Hydraulic loss analysis in a pump-turbine with special emphasis on local rigid vortex and shear

Since the pump as turbine is increasingly employed in energy storage, improving efficiency in both pump and turbine modes is required for economic benefits. This study aims to analyze vortex flow characteristics and vortex control methods in both modes to reduce hydraulic loss. In this paper, a delayed detached eddy simulation was applied in a low specific speed pump-turbine. Based on the entropy production analysis and vorticity binary decomposition in the local vortices, the results show that the local shear is the leading cause of hydraulic loss instead of the existence of vortices. The average wake loss can be 1.6 times higher than the loss in jet regions in pump mode, but there is little difference in the distribution of shear and vortices in the wake flow in turbine mode. The local loss caused by the rotor-stator interaction with a tongue effect at blade passing frequency is up to threefold over the loss without a tongue effect in both modes. Reducing shear and ratio of shear to rigid vorticity of the local vortices via modification in the volute tongue angle to suppress the tongue effect can be an effective way to decrease hydraulic loss in both modes

Assessment of English Teaching From Social - Anthropological Perspective: A Case Study of Microteaching in Warwick SJTU ETD Programme

Microteaching has gained considerable attention for its effectiveness in training teachers. Based on social-anthropological theory, a microteaching workshop in Warwick SJTU ETD Programme for 22 English teachers was investigated. Observation and interview, as the main basic methods, were applied to collect data. The results showed that microteaching offered participants an opportunity to practice teaching and receive useful feedback from peers and professional supervisors. Moreover, it was indicated that the improvement of teaching largely depends on self-reflection. The participants who were aware of teaching objectives and teaching aids, and opened to alternative teaching materials could easily manage the classroom teaching, and activate students’ learning

trans-Cinnamaldehyde Reverses Depressive-Like Behaviors in Chronic Unpredictable Mild Stress Rats by Inhibiting NF-κB/NLRP3 Inflammasome Pathway

trans-Cinnamaldehyde (TCA) is the main active component extracted from Cinnamomum cassia (C. cassia), which has many pharmacological effects, such as anti-inflammation, lowering blood glucose, and improving nerve function. However, there is no report of TCA in the treatment of depression. The purpose of this study was to investigate the antidepressant-like effect of TCA and the mechanism of NF kappa B (NF-κB) pathway and NLRP3 inflammasome inhibition by TCA. We divided 40 rats into the control group, CUMS group, FLU group, and the TCA group. The activation of the NF-κB pathway and NLRP3 inflammasome in prefrontal cortex and hippocampus of rats in each group was observed. After the treatments with FLU and TCA, the sucrose consumptions in rats increased significantly and the immobility time in forced swimming was decreased significantly compared to the CUMS group. The expression of TLR4, NF-κB-1, p-p65, TNF-α, NLRP3, ASC, caspase-1, IL-1β, and IL-18 proteins in prefrontal cortex and hippocampus was decreased, and the expression of IL-1β, IL-18, and TNF-α in serum was downregulated compared to the CUMS group. Similar to FLU, TCA reverses the depression-like behaviors in rats, which indicates that TCA has a significant antidepressant-like effect. The mechanism of the antidepressant property of TCA might be that it inhibits the activation of the NF-κB pathway and NLRP3 inflammasome in the prefrontal cortex and hippocampus of CUMS rats

Promoting effect of low concentration strontium on photosynthetic performance of Chinese cabbage seedlings: Combined leaf characteristics, photosynthetic carbon assimilation and chlorophyll fluorescence

Low concentration strontium (LC-Sr) can promote the growth of plants. In order to explore its promoting mechanism from the aspect of photosynthesis, the leaf characteristics, CO2 assimilation and chlorophyll (Chl) a fluorescence kinetics were investigated with hydroponically LC-Sr-treated Chinese cabbage seedlings. After a 28-d treatment to SrCl2 at different concentrations (0.1, 0.2, 0.5, and 1.0 mmol L−1), we observed an increase in the specific leaf weight (SLW) of Chinese cabbage compared with the control group. Notably, as the strontium concentration increased, a more pronounced improvement trend in the contents of Chl and protein in the leaves was observed, contributing to the enhancement of photosynthesis. However, the statistical differences in Pn among various LC-Sr treatments were not significant. Nevertheless, the leaf starch content exhibited a significant increase after LC-Sr treatments. Additionally, Chl a fluorescence transient has been used as a sensitive indicator of the promotional effect of LC-Sr on photosynthesis. The results of fluorescence parameters showed that LC-Sr treatments accelerated the light reaction speed of leaves (Tfm, dV/dto, dVG/dto), improved the energy utilization efficiency of photosystem (PSI and PSII) (ETo/CSo, ψET,ψRE, δRo, φRo), and ultimately enhanced the photosynthetic performance of leaves (PIabs, SFIabs, DFabs). The increased RCs/CSo and Sm contributed to the enhancement of the light reaction activity of strontium-treated leaves. The LC-Sr treatments had no interference with the calcium absorption, and notably enhanced the photosynthetic capacity of Chinese cabbage, shedding light on potential benefits of LC-Sr for crop cultivation

Single-Chain Variable Fragment Antibody of Vascular Cell Adhesion Molecule 1 as a Molecular Imaging Probe for Colitis Model Rabbit Investigation

Vascular cell adhesion molecule-1 (VCAM-1) can be a promising target for colitis study because of its critical role in inflammation development. Single-chain variable fragment (scFv) antibody presents fast blood clearance when served as an imaging probe. We applied the probe of 99mTc-scFv-VCAM-1 to colitis rabbit to examine its imaging performance. The colitis model rabbit was prepared, and a typical inflammatory lesion was confirmed in the colon. The probe of 99mTc-scFv-VCAM-1 was synthesized and injected into the model animal before imaging examination. Scintigraphy detected colitis lesions in both SPECT planar and SPECT/CT fused images, with higher target-to-nontarget ratios in the model group (2.71 ± 0.31) than those in the control group (1.12 ± 0.10). Biodistribution study determined tracer uptake in different organs, and autoradiography (ARG) confirmed probe accumulation in colon lesions. The uptake ratio of the model colon to the control colon was 4.71 ± 0.61 in quantitative analysis of the ARG regions of interest. Stronger VCAM-1 expression in the model colon than that in the control colon was confirmed by western blotting and immunohistochemistry. Our imaging study indicates molecular imaging with scFv-VCAM-1 as a promising way for inflammatory bowel disease diagnosis and evaluation

Effects of the Newly Isolated T4-like Phage on Transmission of Plasmid-Borne Antibiotic Resistance Genes via Generalized Transduction

Bacteriophages are the most abundant biological entities on earth and may play an important role in the transmission of antibiotic resistance genes (ARG) from host bacteria. Although the specialized transduction mediated by the temperate phage targeting a specific insertion site is widely explored, the carrying characteristics of “transducing particles” for different ARG subtypes in the process of generalized transduction remains largely unclear. Here, we isolated a new T4-like lytic phage targeting transconjugant Escherichia coli C600 that contained plasmid pHNAH67 (KX246266) and encoded 11 different ARG subtypes. We found that phage AH67C600_Q9 can misload plasmid-borne ARGs and package host DNA randomly. Moreover, for any specific ARG subtype, the carrying frequency was negatively correlated with the multiplicity of infection (MOI). Further, whole genome sequencing (WGS) identified that only 0.338% (4/1183) of the contigs of an entire purified phage population contained ARG sequences; these were floR, sul2, aph(4)-Ia, and fosA. The low coverage indicated that long-read sequencing methods are needed to explore the mechanism of ARG transmission during generalized transduction

Optical Interpretation of Oil Emulsions in the Ocean – Part I: Laboratory Measurements and Proof-of-concept with AVIRIS Observations

Optical identification and quantification of various marine-spilled oils play an important role in oil spill monitoring, assessment, and response. Through weathering processes, oil may become emulsified in two forms of oil-water mixture: water in oil (WO) and oil in water (OW). These two forms of oil emulsion are significantly different in their volume concentration (oil/water ratio), physical properties (viscosity, density, thickness), and optical properties (spectral reflectance (Ru(λ), sr−1), and spectral absorption (a(λ), m−1)). In this study, the optical properties of both types of oil emulsion, with different volumetric concentrations, are determined from carefully prepared oil emulsion samples, with the aim of helping to interpret optical remote sensing imagery. The concentrations of stable WO and OW emulsions range from 45% to 95% and from 0.025% to 3%, respectively. They exhibit different Ru spectral shapes in the near-infrared and shortwave-infrared wavelengths, with five “-CH” molecular bonds evident in the WO emulsion spectra. Ru (600–1400 nm) of OW emulsions increases with volume concentrations from 0% to 3.0%, but Ru (600–2400 nm) of the WO emulsions decreases with volume concentrations from 45% to 100%. On the other hand, for a fixed concentration (80%), Ru (600–2400 nm) of WO emulsions increases monotonically with thicknesses of up to ~0.4 mm, beyond which Ru (600–2400 nm) no longer increases with oil thickness. The difference between the Ru spectral shapes of OW and WO emulsions, as well as the statistical relationships between volume concentrations and Ru (NIR-SWIR) and between oil thickness and Ru (NIR-SWIR), provide the basis for developing optical models to classify oil emulsion types and for quantifying oil volume from remote sensing imagery. The potential of such an application is demonstrated using hyperspectral AVIRIS imagery collected over the Deepwater Horizon (DWH) oil spill in the Gulf of Mexico (GoM)