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Oil shale residue concrete is prepared by utilizing oil shale semi-coke. It has advantages such as low cost and a high solid waste utilization rate. The study of its bonding-slip characteristics with steel bars is a prerequisite for their application in engineering structures. To study the bonding-slip performance of reinforced oil shale residue concrete, 12 half-beam specimens were designed for the bonding performance test. The test parameters included the substitution rate of oil shale residue, bonding length, and cover thickness. The influences of the aforementioned factors and variables on the stress-slip curve and bonding strength were analyzed. The results showed that the anchoring bond length had the greatest impact on the average bonding strengths of the steel bar and concrete. As the bonding length increases from 5 d to 10 d , the average bonding strength decreased by approximately 18%. The cover thickness had the second-greatest influence on the bonding strength. As the cover thickness increased from 20 to 30 mm, the average bonding strength increased by more than 12%. The substitution rate of the oil shale residue had the least effect on the average bonding strength, and as the substitution rate increased, the bonding strength decrease with a minor magnitude. Through verification, the bonding-slip constitutive model obtained by fitting the experimental data was found to fit the experimental values well. [ABSTRACT FROM AUTHOR]

Pulse-like ground motions generally contain low-frequency velocity pulse with large amplitude, which can lead to severe damage or even collapse of near-fault structures. This study aims to proposed an adaptive decomposition method and corresponding identifying approach for pulse-like records. Firstly, an adaptive response spectrum-based decomposition (ARSD) method is proposed to decompose the records into several intrinsic mode functions (IMF) and their periods are identified by peak-point method. The decomposed results are compared with two representative methods, ensemble empirical-mode decomposition (EEMD) and variation mode decomposition (VMD). The results show that the proposed method can effectively avoid the mode mixing appears in the decomposed results by EEMD and generates similar results with those by the VMD. Then the low-frequency pulse is extracted by composing the key IMFs with the period and energy change larger than 0.5 s and 0.1. Based on the results of visual inspection method, the threshold of energy-based pulse indicator factor in general form and exponential form is calibrated to 0.26 and 0.30 respectively. The results show that the exponential form can improve identification rate of pulse-like records. The pulse extraction and classification results of the proposed method are comprehensively compared with three benchmark methods. The classification results by the proposed method are generally consistent with the three methods. Moreover, all the four methods can accurately detect the non-pulse records. And the proposed method could detect the most pulse-like records, followed by the Zhai's method, while the Feng's and Baker's methods detected the least pulse type records. The corresponding identification rates are 91.04%, 80.60%, 63.43%, and 63.06%, respectively. Finally, the periods of the records with single mode and multiple modes estimated by the proposed method and three benchmark methods are compared. The estimated periods of the records with single mode by the proposed method are highly consistent with those by the three benchmark methods, while this consistency for the estimated periods of records with multiple modes is reduced at some extent. This is due to the interference of multiple modes embedded in the records to the pulse identification. • An automatic and adaptive response spectrum-based decomposition (ARSD) method is proposed for pulse-type ground motions. • The proposed method exhibits better performance on controlling mode mixing than the existed methods at some conditions. • An identification method to detect pulse-like records is proposed based on the ARSD method. • Ground motions with PI > 0.30 can quantitatively be classified as pulse-like. • The proposed approach can identify the periods of multiple pulse modes embedded in the pulse-like records. [ABSTRACT FROM AUTHOR]

This study investigates the nonlinear seismic responses of a long-span suspension bridge crossing strike-slip faults and their sensitivity to various parameters and conditions. Four sets of near-fault records containing forward directivity and fling-step effects are selected, corrected, and then incorporated into the analysis. Empirical model is proposed using 54 sets of near-fault records to evaluate the dynamic pulse amplitude in fling-step ground motions. A simplified scaling method considering self-consistency is proposed to obtain the fling-step ground motions with different fault static offset and dynamic pulse amplitude. Multiple parameter method is derived by theoretical analysis to consider the effect of the fault-crossing angle on the wave propagation distance and direction. A nonlinear numerical model of double-pylon suspension bridge is established to study the seismic responses of near-fault and fault-crossing suspension bridges. The results indicate that the girder of the fault-crossing bridge rotates around the midspan, and the most of the bridge responses are slightly smaller than those of the near-fault case, whereas the transverse residual bearing displacement is substantially higher. Moreover, the sensitivity of the bridge responses to the fault-crossing angle, fault-crossing location, permanent displacement, dynamic pulse-type motion, ground motion component, and wave passage effect is comprehensively investigated. The minimum bridge responses, except for the residual bearing displacement, are obtained at a fault-crossing angle of 90° and a fault-crossing location at the middle span. The effects of the permanent displacement, dynamic pulse-type motion, and apparent wave velocity on the bridge responses are highly correlated with the fault-crossing angle. At a fault-crossing angle of 90°, all bridge responses are insensitive to these parameters, except that the peak transverse pylon drift and the bearing displacement increase considerably with the increasing amplitude of dynamic pulse-type motion. When the fault-crossing angle is acute (obtuse), the wave passage has a considerable effect on the bridge responses, and most of the bridge responses increase significantly with an increase in the permanent displacement and dynamic pulse-type motion. However, the permanent displacement has a negligible effect on the peak pylon drift. The wave passage effect is more reasonable to be considered using the apparent wave velocity in the horizontal direction than in the bridge axis direction because the influence of the fault-crossing angle on the propagation distance and direction is taken into account. Furthermore, the vertical component exerts a minimal effect on all bridge responses, whereas the fault-normal component significantly affects most bridge responses. • Nonlinear seismic responses of a suspension bridge across fault were studied. • Empirical model for evaluating the dynamic pulse amplitude in fling-step ground motion was proposed. • Simplified procedures for scaling the fling-step ground motion considering self-consistency were proposed. • The sensitivity of bridge responses to various parameters was evaluated. • Multiple parameters method for considering wave passage effect of fault-crossing bridges was developed. [ABSTRACT FROM AUTHOR]

Reconfigurable machine tools (RMTs) are important equipment for enterprises to cope with ever-changing markets because of their flexibility. In design of such equipment, selection of appropriate modules is a very critical decision factor to effectively and efficiently satisfy manufacturing requirements. However, the selection of appropriate modules is a challenging task because it is a multi-domain mapping process relying heavily on experts' domain knowledge, which is usually unstructured and implicit. To effectively support RMT designers, an ontology-based RMT module selection method is proposed. First, a knowledge base is built by development of an ontology to formally represent the taxonomy, properties, and causal relationships of/among three domain core concepts, namely, machining feature, machining operation, and RMT module involved in RMT design. Second, a four-step sequential procedure is established to facilitate the utilization of encoded knowledge from a knowledge base to aid in the selection of appropriate RMT modules. The procedure takes a given part family as the input, automatically infers the required machining operations as well as the RMT modules through rule-based reasoning, and eventually forms a set of RMT configurations that are capable of machining the part family as the output. Finally, the efficacy of the ontology-based RMT module selection method is demonstrated using a plate family manufacturing example. Results show that the approach is effective to support designers by appropriately and rapidly selecting modules and generating configurations in RMT design. [ABSTRACT FROM AUTHOR]

Due to the vast and complex nature of the power systems, the study of distributed solution to multi-objective OPF (MO-OPF) problem is vital. However, the existing distributed MO-OPF approaches are based on mathematical programming techniques. The tedious repetition of algorithmic executions is inevitable. Moreover, they can hardly solve the non-differential problem. In this paper, the coevolutionary multi-objective evolutionary algorithm (MOEA), combining the idea of decomposition, is introduced to solve the distributed MO-OPF problem. The decomposition first occurs on decision variables. After segmenting, multiple subpopulations can coevolve in a distributed manner under the support of a new proposed distributed fitness evaluation method. Further, an objective decomposition (OBD) method is applied to the proposed distributed MO-OPF approach. The problem is decomposed again based on objective functions. By this OBD method, the fitness assignment problem is effectively alleviated and a more extensively covered pareto front can be obtained. The experimental results on two systems of different scales first show the effectiveness of the proposed distributed approach and then demonstrate the excellence of the OBD method in large-scale system. [ABSTRACT FROM AUTHOR]

A meta-analysis was conducted to explore the effects of warming on the physiological processes of coccolithophores and diatoms by synthesizing a large number of published literatures. A total of 154 studies consisting 301 experiments were synthesized in this study. Under a projected temperature increase of 3–5 °C by IPCC AR6 at the end of this century, our results suggest that the growth and photosynthetic rate of coccolithophores were significantly enhanced by the rising temperature, while the calcification of coccolithophores was only slightly promoted. Warming also had significantly positive effects on the growth but not photosynthesis of diatoms. In comparison, the effect size of warming on the growth rate of coccolithophores was larger than that of diatoms. However, there was no significant effect of warming on either the ratio of particulate inorganic carbon to particulate organic carbon (PIC:POC) of coccolithophores or the ratio of biogenic silica to carbon (BSi:C) of diatoms. Furthermore, the results reveal latitudinal and size-specific patterns of the effect sizes of warming. For diatoms, the effects of warming on growth were more prominent in high latitudes, specifically for the Southern Hemisphere species. In addition, the effect size of warming on the small-sized diatoms was larger than that of the large-sized diatoms. For coccolithophores, the growth of the Southern Hemisphere temperate strains was significantly promoted by warming. Overall, the results based on the meta-analysis indicate that the projected warming of the end of this century will be more favor to the growth of coccolithophores than that of diatoms, thus potentially affect the competitive advantages of coccolithophores over diatoms; while the mid-to high latitude species/strains of both coccolithophores and diatoms will benefit more than their counterparts in the lower latitudes. Therefore, this study offers novel insights into predicting both the inter- and intra-group competitive advantages of diatoms and coccolithophores under the future warming climate change scenario. • Coccolithophores exhibit a stronger competitive advantage over diatoms under future warming scenario. • The advantage of small-sized diatoms under warming conditions is notably greater than that of their large-sized counterparts. • The growth and photosynthesis of diatoms and coccolithophores are more sensitive to warming than biomineralization. [ABSTRACT FROM AUTHOR]