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A highly efficient composite sealing material was prepared using drilling cuttings as the base material and a binder, a coagulant, and other additives as auxiliaries. A four-factor, three-level orthogonal test was designed based on the response surface method (RSM), and a response surface regression model was constructed using compressive strength, fluidity, expansion rate, and setting time as performance indexes to analyze the effects of each factor on material performance and optimize the material proportion. The samples were prepared by simulating the grouting process, the permeability of the samples was measured, and the sealability of the material was verified by analyzing the material microscopic morphology. Results showed that the regression model had a high level of confidence and accuracy and could predict the test results accurately within the range of the test. The effects of the interaction between factors on material performance were also examined. The low permeability of the sealing material samples verified the material’s feasibility. Gradual optimization of material performance revealed that the optimal proportion was 52.6% drill cuttings, 44.3% binder, 0.6% coagulant promoter, and 2.5% expansive agent. Under these conditions, the error between the predicted and test values of each material property was less than 5%, and the comprehensive performance was superior. These findings verify the accuracy of RSM and its applicability to the optimization of material performance. This work provides reasonable theoretical guidance for the preparation of drilling cuttings composite (DC) materials in practical engineering.

In this paper, we present a new hardware acceleration method to speedup the ordered-subsets expectation-maximization (OS-EM) algorithm for quantitative single photon emission computed tomography (SPECT) image reconstruction with varying focal-length fan-beam (VFF) collimation. By utilizing the geometrical symmetry of VFF point-spread function (PSF), compensation for object-specific attenuation and system-specific PSF are accelerated using currently available PC video/graphics card technologies. A tenfold acceleration of quantitative SPECT reconstruction is achieved. [ABSTRACT FROM AUTHOR]

Abstract  A 3D metal-organic framework, [C6H3CdN2O4]·NH4, was synthesized solvothermally and structurally characterized by single-crystal X-ray structure determination. This compound crystallizes in the tetragonal system with the space group P42/nmc. The crystal structure presents a 3D framework and open channels, exhibiting guest-coordination sites at channel walls and strong fluorescent emission. Graphical abstract   [ABSTRACT FROM AUTHOR]