Multidisciplinary Development of Autonomous Underwater Vehicle Fleet

Eco-Dolphin – Cooperative Fleet for Surveillance Mission SIAM, Society for Industrial & Applied Mathematics, members have been working for two years on the design, construction and testing of three highly integrated and streamlined autonomous underwater vehicles called Eco-Dolphins. This project is being developed at Embry-Riddle Aeronautical University’s Daytona Beach campus. The Leverage lab is used to create detailed mathematical models and conduct preliminary research for both electrical and mechanical systems. The campus Composites lab is used for the fabrication of structural and aesthetic components used by the high adaptable platform. The Autonomous Underwater Vehicle testing is conducted in the Universities Nonlinear Waves lab. The first phase of design, production and assembly of the yellow Eco-Dolphin prototype has been done in twelve months. The design includes an internal attitude control system, combined with internal propulsion from brushless direct current thrusters, thus allowing the vehicle to ascend and descend. The Eco-Dolphins promise is to be a unique, highly optimized and a competitive underwater vehicle fleet. The team has also successfully completed the second phase of the program, which involved tracking the Eco-Dolphins while submerged underwater. Work has been conducted to add a GPS system for surface tracking. Converting the acoustic system from tethered to wireless to make the ground station more robust. The Eco-Dolphin is configured with recently developed control system software that utilizes a relay combination of Wireless, Sonar and GPS radio wave communication. The current progress on the blue Eco-dolphin will be completed by the summer of 2014, for testing in littoral waters of central Florida. Through the addition of three sequential (yellow, blue, red) vehicles, therefore allows for better position and orientation data to be sent to the teams buoy network. The three vehicles, three buoy communication structure, multiply the data points collected for surveillance and underwater mapping purposes. This additional complexity improves the reliability and increases the application of the product through error elimination software. The team gives hands on research experience to SIAM members through applied mathematics. The outcome of the research goals, results in the application of many fields of study beyond mathematics. When combined the fleet can cooperatively fulfill multitask missions, advanced surveillance and environmental monitoring can be conducted. This opportunity opens the way for better balance between sustainable developments of the coastline

Effect of Grinding Parameters on the Surface Quality of Cutting Tools Made of High-Speed Low-Alloy Steels

The occurrence of defects caused by sharpening leads to the considerable variation of lifetime of cutting tools under identical process conditions. The loss of cutting ability of cutting tools or the change of the blade original geometry influences the quality of the surface finish as well as both dimensional and shape accuracy of workpieces. The effect of the grinding parameters on the surface finish of selected high-speed steels has been investigated. The influence of the grinding parameters has been defined especially for surface roughness, grinding forces and grinding ratio with a wide range of grinding parameters. It is found that the value of average roughness (Ra ) parameter decreases together with an increase in the grinding depth and the feed length. Furthermore, the value of Ra increases proportionally to the grinding depth. To increase the efficiency of sharpening, it is required to increase the feed length other than the grinding depth

Nonlinear Low-to-High-Frequency Energy Cascades in Diatomic Granular Crystals

We study wave propagation in strongly nonlinear one-dimensional diatomic granular crystals under an impact load. Depending on the mass ratio of the “light” to “heavy” beads, this system exhibits rich wave dynamics from highly localized traveling waves to highly dispersive waves featuring strong attenuation. We demonstrate experimentally the nonlinear resonant and antiresonant interactions of particles, and we verify that the nonlinear resonance results in strong wave attenuation, leading to highly efficient nonlinear energy cascading without relying on material damping. In this process, mechanical energy is transferred from low to high frequencies, while propagating waves emerge in both ordered and chaotic waveforms via a distinctive spatial cascading. This energy transfer mechanism from lower to higher frequencies and wave numbers is of particular significance toward the design of novel nonlinear acoustic metamaterials with inherently passive energy redistribution properties

Time as an operator/observable in nonrelativistic quantum mechanics

The nonrelativistic Schroedinger equation for motion of a structureless particle in four-dimensional space-time entails a well-known expression for the conserved four-vector field of local probability density and current that are associated with a quantum state solution to the equation. Under the physical assumption that each spatial, as well as the temporal, component of this current is observable, the position in time becomes an operator and an observable in that the weighted average value of the time of the particle's crossing of a complete hyperplane can be simply defined: ... When the space-time coordinates are (t,x,y,z), the paper analyzes in detail the case that the hyperplane is of the type z=constant. Particles can cross such a hyperplane in either direction, so it proves convenient to introduce an indefinite metric, and correspondingly a sesquilinear inner product with non-Hilbert space structure, for the space of quantum states on such a surface. >... A detailed formalism for computing average crossing times on a z=constant hyperplane, and average dwell times and delay times for a zone of interaction between a pair of z=constant hyperplanes, is presented.Comment: 31 pages, no figures. Differs from published version by minor corrections and additions, and two citation

Chern - Simons Gauge Field Theory of Two - Dimensional Ferromagnets

A Chern-Simons gauged Nonlinear Schr\"odinger Equation is derived from the continuous Heisenberg model in 2+1 dimensions. The corresponding planar magnets can be analyzed whithin the anyon theory. Thus, we show that static magnetic vortices correspond to the self-dual Chern - Simons solitons and are described by the Liouville equation. The related magnetic topological charge is associated with the electric charge of anyons. Furthermore, vortex - antivortex configurations are described by the sinh-Gordon equation and its conformally invariant extension. Physical consequences of these results are discussed.Comment: 15 pages, Plain TeX, Lecce, June 199

Retrospective Data Filter

In a target detection communication system, apparatus and method for determining the presence of probable targets based on contacts (which can indicate the presence of a target, noise, chatter, or objects not of interest) detected within a predefined position sector or sectors over a specified number of scans. The position of each detected contact, as a contact of interest, is compared with the positions of contacts detected at previous times or scans. Velocity profiles indicate which previous contacts support the likelihood that the contact of interest represents a target having a velocity within a defined band. The likelihood, which can be represented by a quality value, may be a function of number of contacts, timing of contacts, or both the number and timing of contacts in a given velocity profile. A preselected threshold value, which is related to false alarm rate, is compared to the most likely, or highest quality, velocity profile associated with a contact of interest. If the highest quality value exceeds the threshold value, an output is provided indicating that the contact of interest represents a probable target having a velocity within the band defined by the highest quality velocity profile

Superposition in nonlinear wave and evolution equations

Real and bounded elliptic solutions suitable for applying the Khare-Sukhatme superposition procedure are presented and used to generate superposition solutions of the generalized modified Kadomtsev-Petviashvili equation (gmKPE) and the nonlinear cubic-quintic Schroedinger equation (NLCQSE).Comment: submitted to International Journal of Theoretical Physics, 23 pages, 2 figures, style change