A 36-element monolithic grid amplifier has been fabricated. The active elements are pairs of heterojunction-bipolar-transistors. Measurements show a peak gain of 5dB at 40GHz with a 3-dB bandwidth of 1.8 GHz(4.5%). Here we also report comparisons of p a t t e r n s and tuning curves between the measurements and theory. The grid includes base stabilizing capacitors which result in a highly stabl...

The influence of the boundary conditions on the added mass of a NACA0009 cantilever hydrofoil has been numerically and experimentally investigated. The study has been focused on the effects of a lateral solid wall close to the hydrofoil tip side and of a partially wetted vertical hydrofoil at different levels with the free surface parallel to the span. A detailed fluid–structure model has been ...

During pregnancy, the female body experiences structural changes, such as weight gain. As pregnancy advances, most of the additional mass is concentrated anteriorly on the lower trunk. The purpose of this study is to analyze kinematic and kinetic changes when load is added anteriorly to the trunk, simulating a physical change experienced during pregnancy. Twenty healthy females walked on a trea...

Original scientific paper Comparison between analytical and numerical determination of the added hydrodynamic mass in ship vibration analysis is performed. Analytical analysis was done on a semi-submerged cylinder of a circular cross section. Numerical calculations were carried out by the boundary element method (BEM) implemented in NX Nastran finite element (FE) software. Fairly good agreement...

Thirty-degree pitch-down helicopter crash pulses were examined at the Patuxent River Horizontal Accelerator facility. The pulses used were representative of standard seat qualification crash corridors for a variety of rotary wing platforms. The primary objectives of this effort were 1) to quantitatively determine the effect of varying helmet weight and center of gravity (CG) during simulated ro...

A mechanism for generating small tree-level Majorana mass for neu-trinos is implemented in the 331 Model. No additional fermions or scalars need to be added, and no mass scale greater than a few TeV is invoked.

The mechanical design of hydraulic turbines is conditioned by the dynamic response of the runner that is usually estimated by a computational model. Nevertheless, the runner has complex boundary conditions that are difficult to include in the computational model. One of these boundary conditions is the water in which the runner is submerged. The effect of the added mass and damping of water can...

Hydropower, a clean and renewable energy resource, has been developed worldwide for the economic development and improvement of people's living standards. It has also been used to improve the stability of the smart power grid. Depending on the water head of hydropower plants, various types of hydraulic turbines such as Francis, Kaplan and Pelton have been designed to maximize efficiency. Franci...