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Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: Bone is a remarkable natural material possessing piezoelectric properties. By harnessing the biomimetic piezoelectric effect, tissue engineering materials can be employed to effectively address bone tissue defects and facilitate their repair. OBJECTIVE: Using a solid-phase force chemistry technique, a piezoelectric scaffold with inherent osteogenic properties was meticulously fabricated. This unique scaffold was then assessed for its impact on osteoblast adhesion, proliferation, and osteogenic differentiation. METHODS: Polyvinylidene fluoride (PVDF) powders, along with commercially available NaCl (mass ratios are 60:40, 50:50, 40:60, and 30:70, respectively), were subjected to solid-phase shear milling technology, resulting in a homogenous mixture. Through a melting process, a substantial material was formed, and subsequent treatment with a pure water solution effectively eliminated the NaCl. Consequently, PVDF piezoelectric foam scaffolds with varying pore sizes were successfully prepared. These materials were categorized as PVDF-40, PVDF-50, PVDF-60, and PVDF-70, denoting the respective mass percentages of NaCl during preparation. The surface morphology, crystal phase composition, thermodynamic behavior, mechanical properties, and piezoelectric properties of each group were meticulously characterized. The four kinds of piezoelectric foam scaffolds were co-cultured with the MG63 osteoblast cell line to evaluate its biocompatibility and potential to promote bone differentiation. RESULTS AND CONCLUSION: (1) The scanning electron microscopy, four groups of scaffolds had multi-level pores. As the NaCl mass fraction in the mixed powder increased, the porosity of the scaffolds increased. X-ray energy dispersion spectrum, X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis collectively revealed the scaffold predominantly comprised the α phase, which inherently lacked piezoelectric properties. However, the application of solid-phase force chemistry successfully stimulated the formation of the β phase, thereby enhancing the scaffold’s piezoelectric properties. Notably, the PVDF-60 group exhibited the highest proportion of the β phase among all the tested groups. The results of cyclic compression testing and piezoelectric performance assessment demonstrated that the PVDF-60 group exhibited superior compressive strength and piezoelectric performance compared to the other groups. (2) The findings from scanning electron microscopy and laser confocal microscopy exhibited that MG63 cells adhered well to the surface of the four groups of scaffolds, with good morphology, extended more pseudopods, and secreted a large amount of extracellular matrix. CCK-8 assay revealed that the proliferative absorbance of PVDF-60 cells cultured for 4 days was higher than that of the other three groups (P < 0.000 1). Alkaline phosphatase staining and alizarin red staining showed that the expression of alkaline phosphatase and the number of calcified nodules in the PVDF-60 group were higher than those in the other three groups (P < 0.01, P < 0.000 1). (3) The piezoelectric PVDF foam-based scaffolds demonstrated favorable cytocompatibility. Notably, the PVDF60 group showed superior mechanical properties, piezoelectric performance, and bone-inducing capabilities. [ABSTRACT FROM AUTHOR]

Copyright of Yellow River is the property of Editorial Board of Yellow River and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Railway Science & Engineering is the property of Journal of Railway Science & Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Polymer Materials Science & Engineering is the property of Sichuan University, Polymer Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Water Conservancy Science & Techonlogy & Economy is the property of Water Conservancy Science & Technology & Economy Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Plastics / Zhongguo Suliao is the property of Journal Office of CHINA PLASTICS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Railway Science & Engineering is the property of Journal of Railway Science & Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Steel Pipe is the property of Steel Pipe Magazine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Railway Science & Engineering is the property of Journal of Railway Science & Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Yellow River is the property of Editorial Board of Yellow River and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Zhengzhou University (Natural Science Edition) is the property of Journal of Zhengzhou University (Natural Science Edition) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Yellow River is the property of Editorial Board of Yellow River and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to evaluate the mechanical properties of the sedimentary soil in the middle and lower region of ihe Yellow River, die standard sand was selected as the reference slaiidard. A series of triaxial consolidation drained shear tesls were carried oul on salurated standard sand. This paper studied emphatically alHiul the influence of freezing method on the stress-strain relationship and shear resislanee indexes of standard sand. The results show that with the increase of relative density, the devialor stress of sample obtained by freezing method or wet method is a trend of growth. And the stress-strain relation curves of sample obtained by lWith method change from hardening to softening. For loose slate standard sand, the deviator stress ol sample obtained wel method is higher than thai bj freezing method with the axial deformation no more than 5%. However, for the dense stale of standard sand, the deviator stress of sample obtained by wel method is less than that by the freezing method with ihe axial deformation no more lhaii 6%. But their residual strength lends lo be ihe same with the increase of axial strain. Whether frozen sample or moist sample, the internal friction angle of sample increases with ihe increasing relative density, but ihe internal friction angle of frozen sample is close to thai of moist sample. The sample in the loose stale of standard sand prepared by moist method is easy to be disturbed in the installation process, which leads lo higher peak strength than thai of freezing method. The disturbance is less for the dense state of standard sand with moisl method and the peak strength of the sample by freezing method is higher than thai of moist method. Therefore, it is suggesled to adopt freezing method for ihe standard sand in loose state and the conventional triaxial test is carried out on the dynamic Iriaxial shear apparatus in order to minimize installation disturbance. [ABSTRACT FROM AUTHOR]

The fatigue testing method of heavy haul railway prestressed concrete beam was proposed based on the existing general test method and the fiber bragg grating (FBG) sensing technology. The feasibility of incorporating FBG sensing technology into fatigue tests of prestressed concrete beams was discussed using the results from two large-scale model beam fatigue tests. The test results show that FBG sensors and fiber reinforced polymer (FRP) intelligent bars have the advantages of high accuracy, large range, good reliability, and that the fatigue resistance and the strain of steel bars can be obtained effectively in the full fatigue test. Under long-term loading of 33 t or above axle weight trains, normal height fully prestressed concrete beams with a span of 32 meters are subject to a great risk of fatigue cracking. Fatigue failure of the beams is caused by rupture of the non-prestressed reinforcing bars. The fatigue damage crack causes significant decrease in the stiffness and fatigue life, and significant increase in the stress range of steel bar. To ensure the safety and to control the deformation of heavy haul railway bridges, the cracking and maximum crack width of the beams should be limited strictly. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Xinyang Normal University Natural Science Edition is the property of Journal of Xinyang Normal University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Because the sluices that located in the middle and lower Yellow River have a similar environment condition, a variety of different strength grades and different mixture ratios of sluice concrete strength has a similar rule in theory. In order to explain the relationship of concrete strength and environmental conditions and their inherent law after using for many years, this paper made a statistical analysis on the different environment of different types of concrete strength results which was showed by the site safety inspection of forty three sluices. Finally found the recommended concrete strength testing method for different concrete types. According to age and environmental factors, this paper studied the strength of concrete and got the following conclusions. In sluice site safety inspection, sluice floor and culvert bottom concrete testing methods are recommended as core method, pier and culvert sidewall concrete testing methods are recommended as core fixed rebound method, roof, parapets, gate and culvert roof testing methods are recommended as rebound method and machine bridge concrete testing method are recommended as ultrasonic rebound synthetic method. In the age of 13-45 a, concrete strength shows a trend of growth, the type II's trend is the highest, the type I is the second and the type III is the minimum. Viewing from the design strength perspective, the No.150 concrete's growth rate is faster than that of the No.200 concrete. Concrete strength tends to be constant value when their age is longer than 45 a. [ABSTRACT FROM AUTHOR]

Copyright of Hydrographic Surveying & Charting / Haiyang Cehui is the property of Hydrographic Surveying & Charting Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The changes of loading rate can affect the strength performance, then the burst performance of coal. Thus, the coals with similar properties (from the same lump coals) were selected for multi-loading rates mechanical test, from which the change law of partial indicators evaluating the burst property (including uniaxial compressive strength and bursting energy index) with loading rates were obtained. Results show that the indicators mentioned above increase first and then decrease with the increase of loading rate, which proves the existence of critical loading rate. The evolution results show all the possibilities from no bursting tendency to strong bursting tendency, while the critical loading rate corresponds with the strongest bursting tendency. Then the “loading rate sensitivity” to describe this behavior and the method to avoid critical loading rate are proposed, furthermore, the conversion process of advance rate of working face and loading rate in laboratory are established, which realizes the application of achievement from laboratory to field. The method shows a good applicability. [ABSTRACT FROM AUTHOR]

Copyright of Jianzhu Cailiao Xuebao: Journal of Building Materials is the property of Journal of Building Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)