Ballast flying problems obsess the ballasted high speed railway, its microscopic mechanics is less of discovered. In the paper, the railway ballast particle force equilibrium is analyzed through basic mechanics and mathematic formula, and a model is set up to discover the factors and influence. The microscopic ballast flying model is used for ballast bed geometry and ballast shape optimization,...

To prevent the dramatic degradation of the device performance of SiGe power heterojunction bipolar transistors (HBTs) and maintain the power efficiency, emitter-ballast resistors and base-ballast resistors have been employed in high power bipolar transistors. The microwave performance of emitter-ballast and base-ballast HBTs has been compared and discussed empirically in the previous work. Howe...

Ballast degradation can cause poor drainage, settlement and reduced lateral stability, which adversely affect railroad track safety and performance. Two indices are commonly used in the North American railroad industry to quantify the level of ballast degradation. These are (i) Fouling Index (FI) and (ii) Percentage Fouling (PF). Identifying these two traditional indices involve ballast samplin...

Abstract Ballast fouling in railroad substructure is detrimental to railroad track effectiveness and its structural capacity. Ground penetrating radar (GPR) provides a rapid, effective and continuous approach to assess railroad substructure condition. However, unknown ballast dielectric constant and unclear interface between clean and fouled ballast limit the GPR assessment accuracy. In this st...

A complete vehicle-ballasted track-bridge coupling dynamic model is established. A program to analyze dynamic characteristics is also invented, which is the first time to systematically analyze the dynamic characteristics of vehicles, tracks and bridges when using mats under ballast on the rigid foundation of bridge, in China. The results show that:(1) The mats under ballast are able to reduce ...

This paper, electronic resonant ballast for a small photovoltaic powered street lighting system in remote rural area was proposed. The street lighting system was designed for rural area where the electrical transmission line cannot be commonly serviced and it is the cascade systems of the solar arrays, switching battery charger, and electronics ballast with small fluorescent lamp. The ballast i...

Ballast water treatment consists of the elimination of exotic species. Currently, the development of alternative methods for this process is directed toward treatment onboard ships. However, we present onshore treatment as a viable alternative for ballast water treatment. We investigated onshore treatment in two iron ore ports with movement capacities of 25 and 90 million tons annually (Mta) th...

The human mediated transfer of harmful organisms via shipping, specifically via ballast water transport, leading to the loss of biodiversity, alteration of ecosystems, negative impacts on human health and in some regions economic loss, has raised considerable attention especially in the last decade. Ballast water sampling is very important for biological invasions risk management. The complexit...

Railway ballast tamping operation is employed in order to restore the geometry of railway track distorted by train traffics. In this paper, based on analysis of tamping principle, the discrete element analysis model of railway ballast is created using the discrete element method, numerical simulations are performed to study the change of railway ballast compactness during tamping process. This ...