The combined toxic effect of nanoparticles and lead in the presence of algae (Raphidocelis)

The elevated toxicity of toxic metals in the presence of nanoparticles (NPs) has raised significant concerns on the NP environmental safety. This research focuses on the impact of environmental conditions, specifically algae, on this type of toxicity. An indicator aquatic organism, Ceriodaphnia dubia (C. dubia), was used to examine the combined toxicity and toxicity mitigation from algae by monitoring its 24-h mortality. Four papers are included in this research, which focus on four aspects of the combined toxicity and the corresponding algae (Raphidocelis) impact. The first paper examines the algae impact on the combined toxicity of lead (Pb) and nano-TiO2. The effect of algae was determined through Pb accumulation by, depuration from, and distribution within the C. dubia. The second paper develops a two-compartment kinetic model to quantify the iron (Fe) and Pb accumulation in C. dubia in the presence of nano-TiO2. The model was used to investigate the major uptake, depuration, and distribution pathways of Fe and Pb in C. dubia. The third paper presents a toxicokinetic-toxicodynamic (TK-TD) model that was used to develop fundamental understanding of the combined toxicity of Pb and nano-TiO2, more specifically, the role of nano-TiO2 in the combined toxicity. The fourth paper focuses on the algae impact on the combined toxicity of Pb and an emerging containment, microplastic (MP). The combined toxicity mechanisms and the effect of algae were investigated through Pb and MP interaction, Pb accumulation, and MP accumulation. This research provides a fundamental understanding on the role of algae, a natural food source for aquatic organisms, on the toxicity of NPs in the presence of other background toxins --Abstract, page iv

Development of a radar simulator for monitoring wake vortices in rainy weather

A simulator for the evaluation of the radar signature of raindrops within wake vortices is presented. Simulated Doppler spectrum of raindrops within vortices let to think that it could be a potential criterion for identifying wake vortex hazard in rainy weather

An Improved Robot Path Planning Algorithm

Robot path planning is a NP problem. Traditionaloptimization methods are not very effective to solve it. Traditional genetic algorithm trapped into the local minimum easily. Therefore, based on a simple genetic algorithm and combine the base ideology of orthogonal design method then applied it to the population initialization, using the intergenerational elite mechanism, as well as the introduction of adaptive local search operator to prevent trapped into the local minimum and improvethe convergence speed to form a new genetic algorithm. Through the series of numerical experiments, the new algorithm has been proved to be efficiency.We also use the proposed algorithm to solve the robot path planning problem and the experiment results indicated that the new algorithm is efficiency for solving the robot path planning problems and the best path usually can be found

Modelling of Temporal‐Spatial Distribution of Airplane Wake Vortex for Scattering Analysis

Aircraft wake vortex is a pair of intensive counter‐rotating airflow generated by a flying aircraft. Wake vortex is one of the most dangerous hazards in aviation because it may cause a following aircraft to roll out of control, particularly during the taking off and landing phases. The real‐time detection of wake vortex is a frontier scientific problem emerging from many fields like aviation safety and atmospheric physics, and the dynamics and scattering characteristics of it remain as key problems to develop corresponding detection technologies. This chapter aims at presenting a simulation scheme for the dynamics of wake vortex under different weather conditions. For wake vortex generated in clear air, changes of the atmospheric dielectric constant produced by the density variation and water vapour variation are analysed; for wake vortex generated in rainy condition, the raindrop distribution in the wake vortex is also analysed. Both of them are essential for further analysing the scattering characteristics and developing new detection algorithms

Cement Improved Highly Weathered Phyllite for Highway Subgrades: A Case Study in Shaanxi Province.

In a cost-saving move, the soft rocks composed of highly-weathered phyllites available onsite were used to fill the subgrade in the eastern Ankang section of the expressway of Shiyan to Tianshui, China. Cement admixture was used to improve the performance of the weathered phyllites. In order to determine the best mix ratio, values corresponding to compaction performance, unconfined compressive strength, and the California bearing ratio (CBR) were analyzed for variable cement content weight percentages (3%, 4%, 5%, and 6%) using test subgrade plots in the field. Field measurements of resilience modulus and deflection confirmed that the strength of the subgrade increased as the cement ratio increased. In order to further evaluate the cement/phyllite mixture, the performance of the 3% cement ratio sample was evaluated under saturated conditions (with various levels of moisture addition and soaking time) using both the wetting deformation and resilient modulus values. Results suggest that moisture added and soaking time are key factors that affect the seepage depth, water content, and resilient modulus. The recommend values for the cement addition and for the water content are given out. This study can aid in prevention of highway damage by improving the foundation capacity and lengthening the lifecycle of the highway in phyllite distributed region at home and abroad

Modeling the Radar Signature of Raindrops in Aircraft Wake Vortices

The present work is dedicated to the modeling and evaluation of the radar signature of raindrops within wake vortices. This is achieved through the computation of the motion equation of raindrops within the wake vortex flow. Based on the inhomogeneous distribution of raindrops within wake vortices, the radar echo model is computed for raindrops in a given pulse resolution volume. Simulated Radar Doppler signature of raindrops within wake vortices is illustrated to be a potential criterion for identifying wake vortex hazard in air traffic control. The dependence of the radar signature on various parameters, including the radial resolution, antenna elevation angle, is also analyzed

Machine Directional Register System Modeling for Shaft-Less Drive Gravure Printing Machines

In the latest type of gravure printing machines referred to as the shaft-less drive system, each gravure printing roller is driven by an individual servo motor, and all motors are electrically synchronized. The register error is regulated by a speed difference between the adjacent printing rollers. In order to improve the control accuracy of register system, an accurate mathematical model of the register system should be investigated for the latest machines. Therefore, the mathematical model of the machine directional register (MDR) system is studied for the multicolor gravure printing machines in this paper. According to the definition of the MDR error, the model is derived, and then it is validated by the numerical simulation and experiments carried out in the experimental setup of the four-color gravure printing machines. The results show that the established MDR system model is accurate and reliable

High cycle fatigue assessment of steel load-carrying cruciform welded joints: an overview of recent results

In this paper, high cycle fatigue failure behavior of steel Load-carrying Cruciform Welded Joints (LCWJ) is assessed by means of local approaches. Different analytical solutions for weld toe and weld root are extended and applied to illustrate the effects of LCWJ geometry under cycle tension and bending based on Notch Stress Intensity Factors (NSIFs). The extended analytical solutions are validated by comparing finite element data from several simulations in terms of LCWJ models, resulting in a good agreement. A bulk of experimental data taken from tests and the literature is calculated by the proposed solutions as the forms of SED, NSIF and Peak Stress Method (PSM). The results show that the NSIF-based analytical solutions for steel LCWJ are effective for high cycle fatigue failure analyse