Hot stretch forming of titanium sheet by resistance heating

Titanium alloys are important aerospace materials due to excellent comprehensive performance, but it is difficult to form at room temperature. Electrically assisted hot stretch forming is used to form the titanium panels of aircraft. This paper studies the effect of temperature, strain, stress relaxation time and cooling rate on forming accuracy by stress relaxation test, tensile test and forming experiment. It is shown that for the influence of temperature on forming accuracy, there is no large difference among 773K, 873K, 973K. And with increase of strain, the forming accuracy becomes lower. For the influence of stress relaxation time, there is no large difference among 0min, 15mins, 30mins. And with decrease of cooling rate, the forming accuracy is improved significantly. It’s concluded that when the temperature reaches a high level, temperature and stress relaxation time have no great influence on forming accuracy. And the forming accuracy is mainly influenced by strain and cooling rate. Electrically assisted hot stretch forming is an effective method to form titanium alloy. And the part with high forming accuracy can be obtained by adopting high temperature, low strain, proper stress relaxation time and low cooling rate

Engineering the poly(vinyl alcohol)-polyaniline colloids for high performance waterborne alkyd anticorrosion coating

The ecofriendly waterborne alkyd coatings generally compromise the coating performance. Incorporation of polyaniline into alkyd to form nanocomposites can improve the corrosion resistance; however, the uniform distribution of polyaniline (PANI) within the alkyd resin remains a challenge. In this work, PANI is grafted onto epoxy functionalized phosphorylated poly (vinyl alcohol) (PPVA) with different side-chain configurations in order to improve compatibility and dispersion stability. These functionalized PPVA are synthesized using epichlorohydrin (ECIP) or γ-glycidyl methacrylate (GMA) as modifying agents, and respectively labeled as E-PPVA and G-PPVA. G-PPVA/PANI dispersion is stable even at a high PANI loading of 50%, while the maximum PANI loading for E-PPVA/PANI is only 30%. With the incorporation of G-PPVA/PANI into waterborne alkyd resins (AR), the coating resistance is increased by 7 orders of magnitude, and the corrosion inhibition efficiency is up to 99.9%. The coating with the incorporation of G-PPVA/PANI also demonstrates superior long-term corrosion resistance in comparison with that AR/E-PPVA/PANI nanocomposite coating

Functionalizing graphene with titanate coupling agents as reinforcement for one-component waterborne poly(urethane-acrylate) anticorrosion coatings

Achieving a uniform dispersion of reduced graphene oxide (RGO) nanosheets in waterborne polymer matrix remains a challenge. Here, we significantly improved the dispersion stability of RGO in a polymer matrix through functionalizing RGO with titanate coupling agent of different dendritic structure. Titanate coupling agents of two branched dioctylpyrophosphate (T2) and three branched dioctylpyrophosphate (T3) were used. Rather than simply blending graphene with polymer matrix, functionalized graphene (T2-RGO or T3-RGO) was introduced into the reaction system with monomers to participate in the polymerization; resulting in improved compatibility and interaction between the graphene and polymer, especially for T3-RGO. One-component waterborne poly (urethane-acrylate) nanocomposite coatings (WPUA/T2G or WPUA/T3G) were then obtained. The particle size of WPUA/T3G colloidal particle size is much smaller than that of WPUA/T2G, the colloidal stability was also increased with the incorporation of T3-RGO. Compared with pure WPUA, the tensile strength of WPUA/T3G nanocomposite increased from 17.78 MPa to 40.01 MPa, and the elongation at break increased from 249% to 424%. The tensile strength and elongation at break of WPUA/T2G were 32.01 MPa and 366%, which were inferior to that of WPUA/T3G. Moreover, in comparison with pure WPUA, the impedance modulus of WPUA/T3G increased from 1.12 x 105 Ω.cm2 to 1.15 x 108 Ω.cm2, the coating resistance of WPUA/T3G increased from 8.41 x 104 Ω.cm2 to 1.39 x 108 Ω.cm2, which was also much higher than the impedance modulus (6.93 x 106 Ω.cm2) and coating resistance (7.31 x 106 Ω.cm2) of WPUA/T2G. WPUA/T3G nanocomposite coating exhibited excellent long-term corrosion resistance, being superior to the previously reported performance of solventborne polyurethane/graphene composite

Repetitive transcranial magnetic stimulation ameliorates cognitive deficits in mice with radiation-induced brain injury by attenuating microglial pyroptosis and promoting neurogenesis via BDNF pathway

Abstract Background Radiation-induced brain injury (RIBI) is a common and severe complication during radiotherapy for head and neck tumor. Repetitive transcranial magnetic stimulation (rTMS) is a novel and non-invasive method of brain stimulation, which has been applied in various neurological diseases. rTMS has been proved to be effective for treatment of RIBI, while its mechanisms have not been well understood. Methods RIBI mouse model was established by cranial irradiation, K252a was daily injected intraperitoneally to block BDNF pathway. Immunofluorescence staining, immunohistochemistry and western blotting were performed to examine the microglial pyroptosis and hippocampal neurogenesis. Behavioral tests were used to assess the cognitive function and emotionality of mice. Golgi staining was applied to observe the structure of dendritic spine in hippocampus. Results rTMS significantly promoted hippocampal neurogenesis and mitigated neuroinflammation, with ameliorating pyroptosis in microglia, as well as downregulation of the protein expression level of NLRP3 inflammasome and key pyroptosis factor Gasdermin D (GSDMD). BDNF signaling pathway might be involved in it. After blocking BDNF pathway by K252a, a specific BDNF pathway inhibitor, the neuroprotective effect of rTMS was markedly reversed. Evaluated by behavioral tests, the cognitive dysfunction and anxiety-like behavior were found aggravated with the comparison of mice in rTMS intervention group. Moreover, the level of hippocampal neurogenesis was found to be attenuated, the pyroptosis of microglia as well as the levels of GSDMD, NLRP3 inflammasome and IL-1β were upregulated. Conclusion Our study indicated that rTMS notably ameliorated RIBI-induced cognitive disorders, by mitigating pyroptosis in microglia and promoting hippocampal neurogenesis via mediating BDNF pathway

Additional file 1 of Repetitive transcranial magnetic stimulation ameliorates cognitive deficits in mice with radiation-induced brain injury by attenuating microglial pyroptosis and promoting neurogenesis via BDNF pathway

Supplementary Material