Tripod-supported offshore wind turbine (OWT) foundation must withstand wind, wave, and seismic loads. In addition, it may be threatened by scouring during its service life, which could affect its ...bearing capacity and the overall OWT dynamic response. This study develops a three-dimensional numerical model of OWT tripod pile foundation to investigate scour effects. The numerical model incorporates a simplified single bounding surface model to simulate the dynamic stress–strain response of clay soil. The results revealed that scouring can reduce the first-order natural frequency of tripod pile-OWT system; however, the reduction usually does not lead to resonance within the 1P frequency range. Nonetheless, as the scour depth increases under wind and wave loads, the horizontal displacement of the wind turbine structure increases monotonously; however, its peak acceleration increases initially then decreases slightly as the scour depth continues to increase. Under seismic loading only, the OWT response exhibits complex evolution pattern as the scour depth increases. On the other hand, the foundation horizontal displacement and rotation angle increase significantly under combined wind-wave-seismic loads when the scouring depth reaches three times the pile diameter. Finally, the scouring depth has a relatively small impact on the foundation vertical displacement.
This study examined the relations among social dominance orientation (SDO), social contact, and attitudes toward international students. SDO was positively associated with prejudice against ...international students, perception of threats from international students, and exclusionism. Men had a higher level of SDO than women, but SDO had a greater effect on female exclusionism. The results show that SDO did not directly predict a general attitude toward international students. Prejudice predicted unfavorable attitudes, but threat perception and exclusionism did not, indicating that the mechanism underlying the effect of SDO on attitudes toward international students was through prejudice rather than threat perception and exclusionism. The negative effect of prejudice remained after controlling for the effect of social contact. However, social contact contributed to a favorable attitude toward international students. Both the number of international-student friends and personal relations with them had positive effects.
Objective
In this study, based on PET/CT radiomics features, we developed and validated a nomogram to predict progression-free survival (PFS) for cases with diffuse large B cell lymphoma (DLBCL) ...treated with immunochemotherapy.
Methods
This study retrospectively recruited 129 cases with DLBCL. Among them, PET/CT scans were conducted and baseline images were collected for radiomics features along with their clinicopathological features. Radiomics features related to recurrence were screened for survival analysis using univariate Cox regression analysis with
p
< 0.05. Next, a weighted Radiomics-score (Rad-score) was generated and independent risk factors were obtained from univariate and multivariate Cox regressions to build the nomogram. Furthermore, the nomogram was tested for their ability to predict PFS using time-dependent receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA).
Results
Blood platelet, Rad-score, and gender were included in the nomogram as independent DLBCL risk factors for PFS. We found that the training cohort areas under the curve (AUCs) were 0.79, 0.84, and 0.88, and validation cohort AUCs were 0.67, 0.83, and 0.72, respectively. Further, the DCA and calibration curves confirmed the predictive nomogram’s clinical relevance.
Conclusion
Using Rad-score, blood platelet, and gender of the DLBCL patients, a PET/CT radiomics-based nomogram was developed to guide cases’ recurrence risk assessment prior to treatment. The developed nomogram can help provide more appropriate treatment plans to the cases.
Key Points
• DLBCL cases can be classified into low- and high-risk groups using PET/CT radiomics based Rad-score.
• When combined with other clinical characteristics (gender and blood platelet count), Rad-score can be used to predict the outcome of the pretreatment of DLBCL cases with a certain degree of accuracy.
• A prognostic nomogram was established in this study in order to aid in assessing prognostic risk and providing more accurate treatment plans for DLBCL cases.
Although flexibility has been considered critical in responding to uncertainty in a business environment, few studies have explored firms' flexibility in sustainable development. To understand the ...nature of firms that can respond better to uncertainty in their sustainable development practices, this study defines sustainable development flexibility and investigates the mechanism underlying its formation. The study proposes a conceptual framework on the interactions of managers' environmental attitude and cognitive style, as well as firms' information integration on sustainable development flexibility. A questionnaire survey was developed to test the corresponding hypotheses, and 241 valid responses were received from middle‐ and top‐level managers in Chinese firms. The results show that (a) the higher the manager's environmental attitude, the higher the firm's information integration and greater sustainable supply chain flexibility, and (b) the more intuitive the manager's cognitive style, the greater the impact of environmental attitude on sustainable development flexibility.
Display omitted
•Harvesting efficiency of over 97% was achieved by using Fe3O4-chitosan composites.•The maximum adsorption capacity of Fe3O4-chitosan composites was 75.43 g/g.•Charge neutralization, ...double layer compression and bridging were the mechanisms.•The supernatant after harvesting could be reused to re-cultivate microalgal cells.
As an environmentally friendly bioflocculant, chitosan has a great application potential for microalgae harvesting due to its biocompatibility. The rapid development of magnetic separation technology has attracted extensive attention because of its reusability, energy and time saving. In this work, Fe3O4-chitosan composites flocculant with high magnetic harvesting ability and fast separation was successfully prepared with sodium tripolyphosphate as crosslinking agent, and applied to the harvesting and separation of microalgae cells. The harvesting efficiency of 97.63% for Chlorella vulgaris was achieved within 3 min using chitosan/Fe3O4 with the weight ratio of 3:1 and the dosage of 0.5 g/L under pH 3.0. Freundlich isotherm was more suitable for Fe3O4-chitosan to harvest microalgae, indicating the microalgae harvesting by Fe3O4-chitosan composites was a heterogeneous multilayer process. The highest adsorption ability of the Fe3O4-chitosan on Chlorella vulgaris could be reached 75.43 g/g. Double-layer compression, charge neutralization and adsorption bridging are primarily harvesting mechanisms between Fe3O4-chitosan composites and microalgae cells. The second-order polynomial model well simulates the experimental data, establishing the relationship between Fe3O4-chitosan and algae slurry pH, concentration of microalgae cells and settling time. The supernatant after Fe3O4-chitosan harvesting could be reused, saving water resources and cost, showing its biocompatibility. The Fe3O4-chitosan composites had excellent reusability, and the harvesting efficiency could reach 85.10% after four cycles, which improved the economic feasibility of magnetic harvesting. Fe3O4-chitosan has the advantages of high efficiency, fast separation, low economic cost, and low energy consumption. This work provides basic guidance and data analysis in the study of Fe3O4-chitosan for microalgae harvesting on a large scale.
•A new paradigm is presented for finite element analysis in CAD environments.•The focus is, firstly, on operating directly with clean-up on the CAD geometry.•The focus is, secondly, on establishing ...efficiently a finite element mesh.•Overlapping finite elements are used to achieve these aims.•The theory of the new scheme and example solutions are given.
A major difficulty in finite element analysis is the preparation of an effective mesh leading to a good response solution. In engineering analyses of complex components, oftentimes, much more time is spent to arrive at an adequate mesh than to obtain the solution of the established finite element model. The difficulty in meshing is due to the fact that finite elements need to abut each other and cannot overlap. This can lead to highly distorted elements, e.g. sliver elements, reducing the accuracy of solution. In practice, to establish an effective mesh, frequently, significant expertise in building meshes is needed, because great care must be taken in cleaning up the CAD geometry and preparing an effective mesh.
The objective in this paper is to present a new finite element solution scheme including meshing in which the elements can overlap. The property that finite elements can overlap removes many of the meshing difficulties, leads to an effective meshing procedure and an overall easy-to-use solution scheme for an analyst or a designer.
We first present the meshing scheme that we propose, which combines the use of traditional finite elements and overlapping finite elements. A particular feature is that the meshing procedure can be directly embedded in CAD driven solutions. We then present the theory used for the formulation of the overlapping finite elements and the coupling with traditional finite elements. We consider spherical and brick-shaped overlapping finite elements for which the theory is largely based on the formulation of the method of finite spheres. Finally, we illustrate the complete solution scheme in the analysis of some two-dimensional problems using the CAD geometry as the starting point.
While the paper presents a new paradigm for analysis in CAD environments, with much potential, we realize that much further study and research is needed on some of the important ingredients of the method to render the complete procedure effective for general practical engineering analyses of static and dynamic problems.
Simulation of soil-tool interaction is challenging due to large deformations of soil around the tool, unconstrained deformation of the free soil surface and the dynamic behaviour of soil-tool ...interaction at the interface. An application of a coupled Eulerian-Lagrangian finite element (CEL-FE) method to the simulation of soil-tool interaction is presented. By combining the merits of both the Lagrangian and the Eulerian formulations, large deformation and unconstrained deformation of soil and the dynamic behaviour of soil-tool interaction are simultaneously simulated. Firstly, interactions between the soil and vertical tines were simulated. The results showed that the predicted soil deformation and draft force were in reasonable agreement with published data from soil bin tests. Then, in order to further validate the feasibility and effectiveness of the CEL-FE method, interactions between the soil and inclined blades at different operating conditions were simulated. Results showed that the numerically simulated and experimentally measured draft forces exhibited similar trends and average values. In addition, the predicted soil deformation was in general agreement with experimental observations. Finally, an example of simulating soil-mouldboard interaction was given and preliminary results indicated that shape complexity of this tool was not a limitation for applying the CEL-FE method. The proposed CEL-FE method provides new possibilities for simulating soil-tool interaction and it is hoped that this method will help to contribute a better understanding of the soil-tool interaction process thereby improving the design of tillage tools.
•An advanced CEL-FE method is presented for the simulation of soil-tool interaction.•The large deformation and free deformation of soil are simulated simultaneously.•The dynamic soil-tool interaction behavior at the interface is simulated.•The CEL-FE method is convenient to use for tillage tools with complex shapes.
This study was designed to assess left ventricular deformation after chronic myocardial infarction (CMI) using cardiac magnetic resonance feature tracking (CMR-FT) technology, and analyze its ...relationship with left ventricular ejection fraction (LVEF) and infarcted transmurality.
Ninety-six patients with CMI and 72 controls underwent 3.0 T CMR scanning. Strain parameters were measured by dedicated software, including global peak longitudinal strain (GPLS), global peak circumferential strain (GPCS), global peak radial strain (GPRS), segmental peak longitudinal strain (PLS), peak circumferential strain (PCS), and peak radial strain (PRS). All enhanced myocardium segments were divided into subendocardial infarction (SI) and transmural infarction (TI) group. Pearson, intraclass correlation coefficient and receiver operating characteristic analysis were performed to compare the parameters' mean values between SI and TI groups.
GPLS, GPRS, and GPCS in CMI group were significantly decreased comparing with control group. PRS and PCS in TI group were significantly lower than those in SI group, whereas no statistical difference was observed in PLS. In Pearson correlation analysis, LVEF was strongly correlated with GPLS, GPRS, and GPCS in CMI patients. Additionally, excellent reproducibility of all strain parameters was observed. In receiver operating characteristic analysis, segmental PRS and PCS might differentiate SI from TI with higher diagnostic efficiency (p < 0.05), while PLS was less valuable (p > 0.05).
CMR-FT could noninvasively and quantitatively assess global and regional myocardial strain in CMI patients with excellent reproducibility and strong correlation with LVEF. Additionally, segmental myocardial strain parameters indicate potential clinical value in differentiating myocardial infarction subtype.
•A new paradigm of solution is considered.•We give the formulation of new overlapping finite elements.•The numerical integration of the element matrices is efficient.•The new elements are quite ...distortion insensitive.•We illustrate the complete solution scheme of the new paradigm.
We present novel overlapping finite elements for a new paradigm of solution proposed in our previous papers, see Bathe (2016) and Bathe and Zhang (2017).
We give the formulation of the new overlapping elements and the solutions of basic numerical examples to investigate the robustness and efficiency of the new finite elements. The results show that the new overlapping elements are quite distortion insensitive and the numerical integration of the element matrices is efficient. The computational effort to integrate the matrices is much less than in meshfree methods. Finally, we illustrate the complete solution scheme of the new paradigm using the overlapping finite elements in the analysis of the bracket problem already considered in Bathe and Zhang (2017).
While the paper proposes and studies new overlapping elements, we conclude that further research is needed to fully harvest the potential of the new analysis approach.
Emissive lanthanide ions are considered as luminescent species or optical probes for the analytes in ambient conditions or even cellular environment. But a variety of factors determine the stability ...of photo-luminescent signals due to the excitation sources, statistical errors or the selection of solvents. In this way, ratiometric assays effectively circumvent such problem and lead to more sensitive and reliable results. Herein, an organic-inorganic hybrid material has been developed with the europium complex as the core and the terbium species can be attached onto the surface of silica host. As for the evaluation of the internal structure, the terbium complex has been integrated into the hybrid network via weak forces and its sensitizing moiety will be easily attacked by Lewis acid-base interactions. In a different manner, the europium complex has been shielded from perturbation due to the protection of the outside silica shells. Such sharp difference in response to fluoride induces drastic signal changes and the conversion of binding process between fluoride and molecular receptors (boronic group) into readable optical outputs has afforded the lower detection limit for F− as 0.17 μM. In addition, the intracellular uptake and distribution of the hybrid material have been explored.
Control of the luminescence could be realized via two lanthanide species in a hybrid inorganic-organic network. The fluoride addition induced the consecutive changes in the form and intensity of terbium emissions, but the europium emissions were maintained stable. The evolvement from two lanthanide luminescence provided a new platform for fluoride recognition. Display omitted
•Both of europium and terbium emissions were achieved.•Optical signal change in the presence of fluoride was unique.•In vitro studies have been realized.
