224 research outputs found

    TRAC: A Textual Benchmark for Reasoning about Actions and Change

    Full text link
    Reasoning about actions and change (RAC) is essential to understand and interact with the ever-changing environment. Previous AI research has shown the importance of fundamental and indispensable knowledge of actions, i.e., preconditions and effects. However, traditional methods rely on logical formalization which hinders practical applications. With recent transformer-based language models (LMs), reasoning over text is desirable and seemingly feasible, leading to the question of whether LMs can effectively and efficiently learn to solve RAC problems. We propose four essential RAC tasks as a comprehensive textual benchmark and generate problems in a way that minimizes the influence of other linguistic requirements (e.g., grounding) to focus on RAC. The resulting benchmark, TRAC, encompassing problems of various complexities, facilitates a more granular evaluation of LMs, precisely targeting the structural generalization ability much needed for RAC. Experiments with three high-performing transformers indicates that additional efforts are needed to tackle challenges raised by TRAC

    1-[(2S)-1-Chloro-3-phenyl­propan-2-yl]-2,4,5-triphenyl-1H-imidazole

    Get PDF
    In the title compound, C30H25ClN2, the chiral center maintains the S configuration of the stating l-phenyl­alaninol. The two phenyl groups closest to the substituted N atom adopt an almost perpendicular orientation relative to the central imidazole ring, with dihedral angles of 88.9 (4) and 84.7 (3)°. The third phenyl group is nearly coplanar with it, making a dihedral angle of 11.0 (5)°

    2-(4,5-Diphenyl-2-p-tolyl-1H-imidazol-1-yl)-3-phenyl­propan-1-ol

    Get PDF
    In the title compound, C31H28N2O, the dihedral angles formed by the imidazole ring with the three aryl substituents are 18.52 (8) and 85.56 (7) and 85.57 (7)°, respectively. In the crystal, mol­ecules are linked by O—H⋯N and C—H⋯O hydrogen bonds into chains parallel to the a axis

    Process, microstructure and mechanical properties

    Get PDF
    Funding Information: This work was supported by National Natural Science Foundation of China (Grant No. 51875168/52002112 ), Natural Science Foundation of Hebei Province (Grant No. E2019208089 ) and “Three-Three-Three Talent Project” Foundation of Hebei Province ( C20221022 ). Sichuan Province Science Funding for Distinguished Young Scholars ( 3NSFJQ0064 ). JPO acknowledges funding by national funds from FCT – Fundação para a Ciência e a Tecnologia, I.P., in the scope of the projects LA/P/0037/2020. Science and Technology Research Project of Colleges and Universities in Hebei Province (Grant No. BJK2022020 ). Publisher Copyright: © 2023 The AuthorsAiming to decouple the inherent relationship between mass transfer and heat transfer in traditional arc-based directed energy deposition, a novel heterogeneous multi-wire indirect arc directed energy deposition (DED) has been developed for in-situ synthesis of Al-Zn-Mg-Cu alloy components. Multi-wires (Al-Cu and Al-Mg) with a bypassing Zn wire have been used to replace the traditional homogeneous twin-wires. The process, microstructure and mechanical properties of the deposited Al-Zn-Mg-Cu alloy components obtained by multi-wire indirect arc DED were investigated. The results indicate that the wire feeding speed, current and angle between the two wires have a significant influence on the multi-wire indirect arc DED process. When the current was 200 A, the different wire feeding speeds could be used for both wires and the angle between them was 90°. The resulting indirect arc presented a ‘heart’ shape and allowed to obtain an Al-5.7Zn-3.4Mg-1.6Cu (wt%) alloy with a high deposition rate of 5.1 kg/h. The Al-5.7Zn-3.4Mg-1.6Cu alloy is mainly composed of α-Al, S (Al2CuMg), η (Mg (Al, Zn, Cu)2) and η′ phases. The composition and phases are in accordance with the 7xxx series aluminum alloys. The microstructure is dominated by columnar and equiaxed grains, and it has obvious periodic distribution along the building direction, which is related to the process thermal cycle. Fine second phases η′ are observed to precipitate during the manufacturing process. Furthermore, the average hardness, ultimate tensile strength and elongation of the fabricated material are 98.6 HV, 243.9 MPa and 5.9%, respectively. These mechanical properties are higher than those of as-cast 7050 aluminum alloy, thus showing the potential of this new process variant to fabricate high strength Al alloys in the as-deposited state. The fracture morphology exhibit features mainly associated to a ductile-like fracture, accompanied by some transgranular and partial cleavage fracture characteristics. This novel multi-wire indirect arc DED provides a new choice for arc-based directed energy deposition of Al-Zn-Mg-Cu alloys and shows great potential for the in-situ synthesis of other high-performance alloys.publishersversionpublishe

    Emissions of nitrogen-based fuel combustion in swirl burner

    Get PDF
    To provide a first insight into combustion characteristics of ammonia-based fuel in gas turbine engines for power generation, a generic swirl burner is tested with ammonia/hydrogen mixtures in this study. Based on the Computational Fluid Dynamics (CFD) simulation results, Chemical Reaction Network (CRN) model is developed to study the NOx emission characteristics of different ammonia/hydrogen mixtures in a gas turbine swirl burner. The NOx emission results predicted by the CRN model using Konnov’s mechanism have shown satisfactory agreement with the experimental data. The parameter study are then performed to estimate the effect of pressure, inlet temperature and equivalence ratio. Areas are identified which more attention for model development and emission need control in future studies

    Clinical Efficacy and Microbiome Changes Following Fecal Microbiota Transplantation in Children With Recurrent Clostridium Difficile Infection

    Get PDF
    Fecal microbiota transplantation (FMT) has been shown as an effective treatment for recurrent clostridium difficile infection (RCDI) in adults. In this study, we aim to evaluate the clinical efficacy of FMT in treating children with RCDI, and explore fecal microbiota changes during FMT treatment. A total of 11 RCDI subjects with a median age of 3.5 years were enrolled in this single-center prospective pilot study. All patients were cured (11/11, 100%) by FMT either through upper gastrointestinal tract route with a nasointestinal tube (13/16, 81.2%) or lower gastrointestinal tract route with a rectal tube (3/16, 18.8%). The cure rate of single FMT was 63.6% (7/11), and 4 (4/11, 36.4%) cases were performed with 2 or 3 times of FMT. Mild adverse events were reported in 4 children (4/11, 36.4%), including transient diarrhea, mild abdominal pain, transient fever and vomit. Gut microbiota composition analysis of 59 fecal samples collected from 34 participants (9 RCDI children, 9 donors and 16 health controls) showed that the alpha diversity was lower in pediatric RCDI patients before FMT than the healthy controls and donors, and fecal microbial community of pre-FMT samples (beta diversity) was apart from that of healthy controls and donors. No significant differences in alpha diversity, beta diversity or phylogenetic distance were detected between donors and healthy controls. Both the richness and diversity of gut microbiota were improved in the pediatric RCDI patients after FMT, and the bacteria community was shifted closer to the donor and healthy control group. Furthermore, FMT re-directed gut microbiome functions of pediatric RCDI toward a health state. Our results indicate that it is safe and tolerant to use FMT in treating pediatric RCDI. FMT shifted the gut microbiome composition and function in children with RCDI toward a healthy state

    Analysis of gut microbiotal diversity in healthy young adults in Sunan County, Gansu Province, China

    Get PDF
    ObjectiveTo examine gut microbiotal diversity in the Han Chinese and Yugur populations of Sunan County, Gansu Province, living in the same environmental conditions, and to analyze possible causes of differences in diversity.MethodsWe selected 28 people, ages 18–45 years old, all of whom were third-generation pure Yugur or Han Chinese from Sunan County. Fresh fecal samples were collected, and total bacterial deoxyribonucleic acid (DNA) was extracted. We performed 16S ribosomal ribonucleic acid (16S rRNA) high-throughput sequencing (HTS) and bioinformatics to study the relationships among between gut microbiota structure, genetics, and dietary habits in Yugur and Han Chinese subjects.ResultsWe found 350 differential operational taxonomic units (OTUs) in Han Chinese and Yugur gut microbiota, proving that gut microbiota differed between the two populations. That were less abundant among Yugurs than Han Chinese were Prevotella_9 and Alloprevotella. That were more abundant among Yugurs than Han Chinese were Anaerostipes and Christensenellaceae_R-7_group. And they were significantly associated with a high-calorie diet In addition. we found differences in predicted gut microbiota structural functions (The main functions were metabolic and genetic information) between the two populations.ConclusionYugur subjects demonstrated differences in gut microbiotal structure from Han Chinese subjects, and this difference influenced by dietary and may be influenced by genetic influences. This finding will provide a fundamental basis for further study of the relationships among gut microbiota, dietary factors, and disease in Sunan County

    High-yield synthesis and optical properties of g-C₃N₄

    Get PDF
    Graphitic carbon nitride (g-C₃N₄), a metal-free semiconductor with a band gap of 2.7 eV, has received considerable attention owing to its fascinating photocatalytic performances under visible-light. g-C₃N₄ exhibits high thermal and chemical stability and non-toxicity such that it has been considered as the most promising photocatalyst for environmental improvement and energy conservation. Hence, it is of great importance to obtain high-quality g-C₃N₄ and gain a clear understanding of its optical properties. Herein, we report a high-yield synthesis of g-C₃N₄ products via heating of high vacuum-sealed melamine powder in an ampoule at temperatures between 450 and 650°C. Using transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), electron energy loss spectroscopy (EELS), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), the chemical composition and crystallization of the as-produced g-g-C₃N₄ are demonstrated. A systematic optical study of g-g-C₃N₄ is carried out with several approaches. The optical phonon behavior of g-C₃N₄ is revealed by infrared and Raman spectroscopy, and the emission properties of g-C₃N₄ are investigated using photoluminescence (PL) spectroscopy, while the photocatalytic properties are explored by the photodegradation experiment

    Assessing Reproducibility of Inherited Variants Detected With Short-Read Whole Genome Sequencing

    Get PDF
    Background: Reproducible detection of inherited variants with whole genome sequencing (WGS) is vital for the implementation of precision medicine and is a complicated process in which each step affects variant call quality. Systematically assessing reproducibility of inherited variants with WGS and impact of each step in the process is needed for understanding and improving quality of inherited variants from WGS. Results: To dissect the impact of factors involved in detection of inherited variants with WGS, we sequence triplicates of eight DNA samples representing two populations on three short-read sequencing platforms using three library kits in six labs and call variants with 56 combinations of aligners and callers. We find that bioinformatics pipelines (callers and aligners) have a larger impact on variant reproducibility than WGS platform or library preparation. Single-nucleotide variants (SNVs), particularly outside difficult-to-map regions, are more reproducible than small insertions and deletions (indels), which are least reproducible when \u3e 5 bp. Increasing sequencing coverage improves indel reproducibility but has limited impact on SNVs above 30×. Conclusions: Our findings highlight sources of variability in variant detection and the need for improvement of bioinformatics pipelines in the era of precision medicine with WGS
    corecore