Nanoplasmonic Waveguides Filled with Electro‐Optical Materials

In this chapter, nanoplasmonic waveguides filled with electro-optical materials are proposed and discussed. Rigorous theoretical modelling is developed to describe the propagation, generation and control of electromagnetic fields confined in these nanoscale waveguides. Two configurations are studied thoroughly. First, a metal-insulator-metal (MIM) nanoplasmonic waveguide filled with lithium niobate (i.e., LiNbO3) is considered for compact terahertz (THz) generation. The waveguide is designed to generate Gaussian THz waves by the means of frequency down-conversion of two surface plasmon polariton (i.e., SPP) modes. THz generation is shown to be viable over the entire range from 1 to 10 THz by properly designing the SPP wavelengths and waveguide dimensions. Future applications of such nanoscale THz sources include nanocommunication systems and body-centric networks. Secondly, an MIM nanoplasmonic waveguide filled with doped LiNbO3 is considered. The interaction between two interfering SPP modes is studied. It is shown that a strong symmetric SPP mode can be coupled to a weak antisymmetric SPP mode by the means of photorefractive effect. Future advances include implementing known photorefractive applications (such as interferometry and holography) in the nanoplasmonic field. The work of this chapter highlights the potential of functioning electro-optical materials in nanoplasmonic waveguides to achieve novel ultra-compact and efficient devices

NUMERICAL AND EXPERIMENTAL STUDIES ON THE SLOW DRIFT MOTIONS AND THE MOORING LINE RESPONSES OF TRUSS SPAR PLATFORMS

An efficient methodology has been developed for the dynamic analysis of offshore floating structures. In this methodology, special attention was given to the second order difference frequency forces and responses. According to this numerical scheme, a MATLAB program named TRSPAR was developed to predict the dynamic responses of truss spar platform in time domain. In this program, the truss spar platform was modeled as a rigid body with three degrees of freedom. Hydrodynamics of the structure, which include the linear and second order wave forces, mean drift forces, added mass, radiation damping, wave drift damping and system stiffness were included in the program. Current and wind forces were also considered showing their effects on the slow drift responses. The wave forces, including inertia and drag forces, were calculated using Morison equation assuming the wave field as undisturbed. An efficient time domain integration scheme was adopted based on Newmark Beta method. Comprehensive experimental studies were conducted and the numerical predictions were systematically compared with model test results. These comparisons consisted of structure’s dynamic responses in different environmental conditions and two structural situations. The first situation was the structure with intact mooring lines and the other one was the structure under mooring line failure. The responses of the platform with mooring line system damage were investigated with the emphasis on finding the critical effects of line failure on the resonant responses. The effects of the second order difference frequency wave forces on the truss spar motion characteristics were examined numerically. Published numerical results were used to verify the developed numerical model in predicting the truss spar dynamic responses when subjected to combined wave, current and wind forces. The effects of strengthening mooring line system on the motion characteristics of the structure were examined numerically. For the assessment of the fluid to mooring nonlinear interactions, a deterministic approach based on lumped mass method with equations of dynamic equilibrium and continuity was adopted. Finally, parametric studies on deepwater mooring line analysis have been conducted for investigating the contributions of the various design parameters on mooring line tension. The experimental results verified the validity of the developed numerical scheme for prediction of the wave frequency and low frequency motions of the truss spar platform with its intact mooring and in the case of mooring line damage condition. RMSD values for the numerical and the experimental results show that the simulated wave frequency responses (WFR) trend was relatively agreed well with the experiments compared to the low frequency responses (LFR). For the intact mooring line condition, RMSD values for the WFR ranged from 109.9 to 182.4 while for LFR were ranged from 499.6 to 550.2. The same has been noticed in the mooring line damage condition in which RMSD values ranged from 107.4 to 323.6 and 209.1 to 1074 for WFR and LFR respectively. With regard to the peak responses, good accuracy has been achieved between the predictions and the measurements. The percentage errors for the peak responses in the intact mooring and the mooring line damage conditions were ranged from 9.5% to 17.3%

High-Fidelity Quantum Information Transmission Using a Room-Temperature Nonrefrigerated Lossy Microwave Waveguide

Quantum microwave transmission is key to realizing modular superconducting quantum computers and distributed quantum networks. A large number of incoherent photons are thermally generated within the microwave frequency spectrum. The closeness of the transmitted quantum state to the source-generated quantum state at the input of the transmission link (measured by the transmission fidelity) degrades due to the presence of the incoherent photons. Hence, high-fidelity quantum microwave transmission has long been considered to be infeasible without refrigeration [3,4]. In this study, we propose a novel method for high-fidelity quantum microwave transmission using a room-temperature lossy waveguide. The proposed scheme consists of connecting two cryogenic nodes (i.e., a transmitter and a receiver) by the room-temperature lossy microwave waveguide. First, cryogenic preamplification is implemented prior to transmission. Second, at the receiver side, a cryogenic loop antenna is placed inside the output port of the waveguide and coupled to an LC harmonic oscillator located outside the waveguide. The loop antenna converts quantum microwave fields (which contain both signal and noise photons) to a quantum voltage across the coupled LC harmonic oscillator. The loop antenna detector at the receiver is designed to extensively suppress the induced photons across the LC oscillator. The signal transmittance is maintained intact by providing significant preamplification gain. Our calculations show that high-fidelity quantum transmission (i.e., more than 95%) is realized based on the proposed scheme for transmission distances reaching 100 m.Comment: 10pages; 6 figure

Configuration of Traffic-Responsive Plan Selection System Parameters and Thresholds: Robust Bayesian Approach

Traffic-responsive plan selection (TRPS) is one of the two major closed-loop system modes of operation. The TRPS mode is more beneficial than its competitor (time-of-day mode) because of its ability to accommodate abnormal traffic conditions such as incidents, special events, and holiday traffic. However, no guidelines are available for optimal setup of TRPS systems. Improper configuration of a TRPS system can result in inefficient system performance or unstable operation in which the closed-loop system operates in a perpetual transitioning state. The TRPS mechanism implemented in current traffic signal controllers is described, and a Bayesian-based methodology for selecting an optimal set of TRPS factors, parameters, and thresholds is proposed. The proposed methodology was tested with data from a closed-loop system in Texas and resulted in 100% classification accuracy

A Real-Time Offset Transitioning Algorithm for Coordinating Traffic Signals

This report introduces an adaptive real-time offset transitioning algorithm that can be viewed as an integrated optimization approach designed to work with traditional coordinated-actuated systems. The Purdue Real-Time Offset Transitioning Algorithm for Coordinating Traffic Signals (PRO-TRACTS) adds to the controllers the ability to adaptively change their offsets in response to changes in traffic pattern, providing an intermediate solution between traditional coordinated-actuated control systems and adaptive control systems. To facilitate implementation, a new National Transportation Communication for ITS Protocol (NTCIP) object for capturing detector actuation at the controller’s level is defined in this report. The unique cycle-based tabulation of volume and occupancy profiles at upstream detectors is used by a newly defined metric to examine the existence of shockwaves generated due to a poor offset downstream. The procedure is modeled after the analysis of variance testing. This procedure is performed on cycle-by-cycle basis to evaluate the offset performance and adjust it accordingly. Simulations of two case studies revealed 0-16% savings in total travel time and up to 44% saving in total number of stops for the coordinated movement when applied to systems with poor offsets. The algorithm is best suited for arterials with primarily through traffic. Heavy movements from the side streets onto the arterial make it difficult for the algorithm to determine which movement should be favored. PRO-TRACTS mitigates problems such as early-return-to-green, waiting queues, and improperly designed offsets using current setups of traffic signals/detectors in the US. The algorithm capitalizes on the existing knowledge and familiarity of traffic engineers and personnel with the current actuated control system to provide a cost-effective solution to improving signal coordination. Future research is needed to improve the stability of the algorithm with highly dispersed platoons and oscillatory traffic patterns caused by situations such as controllers skipping phases due to light traffic volume. It is also recommended that the algorithm should be extended to improve two-way signal progression instead of one-way progression