temperature controls on marine aerobic methane oxidation is still missing. In this study, CH4 consumption and the methanotrophic community structure were investigated by incubating sediments from shallow (Bohai Bay) and deep marine environments (East China Sea) at 4, 15, and 28 °C for up to 250 days. The results show that the abundance of the methanotrophic population, dominated by the family Methylococcaceae (type I methanotrophs), was significantly elevated after all incubations and that aerobic methane oxidation for both areas had a strong temperature sensitivity. A positive correlation between the CH4 oxidation rate and temperature was witnessed in the Bohai Bay incubations, whereas for the East China Sea incubations, the optimum temperature was 15 °C. The systematic variations of pmoA OTUs between the Bohai Bay and East China Sea incubations indicated that the exact behaviors of CH4 oxidation rates with temperature are related to the different methanotrophic community structures in shallow and deep seas. These results are of great significance for quantitatively evaluating the biodegradability of CH4 in different marine environments

Huang chao jing shi wen xu bian : [120 juan] /

On double leaves, oriental style.Mode of access: Internet

Characterization and Transcriptome Analysis of Maize Small-Kernel Mutant <i>smk7a</i> in Different Development Stages

The kernel serves as a storage organ for various nutrients and determines the yield and quality of maize. Understanding the mechanisms regulating kernel development is important for maize production. In this study, a small-kernel mutant smk7a of maize was characterized. Cytological observation suggested that the development of the endosperm and embryo was arrested in smk7a in the early development stage. Biochemical tests revealed that the starch, zein protein, and indole-3-acetic acid (IAA) contents were significantly lower in smk7a compared with wild-type (WT). Consistent with the defective development phenotype, transcriptome analysis of the kernels 12 and 20 days after pollination (DAP) revealed that the starch, zein, and auxin biosynthesis-related genes were dramatically downregulated in smk7a. Genetic mapping indicated that the mutant was controlled by a recessive gene located on chromosome 2. Our results suggest that disrupted nutrition accumulation and auxin synthesis cause the defective endosperm and embryo development of smk7a

Tumor specificity of WNT ligands and receptors reveals universal squamous cell carcinoma oncogenes

Abstract Background The WNT signal pathway has myriad family members, which are broadly involved in embryonic development and human cancer. Over-activation of WNT-β-Catenin signaling promotes cancer cell proliferation and survival. However, how diverse components of WNT signaling specifically engaged in distinct tumor types remains incompletely understood. Methods We analyzed the transcriptomic profiling of WNT ligands and receptors/co-receptors among 26 different tumor types to identify their expression pattern, and further verified these results using clinical oral squamous cell carcinoma (OSCC) and lung squamous cell carcinoma (LUSC) samples. At the same time, we also detected WNT7B expression in oral inflammation and carcinoma, and constructed stable WNT7B knockdown OSCC cell lines to study the effects of WNT7B on the cell migration and invasion ability. Results We found a group of tumor-specific WNT members, including a panel of squamous cell carcinomas (SCCs) specific upregulated WNT ligands and receptors, WNT5A, WNT7B, FZD7 and GPC1. We further revealed a significant correlation between these protein expression characteristics and clinical outcomes of OSCC and LUSC patients. Moreover, WNT7B was demonstrated to contribute to the development of oral chronic inflammation and OSCC, partly due to promoting the invasion ability of tumor cells. Conclusions These results demonstrate that the function of WNT ligands and receptors in specific tumors depends on the origination of tumor tissue type. Collectively, they support the use of WNT components as a highly specific target for pan-tissue-type originated tumors

Overexpression of OsbHLH107, a member of the basic helix-loop-helix transcription factor family, enhances grain size in rice (Oryza sativa L.)

Abstract Background Grain size, which is determined by grain length, grain width, and grain thickness, is an important determinant for grain yield in rice. Identification and characterization of new genes that are associated with grain size will be helpful for the improvement of grain yield in rice. Results We characterized the grain size mutant, larger grain size 1 (lgs1), derived from rice activation-tagged T-DNA insertion lines. Histological analysis showed that increased cell numbers in the longitudinal direction of spikelet hulls was responsible for the grain mutant phenotype in lgs1. Quantitative real-time PCR (qRT-PCR) analysis further showed that the expression levels of genes associated with the cell cycle in the young panicles of the lgs1 were higher than those in the wild type (WT), which might result in the increased cell numbers in lgs1 spikelet hulls. Insertion site analysis together with transgenic experiments confirmed that the lgs1 phenotype was caused by enhanced expression of truncated OsbHLH107, corresponding to the nucleotide (nt) 331–846 region (i.e., the transcriptional activation region of OsbHLH107) of the OsbHLH107 coding sequence (CDS). OsbHLH107 is a nucleus-localized bHLH transcription factor, which can form a homodimer with itself. Phylogenetic analysis showed that OsbHLH107 belonged to the same subfamily as OsPILs. OsPIL13 (OsPIL1) and OsPIL16 (APG) were reported to regulate grain size in rice. By transgenic experiments, we found that OsPIL11 could also regulate grain size. Conclusion We concluded that OsbHLH107 and its homologs are important regulators of grain size development and might be useful for grain yield improvement in rice