A lift-off investigation of next-generation offshore wind turbine generator components for feedering in the U.S.: Creating understanding in the release stage of a tower segment

Climate change is triggering an ever-growing demand for renewable energy. The U.S. is still far behind Europe when it comes to offshore wind energy. They have made ambitious plans to reach 30 GW in offshore wind energy by 2030 while currently 42 MW is installed. One of the main challenges in the U.S. is the installation method since a...

Torsion motions of high-rise buildings due to wind loading

A structural firm will not invest a large sum of money in early design fase on a wind tunnel aeroelastic model to determine the displacements, forces, and moments when the dimensions of a building have only been estimated because the outcomes are only valid for that specific model. It is well-known that the outcomes are hard to determine...

Frequency Response Data-driven LPV Controller Synthesis for MIMO Systems

The linear parameter-varying framework enables systematic control design approaches to meet increasing performance requirements and complexity of systems. The aim of this paper is to develop local frequency response data-based analysis and synthesis conditions for multiple-input multiple-output linear parameter-varying systems to facilitate...

On the Excitation of Anomalous EM Transients Along the Surface of a Thin Highly Contrasting Sheet With Dielectric and Conductive Properties

The electric-line-source excited, pulsed electromagnetic (EM) field response on the surface of a highly contrasting thin sheet with dielectric and conductive properties is studied analytically in the time domain (TD) with the aid of the Cagniard-De Hoop technique. Closed-form TD expressions reveal anomalous highly oscillatory EM transients...

Amplitude-modulated, Cosine PE and WP Pulses: Theory and Applicability

The amplitude-modulated, cosine powerexponential (PE) and windowed-power (WP) pulses are discussed, by insisting on their time-domain normalization. Illustrative examples of signatures and their correspondent frequency-domain behavior are given. These examples compellingly demonstrate the possibility to replace non-causal pulses of prevalent...

Radio Frequency Interference Characterization and Mitigation for Polarimetric Weather Radar: A Study Case

Radio frequency interference (RFI) has become a growing concern for weather radar, distorting radar variable estimation. By simultaneously or alternately transmitting the horizontal and vertical polarized waves, polarimetric weather radar can be referred to as SHV radar or AHV radar. The SHV radar can mimic the AHV radar by discarding either...

Pulsed EM Field Scattering From a Narrow Superconducting Strip: A Solution Based on the Marching-On-In-Time Cagniard-DeHoop Method

Pulsed electromagnetic (EM) scattering from a relatively narrow superconducting strip is analyzed with the aid of the EM reciprocity theorem and the Cagniard-DeHoop (CdH) technique. The analysis yields a stable convolution-type equation that is solved using the marching-on-in-time (MOT) technique for coefficients representing the time-domain (TD...

Causal Excitation in Antenna Simulations

The critical relevance of ensuring the excitation’s causality in electromagnetic (EM) simulations is validated via theoretical arguments and simulation results. Two families of model pulses with an implicitly causal behavior, namely the windowed-power (WP) and the power-exponential (PE) ones, are elaborately discussed. After introducing their...

Fast rotor loss calculations in fractional-slot permanent magnet machines

Permanent magnet machines with fractional slot windings are popular because of their shorter end windings, low cost and ease of manufacturing. On the other hand, fractional slot machines have higher eddy current losses in the rotor magnets and sleeve. An accurate calculation of these losses usually involves a time-stepped finite-element analysis...

A Fully Integrated Discrete-Time Superheterodyne Receiver

The zero/low intermediate frequency (IF) receiver (RX) architecture has enabled full CMOS integration. As the technology scales and wireless standards become ever more challenging, the issues related to time-varying dc offsets, the second-order nonlinearity, and flicker noise become more critical. In this paper, we propose a new architecture of...

The Time-Domain Optical Theorem in Antenna Theory

A special form of the time-domain optical theorem related to a general receiving antenna system is rigorously derived. It is shown that the total energies dissipated in the antenna load and in the antenna system itself can be directly related to the electromagnetic energy of the scattered field and its time-domain far-field<br/>characteristics....

On the Adequacy of the Far-Field Conditions for Pulsed Radiated EM Fields

The far-field region’s bound is investigated in case of the pulsed electromagnetic field radiation. The value predicted by means of “standard,” time-harmonic considerations is compared with that following from the ratio between the maximum value of the time-domain, near- and far-field magnetic field strength<br/>constituents. The adequacy of...

TD Radiation Properties of Array Antennas Composed of Pulsed Electric-Current Excited Elements

A full time-domain analysis is presented of the radiation properties of array antennas composed of identical, mutually translationally shifted, pulsed electric-current excited elements. An expression is derived for the radiated field in the farfield region, the parameters in which provide the basis for studying the pulsed-field beam-shaping and...

Transmission measurement of the photonic band gap of GaN photonic crystal slabs

A high-contrast-ratio (30 dB) photonic band gap in the near-infrared transmission of hole-type GaN two-dimensional photonic crystals (PhCs) is reported. These crystals are deeply etched in a 650 nm thick GaN layer grown on sapphire. A comparison of the measured spectrum with finite difference time domain simulations gives quantitative agreement...

Reliability Study of RTV 566 for Its Application as a “Spring”

This paper reports the preliminary feasibility study of room temperature vulcanization (RTV) 566 for its application as a “spring” for in situ height adjustment in our proposed design for an array of Schottky emitters. The reliability of the RTV 566 is tested in terms of its viscoelastic properties for thicknesses of 95, 142, and 195 ?m. The...

Time-domain modeling of electromagnetic diffusion with a frequency-domain code

We modeled time-domain EM measurements of induction currents for marine and land applications with a frequency-domain code. An analysis of the computational complexity of a number of numerical methods shows that frequency-domain modeling followed by a Fourier transform is an attractive choice if a sufficiently powerful solver is available. A...

A new method for matching stacked seismic data with well log information