Cloud Seeding Evidenced by Coherent Doppler Wind Lidar

Evaluation of the cloud seeding effect is a challenge due to lack of directly physical observational evidence. In this study, an approach for directly observing the cloud seeding effect is proposed using a 1548 nm coherent Doppler wind lidar (CDWL). Normalized skewness was employed to identify the components of the reflectivity spectrum. The spectrum detection capability of a CDWL was verified by a 24.23-GHz Micro Rain Radar (MRR) in Hefei, China (117°15′ E, 31°50′ N), and different types of lidar spectra were detected and separated, including aerosol, turbulence, cloud droplet, and precipitation. Spectrum analysis was applied as a field experiment performed in Inner Mongolia, China (112°39′ E, 42°21′ N ) to support the cloud seeding operation for the 70th anniversary of China’s national day. The CDWL can monitor the cloud motion and provide windshear and turbulence information ensuring operation safety. The cloud-precipitation process is detected by the CDWL, microwave radiometer (MWR) and Advanced Geosynchronous Radiation Imager (AGRI) in FY4A satellites. In particular, the spectrum width and skewness of seeded cloud show a two-layer structure, which reflects cloud component changes, and it is possibly related to cloud seeding effects. Multi-component spectra are separated into four clusters, which are well distinguished by spectrum width and vertical velocity. In general, our findings provide new evidence that the reflectivity spectrum of CDWL has potential for assessing cloud seeding effects.

Designing an intelligent monitoring system for corn seeding by machine vision and Genetic Algorithm-optimized Back Propagation algorithm under precision positioning

Objective To realize the regulation of the position of corn seed planting in precision farming, an intelligent monitoring system is designed for corn seeding based on machine vision and the Genetic Algorithm-optimized Back Propagation (GABP) algorithm. Methods Based on the research on precision positioning seeding technology, comprehensive application of sensors, Proportional Integral Derivative (PID) controllers, and other technologies, combined with modern optimization algorithms, the online dynamic calibration controls of line spacing and plant spacing are implemented. Based on the machine vision and GABP algorithm, a test platform for the seeding effect detection system is designed to provide a reference for further precision seeding operations. GA can obtain better initial network weights and thresholds and find the optimal individual through selection, crossover, and mutation operations; that is, the optimal initial weight of the Back Propagation (BP) neural network. Field experiments verify the seeding performance of the precision corn planter and the accuracy of the seeding monitoring system. Results 1. The deviation between the average value of the six precision positioning seeding experiments of corn under the random disturbance signal and the ideal value of the distance is less than or equal to 0.5 cm; the deviation between the average value of the six precision positioning seeding experiments of corn under the sine wave disturbance signal (1 Hz) is less than or equal to 0.4 cm; the qualified rate of grain distance reaches 100%. 2. The precision control index, replay index, and missed index of the designed corn precision seeding intelligent control system have all reached the national standard. During the operation of the seeder, an alarm of the seeder leaking occurred, and the buzzer sounded and the screen displayed 100 times each; therefore, the reliability of the alarm system is 100%. Conclusion The intelligent corn seeder designed based on precision positioning seeding technology can reduce the seeding rate of the seeder and ensure the stability of the seed spacing effectively. Based on the machine vision and GABP algorithm, the seeding effect detection system can provide a reference for the further realization of precision seeding operations.

Impact of aging on the hydration of tricalcium aluminate (C3A)/gypsum blends and the effectiveness of retarding admixtures

In the production of concrete from cement powder and water, setting behavior of the slurry is determined by the formation of ettringite (Ca6Al2(OH)12 · (SO4)3 · 26 H2O) from tricalcium aluminate (Ca9Al6O18, abbreviated C3A) and gypsum (CaSO4 · 2 H2O). Due to the high reaction potential of cement and water, premature hydration can occur after unintentional exposure to moisture. Model binary mixtures of C3A and gypsum stored at 90% relative humidity and 35 °C produced ample amounts of ettringite, which subsequently reacted with atmospheric CO2 to CaCO3, Al(OH)3 and gypsum. Investigated were the two main polymorphs of tricalcium aluminate encountered in cement, pure, cubic C3A and orthorhombic C3A in which calcium is partially substituted by sodium or potassium. Alkali substituted C3A converted to ettringite faster and more completely than pure C3A. Ettringite from prehydration caused a seeding effect, which promotes crystal growth and accelerates bulk hydration of the C3A/gypsum mixtures. Set retarders commonly applied in cement were dissolved in the mixing water prior to hydration to investigate their ability to counteract this acceleration. Sodium gluconate merely delayed the crystal growth but does not prolong the hydration process overall. Potassium pyrophosphate retarded much more effectively by suppressing the seeding effect via removal of calcium ions from the hydration reaction.

Seeding Performance Simulations and Experiments for a Spoon-Wheel Type Precision Cottonseed-Metering Device Based on EDEM

To study the effects of seed metering on seeding performance under different motion parameters, a simulation model for a spoon-wheel type seeder was established. A seed meter was tested by using EDEM (Engineering Discrete Element Method) software to simulate its working process at different speeds and tilt angles. The trajectories of individual cottonseeds in the seed-metering device were obtained, concurrently, the stress trend in the grain group was determined as a function of time. The simulation results suggest that at larger speeds, the metering index of the seed meter gradually decreases, while the index and the missing index gradually increase. As the tilt angle increased, the multiples index and missing index gradually decreased, while the multiples index gradually increased. When the seed meter speed reached 50 r/min and the tilt angle was 15°, the seed meter had a relatively good working performance with a seed spacing acceptance index of 92.59%, a multiples index of 1.85%, and a missing rate index of 5.56%. The seed meter was tested on a bench by using a JPS-12 performance-tester bench. At the aforementioned speed and angle, the coefficient of variation for the cottonseed spacing was 2.1%. The field trial results indicated that the multiples and the missing rates were higher than those for the tester bench but still met a passing rate of more than 90%. The coefficient of variation for the seed spacing was less than 10%, suggesting that the design could be used for field sowing. The resulting seeding uniformity was higher under these conditions, which indicates that the seed meter has a better working performance and the bench has a good seeding effect.

α-Linolenic acid modulates phagocytosis of extracellular Tau and induces microglial migration

The seeding effect of extracellular Tau species is an emerging aspect to study the Tauopathies in Alzheimer’s disease. Tau seeds enhance the propagation of disease along with its contribution to microglia-mediated inflammation. Omega-3 fatty acids are known to exert the anti-inflammatory property to microglia by modulating cell membrane compositions that influence various receptors expression and signaling cascade. The immunomodulatory function of omega-3 fatty acids exerts anti-inflammatory properties to microglia. Owing to the imparted anti-inflammatory nature enhance phagocytosis and increased migration property has been observed in microglia. The increased phagocytosis of extracellular Tau monomer and aggregates has been observed upon ALA exposure to microglia cells. The intracellular degradation of internalized Tau species was targeted by early and late endosomal markers Rab5 and Rab7. The increased levels of LAMP-2A and colocalization with internalized Tau indicated the degradation via lysosome. These results indicate the degradation of internalized Tau species in the presence of ALA instead of getting accumulated in the cell. The enhanced migratory ability of microglia in the presence of ALA induces the MTOC repolarization. Tau seeds greatly contribute to the spread of disease, one way to reduce the spreading is to reduce the presence of extracellular Tau seed. Microglia could be influenced to reduce extracellular Tau seed with dietary fatty acids. Our results suggest that dietary fatty acids ALA significantly enhances phagocytosis and intracellular degradation of internalized Tau. Enhanced migration supports the phagocytosis process. Our approach provides insights into the beneficial role of ALA as an anti-inflammatory dietary supplement to treat AD.

Observation of seasonal asymmetry in the range spread F occurrence at different longitudes during low and moderate solar activity

A comparative study of the equatorial spread F occurrence was conducted at different longitudes during 2010 and 2013 representing the low (LSA) and moderate (MSA) solar activity periods respectively. The ionogram data were recorded at low-latitude stations including Jicamarca (JIC;75.76∘ W, 8.17∘ S), Fortaleza (FZA; 38.52∘ W, 3.73∘ S), Ilorin (ILR; 7.55∘ E, 9.93∘ N), Chumphon (CPN; 88.46∘ E, 11∘ N) and Kwajalein (KWA; 167.73∘ E, 8.72∘ N). The range type spread F (RSF) occurrence was manually recorded at an hourly interval between 18:00 and 06:00 LT, and a monthly average of the RSF occurrence was estimated for each season. The longitudinal distribution of the RSF occurrence features included the observed difference in the onset time, the duration and the seasonal occurrence peak. The seasonal asymmetry in the RSF occurrence distribution was analysed in relation to the zonal drift reversal’s effect on the plasma irregularity initiation. We believe that the inconsistent equinoctial asymmetry pattern in the RSF occurrence is modulated by the seasonal/longitudinal variation of the zonal drift reversal delay during both solar epochs. Likewise, the seeding effect and the background ionospheric condition were also considered as major factors influencing the frequency of irregularity generation in these regions.