There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Systems and methods are provided for swapping the battery on an unmanned aerial vehicle (UAV). The UAV may be able to identify and land on an energy provision station autonomously. The UAV may take off and/or land on the energy provision station. The UAV may communicate with the energy provision station. The energy provision station may store and charge batteries for use on a UAV.

Systems and methods for uav battery exchange

Systems and methods are provided for docking an unmanned aerial vehicle (UAV) with a vehicle. The UAV may be able to distinguish a companion vehicle from other vehicles in the area and vice versa. The UAV may take off and/or land on the vehicle. The UAV may be used to capture images and stream the images live to a display within the vehicle. The vehicle may control the UAV. The UAV may be in communication with the companion vehicle while in flight.

Systems and methods for uav docking

Impact resistance of fiber-metal laminates: A review

Low velocity impact response of fibre-metal laminates – A review

In order to improve the understanding of the dynamic recrystallization (DRX) behaviors of as-cast AZ80 magnesium alloy, a series of isothermal upsetting experiments with height reduction 60% were performed at the temperatures of 523 K, 573 K, 623 K and 673 K, and the strain rates of 001 s−1, 01 s−1, 1 s−1 and 10 s−1 on a Gleeble 1500 thermo-mechanical simulator Dependence of the flow stress on temperature and strain rate is described by means of the conventional hyperbolic sine equation By regression analysis, the activation energy of DRX in the whole range of deformation temperature was determined to be Q = 21582 kJ mol−1 Based on dσ/dɛ versus σ curves and their processing results, the ﬂow stress curves for AZ80 magnesium alloy were evaluated that they have some characteristic points including the critical strain for DRX initiation (ɛc), the strain for peak stress (ɛp), and the strain for maximum softening rate (ɛ*), which means that the evolution of DRX can be expressed by the process variables In order to characterize the evolution of DRX volume fraction, the modified Avrami type equation including ɛc and ɛ* as a function of the dimensionless parameter controlling the stored energy, Z/A, was evaluated and the effect of deformation conditions was described in detail Finally, the theoretical prediction on the relationships between the DRX volume fractions and the deformation conditions were validated by the microstructure graphs

Constitutive modeling for the dynamic recrystallization evolution of AZ80 magnesium alloy based on stress–strain data

Experimental and Numerical Investigation on Impact Performance of Carbon Reinforced Aluminum Laminates

Stochastic approach to kinematic reliability of open-loop mechanism with dimensional tolerance

The workability evaluation of wrought AZ80 magnesium alloy in hot compression

An unmanned aerial vehicle equipped with a spherical locking portion for landing on an unmanned ground vehicle is disclosed. The spherical locking portion can be the body of the unmanned aerial vehicle. Further, an unmanned ground vehicle for landing of an unmanned aerial vehicle, comprising a landing portion configured to have some of a spherical locking portion of the unmanned aerial vehicle inserted therein is disclosed.

Woo-Jin Song

Papers

Constitutive modeling for the dynamic recrystallization evolution of AZ80 magnesium alloy based on stress–strain data

Experimental and Numerical Investigation on Impact Performance of Carbon Reinforced Aluminum Laminates

Stochastic approach to kinematic reliability of open-loop mechanism with dimensional tolerance

The workability evaluation of wrought AZ80 magnesium alloy in hot compression

Unmanned Aerial Vehicle Having Spherical Loading Portion and Unmanned Ground Vehicle Therefor