Search

With the acceleration of highway construction and growing retain number of vehicles, the road traffic pollution besides industrial pollution is one of the main sources of heavy-metal pollution in soil, especially heavy-metal pollution to roadside soil, and among others, zinc (Zn) is one of the main heavy-metal pollutants. Previous studies mostly focused on the pollution characteristics, distribution rules and qualitative sources of Zn in roadside soil, but systematic analysis of the quantitative analysis is not enough, so it is difficult to provide effective support for the prevention and control of roadside soil heavy-metal pollution. In this study, with roadside soil, atmosphere dust-fall and pavement sediments being taken as the research objects, the values of Zn isotopes in roadside atmospheric dust-fall, pavement sediments, automobile tires and roadside soil were determined by using ICP-MS, and the sources of Zn pollution to roadside soil, and their contribution rate were quantitatively analyzed by isotope tracer method. Consequently, it was showed that the wear of automobile tires contributed the greatest Zn pollution to the roadside soil, followed by the road sediments and the roadside atmospheric dust, and specifically, in non-industrial areas the contribution of tires wear was in the range of 71%~77%, road sediments 12%~18% and atmospheric dustfall 10%~11%, while in industrial areas, the contribution of tire wear in the range of 65%~70%, road sediment 19%~24% and atmospheric dust-fall 10%~12%. It is expected that the result of the study could provide a basis for the prevention and control of Zn pollution in roadside soil. [ABSTRACT FROM AUTHOR]

Insects can navigate in cluttered spaces and perform challenging functions such as pollination and collective object transport. By exploiting scaling laws and bioinspired designs, insect‐scale micro‐aerial‐vehicles (MAVs) have demonstrated impressive flight capabilities such as in‐flight collision resilience and acrobatic maneuvers. However, existing subgram MAVs are difficult to design, construct, and repair. Coupled with challenges in robot sensing and control, existing subgram MAVs have not achieved insect‐like swarm flight, which limits potential studies of swarm behaviors and future applications such as collective sensing. Herein, a new design and fabrication method is developed to substantially improve the fabrication scalability of subgram MAVs. Based on a small set of design parameters, an automated algorithm generates the laser cut files of microrobotic components. To reduce fabrication and assembly time, stereolithographic 3D printing is used for making static components such as the airframe and connectors. The modular design enables straightforward assembly and repair, which reduces the overall fabrication time by over 2 times. Owing to the ease of fabrication and good reliability, two subgram MAVs demonstrate controlled hovering flight and coordinated lifting of an object. This result lays the foundation for future robotic studies of collective insect flight. [ABSTRACT FROM AUTHOR]

Aerial insects are exceptionally agile and precise owing to their small size and fast neuromotor control. They perform impressive acrobatic maneuvers when evading predators, recovering from wind gust, or landing on moving objects. Flapping-wing propulsion is advantageous for flight agility because it can generate large changes in instantaneous forces and torques. During flapping-wing flight, wings, hinges, and tendons of pterygote insects endure large deformation and high stress hundreds of times each second, highlighting the outstanding flexibility and fatigue resistance of biological structures and materials. In comparison, engineered materials and microscale structures in subgram micro-aerial vehicles (MAVs) exhibit substantially shorter lifespans. Consequently, most subgram MAVs are limited to hovering for less than 10 seconds or following simple trajectories at slow speeds. Here, we developed a 750-milligram flapping-wing MAV that demonstrated substantially improved lifespan, speed, accuracy, and agility. With transmission and hinge designs that reduced off-axis torsional stress and deformation, the robot achieved a 1000-second hovering flight, two orders of magnitude longer than existing subgram MAVs. This robot also performed complex flight trajectories with under 1-centimeter root mean square error and more than 30 centimeters per second average speed. With a lift-to-weight ratio of 2.2 and a maximum ascending speed of 100 centimeters per second, this robot demonstrated double body flips at a rotational rate exceeding that of the fastest aerial insects and larger MAVs. These results highlight insect-like flight endurance, precision, and agility in an at-scale MAV, opening opportunities for future research on sensing and power autonomy.