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  • Hindawi Limited  (9)
  • Wang, Yu  (9)
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  • Hindawi Limited  (9)
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  • 1
    Online-Ressource
    Online-Ressource
    Investigation of the Effects of Freeze-Thaw Cycles on Geomechanical and Acoustic Characteristics of Tuff Specimens under Different Stress Paths
    Hindawi Limited ; 2020
    In:  Advances in Civil Engineering Vol. 2020 ( 2020-12-21), p. 1-20
    Details
    In: Advances in Civil Engineering, Hindawi Limited, Vol. 2020 ( 2020-12-21), p. 1-20
    Kurzfassung: In the process of development and construction of open-pit mine slope in the high altitude and cold area, freeze-thaw (F-T) cycles have an important impact on rock engineering structure. F-T cycles lead to the decrease in physical and mechanical properties of rock, which is closely related to the stability of open-pit slope. In this paper, the influence of F-T cycles on geomechanical and acoustic emission (AE) characteristics of tuff specimens under different stress paths was studied by using F-T cycle treatment, in situ AE monitoring, and uniaxial loading test. The results indicated that under the same stress path, the cumulative AE count/energy of rock samples subjected to F-T cycles was less than that of rock samples not subjected to F-T cycles. The peak frequency distribution of AE signal during the loading process of rock specimen presented the phenomenon of frequency bands. The width of the low-frequency band of the rock samples subjected to F-T cycles was larger than that of the rock samples under the natural state. The frequency and width of the high-frequency band of the rock samples subjected to F-T cycles were larger than those of the rock samples under the natural state. The rock samples subjected to F-T cycles had higher plastic strain than those without F-T cycles. According to the uniaxial compression test results of F-T rock samples under different stress paths, the peak stress and peak strain have little change, but the AE characteristics were obviously different.
    Materialart: Online-Ressource
    ISSN: 1687-8094 , 1687-8086
    URL: Article
    DOI: 10.1155/2020/6689181
    Sprache: Englisch
    Verlag: Hindawi Limited
    Publikationsdatum: 2020
    ZDB Id: 2449760-5
    Standort Signatur Einschränkungen Verfügbarkeit
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    Online-Ressource
  • 2
    Online-Ressource
    Online-Ressource
    Experimental Investigations on Microcracks in Vibrational and Conventional Drilling of Cortical Bone
    Hindawi Limited ; 2013
    In:  Journal of Nanomaterials Vol. 2013 ( 2013), p. 1-5
    Details
    In: Journal of Nanomaterials, Hindawi Limited, Vol. 2013 ( 2013), p. 1-5
    Kurzfassung: Bone drilling is widely used in orthopedic surgery. Microcracks will be generated in bone drilling, which may cause fatigue damages and stress fractures. Fresh bovine cortical bones were drilled via vibrational and conventional ways. Drilling operations were performed by a dynamic material testing machine, which can provide the vibration while maintaining uniform feed motion. The drill site and bone debris were observed through scanning electron microscope (SEM). The experimental results showed that fewer and shorter micro-cracks were formed in vibrational drilling than those formed in conventional way. And the surface morphology of bone debris from two different drilling ways was also quite different. It is expected that vibrational drilling in orthopedic surgery operation could decrease the microdamage to the bone, which could lower the incidence of stress fracture and contribute to the postoperative recovery.
    Materialart: Online-Ressource
    ISSN: 1687-4110 , 1687-4129
    URL: Article
    DOI: 10.1155/2013/845205
    Sprache: Englisch
    Verlag: Hindawi Limited
    Publikationsdatum: 2013
    ZDB Id: 2229480-6
    Standort Signatur Einschränkungen Verfügbarkeit
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    Online-Ressource
  • 3
    Online-Ressource
    Online-Ressource
    The Prevalence and Causes of Visual Impairment in Type 2 Diabetes Mellitus in Northeast China
    Hindawi Limited ; 2020
    In:  Journal of Ophthalmology Vol. 2020 ( 2020-11-29), p. 1-7
    Details
    In: Journal of Ophthalmology, Hindawi Limited, Vol. 2020 ( 2020-11-29), p. 1-7
    Kurzfassung: Purpose. To evaluate the prevalence and causes of visual impairment in a group of community people with type 2 diabetes mellitus (T2DM) in Northeast China. Methods. Population-based cross-sectional survey. Patients diagnosed with T2DM residing in 15 communities in Fushun, Northeast China, were enrolled between July 2012 and May 2013. All participants underwent an extensive and standardized eye examination (visual acuity testing, slit-lamp, and fundus examination). Low vision was defined as presenting VA of better-seeing eye 〈 20/60 and ≥20/400, and blindness was defined as VA 〈 20/400, according to the World Health Organization (WHO) definitions. The primary causes of blindness and low vision were assessed by senior ophthalmologists. Results. Visual acuity measurements were available for 1998 (89.8%) of 2224 subjects in the study. The prevalence of bilateral blindness and low vision defined was 0.90% and 10.81%. Uncorrected refractive error was the first leading cause of low vision (75.0%) and blindness (38.9%). After correcting the refractive error, the first leading cause of low vision was cataract (44.4%), followed by diabetic retinopathy (29.6%) and myopic maculopathy (18.5%), while the first leading cause of blindness was proliferative DR (45.4%), followed by cataract (36.4%) and myopic maculopathy (18.2%). Conclusions. This study suggested a high prevalence of low vision and blindness in this study cohort. Uncorrected refractive error and cataract remain the leading cause of visual impairment, but the major challenge is the early diagnosis and intervention of diabetic retinopathy to reduce diabetes-related blindness.
    Materialart: Online-Ressource
    ISSN: 2090-0058 , 2090-004X
    URL: Article
    DOI: 10.1155/2020/5969816
    Sprache: Englisch
    Verlag: Hindawi Limited
    Publikationsdatum: 2020
    ZDB Id: 2546525-9
    Standort Signatur Einschränkungen Verfügbarkeit
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    Online-Ressource
  • 4
    Online-Ressource
    Online-Ressource
    Undrained Cyclic Response and Resistance of Saturated Calcareous Sand considering Initial Static Shear Effect
    Hindawi Limited ; 2021
    In:  Geofluids Vol. 2021 ( 2021-8-20), p. 1-12
    Details
    In: Geofluids, Hindawi Limited, Vol. 2021 ( 2021-8-20), p. 1-12
    Kurzfassung: Sand elements in the natural or manmade field have often undergone initial static shear stresses before suffering cyclic loading. To explore the effect of static shear stress, a series of undrained cyclic triaxial tests were performed on dense and loose calcareous sand under different initial and cyclic shear stresses. The triaxial test results are used to describe the effect of static shear stress on the cyclic response of the calcareous sand with different relative density. Cyclic mobility, flow deformation, and residual deformation accumulation are the three main failure modes under varying static and cyclic shear stress levels. The cyclic resistance of dense sand is greater than that of loose sand, but the initial static stress has different effects on the cyclic resistance of the two kinds of sand. The dense sand owns a higher cyclic resistance with SSR increasing, while for the loose sand, 0.12 is the critical SSR corresponding to the lowest value of the cyclic resistance. The dense sand has more fast accumulation of dissipated energy, compared with loose sand. Additionally, an exponential relationship is established between static shear stress, relative density, and normalized energy density.
    Materialart: Online-Ressource
    ISSN: 1468-8123 , 1468-8115
    URL: Article
    DOI: 10.1155/2021/4616747
    Sprache: Englisch
    Verlag: Hindawi Limited
    Publikationsdatum: 2021
    ZDB Id: 2045012-6
    SSG: 13
    Standort Signatur Einschränkungen Verfügbarkeit
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    Online-Ressource
  • 5
    Online-Ressource
    Online-Ressource
    Evaluation Method of Water Hazard Control Effect of Coal Seam Floor in Deep Mining: Sequence Verification Evaluation
    Hindawi Limited ; 2022
    In:  Geofluids Vol. 2022 ( 2022-10-29), p. 1-16
    Details
    In: Geofluids, Hindawi Limited, Vol. 2022 ( 2022-10-29), p. 1-16
    Kurzfassung: Deep, highly pressurized aquifers seriously threaten the exploitation of resources of North China coalfield. At present, there is no particular guidance system to evaluate the prevention and control effect of water inrush disaster in deep coal seam mining. Therefore, this research focuses on the evaluation of the method for confined water disaster prevention and control effect of deep coal seam mining. Based upon various methods, such as effective thickness and water resistance capacity of aquifuge, water inrush coefficient, GIS (Geographic Information System) analysis of grouting data, dense drilling verification, and professional analysis system based on integrated sequence evaluation, the evaluation of the method for confined water disaster prevention and control effect of deep coal seam mining was put forward for the first time. The proposed method was called the “sequence verification evaluation (SVE)” method. The prevention and control of the effects of Ordovician water inrush disaster in deep mining of Huanghebei coalfield was evaluated using the proposed SVE method. The results show that the SVE method can effectively reflect the prevention and control of the effects of water inrush from confined water and provide scientific basis for the safe production of deep coal seam mining.
    Materialart: Online-Ressource
    ISSN: 1468-8123 , 1468-8115
    URL: Article
    DOI: 10.1155/2022/6728045
    Sprache: Englisch
    Verlag: Hindawi Limited
    Publikationsdatum: 2022
    ZDB Id: 2045012-6
    SSG: 13
    Standort Signatur Einschränkungen Verfügbarkeit
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    Online-Ressource
  • 6
    Online-Ressource
    Online-Ressource
    Immune and antioxidant responses of pearl oyster Pinctada maxima exposed to acute salinity stress
    Hindawi Limited ; 2022
    In:  Aquaculture Research Vol. 53, No. 6 ( 2022-04), p. 2439-2447
    Details
    In: Aquaculture Research, Hindawi Limited, Vol. 53, No. 6 ( 2022-04), p. 2439-2447
    Materialart: Online-Ressource
    ISSN: 1355-557X , 1365-2109
    URL: Issue
    URL: Article
    DOI: 10.1111/are.v53.6
    DOI: 10.1111/are.15761
    Sprache: Englisch
    Verlag: Hindawi Limited
    Publikationsdatum: 2022
    ZDB Id: 2207423-5
    ZDB Id: 1227359-4
    ZDB Id: 2019895-4
    SSG: 21,3
    Standort Signatur Einschränkungen Verfügbarkeit
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    Online-Ressource
  • 7
    Online-Ressource
    Online-Ressource
    Predicting Response of Constructed Tunnel to Adjacent Excavation with Dewatering
    Hindawi Limited ; 2021
    In:  Geofluids Vol. 2021 ( 2021-3-17), p. 1-17
    Details
    In: Geofluids, Hindawi Limited, Vol. 2021 ( 2021-3-17), p. 1-17
    Kurzfassung: This paper proposes a new method for predicting the displacement and internal force of constructed tunnels induced by adjacent excavation with dewatering. In this method, the total excavation-induced additional stress on the constructed tunnel is derived by superposing the additional stresses induced by excavation unloading and dewatering effects. The additional stress induced by unloading effect is calculated using Mindlin’s solution. The additional stress induced by dewatering effect is calculated using the principle of effective stress and the Dupuit precipitation funnel curve. With the beam on elastic foundation method, the total additional stress is then used for calculating the tunnel displacement and internal force caused by adjacent excavation with dewatering. Based on three well-documented case histories, the performance of the proposed method is verified. Moreover, a parametric analysis is also performed to capture the effects of excavation depth, tunnel-to-excavation distance, initial water level, excavation plan view size, and specific yield on the responses of the constructed tunnels. The results indicate that the effect of excavation depth on the tunnel maximum vertical displacement, maximum bending moment, and maximum shear force is more significant at an excavation depth greater than the cover depth of the constructed tunnel. The tunnel maximum vertical displacement, maximum bending moment, and maximum shear force decrease nonlinearly with an increase in the tunnel-to-excavation distance and the initial water level. Among the investigated parameters, the excavation dimension in the tunnel longitudinal direction affects most the tunnel responses. The effect of specific yield on the tunnel displacement and internal force induced by adjacent excavation with dewatering becomes more obvious as increasing the initial water level and excavation depth.
    Materialart: Online-Ressource
    ISSN: 1468-8123 , 1468-8115
    URL: Article
    DOI: 10.1155/2021/5548817
    Sprache: Englisch
    Verlag: Hindawi Limited
    Publikationsdatum: 2021
    ZDB Id: 2045012-6
    SSG: 13
    Standort Signatur Einschränkungen Verfügbarkeit
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    Online-Ressource
  • 8
    Online-Ressource
    Online-Ressource
    Experimental Investigation into Limit Void Ratio Characteristics of Calcareous Sands considering Various Factors
    Hindawi Limited ; 2021
    In:  Geofluids Vol. 2021 ( 2021-6-24), p. 1-9
    Details
    In: Geofluids, Hindawi Limited, Vol. 2021 ( 2021-6-24), p. 1-9
    Kurzfassung: Relative density is an important index affecting the mechanical behaviors of calcareous sands. The dense sands present softening strength, whereas the loose sands exhibit hardening strength. Furthermore, the relative density is determined based on the maximum and minimum void ratios obtained by using the maximum and minimum dry density test. In this study, a series of tests were carried out on various mixed graded sands to explore their material properties and the relationship between the limit void ratio, considering the effects of test methods, equipment, and fine content. It is shown that a more accurate maximum void ratio can be attained by using the 1000 mL measuring cylinder with low rotation speed. In addition, in order to avoid particle breakage of calcareous sands, it is suggested that the minimum void ratio should be obtained with the 1000 mL compaction cylinder combining vibration with hit. The results also show that a linear relationship exists among the limit void ratio of various mixed graded sands. Besides, the void ratio is significantly affected by the fine content. 40% is the critical fine content corresponding to the lowest value of the limit void ratio.
    Materialart: Online-Ressource
    ISSN: 1468-8123 , 1468-8115
    URL: Article
    DOI: 10.1155/2021/3686852
    Sprache: Englisch
    Verlag: Hindawi Limited
    Publikationsdatum: 2021
    ZDB Id: 2045012-6
    SSG: 13
    Standort Signatur Einschränkungen Verfügbarkeit
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    Online-Ressource
  • 9
    Online-Ressource
    Online-Ressource
    Synthesis of Renewable Energy Materials, Sodium Aluminum Hydride by Grignard Reagent of Al
    Hindawi Limited ; 2015
    In:  Journal of Nanomaterials Vol. 2015 ( 2015), p. 1-5
    Details
    In: Journal of Nanomaterials, Hindawi Limited, Vol. 2015 ( 2015), p. 1-5
    Kurzfassung: The research on hydrogen generation and application has attracted widespread attention around the world. This paper is to demonstrate that sodium aluminum hydride can be synthesized under simple and mild reaction condition. Being activated through organics, aluminum powder reacts with hydrogen and sodium hydride to produce sodium aluminum hydride under atmospheric pressure. The properties and composition of the sample were characterized by FTIR, XRD, SEM, and so forth. The results showed that the product through this synthesis method is sodium aluminum hydride, and it has higher purity, perfect crystal character, better stability, and good hydrogen storage property. The reaction mechanism is also discussed in detail.
    Materialart: Online-Ressource
    ISSN: 1687-4110 , 1687-4129
    URL: Article
    DOI: 10.1155/2015/296486
    Sprache: Englisch
    Verlag: Hindawi Limited
    Publikationsdatum: 2015
    ZDB Id: 2229480-6
    Standort Signatur Einschränkungen Verfügbarkeit
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    Online-Ressource
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