Development of Bicycle Surrogate for Bicyclist Pre-Collision System Evaluation

As part of active safety systems for reducing bicyclist fatalities and injuries, Bicyclist Pre-Collision System (BPCS), also known as Bicyclist Autonomous Emergency Braking System, is being studied currently by several vehicles manufactures. This paper describes the development of a surrogate bicyclist which includes a surrogate bicycle and a surrogate bicycle rider to support the development and evaluation of BPCS. The surrogate bicycle is designed to represent the visual and radar characteristics of real bicyclists in the United States. The size of bicycle surrogate mimics the 26 inch adult bicycle, which is the most popular adult bicycle sold in the US. The radar cross section (RCS) of the surrogate bicycle is designed based on RCS measurement of the real adult sized bicycles. The surrogate bicycle is constructed with detachable components with shatter resistant material to prevent structural damage during a collision, and matches the look and RCS of a real 26 inch mountain bicycle from all 360 degree angles. The surrogate bicycle rider is a 168 cm tall adult with CNC machined realistic body shape. The skin of the surrogate bicycle rider has the RCS of a real human skin. Combined skin with realistic body shape, the surrogate bicyclist has the RCS matching to that of a same sized real human from 360 degree angles in the view of 77GHz automotive radar. The surrogate bicyclist has articulated leg motion which is important for micro Doppler sensing and can be supported on a sled or a mobile carrier. It can be moved at a speed of 20 mph and can be collided by vehicles from any direction and be reassembled in less than 5 minutes

Soil Carbon, Nitrogen, and Phosphorus Storages and Their Stoichiometry Due to Mixed Afforestation with <i>Hippophae rhamnoides</i> in the Loess Hilly Region, China

Mixed-species tree plantations have additional ecological benefits over single-species tree plantations, such as habitat restoration and increasing biodiversity. However, changes in the soil carbon, nitrogen, and phosphorus storages and stoichiometry after mixed afforestation with the N-fixing tree species under the “Grain for Green Project” in the Loess Plateau of China are not well understood. Typical restoration types, including the mixed plantations of Pinus tabuliformis with Hippophae rhamnoides (HrPt) and Robinia pseudoacacia with H. rhamnoides (HrRp), as well as the pure forests of P. tabuliformis (Pt) and R. pseudoacacia (Rp), were chosen to examine changes in the storages and stoichiometry of soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) in 0–100 cm soil layers. The results showed that compared with the corresponding pure forest, HrRp significantly increased the SOC content in the 0–20 cm soil layer and the SOC storage in the 0–100 cm layer, while HrPt significantly increased the SOC content in the 0–10 cm layer, but there was no significant difference for SOC storage in the 0–100 cm layer between Pt and HrPt. Similarly, HrRp significantly increased the TN content in the 0–10 cm layer and the TN storage in the 0–100 cm layer, but there was no significant difference in TN storage between Pt and HrPt. Furthermore, HrRp significantly increased the TP content in the 0–100 cm layer and TP storage was higher than that of Rp, while there were no significant differences in TP content and storage between Pt and HrPt. In the 0–10 cm soil layer, HrRp significantly reduced C:N and increased N:P, but HrPt significantly increased C:P. In addition, compared with the pure forest, the soil physical and chemical properties had a stronger control effect on the soil storages and stoichiometric ratios in the mixed forests. In summary, compared with P. tabuliformis, the introduction of N-fixing tree species into the R. pseudoacacia forest was more conducive to the accumulation of SOC, TN, and TP reserves and the improvement of the N and P utilization efficiency. These results have important implications for the restoration of degraded vegetation and scientific management of mixed plantations on the Loess Plateau and can provide basic data for the assessment of soil quality at the regional scale