180 research outputs found
Mechanical properties of multi-recycled aggregate concrete under combined compression and shear
No full textThe mechanical properties and strength failure criteria of natural aggregate concrete and multi-recycled aggregate concrete (multi-RAC) under combined compression and shear loading states are investigated in this study. The peak shear strength, peak shear displacement, and failure patterns are compared under different regeneration cycles and normal compressive stress ratios. The results reveal that both the peak shear strength and peak shear displacement increase with the increased normal stress ratio. The shear failure pattern with higher severity corresponds to more spalling powder and debris deposited on the shear fracture surface. When the regeneration cycles of coarse aggregate increase, the peak shear strength decreases and the descending trend become more evident with the higher vertical compressive stress ratio, whereas the peak shear displacement significantly fluctuates, regardless of the regeneration cycles and normal compressive stress ratios. Under the normal compressive stress, contact friction strength is the dominant component of peak shear strength in terms of cohesive strength, contact friction strength, and shear dilation strength. Based on different stress expressions, three compression-shear failure criterion models considering the regeneration cycles of coarse aggregate under planar stress state were established for RAC. The stress invariance failure criterion model and octahedral stress failure criterion model in quadratic parabolic functional forms can provide the high prediction accuracies.This is a manuscript of an article published as Lei, Bin, Hongchen Yu, Yipu Guo, Hanbing Zhao, Kejin Wang, and Wengui Li. "Mechanical properties of multi-recycled aggregate concrete under combined compression and shear." Engineering Failure Analysis 143, Part A (2023): 106910.
DOI: 10.1016/j.engfailanal.2022.106910.
Copyright 2022 Elsevier Ltd.
Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0).
Posted with permission
Fracture behaviours of sustainable multi-recycled aggregate concrete under combined compression-shear loading
No full textThe mechanical properties and strength failure criteria of natural coarse aggregate and multiple recycled coarse aggregate concrete under the combined compression and shear loading states are investigated in this study. The failure pattern, peak shear strength, and peak shear displacement are compared in terms of the number of regeneration cycles and normal compressive stress ratios. The results reveal that both the peak shear strength and peak shear displacement of concrete increase with the enlarged normal stress ratio. The shear failure pattern with higher severity corresponds to more spalling powder and debris deposited on the shear fracture surface. When the times of coarse aggregate regeneration increase, the peak shear strength decreases, and the descending trend becomes more evident with the increased vertical compressive stress ratio, whereas the peak shear displacement significantly fluctuates, regardless of the regeneration time and the normal compressive stress ratios. With normal compressive stress, the contact friction strength becomes the dominated component of peak shear strength consisting of cohesive strength, contact friction strength, and shear dilation strength. Based on the different stress expressions, three compression-shear failure criterion models considering the times of coarse aggregate regeneration under planar stress state were established for concrete. Despite the strong correlation with the correlation factors (R2) larger than 0.96 for all the models, the failure criterion model based on stress invariance and failure criterion model based on octahedral stresses in the quadratic parabolic functional forms provides the highest predictive accuracy. The related outcomes are expected to fill the gap of the related research on recycled aggregate concrete.This is a manuscript of an article published as Lei, Bin, Hongchen Yu, Yipu Guo, Wenkui Dong, Rui Liang, Xiaonan Wang, Xuqun Lin, Kejin Wang, and Wengui Li. "Fracture behaviours of sustainable multi-recycled aggregate concrete under combined compression-shear loading." Journal of Building Engineering (2023): 106382.
DOI: 10.1016/j.jobe.2023.106382.
Copyright 2023 Elsevier Ltd.
Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0).
Posted with permission
Liu Jishan xin xing lun tan wei: wei Mou Zongsan de "yi xin zhe xing" zuo bian hu
No full textM.Phil.In this thesis, I will focus on the discussion of Liu Jishan (Liu Zongzhou)’s theory of heart-mind and nature, based on the outcome of contemporary studies. The reason for investigating Liu’s theory is that he had developed a unique and complicated theory of heart-mind and nature based on the late Ming development of Confuciansim, which making him “The Last Neo-Confucian”. Due to the historical background and the complicity of his theory, Liu’s system is difficult to understand and opens for different interpretations. In my opinion, Mou Zongsan’s theory of “manifest nature by heart-mind” is the best interpretation to grasp Liu’s insight among the contemporary studies. Therefore, this thesis argues for Mou’s interpretation to Liu’s theory by analyzing Liu’s text and defending contemporary criticisms to Mou.This thesis includes four parts: First, it analyzes Liu’s problematic from the historical background of late Ming Confucian thoughts. Second, it illustrates Mou’s view in detail and explains why his interpretation fitting into Liu’s thought. Third, it analyzes the contemporary studies of Liu to see their understanding and criticisms to Mou. Finally, it defends for Mou’s view, by arguing Mou’s view grasping Liu’s insight by developing a system of covering both the subjective-moral aspect and the objective-ontological aspect, in order to solve the difficulties of moral practices caused by the School of Heart-mind.這篇論文的工作是在建基於當代研究的視野下，對明末大儒劉蕺山（宗周）的心性論作進一步的討論。以蕺山為研究對像的原因，是由於他在修正明末各種思潮的脈絡下發展出一套較為複雜的心性論系統。他在心性論上的創穫，使他獲得「宋明理學殿軍」之美譽。但亦因為蕺山在思想背景及其心性論系統上的複雜性，這使得他的系統艱澀難懂外，亦引不少詮釋上的爭議。而筆者認為，在當代研究之中，最能說明和闡發蕺山的心性論的洞見者當屬牟宗三的以心著性系統。故本文的目的在於疏解蕺山的心性論文字的同時論證牟宗三的以心著性是對蕺山最佳的解讀，並嘗試為牟宗三的觀點辯護，以回應當代學界的批評。為此，本篇論文主要處理四項工作：一、從明末思潮的脈絡梳理蕺山的問題意識。二、對牟宗三的以心著性觀點作出詳細的分析，並解釋此觀點何以契合蕺山的文字。三、分析當代蕺山研究中贊同及反對牟說的觀點，以說明當代學界對於以心著性的理解。四、為牟說作出辯護，論證以心著性系統以分言主觀道德面與客觀存有面的方式堵塞心學工夫的流弊是最能把握蕺山心性論洞見的說法。筆者希望著此來說明一套主客兼備的心性論系統在宋明理學中的哲學洞見。張鴻辰."2019年7月".Thesis M.Phil. Chinese University of Hong Kong 2019.Includes bibliographical references (leaves 246-256).Abstracts in Chinese and English.Title from PDF title page (viewed on February 23, 2022).Zhang Hongchen
Thermophilic and Halophilic Extremophiles in Eurasian Environments
No full textThis eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contac
Joint Application of Multiple Inflammatory Cytokines in Diagnosis of Gout Flare
No full textHanqing Yu,* Wen Xue,* Hanjie Yu, Hongchen Gu, Ling Qin, Ai Peng Center for Nephrology and Clinical Metabolomics, Division of Nephrology, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, People’s Republic of China*These authors contributed equally to this workCorrespondence: Ai Peng; Ling Qin, Center for Nephrology and Clinical Metabolomics, Division of Nephrology, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, 200072, People’s Republic of China, Email [email protected]; [email protected]: This study aimed to explore the accuracy for joint application of inflammatory cytokines in diagnosis of gout flare by comparison with peripheral blood cells.Methods: We collected the clinical data of 96 acute gout patients and 144 remission gout patients, and compared the levels of peripheral blood cells, inflammatory cytokines and blood biochemistry indexes between acute and remission gout. We respectively assessed the area under curves (AUCs) for single and multiple inflammatory cytokines including C-reactive protein (CRP), interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), and single and multiple peripheral blood cells including platelet (PLT), white blood cell (WBC), percentages of neutrophils (N%), lymphocytes (L%), eosinophils (E%), basophils (B%) in diagnosis of acute gout by receiver operating characteristic (ROC) curve analysis.Results: By contrast with remission gout, the levels of PLT, WBC, N%, CRP, IL-1β, IL-6 and TNF-α increased, and the levels of L%, E% and B% decreased in acute gout. The AUCs of PLT, WBC, N%, L%, E% and B% in diagnosis of acute gout were respectively 0.591, 0.601, 0.581, 0.567, 0.608 and 0.635, while the AUC for joint application of these peripheral blood cells was 0.674. Moreover, the AUCs of CRP, IL-1β, IL-6 and TNF-α in diagnosis of acute gout were respectively 0.814, 0.683, 0.622 and 0.746, while the AUC for joint application of these inflammatory cytokines was 0.883, reflecting significantly higher levels than peripheral blood cells.Conclusion: The joint application of multiple inflammatory cytokines can better distinguish acute gout from remission gout compared with peripheral blood cells.Keywords: acute gout, diagnosis, multiple inflammatory cytokine
Multiferroic CoFe2O4-BiFeO3 core-shell nanofibers and their nanoscale magnetoelectric coupling
No full textMultiferroic CoFe2O4-BiFeO3 (CFO-BFO) core-shell nanofibers were synthesized by coaxial electrospinning. The spinel structure of CFO and perovskite structure of BFO were confirmed by x-ray diffraction and high-resolution transmission electron microscopy. The core-shell configuration of nanofibers was verified by scanning electron microscopy and transmission electron microscopy images. The macroscopic ferromagnetic property of core-shell nanofibers was demonstrated by magnetic hysteresis loop. The local magnetoelectric (ME) coupling was confirmed by using dual frequency piezoresponse force microscopy (PFM) under an external magnetic field, showing magnetically induced evolution of piezoresponse and domain structure. The ferroelectric characteristics are demonstrated by the switching spectroscopy PFM. From PFM hysteresis and butterfly loops, it is observed that the piezoresponse amplitude is reduced while coercive voltage increased under external in-plane magnetic field, induced through the mechanical interactions between magnetostrictive CFO and piezoelectric BFO, from which the lateral ME coupling can be estimated quantitatively. The nanofibers thus can find a variety of applications as a one-dimensional multiferroic material
Development of an apparent face-shear mode (d(36)) piezoelectric transducer for excitation and reception of shear horizontal waves via two-dimensional antiparallel poling
No full textThe non-dispersive fundamental shear horizontal (SH0) wave is extremely useful in guided-wave-based inspection techniques. However, the generation or reception of the SH0 wave by using a piezoelectric transducer is always a challenge. In this work, first, we realized the apparent face-shear (d(36)) mode in PbZr1-xTixO3 (PZT) ceramics via two-dimensional antiparallel poling. Then, we demonstrated via finite element simulations that the apparent d(36) mode PZT wafer can behave as both a SH0 wave actuator and a SH0 wave sensor. Next, by using the apparent d(36) PZT wafer as an actuator and a face-shear d(36) 0.72[Pb(Mg1/3Nb2/3)O-3]-0.28[PbTiO3] crystal as the sensor, almost a pure SH0 wave with a high signal-to-noise ratio was successfully excited in an aluminum plate from 180 kHz to 200 kHz. Later, experiments showed that the proposed apparent d(36) PZT wafer can also serve as a sensor to detect the SH0 wave over a wide frequency range (160 kHz to 230 kHz). Finally, the amplitude directivity of the SH0 wave generated by the apparent d(36) PZT wafer was also investigated. The wave amplitude reaches its maxima at the main direction (0 degrees and 90 degrees) and then decreases monotonically when the propagation direction deviates from the main directions, with the symmetric axis along the 45 degrees direction. The proposed apparent d(36) PZT wafer is very suitable for severing as SH0 wave actuators and sensors in structural health monitoring systems. Published by AIP Publishing.National Natural Science Foundation of China [11422216, 11672003, 11521202]SCI(E)[email protected]
Identifying a suitable revegetation technique for soil restoration on water-limited and degraded land: Considering both deep soil moisture deficit and soil organic carbon sequestration
No full textRevegetation is an important means to improve the ecosystem services delivered by degraded land; however, inappropriate revegetation can result in severe soil desiccation and ecosystem degradation in water-limited regions. Here we evaluated seven common revegetation techniques by considering both deep soil moisture deficit and soil organic carbon (SOC) sequestration on the Loess Plateau of China, attempting to identify a suitable method for soil restoration of severely degraded ecosystems. The seven revegetation techniques considered were: two single-species shrub plantations (Caragana korshinskii and Hippophae rhamnoides), two single species tree plantations (Platycladus orientalis with terracing and Robinia pseudoacacia), and three mixed plantations (P. orientalis/H. rhamnoides with terracing, R. pseudoacacia/H. rhamnoides, R. pseudoacacia/P. orientalis). A 12-year-old abandoned cropland served as the control. The results showed that the single-species plantation of P. orientalis with terracing had the lowest soil moisture deficit in deep layers (200-800 cm) but also had the lowest SOC sequestration. In contrast, the mixed plantation of R. pseudoacacia/H. rhamnoides had the highest SOC sequestration but also had significant deep soil moisture deficit. In contrast, the mixed plantation of P. orientalis/H. rhamnoides with terracing showed near-zero deep soil moisture deficit and significant, positive SOC sequestration. Therefore, this mixed plantation was identified as representing a suitable revegetation technique for this region. The results here suggest that appropriate mixed tree/shrub plantations with appropriate land engineering measures could deliver effective soil restoration in such environments. Our results provide an insight into revegetation in areas with degraded land
Excitation and reception of non-dispersive guided waves using face-shear d24 mode piezoelectric transducers
No full textThe non-dispersive fundamental shear horizontal (SH0) and torsional [T(0,1)] waves are extremely useful in guidedwave-based inspection techniques. However, excitation of SH0 and T(0,1) waves using piezoelectrics is always a challenge. In this work, firstly, a newly defined face-shear d24 PZT wafer is proposed to excite and receive SH0 wave mode. The d24 wafer is in-plane poled and its working electric field is applied along another orthogonal in-plane direction. Both finite element simulations and experiments show that single SH0 mode can be excited by using the d24 wafer along two orthogonal directions (0 degrees and 90 degrees). Then an omnidirectional SH0 wave piezoelectric transducer (OSH-PT) is developed which consists of a circular array of twelve face-shear d24 trapezoidal PZT elements. Results show that the proposed OSH-PT exhibits good omnidirectional properties, no matter it is used as a SH0 wave transmitter or receiver. Finally, the development of a T(0,1) wave transducer for pipes based on a ring array of d24 PZT elements is described. Both finite element simulations and experiments show that the d24 elements ring can excite single T(0,1) mode and suppress all the unwanted non-axisymmetric modes. This work may greatly promote the applications of SH0 and T(0,1) waves in nondestructive testing (NDT) and structural health monitoring (SHM).National Natural Science Foundation of China [11422216, 11672003, 11521202]CPCI-S(ISTP)1016
The development of English learning motivation and learners' identities: A structural equation modeling analysis of longitudinal data from Chinese universities
No full textThis paper reports a structural equation modeling analysis of the relationship between English learning motivation types and learners' identity changes. The data were collected through a questionnaire in a longitudinal study, implemented five times in four years, on over 1300 students from five Chinese universities. According to SEM results of the five tests, two-directional relations were found between the latent variables of motivation and identity change, yet the influence of the former on the later was stronger at the beginning, while the reverse was the case towards graduation. Positive correlations were constantly found between individual development motivation and positive self-confidence identity change, between going-abroad motivation and subtractive identity change, and between immediate achievement motivation and learning situation motivation. The results indicated relevance of L2 identity changes in English as a Foreign Language environments, the ranked weight of motivation categories in terms of influence, and the emergent nature of L2 identity as well as its impact on motivation. (C) 2014 Elsevier Ltd. All rights reserved.Education & Educational [email protected]
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