CFD simulation of hydrodynamic characteristics in a modified internally circulating fluidized bed mixer

A modified internally circulating fluidized bed (MICFB) was proposed as a particle mixer by coupling a pre-mixing section and a modified ICFB section[1]. Four slots were opened at the upside of the draft tube to improve further particle mixing. Hydrodynamics of MICFB was numerically investigated by multi-scale simulation based on a structure–dependent EMMS model[2]. Results showed that strong particle mixing mainly occurred in three regions, the bottom region, the draft tube region and the rectangular slots affected region. At the bottom region, due to the jet and the particles circulating from the annulus, bed density and particle velocity distributed unevenly. A cross-flow occurred in this region, with the circulating particles moving horizontally and the initial bubbles rising vertically. With increasing superficial gas velocity, particle rising velocity and particle circulating mass flow rate increased, leading to better particle mixing. In the slots affected region, radial distribution of bed density seems flat and the rising velocity decreased in the draft tube, while bed density significantly increased in the annulus. Nearly 62 wt. % particles entered the gas-solid separator region and then flowed into the annulus region, while the rest particles directly circulated into the annulus through the slots. A cross-flow of particles was also observed near the slots, with particles from the gas-solid separator region moving downwards and those circulating through slots flowing horizontally. Compared with ICFB with no slots, MICFB had a greater particle circulation mass flow rate with an increase of 20%, which consequently resulted in further particle mixing. Please click Additional Files below to see the full abstract

On the Emergence of Symmetrical Reality

Artificial intelligence (AI) has revolutionized human cognitive abilities and facilitated the development of new AI entities capable of interacting with humans in both physical and virtual environments. Despite the existence of virtual reality, mixed reality, and augmented reality for several years, integrating these technical fields remains a formidable challenge due to their disparate application directions. The advent of AI agents, capable of autonomous perception and action, further compounds this issue by exposing the limitations of traditional human-centered research approaches. It is imperative to establish a comprehensive framework that accommodates the dual perceptual centers of humans and AI agents in both physical and virtual worlds. In this paper, we introduce the symmetrical reality framework, which offers a unified representation encompassing various forms of physical-virtual amalgamations. This framework enables researchers to better comprehend how AI agents can collaborate with humans and how distinct technical pathways of physical-virtual integration can be consolidated from a broader perspective. We then delve into the coexistence of humans and AI, demonstrating a prototype system that exemplifies the operation of symmetrical reality systems for specific tasks, such as pouring water. Subsequently, we propose an instance of an AI-driven active assistance service that illustrates the potential applications of symmetrical reality. This paper aims to offer beneficial perspectives and guidance for researchers and practitioners in different fields, thus contributing to the ongoing research about human-AI coexistence in both physical and virtual environments.Comment: IEEE VR 202

Reservoir and lithofacies shale classification based on NMR logging

© 2020 Chinese Petroleum Society Shale gas reservoirs have fine-grained textures and high organic contents, leading to complex pore structures. Therefore, accurate well-log derived pore size distributions are difficult to acquire for this unconventional reservoir type, despite their importance. However, nuclear magnetic resonance (NMR) logging can in principle provide such information via hydrogen relaxation time measurements. Thus, in this paper, NMR response curves (of shale samples) were rigorously mathematically analyzed (with an Expectation Maximization algorithm) and categorized based on the NMR data and their geology, respectively. Thus the number of the NMR peaks, their relaxation times and amplitudes were analyzed to characterize pore size distributions and lithofacies. Seven pore size distribution classes were distinguished; these were verified independently with Pulsed-Neutron Spectrometry (PNS) well-log data. This study thus improves the interpretation of well log data in terms of pore structure and mineralogy of shale reservoirs, and consequently aids in the optimization of shale gas extraction from the subsurface

Synthesis of new 2′-deoxy-2′-fluoro-4′-azido nucleoside analogues as potent anti-HIV agents

We prepared 1-(4′-azido-2′-deoxy-2′-fluoro-β -D-arabinofuranosyl)cytosine (10) and its hydrochloride salt (11) as potential antiviral agents based on the favorable antiviral profiles of 4′-substituted nucleosides. Compounds 10 and 11 were synthesized from 1,3,5-O-tribenzoyl-2-deoxy-2-fluoro-D-arabinofuranoside in multiple steps, and their structures were unequivocally established by IR, 1H NMR, 13C NMR, and 19F NMR spectroscopy, HRMS, and X-ray crystallography. Compounds 10 and 11 exhibited potent anti-HIV-1 activity (EC50: 0.3 and 0.13 nM, respectively) without significant cytotoxicity in concentrations up to 100 μM. Compound 11 exhibited extremely potent anti-HIV activity against NL4-3 (wild-type), NL4-3 (K101E), and RTMDR viral strains, with EC50 values of 0.086, 0.15, and 0.11 nM, respectively. Due to the high potency of 11, it was also screened against an NIH Reagent Program NRTI-resistant virus panel containing eleven mutated viral strains and for cytotoxicity against six different human cell lines. The results of this screening indicated that 11 is a novel NRTI that could be developed as an anti-AIDS clinical trial candidate to overcome drug-resistance issues

Detection of genome-wide structural variations in the Shanghai Holstein cattle population using next-generation sequencing

Objective The Shanghai Holstein cattle breed is susceptible to severe mastitis and other diseases due to the hot weather and long-term humidity in Shanghai, which is the main distribution centre for providing Holstein semen to various farms throughout China. Our objective was to determine the genetic mechanisms influencing economically important traits, especially diseases that have huge impact on the yield and quality of milk as well as reproduction. Methods In our study, we detected the structural variations of 1,092 Shanghai Holstein cows by using next-generation sequencing. We used the DELLY software to identify deletions and insertions, cn.MOPS to identify copy-number variants (CNVs). Furthermore, we annotated these structural variations using different bioinformatics tools, such as gene ontology, cattle quantitative trait locus (QTL) database and ingenuity pathway analysis (IPA). Results The average number of high-quality reads was 3,046,279. After filtering, a total of 16,831 deletions, 12,735 insertions and 490 CNVs were identified. The annotation results showed that these mapped genes were significantly enriched for specific biological functions, such as disease and reproduction. In addition, the enrichment results based on the cattle QTL database showed that the number of variants related to milk and reproduction was higher than the number of variants related to other traits. IPA core analysis found that the structural variations were related to reproduction, lipid metabolism, and inflammation. According to the functional analysis, structural variations were important factors affecting the variation of different traits in Shanghai Holstein cattle. Our results provide meaningful information about structural variations, which may be useful in future assessments of the associations between variations and important phenotypes in Shanghai Holstein cattle. Conclusion Structural variations identified in this study were extremely different from those of previous studies. Many structural variations were found to be associated with mastitis and reproductive system diseases; these results are in accordance with the characteristics of the environment that Shanghai Holstein cattle experience