Publications by authors named "Changjiang Zheng"
In order to solve the problems caused by asphalt diseases and prolong the life cycle of asphalt pavement, many studies on the properties of modified asphalt have been conducted, especially polyurethane (PU) modified asphalt. This study is to replace part of the styrene-butadiene-styrene (SBS) modifier with waste polyurethane (WP), for preparing WP/SBS composite modified asphalt, as well as exploring its properties and microstructure. On this basis, this paper studied the basic performance of WP/SBS composite modified asphalt with a conventional performance test, to analyze the high- and low-temperature rheological properties, permanent deformation resistance and storage stability of WP/SBS composite modified asphalt by dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests.
View Article and Find Full Text PDFThis study presents an effort to investigate the determinants of driver injury severity in run-off-road (ROR) crashes. In order to account for unobserved heterogeneity, a random parameter ordered probit with heterogeneity in the means approach is applied. The police-reported ROR crash data that occurred from 2014 to 2017 in the state of North Carolina is used.
View Article and Find Full Text PDFBackground: Low back pain exerts a tremendous burden on individual patients and society due to its prevalence and ability to cause long-term disability. Contemporary treatment and prevention efforts are stymied by the absence of a confirmed cause for the majority of low back pain patients.
Methods: A system dynamics approach is used to build a physiologically-based model investigating the relationship between disc degeneration and low back pain.
Article Synopsis
- The study introduces a new "curvature" index (k(max)) to quantify the curvilinearity observed in the expiratory flow-volume curve, which helps assess airway obstruction more accurately.
- The researchers fit a hyperbolic function to spirometry data from 67 patients and found that this curvature index correlates well with FEV(1) values, indicating an exponential relationship.
- This new index could improve the quantitative analysis of lung disease and assist in future clinical evaluations by linking curvilinearity to obstructive lung disease more effectively.
Background: The number of founding germ cells (FGCs) in mammals is of fundamental significance to the fidelity of gene transmission between generations, but estimates from various methods vary widely. In this paper we obtain a new estimate for the value in humans by using a mathematical model of germ cell development that depends on available oocyte counts for adult women.
Results: The germline-development model derives from the assumption that oogonial proliferation in the embryonic stage starts with a founding cells at t = 0 and that the subsequent proliferation can be defined as a simple stochastic birth process.