The paper presents finite element (FE) model development and experimental validation for a truck tractor with a three axle single drop lowboy trailer. The main objective of this research activity was to create a simplified, three dimensional virtual FE model, applicable for computer simulation of dynamic interaction between a vehicle and a bridge or road structure. Such model should provide a r...

Probe-after-bump is the primary probing procedure for flip chip technology, since it does not directly contact the bump pad, and involves a preferred under bump metallurgy (UBM) step coverage on the bump pads. However, the probe-after-bump procedure suffers from low throughputs and high cost. It also delays the yield feedback to the fab, and makes difficult clarification of the accountability o...

When designing control strategies for differentialdrive mobile robots, one standard tool is the consideration of a point at a fixed distance along a line orthogonal to the wheel axis instead of the full pose of the vehicle. This abstraction supports replacing the non-holonomic, three-state unicycle model with a much simpler two-state single-integrator model (i.e., a velocitycontrolled point). Y...

The purpose of this note is to establish the entireness of spinor L-function of certain automorphic cuspidal representations of the group similitude symplectic group of order four over the rational numbers. Our study of spinor L-function is based on an integral representation which works only for generic representations. For this reason, while methods of this papers do not directly apply to the...

When electric current flows in a solder bump, electromigration generates stress, but creep relaxes it. After some time, the bump develops a steady-state stress field. We present a theory to show that the two processes — electromigration and creep — set an intrinsic length. When the intrinsic length is large compared to the height of the bump, electromigration is fast relative to creep and the s...

The effect of polyimide (PI) thermal process on the bump resistance of flip-chip solder joint is investigated for 28 nm technology device with aggressive extreme low-k (ELK) dielectric film scheme and lead-free solder. Kelvin structure is designed in the bump array to measure the resistance of single solder bump. An additional low-temperature pre-baking before standard PI curing increases the b...

Reliability in flip chip and Ball Grid Array is a major concern. Solder joint geometry is extremely important from a reliability point of view. Commonly, the flip chip solder bump takes on the shape of a spherical segment. Mathematical calculations and finite element modeling have shown that the hourglass-shaped solder bumps experience the lowest plastic strain and have the longest lifetime. In...

The time integrals of the responses of dark-adapted Limulus ventral photoreceptors to flashes exhibit a supralinear dependence on intensity at intermediate intensities. By decomposing the responses into their elementary single-photon components ("bumps"), we are able to calculate the overall quantum efficiency and to display the time courses of the bump amplitude and rate of appearance. Since t...