Adaptable strategy for reactivation and recycling of spent S-Zorb adsorbents at the laboratory and pilot scale.

The spent S-Zorb adsorbents containing Ni and Zn elements are hazardous wastes. It would generate significant economic and environmental benefits to reactivate and recycle these solid wastes through a reactivation strategy. Furthermore, adaptability investigation of this strategy is also indispensable before its industrial application. Herein, the spent S-Zorb adsorbents (Spent-TJ/MM/QD) from different plants were reactivated at laboratory and pilot scale in 3 m3 reactor via an acid-base coupling reactivation strategy. The spent adsorbents exhibit distinct phase compositions and microstructures of active components. Formation of ZnSi2O4 and ZnS is the primary reason for abandonment of the Spent-TJ (Spent-MM) and Spent-QD, respectively. The nickel species also exhibit different aggregation extent. Fortunately, the inert zinc and nickel species are respectively converted into ZnO and NiO during the reactivation process. Higher surface area (1.7-4.0 times that of the spent adsorbents) and more acid sites are generated over the reactivated adsorbents. Besides, all the reactivated adsorbents possess similar phase compositions and microstructures. Both the adsorbents reactivated at pilot and laboratory scale exhibit comparable desulfurization activity to fresh ones. The sulfur content of the gasoline desulfurized by the reactivated adsorbents is below 10 µg g-1, meeting the Euro V legislations. All the results indicate the excellent adaptability and commercial potential of the reactivation strategy. The possible mechanism for the excellent adaptability of the reactivation method was proposed.

Tissue ultrasound imaging based on wavelet correlation analysis and pulse-inversion technique.

BACKGROUND: Pulse-inversion-based tissue harmonic imaging has been utilized for many years because it can effectively eliminate the harmonic leakage and produce low side-lobe. However, the pulse inversion method is sensitive to imaging object movements, which may result in motion artifacts. Spatial resolution and contrast were limited. OBJECTIVE: To improve ultrasound image quality by a new pulse-inversion-based tissue harmonic imaging technique. METHODS: Continuous wavelet transform is applied to investigate the correlation between mother wavelet and the received echoes from two opposite pulses. To get a better correlation, a novel mother wavelet named 'tissue wavelet' is designed based on the Khokhlov-Zabolotskaya- Kuznetsov (KZK) wave equation. Radio frequency data were obtained from open Ultrasonix SonixTouch imaging system. Experiments were carried on ultrasonic tissue phantom, human carotid artery and human liver. RESULTS: The average improvement of lateral spatial resolution is 49.52% compared to pulse-inversion-based tissue second-harmonic Imaging (PIHI). Contrast ratio (CR) and contrast-to-noise ratio (CNR) increased by 5.55 dB and 1.40 dB over PIHI. Tissue wavelet performs better than Mexh and Morl wavelet in lateral spatial resolution, CR, and CNR. CONCLUSION: The proposed technique effectively improves the imaging quality in lateral spatial resolution, CR, and CNR.

ARU-GAN: U-shaped GAN based on Attention and Residual connection for super-resolution reconstruction.

Plane-wave ultrasound imaging technology offers high-speed imaging but lacks image quality. To improve the image spatial resolution, beam synthesis methods are used, which often compromise the temporal resolution. Herein, we propose ARU-GAN, a super-resolution reconstruction model based on residual connectivity and attention mechanisms, to address this issue. ARU-GAN comprises a Full-scale Skip-connection U-shaped Generator (FSUG) with an attention mechanism and a Residual Attention Patch Discriminator (RAPD). The former captures global and local features of the image by using full-scale skip-connections and attention mechanisms. The latter focuses on changes in the image at different scales to enhance its discriminative ability at the patch level. ARU-GAN was trained using a combined loss function on the Plane-Wave Imaging Challenge in Medical Ultrasound (PICMUS) 2016 dataset, which includes three types of targets: point targets, cyst targets, and in-vivo targets. Compared to Coherent Plane-Wave Compounding (CPWC), ARU-GAN achieved a reduction in Full Width at Half Maximum (FWHM) by 5.78%-20.30% on point targets, improved Contrast (CR) by 7.59-11.29 percentage points, and Contrast to Noise Ratio (CNR) by 30.58%-45.22% on cyst targets. On in-vivo target, ARU-GAN improved the Peak Signal-to-Noise Ratio (PSNR) by 11.94%, the Complex-Wavelet Structural Similarity Index Measurement (CW-SSIM) by 17.11%, and the Normalized Cross Correlation (NCC) by at least 2.17% compared to existing deep learning methods. In conclusion, ARU-GAN is a promising model for the super-resolution reconstruction of plane-wave medical ultrasound images. It provides a novel solution for improving image quality, which is essential for clinical practice.

Scale-up reactivation of spent S-Zorb adsorbents for gasoline desulfurization.

Reactivating and recycling spent S-Zorb adsorbents reduce fresh adsorbents consumption and hazardous wastes emissions. Though the spent adsorbents have been successfully reactivated in the laboratory, a pilot-scale practice is indispensable before the industrial production. Herein, the reactivation of spent adsorbents was performed at laboratory (1.0 L), middle (10 L) and pilot (3000 L) scale, respectively. The inert Zn2SiO4 and ZnS over the spent adsorbents are recovered to active ZnO, and the NiS is transformed into NiO. There is almost no amplification effect in pore structure and acidity of the reactivated adsorbents, while NiO particle size reduces slightly with the reactivation scales. The computational fluid dynamic simulation indicates that enhanced contact between spent adsorbents and acid/alkaline reagents at larger scale account for the smaller NiO particle. It provides more hydrogenolysis centers for CS bonds breakage after reduction, increasing initial desulfurization activity. More importantly, the adsorbent reactivated at pilot scale exhibits comparable activity to the fresh one in gasoline desulfurization. The sulfur content in the outlet decreases to less than 10 µg g-1 from 1 h of reaction. Thus, the reactivation of spent S-Zorb adsorbents is successfully scaled up to the pilot scale, accelerating industrial practice in recycling the spent adsorbents.

Enhanced dispersion of nickel nanoparticles on SAPO-5 for boosting hydroisomerization of n-hexane.

The nickel based bifunctional catalyst with enhanced hydroisomerization performance was developed using an in-situ solid synthesis method. It was achieved to stabilize smaller Ni active sites on SAPO-5 using ethylenediaminetetraacetic acid (EDTA) ligands. The role of EDTA ligands was clarified by controlling the molar ratio of EDTA to Ni2+ (EDTA/Ni2+) over Ni/SAPO-5 catalysts. EDTA ligands inhibited the formation of nickel aluminate spinel and aggregation of NiO species during calcination, which dispersed Ni nanoparticles in a mean size of 4.7 nm on SAPO-5. The size of Ni nanoparticles could be controlled by regulating EDTA/Ni2+ ratio in [Ni-EDTA]2- complex. The prepared catalyst exhibited high yield of isomers (54.0%) and di-branched isomers selectivity (18.0%) in the n-hexane hydroisomerization, which was approximately 2 times higher than that of the Ni/SAPO-5 catalyst without EDTA ligands at similar conversion. These results are important to propose a facile approach for the preparation of highly dispersed non-noble metal based bifunctional catalysts at a high loading.

Determination of Construction Temperatures of Crumb Rubber Modified Bitumen Mixture Based on CRMB Mastic.

Crumb rubber modified bitumen (CRMB) has been widely used in pavement construction and provides an effective way to recycle waste tires and helps alleviate the "black pollution" problem. There are no current specifications regarding the appropriate mixing and compaction temperatures of the CRMB mixture. There is a direct relationship between the mixing and the compaction temperatures of the CRMB mixture and the viscosity of the CRMB mastic. In this study, we first prepared CRMB using crumb rubber powder and penetration grade 70 neat bitumen, then prepared the CRMB mastic using CRMB and fillers (limestone mineral powder and cement). Finally, we used the CRMB mastic and aggregate to make mixture specimens. The best air void of the specimens was subsequently used to demarcate the viscosity of the CRMB mastic, and the construction temperatures (including the mixing temperature and the compaction temperature) were calculated based on the viscosity of the CRMB mastic from the viscosity-temperature curves. Test results indicated that the best viscosity of the CRMB mastic was 2.7 ± 0.2 Pa·s and 3.9 ± 0.3 Pa·s that corresponded to the mixing and compaction temperatures, respectively.

Silicoaluminophosphate-11 (SAPO-11) molecular sieves synthesized via a grinding synthesis method.

Aluminophosphate molecular sieves with an AEL-type structure and various framework compositions were prepared via a grinding synthesis method (GSM). The rapid crystal growth rate was due to the enhanced interactions between the templates and aluminum species and abundant low-polymerized phosphorus species. The amount of template and water used was substantially reduced, which has a great economic and environment impact for large-scale synthesis.

Promoter effect of heteroatom substituted AlPO-11 molecular sieves in hydrocarbons cracking reaction.

It is important to develop new promoters of fluid catalytic cracking (FCC) catalyst to increase iso-paraffin yield and avoid the decrease of research octane number (RON) caused by olefin saturation in gasoline hydrofining. SAPO-11 and LaAPO-11 molecular sieves were used as promoters to FCC catalyst to increase gasoline RON and were tested in the cracking reaction of n-dodecane on FCC conditions. LaAPO-11 molecular sieve has less and weaker acidity than SAPO-11 molecular sieve. LaAPO-11's metallic sites polarize the CH bonds to form carbenium ions for isomerization reaction and weak acid sites make less contributions to the cracking of iso-paraffin. LaAPO-11 promoter increases the yield of iso-paraffin (C5-9) from 6.4% to 10.2%. Besides that, a high yield of arene (2.0%) is caused by the dehydrogenation activity of LaAPO-11 promoter. The new contributions of this paper are the synthesis of a hydrothermal stable LaAPO-11 molecular sieve with isomerization activity and proposing the reaction routes of iso-paraffin. These new contributions are important for developing more effective RON promoters of FCC catalyst.