Mechanism of motion of an optical fiber aligned by a solder droplet

Solder is often used as an adhesive to attach optical fibers to a circuit board. In this proceeding we will discuss efforts to model the motion of an optical fiber during the wetting and solidification of the adhesive solder droplet. The extent of motion is determined by several competing forces, during three “stages” of solder joint formation. First, capillary forces of the liquid phase control the fiber position. Second, during solidification, the presence of the liquid-solid-vapor triple line as well as a reduced liquid solder volume leads to a change in the net capillary force on the optical fiber. Finally, the solidification front itself impinges on the fiber. Publicly-available finite element models are used to calculate the time-dependent position of the solidification front and shape of the free surface.

World in motion

Professor Ed Galea CEng, MIFireE provides a welcome to Pedestrian and Evacuation Dynamics 2003, (PED 2003) to be held in London on 20-22 August 2003.

Design of differential amplifier with negative impedance compensation

Design of differential amplifier with high gain accuracy and high linearity is presented in the paper. The amplifier design is based on the negative impedance compensation technique reported by the authors in [1]. A negative impedance with high precision, low sensitivity, wide input signal range and simple structure is used for the compensation of differential amplifier. Analysis and simulation results show that gain accuracy and linearity can be improved significantly with the negative impedance compensation

Stability analysis of the amplifier with negative impedance compensation

A novel amplifier design technique based on negative impedance compensation has been proposed in our recent paper. In this paper, we investigate the stability of this amplifier system. The parameter space approach has been used to determine system parameters in the negative impedance circuit such that the stability of the amplifier system can be guaranteed in a certain region represented by those parameters. The simulation results have demonstrated that stable circuit behavior for the amplifier can be achieved

Challenges to Slovakia and Poland health policy decisions: use of investment treaties to claim compensation for reversal of privatisation/liberalisation policies

Investment treaties, and possibly the EU Treaty itself, are being used by multinational companies Penta and Eureko to try and force the Slovak government to pay compensation for reversing health privatisation and liberalisation policies. Similar action has been used against the Polish government by Eureko to win compensation worth nearly 2 billion Euros and a policy commitment to further privatisation.