Purpose–MxV Rail conducted multiple single tie push tests(STPTs)between 2020 and 2023 to assess the changes in lateral tie resistance from tonnage accumulation,dynamic track stabilizers(DTS),tie type and ballast cond...Purpose–MxV Rail conducted multiple single tie push tests(STPTs)between 2020 and 2023 to assess the changes in lateral tie resistance from tonnage accumulation,dynamic track stabilizers(DTS),tie type and ballast condition.High lateral tie resistance is necessary for preventing lateral misalignments and track buckles.Therefore,understanding how various factors affect the lateral tie resistance will aid in the development of track buckling risk assessments and ballast maintenance best practices.Design/methodology/approach–The test involved tamping a section of track that consisted of both concrete and wood ties and then increasing the lateral tie resistance,using either tonnage during speed restrictions or a DTS.The STPTs and top-of-rail(TOR)elevation measurements were taken at multiple stages,including immediately after tamping and then after different tonnage increments or DTS.The results from this test were then added to a compiled measurement from previous tests,and the results from all the tests were used to develop general guidelines for ballast maintenance best practices and trade-off considerations.Findings–The results showed multiple factors affect the lateral track strength and therefore the susceptibility to misalignments and track buckles.The disturbance from ballast tamping can reduce the lateral track strength by 20–80%(∼45%median)and can be compacted from either tonnage(25–50%regain in strength after 0.1 m gross ton or MGT)or DTS(33–78%regain in strength).The amount of ballast(shoulder width and crib height),tie type and ballast characteristics all have a meaningful role in lateral track strength.Originality/value–This paper is based on the testing programs conducted by authors at MxV Rail.展开更多
The scattering and resonance reactions of ^22Mg＋p and ^22Mg＋α play crucial roles for studying deeply not only in the structure of proton-rich nuclei of ^23A1 and ^26Si but also for the interest of astrophysics. It ...The scattering and resonance reactions of ^22Mg＋p and ^22Mg＋α play crucial roles for studying deeply not only in the structure of proton-rich nuclei of ^23A1 and ^26Si but also for the interest of astrophysics. It is believed that ^22Mg nucleus is a waiting point in the αp-process of nucleosynthesis in novae. We supposed to perform direct measurement the ^22Mg＋α system in invert kinematics using radioactive ion （RI） beam. The ^22Mg beam of 3.73 MeV/u was produced at CRIB facility of the University of Tokyo located at RIKEN, Japan in 2011. In this paper, we report the results the scattering and resonance reactions with the alpha target. of the ^22Mg beam production used for the direct measurement of展开更多
Tip growth is a common strategy for the rapid elongation of cells to forage the environment and/or to target to long-distance destinations. In the model tip growth system of Arabidopsis pollen tubes, several small- mo...Tip growth is a common strategy for the rapid elongation of cells to forage the environment and/or to target to long-distance destinations. In the model tip growth system of Arabidopsis pollen tubes, several small- molecule hormones regulate their elongation, but how these rapidly diffusing molecules control extremely localized growth remains mysterious. Here we show that the interconvertible salicylic acid （SA） and meth- ylated SA （MESA）, well characterized for their roles in plant defense, oppositely regulate Arabidopsis pollen tip growth with SA being inhibitory and MeSA stimulatory. The effect of SA and MeSA was independent of known NPR3/NPR4 SA receptor-mediated signaling pathways. SA inhibited clathrin-mediated endocytosis in pollen tubes associated with an increased accumulation of less stretchable demethylated pectin in the apical wall, whereas MeSA did the opposite. Furthermore, SA and MeSA alter the apical activation of ROP1 GTPase, a key regulator of tip growth in pollen tubes, in an opposite manner. Interestingly, both MeSA methylesterase and SA methyltransferase, which catalyze the interconversion between SA and MESA, are localized at the apical region of pollen tubes, indicating of the tip-localized production of SA and MeSA and consistent with their effects on the apical cellular activities. These findings suggest that local generation of a highly diffusible signal can regulate polarized cell growth, providing a novel mechanism of cell polarity control apart from the one involving protein and mRNA polarization.展开更多
文摘Purpose–MxV Rail conducted multiple single tie push tests(STPTs)between 2020 and 2023 to assess the changes in lateral tie resistance from tonnage accumulation,dynamic track stabilizers(DTS),tie type and ballast condition.High lateral tie resistance is necessary for preventing lateral misalignments and track buckles.Therefore,understanding how various factors affect the lateral tie resistance will aid in the development of track buckling risk assessments and ballast maintenance best practices.Design/methodology/approach–The test involved tamping a section of track that consisted of both concrete and wood ties and then increasing the lateral tie resistance,using either tonnage during speed restrictions or a DTS.The STPTs and top-of-rail(TOR)elevation measurements were taken at multiple stages,including immediately after tamping and then after different tonnage increments or DTS.The results from this test were then added to a compiled measurement from previous tests,and the results from all the tests were used to develop general guidelines for ballast maintenance best practices and trade-off considerations.Findings–The results showed multiple factors affect the lateral track strength and therefore the susceptibility to misalignments and track buckles.The disturbance from ballast tamping can reduce the lateral track strength by 20–80%(∼45%median)and can be compacted from either tonnage(25–50%regain in strength after 0.1 m gross ton or MGT)or DTS(33–78%regain in strength).The amount of ballast(shoulder width and crib height),tie type and ballast characteristics all have a meaningful role in lateral track strength.Originality/value–This paper is based on the testing programs conducted by authors at MxV Rail.
文摘The scattering and resonance reactions of ^22Mg＋p and ^22Mg＋α play crucial roles for studying deeply not only in the structure of proton-rich nuclei of ^23A1 and ^26Si but also for the interest of astrophysics. It is believed that ^22Mg nucleus is a waiting point in the αp-process of nucleosynthesis in novae. We supposed to perform direct measurement the ^22Mg＋α system in invert kinematics using radioactive ion （RI） beam. The ^22Mg beam of 3.73 MeV/u was produced at CRIB facility of the University of Tokyo located at RIKEN, Japan in 2011. In this paper, we report the results the scattering and resonance reactions with the alpha target. of the ^22Mg beam production used for the direct measurement of
文摘Tip growth is a common strategy for the rapid elongation of cells to forage the environment and/or to target to long-distance destinations. In the model tip growth system of Arabidopsis pollen tubes, several small- molecule hormones regulate their elongation, but how these rapidly diffusing molecules control extremely localized growth remains mysterious. Here we show that the interconvertible salicylic acid （SA） and meth- ylated SA （MESA）, well characterized for their roles in plant defense, oppositely regulate Arabidopsis pollen tip growth with SA being inhibitory and MeSA stimulatory. The effect of SA and MeSA was independent of known NPR3/NPR4 SA receptor-mediated signaling pathways. SA inhibited clathrin-mediated endocytosis in pollen tubes associated with an increased accumulation of less stretchable demethylated pectin in the apical wall, whereas MeSA did the opposite. Furthermore, SA and MeSA alter the apical activation of ROP1 GTPase, a key regulator of tip growth in pollen tubes, in an opposite manner. Interestingly, both MeSA methylesterase and SA methyltransferase, which catalyze the interconversion between SA and MESA, are localized at the apical region of pollen tubes, indicating of the tip-localized production of SA and MeSA and consistent with their effects on the apical cellular activities. These findings suggest that local generation of a highly diffusible signal can regulate polarized cell growth, providing a novel mechanism of cell polarity control apart from the one involving protein and mRNA polarization.
