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The ability to grow properly sized and good quality crystals is one of the cornerstones of single-crystal diffraction, is advantageous in many industrial-scale chemical processes.sup.1-3, and is important for obtaining institutional approvals of new drugs for which high-quality crystallographic data are required.sup.4-7. Typically, single crystals suitable for such processes and analyses are grown for hours to days during which any mechanical disturbances--believed to be detrimental to the process--are carefully avoided. In particular, stirring and shear flows are known to cause secondary nucleation, which decreases the final size of the crystals (though shear can also increase their quantity.sup.8-14). Here we demonstrate that in the presence of polymers (preferably, polyionic liquids), crystals of various types grow in common solvents, at constant temperature, much bigger and much faster when stirred, rather than kept still. This conclusion is based on the study of approximately 20 diverse organic molecules, inorganic salts, metal-organic complexes, and even some proteins. On typical timescales of a few to tens of minutes, these molecules grow into regularly faceted crystals that are always larger (with longest linear dimension about 16 times larger) than those obtained in control experiments of the same duration but without stirring or without polymers. We attribute this enhancement to two synergistic effects. First, under shear, the polymers and their aggregates disentangle, compete for solvent molecules and thus effectively 'salt out' (that is, induce precipitation by decreasing solubility of) the crystallizing species. Second, the local shear rate is dependent on particle size, ultimately promoting the growth of larger crystals (but not via surface-energy effects as in classical Ostwald ripening). This closed-system, constant-temperature crystallization driven by shear could be a valuable addition to the repertoire of crystal growth techniques, enabling accelerated growth of crystals required by the materials and pharmaceutical industries. A method of growing crystals that does not require undisturbed solutions involves adding polyelectrolytes to the starter solution and shearing (that is, stirring)., Author(s): Jian-Ke Sun [sup.1] [sup.3] , Yaroslav I. Sobolev [sup.1] , Weiyi Zhang [sup.4] , Qiang Zhuang [sup.1] [sup.5] , Bartosz A. Grzybowski [sup.1] [sup.2] Author Affiliations: (1) Center for [...]

Phenotype analysis of leafy green vegetables in planting environment is the key technology of precision agriculture. In this paper, deep convolutional neural network is employed to conduct instance segmentation of leafy greens by weakly supervised learning based on box-level annotations and Excess Green (ExG) color similarity. Then, weeds are filtered based on area threshold, K-means clustering and time context constraint. Thirdly, leafy greens tracking is achieved by bipartite graph matching based on mask IoU measure. Under the framework of phenotype tracking, some time-context-dependent phenotype analysis tasks such as growth monitoring can be performed. Experiments show that the proposed method can achieve 0.95 F1-score and 76.3 sMOTSA (soft multi-object tracking and segmentation accuracy) by using weakly supervised annotation data. Compared with the fully supervised approach, the proposed method can effectively reduce the requirements for agricultural data annotation, which has more potential in practical applications.

For the investigation of the cavitation of non-jammed submersible grinder pumps, a GSP-22 model pump was numerically simulated based on CFX. ICEM-CFD was applied to a structured mesh for the flow components. Pump performance and the influence of the cutter head on cavitation with different cutter head numbers and shapes were investigated. The results were as follows: with increases in the number of cutter heads, the effects of the cutter heads on the water increased, and the flow rate near the cutter head increased correspondingly—which eventually led to aggravated cavitation near the cutter head of the non-jammed submersible grinder pump. The head of the submersible grinder pump with a streamlined cutter changed little compared to the pump with a non-streamlined cutter; the overall power declined by 13.2% and the highest efficiency increased by 6%. For all pumps with different numbers of cutter heads, the vapor volume fraction of the streamlined cutter head was lower than that of the non-streamlined cutter head, and the vapor distribution area size of the streamlined cutter head was smaller than that of the non-streamlined cutter head. This means that changing the cutter head shape to streamlined can effectively control the cavitation intensity near the cutter head.

Zeolitic imidazolate framework-8 was synthesized in a containerless state via acoustic levitation. The cavitation effect of ultrasound affected the coordination connection of organic ligands in acoustically levitated droplets and they exhibited a conspicuous difference in the particle size distribution as compared with those under normal conditions. Herein, methanol was chosen as the solvent to investigate the influence of droplet evaporation on acoustic levitation synthesis. The kinetic parameters of droplet evaporation such as geometrical morphology transformation, concentration change and temperature evolution were measured for the levitation state. Surface evaporation resulted in the drastic deformation of the droplet during ZIF-8 synthesis and caused its vertical vibration and shape oscillation. The abrupt change of the levitation state aggravated the sound field effect on the containerless synthesis and caused a decrease of particle size distribution. A two-dimensional axis-symmetry model was used to visually simulate the sound field distribution during acoustic levitation synthesis based on the finite element method. The fabricated ZIF-8 was able to remove phthalic acid in wastewater through adsorption, and its kinetic features followed a pseudo second-order rate model. [ABSTRACT FROM AUTHOR]

AgNbO3 (ANO)-based lead-free antiferroelectric ceramics with high energy storage density show potential application in pulsed power systems. Structural heterogeneity via doping different ions offers an effective route to explore high performance dielectric materials. The effect of A-site and B-site modified ANO-based ceramics at the same doping amount of 50% on ferroelectricity was investigated. The result shows that the A/B site structural heterogeneities both improved relaxor features, which make a great contribution to the energy storage efficiency, while the B-site modification shows a more effective influence on the structure, grain growth, and ferroelectricity regulation. In this case, the optimized recoverable energy storage density of 2.6 J/cc with an improved efficiency of 87.6% was achieved in the Ta-ANO component. [ABSTRACT FROM AUTHOR]