The Experts below are selected from a list of 213 Experts worldwide ranked by ideXlab platform

Zongsheng Yin - One of the best experts on this subject based on the ideXlab platform.

  • Potential In Vitro Tissue-Engineered Anterior Cruciate Ligament by Copolymerization of Polyvinyl Alcohol and Collagen.
    The Journal of craniofacial surgery, 2020
    Co-Authors: Zhengjun Pan, Hao Yin, Shuangli Wang, Gaoxin Xiong, Zongsheng Yin
    Abstract:

    BACKGROUND AND PURPOSE Suitable tissue-engineered scaffolds to replace human anterior cruciate ligament (ACL) are well developed clinically as the development of tissue engineering. As water-soluble polymer compound, polyvinyl alcohol (PVA) has been wildly used as the materials to replace ACL. The aim of this study was to explore the feasibility of constructing tissue-engineered ACL by the copolymerization of PVA and collagen (PVA/COL). METHODS PVA and COL were copolymerized at a mass ratio of 3:1. The pore size and porosity of the scaffold were observed by electron microscope. The maximum tensile strength of the scaffold was determined by electronic Tension Machine. The cytotoxicity of the scaffold was evaluated by MTT assay. The morphology of ACL cells cultured on the surface of the scaffold was observed by inverted microscope. The degradation of the scaffold was recorded in the rabbit model. RESULTS The average pore size of the polymer scaffold was 100 to 150 μm and the porosity was about 90%. The maximum tensile strength of the scaffold material was 8.10 ± 0.28 MPa. PVA/COL could promote the proliferation ability of 3T3 cells. ACL cells were successfully cultured on the surface of PVA/COL scaffold, with natural growth rate, differentiation, and proliferation. Twenty-four weeks after the plantation of scaffold, obvious degradations were observed in vivo. CONCLUSION The model of in-vitro tissue-engineered ACL was successfully established by PVA/COL scaffolds.

  • Potential In Vitro Tissue-Engineered Anterior Cruciate Ligament by Copolymerization of Polyvinyl Alcohol and Collagen.
    The Journal of craniofacial surgery, 2020
    Co-Authors: Zhengjun Pan, Hao Yin, Shuangli Wang, Gaoxin Xiong, Zongsheng Yin
    Abstract:

    Suitable tissue-engineered scaffolds to replace human anterior cruciate ligament (ACL) are well developed clinically as the development of tissue engineering. As water-soluble polymer compound, polyvinyl alcohol (PVA) has been wildly used as the materials to replace ACL. The aim of this study was to explore the feasibility of constructing tissue-engineered ACL by the copolymerization of PVA and collagen (PVA/COL). PVA and COL were copolymerized at a mass ratio of 3:1. The pore size and porosity of the scaffold were observed by electron microscope. The maximum tensile strength of the scaffold was determined by electronic Tension Machine. The cytotoxicity of the scaffold was evaluated by MTT assay. The morphology of ACL cells cultured on the surface of the scaffold was observed by inverted microscope. The degradation of the scaffold was recorded in the rabbit model. The average pore size of the polymer scaffold was 100 to 150 μm and the porosity was about 90%. The maximum tensile strength of the scaffold material was 8.10 ± 0.28 MPa. PVA/COL could promote the proliferation ability of 3T3 cells. ACL cells were successfully cultured on the surface of PVA/COL scaffold, with natural growth rate, differentiation, and proliferation. Twenty-four weeks after the plantation of scaffold, obvious degradations were observed in vivo. The model of in-vitro tissue-engineered ACL was successfully established by PVA/COL scaffolds. Copyright © 2020 by Mutaz B. Habal, MD.

Odd Sture Hopperstad - One of the best experts on this subject based on the ideXlab platform.

  • Impact against X65 steel pipes - An experimental investigation
    International Journal of Solids and Structures, 2013
    Co-Authors: Martin Kristoffersen, Tore Børvik, Ida Westermann, Magnus Langseth, Odd Sture Hopperstad
    Abstract:

    Abstract Offshore pipelines subjected to accidental loads, such as impacts from trawl gear or anchors, may experience large global displacements from its initial position and large local strains. The axial forces set up during deformation move the pipeline back towards its initial position, thereby creating a complex local stress and strain history that may lead to fracture in the pipeline. In this study, material and component tests have been carried out on an X65 offshore pipeline material to investigate the behaviour during impact, and to observe if fracture occurs. Pipes were first impacted in a pendulum accelerator at varying velocities before they were pulled straight in a Tension Machine. Fracture was found in the impacted area of all the pipes. Material tests were carried out to determine the characteristics of the X65 pipeline material. A metallurgical investigation was also conducted, revealing that fracture initiated both inside the pipe wall and on the surface.

  • Damage and Failure in an X65 Steel Pipeline Caused by Trawl Gear Impact
    Volume 2B: Structures Safety and Reliability, 2013
    Co-Authors: Martin Kristoffersen, Tore Børvik, Odd Sture Hopperstad, Magnus Langseth, Håvar Ilstad, Erik Levold
    Abstract:

    Offshore pipelines subjected to accidental impact loads from trawl gear or anchors may experience large global deformations and large local strains, creating a complex stress and strain history. In this study experiments and numerical simulations have been carried out to investigate the impact of a pipeline which is subsequently hooked and released. Material and component tests have been performed to investigate the behaviour during impact, and to observe if/when fracture occurs. The pipes were first impacted in a pendulum accelerator at varying velocities before they were pulled straight in a Tension Machine. Fracture was found in the impacted area of all the pipes during straightening. Material tests were done to determine the characteristics of the X65 grade steel. Numerical simulations showed excellent compliance with the impact phase, while the load level in the stretching phase was a bit overestimated.Copyright © 2013 by ASME

Xuehui Shen - One of the best experts on this subject based on the ideXlab platform.

  • Influences of Stress State, Temperature, and Strain Rate on Ductility of Pure Iron
    Journal of Materials Engineering and Performance, 2021
    Co-Authors: Yi Liu, Xiaodong Xiao, Peirong Zhang, Xuehui Shen
    Abstract:

    In this study, the plastic response of pure iron DT8 at different stress states, temperatures, and strain rates is investigated. Specimens with different structures designed for different stress states are subjected to quasi-static uniaxial Tension tests to investigate the effect of stress state on the fracture behavior of pure iron. Standard specimens at temperatures ranging from 100 to 900 °C are tested by a quasi-static uniaxial Tension Machine. Double-notch shear specimens are subjected to a universal electronic tensile testing Machine and an improved split-Hopkinson pressure bar device with strain rates ranging from 0.0033 to 227450/s to investigate the effect of strain rate on the fracture behavior of pure iron. Results show that the flow stress of pure iron DT8 slightly increases with the increase in stress triaxiality before the material breaks. With the increase in stress triaxiality from 0.333 to 0.550, the fracture strain of pure iron DT8 decreases almost linearly from 1.949 to 0.898. With the increase in temperature, the fracture strain increases almost linearly from 1.43 at 100 °C to 3.19 at 900 °C. A blue brittleness effect occurs at about 300 °C, where the yield and tensile strengths of pure iron increase slightly. In the low strain rate range from 0.0033 to 800/s, the fracture strain of pure iron is almost stable at approximately 2.0. Then, the fracture strain increases with the further increase in strain rate. When the strain rate reaches 120850/s, the fracture strain reaches its peak value of 3.64. Thereafter, the fracture strain decreases rapidly as the strain rate increases. The fracture surfaces of the specimens take on different fracture morphologies with the increase in strain rate. The nature of the strain rate’s effect on material ductility is discussed.

Zhengjun Pan - One of the best experts on this subject based on the ideXlab platform.

  • Potential In Vitro Tissue-Engineered Anterior Cruciate Ligament by Copolymerization of Polyvinyl Alcohol and Collagen.
    The Journal of craniofacial surgery, 2020
    Co-Authors: Zhengjun Pan, Hao Yin, Shuangli Wang, Gaoxin Xiong, Zongsheng Yin
    Abstract:

    BACKGROUND AND PURPOSE Suitable tissue-engineered scaffolds to replace human anterior cruciate ligament (ACL) are well developed clinically as the development of tissue engineering. As water-soluble polymer compound, polyvinyl alcohol (PVA) has been wildly used as the materials to replace ACL. The aim of this study was to explore the feasibility of constructing tissue-engineered ACL by the copolymerization of PVA and collagen (PVA/COL). METHODS PVA and COL were copolymerized at a mass ratio of 3:1. The pore size and porosity of the scaffold were observed by electron microscope. The maximum tensile strength of the scaffold was determined by electronic Tension Machine. The cytotoxicity of the scaffold was evaluated by MTT assay. The morphology of ACL cells cultured on the surface of the scaffold was observed by inverted microscope. The degradation of the scaffold was recorded in the rabbit model. RESULTS The average pore size of the polymer scaffold was 100 to 150 μm and the porosity was about 90%. The maximum tensile strength of the scaffold material was 8.10 ± 0.28 MPa. PVA/COL could promote the proliferation ability of 3T3 cells. ACL cells were successfully cultured on the surface of PVA/COL scaffold, with natural growth rate, differentiation, and proliferation. Twenty-four weeks after the plantation of scaffold, obvious degradations were observed in vivo. CONCLUSION The model of in-vitro tissue-engineered ACL was successfully established by PVA/COL scaffolds.

  • Potential In Vitro Tissue-Engineered Anterior Cruciate Ligament by Copolymerization of Polyvinyl Alcohol and Collagen.
    The Journal of craniofacial surgery, 2020
    Co-Authors: Zhengjun Pan, Hao Yin, Shuangli Wang, Gaoxin Xiong, Zongsheng Yin
    Abstract:

    Suitable tissue-engineered scaffolds to replace human anterior cruciate ligament (ACL) are well developed clinically as the development of tissue engineering. As water-soluble polymer compound, polyvinyl alcohol (PVA) has been wildly used as the materials to replace ACL. The aim of this study was to explore the feasibility of constructing tissue-engineered ACL by the copolymerization of PVA and collagen (PVA/COL). PVA and COL were copolymerized at a mass ratio of 3:1. The pore size and porosity of the scaffold were observed by electron microscope. The maximum tensile strength of the scaffold was determined by electronic Tension Machine. The cytotoxicity of the scaffold was evaluated by MTT assay. The morphology of ACL cells cultured on the surface of the scaffold was observed by inverted microscope. The degradation of the scaffold was recorded in the rabbit model. The average pore size of the polymer scaffold was 100 to 150 μm and the porosity was about 90%. The maximum tensile strength of the scaffold material was 8.10 ± 0.28 MPa. PVA/COL could promote the proliferation ability of 3T3 cells. ACL cells were successfully cultured on the surface of PVA/COL scaffold, with natural growth rate, differentiation, and proliferation. Twenty-four weeks after the plantation of scaffold, obvious degradations were observed in vivo. The model of in-vitro tissue-engineered ACL was successfully established by PVA/COL scaffolds. Copyright © 2020 by Mutaz B. Habal, MD.

Martin Kristoffersen - One of the best experts on this subject based on the ideXlab platform.

  • Impact against X65 steel pipes - An experimental investigation
    International Journal of Solids and Structures, 2013
    Co-Authors: Martin Kristoffersen, Tore Børvik, Ida Westermann, Magnus Langseth, Odd Sture Hopperstad
    Abstract:

    Abstract Offshore pipelines subjected to accidental loads, such as impacts from trawl gear or anchors, may experience large global displacements from its initial position and large local strains. The axial forces set up during deformation move the pipeline back towards its initial position, thereby creating a complex local stress and strain history that may lead to fracture in the pipeline. In this study, material and component tests have been carried out on an X65 offshore pipeline material to investigate the behaviour during impact, and to observe if fracture occurs. Pipes were first impacted in a pendulum accelerator at varying velocities before they were pulled straight in a Tension Machine. Fracture was found in the impacted area of all the pipes. Material tests were carried out to determine the characteristics of the X65 pipeline material. A metallurgical investigation was also conducted, revealing that fracture initiated both inside the pipe wall and on the surface.

  • Damage and Failure in an X65 Steel Pipeline Caused by Trawl Gear Impact
    Volume 2B: Structures Safety and Reliability, 2013
    Co-Authors: Martin Kristoffersen, Tore Børvik, Odd Sture Hopperstad, Magnus Langseth, Håvar Ilstad, Erik Levold
    Abstract:

    Offshore pipelines subjected to accidental impact loads from trawl gear or anchors may experience large global deformations and large local strains, creating a complex stress and strain history. In this study experiments and numerical simulations have been carried out to investigate the impact of a pipeline which is subsequently hooked and released. Material and component tests have been performed to investigate the behaviour during impact, and to observe if/when fracture occurs. The pipes were first impacted in a pendulum accelerator at varying velocities before they were pulled straight in a Tension Machine. Fracture was found in the impacted area of all the pipes during straightening. Material tests were done to determine the characteristics of the X65 grade steel. Numerical simulations showed excellent compliance with the impact phase, while the load level in the stretching phase was a bit overestimated.Copyright © 2013 by ASME