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C16H11NO10U, monoclinic, P21/c (no. 14), a = 16.4675(12) Å, b = 11.7192(8) Å, c = 9.6663(7) Å, β = 100.823(2)°, V = 1832.3(2) Å3, Z = 4, R gt(F) = 0.0277, wR ref(F2) = 0.0673, T = 170.0 K.

PurposeDose calculation is one of the most computationally intensive, yet essential tasks in the treatment planning process. With the recent interest in automatic beam orientation and arc trajectory optimization techniques, there is a great need for more efficient model-based dose calculation algorithms that can accommodate hundreds to thousands of beam candidates at once. Foundational work has shown the translation of dose calculation algorithms to graphical processing units (GPUs), lending to remarkable gains in processing efficiency. But these methods provide parallelization of dose for only a single beamlet, serializing the calculation of multiple beamlets and under-utilizing the potential of modern GPUs. In this paper, the authors propose a framework enabling parallel computation of many beamlet doses using a novel beamlet context transformation and further embed this approach in a scalable network of multi-GPU computational nodes.MethodsThe proposed context-based transformation separates beamlet-local density and TERMA into distinct beamlet contexts that independently provide sufficient data for beamlet dose calculation. Beamlet contexts are arranged in a composite context array with dosimetric isolation, and the context array is subjected to a GPU collapsed-cone convolution superposition procedure, producing the set of beamlet-specific dose distributions in a single pass. Dose from each context is converted to a sparse representation for efficient storage and retrieval during treatment plan optimization. The context radius is a new parameter permitting flexibility between the speed and fidelity of the dose calculation process. A distributed manager-worker architecture is constructed around the context-based GPU dose calculation approach supporting an arbitrary number of worker nodes and resident GPUs. Phantom experiments were executed to verify the accuracy of the context-based approach compared to Monte Carlo and a reference CPU-CCCS implementation for single beamlets and broad beams composed by addition of beamlets. Dose for representative 4π beam sets was calculated in lung and prostate cases to compare its efficiency with that of an existing beamlet-sequential GPU-CCCS implementation. Code profiling was also performed to evaluate the scalability of the framework across many networked GPUs.ResultsThe dosimetric accuracy of the context-based method displays

Because of the increasingly deteriorating quality of petroleum coke raw materials, abnormal furnace conditions, such as "firing and blasting", frequently arise during the calcination of petroleum coke with a high powder/coke ratio in a vertical shaft calciner. This poses an urgent technical challenge that needs to be addressed. In iron and steel metallurgy, the burden distribution system is an important way to regulate blast furnace conditions and improve the permeability of a particle packed bed. In this work, advanced burden distribution concepts were introduced into the calcination process of petroleum coke in a vertical shaft calciner. Experimental devices were established to determine the resistance characteristics of a petroleum coke particle packed bed, along with a cold physical model of a 1/8 scale vertical shaft calciner. The influence of particle size and burden distribution methods on the resistance characteristics and particle motion behavior of the petroleum coke particle packed bed was systematically studied. The research findings indicate that both particle size and burden distribution methods significantly impact the resistance characteristics of petroleum coke particle packed beds. The smaller the particle size, the poorer the permeability of the bed. The layered burden distribution, symmetrical burden distribution, and dual‐particle mixed conventional burden distribution all contribute to improving the permeability of the petroleum coke particle packed bed in the vertical shaft calciner. Furthermore, employing symmetrical burden distribution in Bed‐3, which is packed with petroleum coke particles of diameters −3.2 + 2.5 mm and −1.0 + 0.8 mm, results in the smallest unit pressure drop, at only 1.7% of that of the conventional burden distribution of unscreened raw materials. This is the most effective means of improving the permeability of the bed. During the discharging process, particle size and symmetrical burden distribution have no significant impact on the motion characteristics of petroleum coke particles in the vertical shaft calciner. In general, in the calciner area, particles primarily move in a plug flow pattern and gradually transform into funnel flow in the cooling water jacket area. These research results provide the theoretical basis for addressing the technical challenges associated with powder coke calcination in vertical shaft calciners through reasonable burden distribution methods for fine and coarse particles. [ABSTRACT FROM AUTHOR]

As the numerous industrial solid waste, coal gangue caused serious environmental pollution in China, while the it could be modified and reused as an effective adsorption material in environmental remediation. In the current study, the coal gangue was modified by environmentally friendly ball-milling chemical modification method and used for simultaneous adsorption heavy metal and ammonia in wastewater. Both the initial and modified coal gangue were characterized for structure and composition. Optimization of ball-milling conditions and adsorption parameters was carried out, followed by thermodynamic and kinetic experiments under the defined conditions. The results showed that the adsorption of Pb2+, Zn2+, and NH4+–N accorded with the quasi-second-order kinetic model, with all adsorption isotherms conforming to the Langmuir model. Thermodynamic analysis indicates that the adsorption of Pb2+, Zn2+, and NH4+–N is an exothermic process, and the adsorption reaction can occur independently. Moreover, modified coal gangue exhibited sufficient adsorption sites for the combination of Pb2+, Zn2+, and NH4+–N at low concentrations in adsorption competition experiment, with an adsorption sequence like Pb2+ > Zn2+ > NH4+–N. Our results provide that ball-milling-modified coal gangue can be used as a helpful adsorption material for heavy metal ions and ammonia removal in wastewater treatment. [ABSTRACT FROM AUTHOR]

The adsorption–desorption behaviours of La3+, Sm3+, and Y3+ on 2‐ethylhexylphosphonic acid mono‐2‐ethyl hexyl ester (HEHEHP) extraction resin were investigated in a chloride medium. The effects of reaction time, pH, hydrochloric acid concentration, flow rate, and adsorption mechanism were studied in detail using static and dynamic experimental methods. The results show that La3+ is the first to reach adsorption equilibrium, followed by Sm3+ and Y3+; the highest adsorption capacities of La3+, Sm3+, and Y3+ are obtained at solution pH of 4 and in the order of Y3+ > Sm3+ > La3+. La3+, Sm3+, and Y3+ can be eluted by 0.3, 0.5, and 3 mol/L hydrochloric acid, respectively, indicating that La3+ elutes most easily, and Y3+ is difficult. Moreover, the flow rate has little effect on the peak of rare earth desorption. The adsorption process is chemisorption; the slope method indicates that for each mol Sm3+ or Y3+ ion adsorbed, 3 mol H+ ions are simultaneously released, but two for La3+ under the given pH conditions. It is expected to provide theoretical and technical support for preparation of ultra‐high purity rare earth by HEHEHP extraction resin. [ABSTRACT FROM AUTHOR]