Kármán Vortex Street Driven Membrane Triboelectric Nanogenerator for Enhanced Ultra-Low Speed Wind Energy Harvesting and Active Gas Flow Sensing

[Image: see text] Wind energy harvesting and sensing have a huge prospect in constructing self-powered sensor nodes, but the energy transducing efficiency at low and ultra-low wind speeds is still limited. Herein, we proposed a Kármán vortex street driven membrane triboelectric nanogenerator (KVSM-TENG) for ultra-low speed wind energy harvesting and flow sensing. By introducing Kármán vortex in the KVSM-TENG, the cut-in wind speed of the KVSM-TENG decreased from 1 to 0.52 m/s that is the lowest cut-in wind speed in current TENGs. The instantaneous output density of the KVSM-TENG significantly increased by 1000 times and 2.65 times at the inlet wind speeds of 1 and 2 m/s, respectively. In addition, with the excellent energy transducing performance at the ultra-low speed range, the KVSM-TENG was successfully demonstrated to detect a weak leakage of gas pipeline (∼0.6 m/s) for alarming with high sensitivity. The interaction mechanism between the vortex and KVSM-TENG was systematically investigated. Through the simulation and experimental validation, the enhancement mechanism of vortex dependence on the cylinder diameter and placement location of KVSM-TENG was investigated in detail. The influence of parameters such as membrane length, width, thickness, and electrode gap on the performance of the KVSM-TENG was systematically studied. This work not only provided an ingenious strategy for ultra-low speed wind energy harvesting but also demonstrates the promising prospects for monitoring the air flow in the natural gas exploitation and transportation

Analysis of key issues in construction project management of construction engineering

In recent years, with the continuous rapid growth of China's economy and the acceleration of new urbanization, large-scale basic construction projects are increasing day by day. In the wave of market economy, the importance of construction management has become increasingly prominent. Construction management is not only related to the progress, quality and safety of the entire project, but also has a very close relationship with economic benefits. For this reason, this article analyzes the problems existing in the construction project management of construction projects, and puts forward reasonable solutions for reference only. I hope that readers can do a good job in construction management in the construction of construction projects

Experimental study on shear mechanical properties of improved loess based on rubber particle incorporation and EICP technology

Loess is often not suitable for direct use as a roadbed or building foundation due to its collapsibility, and it needs to be improved by adding curing agents. Taking the loess in Xi’an area as the research object, the reinforcement of loess was carried out using waste tire rubber particles and Enzyme Induced Carbonate Precipitation (EICP) technology. The change of shear strength and shear strength index of improved soil with rubber content and rubber particle size under different strengthening conditions was analyzed, and the strengthening mechanism was also expounded. The results show that rubber powder can improve the shear strength of loess to a certain extent, and the combination of EICP technology can increase the strength of improved loess by nearly 50%. In addition, rubber particles have a certain inhibitory effect on EICP, and the shear strength growth rate decreases with the increase of rubber content. When the rubber particle size is 1–2 mm, the shear strength growth rate is the highest. It is suggested that when adding rubber particles or adding rubber particles combined with EICP technology is used to improve loess, the rubber particle size should be selected as 1–2 mm, and the content is about 10%. The test results can provide a scientific basis for the reduction of geologic disasters in loess areas, and at the same time can provide a non-polluting way for the disposal of waste tires

Static pressure and dynamic impact characteristics of filled jointed rock after frozen-thaw cycle damage

In the construction project, rock mass is often destroyed from the joint plane, and the jointed rock mass is easy to be eroded by freeze-thaw environment. Therefore, the damage mechanical properties of filled jointed rock mass under freeze-thaw action are very important for construction disaster prevention, engineering safety evaluation and reinforcement. In order to research the effect of the freeze-thaw cycle on the mechanical deterioration properties and damage characteristics of filled jointed rocks, prefabricated filled jointed rock samples are tested with different numbers of freeze-thaw cycles under the temperature range of -20°C~20°C. Then the wave velocity test, static compression test and SHPB impact test are conducted on the rock samples after freeze-thaw. Based on the test results, the change regularity of wave velocity degradation, static compression mechanical properties and dynamic compression mechanical properties of filled jointed rocks under the effect of freeze-thaw cycles were analyzed. The results show that the wave velocity, static compressive strength and dynamic compressive strength of the filled jointed rocks all show a downtrend with the increase of the number of freeze-thaw cycles, and each parameter is positively correlated with the strength of the filling materials. Among them, the decrease in the wave velocity of the rock sample after 30 freeze-thaw cycles is greater than 30%, and the strength loss of the static peak compressive strength exceeds half of its initial strength. The static peak strain rises exponentially with the increase of the number of freeze-thaw cycles while the dynamic peak strain does not show a clear trend. The dynamic peak strain is about 1/10 to 1/5 of the static peak strain. Under the same freeze-thaw action, the lower the strength of filling material, the more serious the damage

Injectable kartogenin and apocynin loaded micelle enhances the alleviation of intervertebral disc degeneration by adipose-derived stem cell.

Cell transplantation has been proved the promising therapeutic effects on intervertebral disc degeneration (IVDD). However, the increased levels of reactive oxygen species (ROS) in the degenerated region will impede the efficiency of human adipose-derived stem cells (human ADSCs) transplantation therapy. It inhibits human ADSCs proliferation, and increases human ADSCs apoptosis. Herein, we firstly devised a novel amphiphilic copolymer PEG-PAPO, which could self-assemble into a nanosized micelle and load lipophilic kartogenin (KGN), as a single complex (PAKM). It was an injectable esterase-responsive micelle, and showed controlled release ability of KGN and apocynin (APO). Oxidative stimulation promoted the esterase activity in human ADSCs, which accelerate degradation of esterase-responsive micelle. Compared its monomer, the PAKM micelle possessed better bioactivities, which were attributed to their synergistic effect. It enhanced the viability, autophagic activation (P62, LC3 II), ECM-related transcription factor (SOX9), and ECM (Collagen II, Aggrecan) maintenance in human ADSCs. Furthermore, it is demonstrated that the injection of PAKM with human ADSCs yielded higher disc height and water content in rats. Therefore, PAKM micelles perform promoting cell survival and differentiation effects, and may be a potential therapeutic agent for IVDD

Identifying the substrate proteins of U-box E3s E4B and CHIP by orthogonal ubiquitin transfer

E3 ubiquitin (UB) ligases E4B and carboxyl terminus of Hsc70-interacting protein (CHIP) use a common U-box motif to transfer UB from E1 and E2 enzymes to their substrate proteins and regulate diverse cellular processes. To profile their ubiquitination targets in the cell, we used phage display to engineer E2-E4B and E2-CHIP pairs that were free of cross-reactivity with the native UB transfer cascades. We then used the engineered E2-E3 pairs to construct “orthogonal UB transfer (OUT)” cascades so that a mutant UB (xUB) could be exclusively used by the engineered E4B or CHIP to label their substrate proteins. Purification of xUB-conjugated proteins followed by proteomics analysis enabled the identification of hundreds of potential substrates of E4B and CHIP in human embryonic kidney 293 cells. Kinase MAPK3 (mitogen-activated protein kinase 3), methyltransferase PRMT1 (protein arginine N-methyltransferase 1), and phosphatase PPP3CA (protein phosphatase 3 catalytic subunit alpha) were identified as the shared substrates of the two E3s. Phosphatase PGAM5 (phosphoglycerate mutase 5) and deubiquitinase OTUB1 (ovarian tumor domain containing ubiquitin aldehyde binding protein 1) were confirmed as E4B substrates, and b-catenin and CDK4 (cyclin-dependent kinase 4) were confirmed as CHIP substrates. On the basis of the CHIP-CDK4 circuit identified by OUT, we revealed that CHIP signals CDK4 degradation in response to endoplasmic reticulum stress

A method for estimating yield of maize inbred lines by assimilating WOFOST model with Sentinel-2 satellite data

Maize is the most widely planted food crop in China, and maize inbred lines, as the basis of maize genetic breeding and seed breeding, have a significant impact on China’s seed security and food safety. Satellite remote sensing technology has been widely used for growth monitoring and yield estimation of various crops, but it is still doubtful whether the existing remote sensing monitoring means can distinguish the growth difference between maize inbred lines and hybrids and accurately estimate the yield of maize inbred lines. This paper explores a method for estimating the yield of maize inbred lines based on the assimilation of crop models and remote sensing data, initially solves the problem. At first, this paper analyzed the WOFOST(World Food Studies)model parameter sensitivity and used the MCMC(Markov Chain Monte Carlo) method to calibrate the sensitive parameters to obtain the parameter set of maize inbred lines differing from common hybrid maize; then the vegetation indices were selected to establish an empirical model with the measured LAI(Leaf Area Index) at three key development stages to obtain the remotely sensed estimated LAI; finally, the yield of maize inbred lines in the study area was estimated and mapped pixel by pixel using the EnKF(Ensemble Kalman Filter) data assimilation algorithm. Also, this paper compares a method of assimilation by setting a single parameter. Instead of the WOFOST parameter optimization process, a parameter representing the growth weakness of the inbred lines was set in WOFOST to distinguish the inbred lines from the hybrids. The results showed that the yield estimated by the two methods compared with the field measured yield data had R2: 0.56 and 0.18, and RMSE: 684.90 Kg/Ha and 949.95 Kg/Ha, respectively, which proved that the crop growth model of maize inbred lines established in this study combined with the data assimilation method could initially achieve the growth monitoring and yield estimation of maize inbred lines

Real-Valued Covariance Vector Sparsity-Inducing DOA Estimation for Monostatic MIMO Radar

In this paper, a real-valued covariance vector sparsity-inducing method for direction of arrival (DOA) estimation is proposed in monostatic multiple-input multiple-output (MIMO) radar. Exploiting the special configuration of monostatic MIMO radar, low-dimensional real-valued received data can be obtained by using the reduced-dimensional transformation and unitary transformation technique. Then, based on the Khatri–Rao product, a real-valued sparse representation framework of the covariance vector is formulated to estimate DOA. Compared to the existing sparsity-inducing DOA estimation methods, the proposed method provides better angle estimation performance and lower computational complexity. Simulation results verify the effectiveness and advantage of the proposed method