8 research outputs found
Robust H-Infinity Filtering for Networked Control Systems with Markovian Jumps and Packet Dropouts
Examining the generalizability of research findings from archival data
This initiative examined systematically the extent to which a large set of archival research findings generalizes across contexts. We repeated the key analyses for 29 original strategic management effects in the same context (direct reproduction) as well as in 52 novel time periods and geographies; 45% of the reproductions returned results matching the original reports together with 55% of tests in different spans of years and 40% of tests in novel geographies. Some original findings were associated with multiple new tests. Reproducibility was the best predictor of generalizability—for the findings that proved directly reproducible, 84% emerged in other available time periods and 57% emerged in other geographies. Overall, only limited empirical evidence emerged for context sensitivity. In a forecasting survey, independent scientists were able to anticipate which effects would find support in tests in new samples
Experimental study on tensile mechanism of UHPC grouted sleeve splice
Funding Information: This study was financially funded by the Shaanxi Provincial Department of Science and Technology (Grant No. 2022JZ-32), and Chang’an University (Grant No. 300102212212). This paper was written during the academic visit of the first author to Aalto University in Finland, financially supported by the China Scholarship Council. Publisher Copyright: © 2022 The Author(s)The grouted sleeve splice is a competitive splice in the prefabricated structure that plays a key role in ensuring the stability of the whole structure. Despite the large amounts of experiments performed, its force mechanism has rarely been explored. In this study, a novel method was developed to calculate the constitutive model of grouted sleeve splice, and a comprehensive understanding of the force mechanism was analyzed. Tensile tests of 24 specimens were conducted to explore the mechanical properties of the grouted sleeve splice. The results showed that the anchorage length of rebar with ultra-high-performance grout material can be shorter than that recommended in design standards. The anchorage length and eccentricity of rebars have a significant impact on the mechanical performance of the grouted sleeve splice, which deserves special attention in the structure design and construction. The non-anchorage section of the grouted sleeve splice offers little contribution to the bearing capacity. Based on the concept of equivalent section elastic moduli, a theoretical calculation method was established to reveal the stress–strain relationship of the grouted sleeve splice. The errors between the theoretical model and test results vary from 0.20% to 18.90%. This study provides new perspectives for theoretical research on the mechanism of grouted sleeve splice.Peer reviewe
Experimental Study on Seismic Performance of Precast Columns Repaired with CFRP Fabrics
Funding Information: This research was funded by the Shaanxi Province Science and Technology Department, grant number 2022JZ-32, and Chang’an University, grant number 300102212212. This paper was written during the academic visit of the second author to Aalto University in Finland, financially supported by the China Scholarship Council. Publisher Copyright: © 2022 by the authors.Earthquakes worldwide highlight the seismic vulnerability of reinforced concrete (RC) bridge columns. RC bridges are likely to collapse or lose service function due to damage to the bridge columns from strong earthquakes. Rapid repair of RC bridge columns is of great significance for maintaining traffic lines for emergency rescue work after earthquakes. In this study, an improved rapid repair method was developed to restore the bearing capacity of a damaged precast column after earthquake damage. A cyclic loading test was performed to simulate the seismic loading. The original column and the repaired column were both tested. The test results showed that the bearing capacity of the repaired columns was increased by 8%, and the energy dissipation capacity was 53% higher than that of the original column. The ductility decreased because the test for the repaired specimen ended in advance. The initial stiffness of the repaired columns was reduced, but the stiffness was significantly developed in the later loading stage. The rapid repair method proposed in this study exhibited an excellent effect on restoring the seismic resistance of the damaged columns.Peer reviewe
Seismic performance of short precast columns with UHPC grouted sleeve connections : An experimental and numerical study
Funding Information: This study was financially funded by the Shaanxi Province Science and Technology Department [Grant Number 2022JZ-32], and Chang'an University [Grant Number 300102212212]. This paper was written during the academic visit of the first author to Aalto University in Finland, financially supported by the China Scholarship Council. Funding Information: This study was financially funded by the Shaanxi Province Science and Technology Department [Grant Number 2022JZ-32], and Chang’an University [Grant Number 300102212212]. This paper was written during the academic visit of the first author to Aalto University in Finland, financially supported by the China Scholarship Council. Publisher Copyright: © 2023 The Author(s)Grouted sleeve connections have been developed in various precast structures such as columns in buildings and bridges. When they are used in precast columns, the aspect ratio of the column is reduced owing to the shifted plastic hinge phenomenon. In contrast, short columns with aspect ratios of less than three are susceptible to shear failure under earthquakes. This study investigated the effect of UHPC (ultra-high-performance concrete) grouted sleeve connections on the seismic performance of precast columns. One cast-in-place column (CIP) and two precast columns (PCGS1 and PCGS2) with an original aspect ratio of 3.11 were manufactured. The two precast columns were designed with grouted sleeve connections at different positions, which were supposed to have lower actual aspect ratios according to the shifted plastic-hinging phenomenon. Cyclic loading tests were conducted on all the columns to study their seismic performance. The damage progression and seismic responses were analyzed experimentally. Shifted plastic hinging was theoretically calculated, and a numerical model was developed using OpenSees platform. From the acquired results, the precast column PCGS1, which was connected by grouted sleeve connections at the bottom, failed in shear failure. The other two columns failed in flexure-shear failure. The seismic performance of precast column PCGS1 was significantly reduced through a comparison of the hysteretic responses. A calculation method was proposed to obtain the critical height of the grouted sleeve connections, which helped the short columns avoid shear failure during earthquakes. The numerical analysis showed that the location of grouted sleeves had a negligible effect on seismic performance when placed above the critical height. The increase in the compression ratio and rebar strength positively affected the bearing capacity but negatively influenced the ductility.Peer reviewe
Kylin 1.0: An Ab-Initio Density Matrix Renormalization Group Quantum Chemistry Program
The accurate evaluation of electron correlations is highly necessary for the proper descriptions of the electronic structures in strongly correlated molecules, ranging from bond-dissociating molecules, polyradicals, to large conjugated molecules and transition metal complexes. For this purpose, in this paper, a new ab-initio quantum chemistry program Kylin 1.0 for electron correlation calculations at various quantum many-body levels, including configuration interaction (CI), perturbation theory (PT), and density matrix renormalization group (DMRG), is presented. In addtion, fundamental quantum chemical methods such as Hartree-Fock self-consistent field (HF-SCF) and the complete active space SCF (CASSCF) are aslo implemented. The Kylin 1.0 program possesses these features: (1) efficient DMRG implementation based on the matrix product operator (MPO) formulation for describing static electron correlation within a large active space composed of more than 100 orbitals, supporting both and symmetries; (2) efficient second-order DMRG-self-consistent field (SCF) implementation; (3) externally-contracted multi-reference CI (MRCI) and Epstein-Nesbet PT with DMRG reference wave functions for including the remaining dynamic electron correlation outside the large active spaces. In this paper, we introduce the capabilities and numerical benchmark examples of the Kylin 1.0 program