Radio Frequency Interference /RFI/ design guide for aerospace communications systems

Radio frequency interference design guide for aerospace communications system

Lateral-directional control of the x-15 airplane

Lateral directional control and stability characteristics of X-15 aircraf

Solution of ordinary differential equations by means of Lie series

Solution of ordinary differential equations by Lie series - Laplace transformation, Weber parabolic-cylinder functions, Helmholtz equations, and applications in physic

Lecture conjointe et apprentissage de la lecture

International audienc

A critical assessment of the resource depletion potential of current and future lithium-ion batteries

Resource depletion aspects are repeatedly used as an argument for a shift towards new battery technologies. However, whether serious shortages due to the increased demand for traction and stationary batteries can actually be expected is subject to an ongoing discussion. In order to identify the principal drivers of resource depletion for battery production, we assess different lithium-ion battery types and a new lithium-free battery technology (sodium-ion) under this aspect, applying different assessment methodologies. The findings show that very different results are obtained with existing impact assessment methodologies, which hinders clear interpretation. While cobalt, nickel and copper can generally be considered as critical metals, the magnitude of their depletion impacts in comparison with that of other battery materials like lithium, aluminum or manganese differs substantially. A high importance is also found for indirect resource depletion effects caused by the co-extraction of metals from mixed ores. Remarkably, the resource depletion potential per kg of produced battery is driven only partially by the electrode materials and thus depends comparably little on the battery chemistry itself. One of the key drivers for resource depletion seems to be the metals (and co-products) in electronic parts required for the battery management system, a component rather independent from the actual battery chemistry. However, when assessing the batteries on a capacity basis (per kWh storage capacity), a high-energy density also turns out to be relevant, since it reduces the mass of battery required for providing one kWh, and thus the associated resource depletion impacts

On Foundation of the Generalized Nambu Mechanics

We outline the basic principles of canonical formalism for the Nambu mechanics---a generalization of Hamiltonian mechanics proposed by Yoichiro Nambu in 1973. It is based on the notion of Nambu bracket which generalizes the Poisson bracket to the multiple operation of higher order $n \geq 3$ on classical observables and is described by Hambu-Hamilton equations of motion given by $n-1$ Hamiltonians. We introduce the fundamental identity for the Nambu bracket which replaces Jacobi identity as a consistency condition for the dynamics. We show that Nambu structure of given order defines a family of subordinated structures of lower order, including the Poisson structure, satisfying certain matching conditions. We introduce analogs of action from and principle of the least action for the Nambu mechanics and show how dynamics of loops ($n-2$-dimensional objects) naturally appears in this formalism. We discuss several approaches to the quantization problem and present explicit representation of Nambu-Heisenberg commutation relation for $n=3$ case. We emphasize the role higher order algebraic operations and mathematical structures related with them play in passing from Hamilton's to Nambu's dynamical picture.Comment: 27 page

Toward a cell-chemistry specific life cycle assessment of lithium-ion battery recycling processes

On the basis of a review of existing life cycle assessment studies on lithium‐ion battery recycling, we parametrize process models of state‐of‐the‐art pyrometallurgical and hydrometallurgical recycling, enabling their application to different cell chemistries, including beyond‐lithium batteries such as sodium‐ion batteries. These processes are used as benchmark for evaluating an advanced hydrometallurgical recycling process, which is modeled on the basis of primary data obtained from a recycling company, quantifying the potential reduction of environmental impacts that can be achieved by the recycling of different cell chemistries. Depending on the cell chemistry, recycling can reduce significantly the potential environmental impacts of battery production. The highest benefit is obtained via advanced hydrometallurgical treatment for lithium nickel manganese cobalt oxide and lithium nickel cobalt aluminum oxide‐type batteries, mainly because of the recovery of cobalt and nickel. Especially under resource depletion aspects, recycling of these cells can reduce their impact to an extent that even leads to a lower “net impact” than that of cells made from majorly abundant and cheap materials like lithium iron phosphate, which shows a more favorable performance when recycling is disregarded. For these cells, recycling does not necessarily provide benefits but can rather cause additional environmental impacts. This indicates that maximum material recovery might not always be favorable under environmental aspects and that, especially for the final hydrometallurgical treatment, the process would need to be adapted to the specific cell chemistry, if one wants to obtain maximum environmental benefit