FIELD TEST ON THE COOPERATION OF NSM STRENGTHENING AND EXTERNAL TENDON RETROFITTING TECHNIQUE

In this paper, post-tension and steel plate near-surface mounted (NSM) strengthening systems are proposed to strengthen deteriorated and cracked large box girder rigid frame bridge without altering appearance and dimension of the bridge. The reinforcement method mainly improves the bearing capacity through external prestressed tendons, and bonding steel plate can enhance the shear resistance of the bridge. The main purpose is to study the structural mechanical properties before and after the reinforcement of rigid frame bridges. Take a 540m rigid frame box girder bridge as an example. The static load test of the bridge before and after reinforcement is carried out. The deflection and strain of the middle cross section of the span are measured in the static test. A finite element analysis model was also developed and verified static loading test data. The results show that structural bearing capacity and performance of the bridge were enhanced with the post-tension and NSM strengthening systems cooperatively

Uni-QSAR: an Auto-ML Tool for Molecular Property Prediction

Recently deep learning based quantitative structure-activity relationship (QSAR) models has shown surpassing performance than traditional methods for property prediction tasks in drug discovery. However, most DL based QSAR models are restricted to limited labeled data to achieve better performance, and also are sensitive to model scale and hyper-parameters. In this paper, we propose Uni-QSAR, a powerful Auto-ML tool for molecule property prediction tasks. Uni-QSAR combines molecular representation learning (MRL) of 1D sequential tokens, 2D topology graphs, and 3D conformers with pretraining models to leverage rich representation from large-scale unlabeled data. Without any manual fine-tuning or model selection, Uni-QSAR outperforms SOTA in 21/22 tasks of the Therapeutic Data Commons (TDC) benchmark under designed parallel workflow, with an average performance improvement of 6.09\%. Furthermore, we demonstrate the practical usefulness of Uni-QSAR in drug discovery domains

Seismic performance of horizontal swivel system of asymmetric continuous girder bridge

The bridge horizontal swivel system generally adopts a symmetrical structure and uses a spherical hinge structure that can adjust the rotation to complete rotation construction. Because of the complexity of railway lines under bridges, some asymmetrical horizontal swivel systems have been increasingly applied in practical engineering in recent years. This system is more suitable for areas with complex railway lines, reduces the bridge span, and provides better economic benefits. However, it is also extremely unstable. In addition, instability can easily occur under dynamic loads, such as earthquake action and pulsating wind effects. Therefore, it is necessary to study their mechanical behavior. Based on the horizontal swivel system of an 11,000-ton asymmetric continuous girder bridge, the dynamic response of the horizontal swivel system to seismic action was studied using the finite element simulation analysis method. Furthermore, using the Peer database, seismic waves that meet the calculation requirements are screened for time-history analysis and compared to the response spectrum method. The mechanical properties of the structural system during and after rotation were obtained through calculations. During rotation, the seismic response of the structure is greater. To reduce the calculation time cost, an optimization algorithm based on the mode shape superposition method is proposed. The calculation result is 87% that of the time-history analysis, indicating a relatively high calculation accuracy

Effects of High-Stakes Accountability Testing on Teacher Motivation

There is always a driving force behind our actions in any given situation. In 2000, NCLB instituted accountability testing with strict requirements for all schools in the U.S., hoping to motivate teachers to reach higher levels of instruction by using sanctions or rewards against teachers when standards were not met. However, Deci and Ryan¿s (2000) SDT explains that fostering intrinsic motivation and providing autonomy support for an individual results in more effective outcomes and increased satisfaction. Private and public school teachers in PA were surveyed using the Work Climate Questionnaire and the Work Task Motivation Scale for Teachers to examine differences in self-reported motivation and perceived autonomy support in order to investigate if the use of high-stakes accountability testing (HST) is related to decreased teacher motivation. The results from ANOVAs and correlations indicate differences in self-reported motivation levels of teachers in public and private schools, as well as aid ratio, grade taught, number of years in teaching, and the time the participant responded (before or after the PSSA), as well as perceived autonomy support, suggesting that the presence of HST may influence motivation in teachers

Robust cross-linked Na3V2(PO4)2F3 full sodium-ion batteries

Sodium-ion batteries (SIBs) have rapidly risen to the forefront of energy storage systems as a promising supplementary for Lithium-ion batteries (LIBs). Na3V2(PO4)2F3 (NVPF) as a common cathode of SIBs, features the merits of high operating voltage, small volume change and favorable specific energy density. However, it suffers from poor cycling stability and rate performance induced by its low intrinsic conductivity. Herein, we propose an ingenious strategy targeting superior SIBs through cross-linked NVPF with multi-dimensional nanocarbon frameworks composed of amorphous carbon and carbon nanotubes (NVPF@C@CNTs). This rational design ensures favorable particle size for shortened sodium ion transmission pathway as well as improved electronic transfer network, thus leading to enhanced charge transfer kinetics and superior cycling stability. Benefited from this unique structure, significantly improved electrochemical properties are obtained, including high specific capacity (126.9 mAh g−1 at 1 C, 1 C = 128 mA g−1) and remarkably improved long-term cycling stability with 93.9% capacity retention after 1000 cycles at 20 C. The energy density of 286.8 Wh kg−1 can be reached for full cells with hard carbon as anode (NVPF@C@CNTs//HC). Additionally, the electrochemical performance of the full cell at high temperature is also investigated (95.3 mAh g−1 after 100 cycles at 1 C at 50 oC). Such nanoscale dual-carbon networks engineering and thorough discussion of ion diffusion kinetics might make contributions to accelerating the process of phosphate cathodes in SIBs for large-scale energy storages

Study on Fatigue Test and Life Prediction of Polyurethane Cement Composite (PUC) under High or Low Temperature Conditions

There are many diseases in the deck pavement of long-span steel bridges under the action of vehicles, rainwater, and freezing. It is necessary to study a new type of pavement material with high waterproof property, light weight, and high bonding performance for steel deck pavement. Polyurethane cement composite (PUC) can be used for steel deck pavement. In order to find out the temperature effect on fatigue properties of PUC, the four-point bending fatigue test was carried out at different temperatures. In this paper, the optimum mix ratio of PUC was selected by compressive and flexural tests, and then the bending fatigue test was conducted under strain control mode. Under temperature and external force coupling condition, a method for predicting fatigue life of PUC is proposed by the combination of theoretical deduction and experimental research. The results show that the proposed formula can effectively describe the fatigue life and fatigue limit of PUC. Finally, compared with three different asphalt mixtures for steel deck pavement, it is found that the fatigue performance of polyurethane cement is better than that of asphalt mixture

Deep Desulfurization of Diesel Oil with Extraction Using Pyridinium-Based Ionic Liquids

The pyridinium-based ionic liquids (ILs) 1-butyl-3,5-dimethylpyridinium tetrafluoroborate [((C4DMPy)-D-3,5][BF4]), 1-hexyl-3,5-dimethylpyridinium tetrafluoroborate [((C6DMPy)-D-3,5][BF4]) and, 1-octyl-3,5-dimethylpyridinium tetrafluoroborate [((C8DMPy)-D-3,5] [BF4]) were found to be effective for the selective removal of aromatic heterocyclic sulfur compounds from diesel. The results suggested that the structure and size of the cation greatly affect the extractive performance of ILs. For each sulfur compound studied here (4,6-Dimethyldibenzothiophene (4,6-DMDBT), dibenzothiophene (DBT), benzothiophene (BT), and thiophene (TS)), the extractive performance using pyridinium-based ILs followed the order of [C4Py][BF4] < [C6Py][BF4] < [C8Py][BF4] < [(C4MPy)-M-3] [BF4] < [(C4DMPy)-D-3,5][BF4] < [(C6MPy)-M-3][BF4] < [(C8MPy)-M-3][BF4] < [(C6DMPy)-D-3, 5][BF4] < [(C8DMPy)-D-3,5][BF4]. In addition, the pyridinium-based ILs would not contaminate the diesel due to their insolubility. On the other hand, diesel has a certain solubility in pyridinium-based ILs, varying from 0.49 wt% for [C4Py][BF4] to 19.6 wt% for [(C8DMPy)-D-3,5][BF4]. Considering these results, ILs studied in this work are more competitive and feasible for extractive desulfurization applications. Moreover, the extractive desulfurization using pyridinium-based ILs could be used at least as a complementary process to hydrodesulfurization (HDS)

Research on the degradation behaviors of wood pulp cellulose in ionic liquids

Utilizing phosphate-based ionic liquids (ILs) solvents for dissolving cellulose to prepare cellulose fibers has attracted much attention for its convenience, high yield, stability and sustainability. However, the degradation behavior during dissolving of cellulose in ILs, which is an important factor for fabricating cellulose fiber, is still unclear. In this work, the degradation of wood pulped cellulose (WPC) in three kinds of phosphate-based ILs: 1-ethyl-3-methylimidazolium dimethyl phosphate ([Emim]DMP), 1-ethyl-3methylimidazolium diethyl phosphate ([Emim]DEP) and 1-butyl-3-ethylimidazolium diethyl phosphate ([Beim]DEP), were systematically investigated at different dissolution temperatures and dissolution times. The results indicated that the degradation degree of WPC in three ILs follows the order of [Emim]DEP > [Beim]DEP > [Emim]DMP, which is consistent with interaction results obtained by quantum chemical calculation, and degradation degree increases follows the rising of dissolution temperature and the accumulation of dissolution time. Moreover, no reducing sugar (RS) was found in any recycled ILs even when the degree of polymerization (DP) of regenerated cellulose (RC) decreased by 30.4%. In addition, according to the Fourier transform infrared and X-ray diffraction data, the results further proved that the crystallization type of RC changed from type I to type II. Here, preferable dissolving parameters and experiments data of multiple conditions are provided, which may provide practical reference and guidance for both scientific research and industrial.(c) 2022 Elsevier B.V. All rights reserved

Screening Ionic Liquids by the COSMO-RS Method for the Preparation of Antibacterial Cellulose Fibers

The application of natural antibacterial agents seems to be one of the popular research topics in the field of antibacterial materials due to their unique properties such as good biocompatibility and biodegradability. In this work, 1-ethyl-3-methylimidazolium diethylphosphate ([Emim]DEP) with a better ability to dissolve three natural antibacterial agents (thymol, quercetin, and aloe-emodin) was screened out from 195 kinds of ILs formed by 13 cations and 15 anions using the conductor-like screening model for real solvents method. The antibacterial cellulose fibers were prepared using cellulose and three natural antibacterial agents as raw materials and [Emim]DEP as the solvent. The results indicated that three natural antibacterial agents are successfully added into the corresponding antibacterial cellulose fibers according to the Fourier transform infrared, X-ray diffraction, and thermogravimetric analysis data. The scanning electron microscopy results suggested that the antibacterial cellulose fibers have smooth and uniform surfaces. Moreover, the thymol/cellulose antibacterial fibers (TCFs) could inhibit more than 92.3% of E. coli and 90.2% of S. aureus when the content of thymol is 25 wt % and the breaking strength and breaking elongation of the TCFs are up to 580 MPa and 13.8%, respectively. In addition, after 15 times of standard washing in water, the TCFs still have more than 75% antibacterial activities against E. coli and S. aureus

Research on the degradation behaviors of wood pulp cellulose in ionic liquids

Utilizing phosphate-based ionic liquids (ILs) solvents for dissolving cellulose to prepare cellulose fibers has attracted much attention for its convenience, high yield, stability and sustainability. However, the degradation behavior during dissolving of cellulose in ILs, which is an important factor for fabricating cellulose fiber, is still unclear. In this work, the degradation of wood pulped cellulose (WPC) in three kinds of phosphate-based ILs: 1-ethyl-3-methylimidazolium dimethyl phosphate ([Emim]DMP), 1-ethyl-3methylimidazolium diethyl phosphate ([Emim]DEP) and 1-butyl-3-ethylimidazolium diethyl phosphate ([Beim]DEP), were systematically investigated at different dissolution temperatures and dissolution times. The results indicated that the degradation degree of WPC in three ILs follows the order of [Emim]DEP > [Beim]DEP > [Emim]DMP, which is consistent with interaction results obtained by quantum chemical calculation, and degradation degree increases follows the rising of dissolution temperature and the accumulation of dissolution time. Moreover, no reducing sugar (RS) was found in any recycled ILs even when the degree of polymerization (DP) of regenerated cellulose (RC) decreased by 30.4%. In addition, according to the Fourier transform infrared and X-ray diffraction data, the results further proved that the crystallization type of RC changed from type I to type II. Here, preferable dissolving parameters and experiments data of multiple conditions are provided, which may provide practical reference and guidance for both scientific research and industrial.(c) 2022 Elsevier B.V. All rights reserved