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Time Domain Spectral LiDAR Enabled by Cascaded Raman in a Hydrogen-filled Transmitter
Get PDFWe introduce what we believe to be novel spectral light detection and ranging (LiDAR) architectures that enable ultra-compact systems by a transition from spectral signal processing in space (gratings) to processing in time. The architectures leverage temporal dispersion and the unique spectro-temporal waveforms produced from the cascaded Raman scattering generated in the (H2) filled hollow core fiber. The characterized Raman source yields as many as six Raman orders from 1.06-1.70 μm; their unique spectro-temporal waveforms are measured. System performance simulations based on measured Raman waveforms show that high accuracy measurement of range and reflectivity are possible with proper selection of signal-to-noise ratio and detector bandwidth. Materials classification analysis based on the system performance analysis shows that near-optimal classification is feasible with time domain processing
Advanced Integration of 3D Optomechanical Sensor Microsystems with Optical Fibers
No full textThe ever-increasing demand for affordable, compact, and integrated sensors necessitates innovations that outperform traditional, bulkier counterparts. This paper introduces an advanced integration of 3D optomechanical sensor microsystems with optical fibers, using a two-photon nanomachining process. This technique enables the fabrication of complex 3D structures, including dynamic and movable features, unattainable through conventional photolithography. We present sensor microsystems incorporating resonant and non-resonant cavities, demonstrating exceptional sensitivity and operational range. The resonant microsensors offer heightened sensitivity to environmental conditions, while the non-resonant counterparts use rotating reflective microblades for precise flow sensing. Utilizing optical fiber as the substrate, these sensors transmit detected information in real-time to remote locations with minimal loss, eliminating the need for additional packaging, amplifiers, signal processing, and data transmission components. This innovative integration promises a new generation of highly sensitive, compact, and versatile sensor systems, ideal for contemporary engineering applications. Abstract © IEEE
Improved Methods for Distribution Identification and Regression Parameter Estimation in a Satellite Reliability Application. IEEE Transactions on Reliability, 1–13
No full textSun-Earth debris study, Part 2: Preliminary investigation of debris-induced spacecraft survivability risks near the Sun-Earth collinear Lagrange points
No full textExcerpt: In the past two years of 2023-2024, two space vehicles were inserted into orbits about Sun-Earth Lagrange points, joining eight other spacecraft about the L1 and L2 points. As interest in these points grows and become more populated, the chance for artificial space debris to inflict hazard on the region increases. The Circular Restricted Three-Body Problem (CR3BP) may be used to propagate the motion of debris in the region, and this paper investigates the risks associated with a catastrophic spacecraft breakup occurring in currently used or planned orbits about the Sun-Earth L1 and L2 points
Decomposing a Renewable Energy Design and Dispatch Model
No full textExcerpt: We address a mixed-integer linear programming model which selects a cost-minimizing set of available technologies with which to design a renewable energy system and prescribe their associated dispatch decisions. Realistically sized instances of such models pose computational challenges. To this end, we develop a Lagrangian heuristic based on a decomposition methodology which partitions the model into blocks and optimizes these more manageable, smaller subproblems
Superconducting Ring Array Pattern Modeling, Characterization, and Propagation for Microwave Through Terahertz Frequencies
No full textIn recent work, we have demonstrated the capability of directional beam forming in the microwave portion of the electromagnetic spectrum using linear superconducting ring arrays, triggered by an ultra-fast laser pulse. This paper extends these developments by presenting modeling of microwave radiation patterns covering the entire four pi steradian sphere, and outlining an experimental plan for detailed characterization of planar arrays. Experimental data is compared with the simulations conducted in this study, showing good agreement that builds confidence for further work. Planned research is presented to include array design optimizations for varying frequencies into the THz region. Additional research will include experimental and computational investigation of THz propagation using previously developed laser atmospheric propagation software. If successful, the numerical models used could prove beneficial in predicting real time absorption characteristics
Flight Dynamics Issues of Control Coupling / Inertia Coupling Prone High-Speed Aircraft
No full textExcerpt: The authors developed a nonlinear, time-domain aircraft flight simulation program to determine the transient, open-loop response of the Bell X-1A Aircraft. With this tool, we demonstrated the response of the X-1A to aileron inputs at select points in its flight envelope
An assessment of the energy balance Bowen ratio method to quantify optical turbulence in the maritime environment
No full textAn Experimental and Computational Investigation of Ranque–Hilsch Vortex Tube Heat Transfer Characteristics
No full textRanque–Hilsch vortex tubes have the extraordinary ability to split an incoming stream of fluid into two streams—one with a lower absolute total temperature than the incoming flow and the other with greater total temperature. The physical mechanism involves inducing an intense swirl of the flow down the length of the tube. The warmer flow exits around the periphery at the end of the tube, while the cooler central flow changes direction within the core and exits the opposite end. While much research has focused on the physical mechanisms of the energy separation, relatively little attention has been paid to the heat transfer behavior should a heat flux be applied to the walls. In the present work, experiments were performed using a vortex tube with air and varying levels of heat addition, up to approximately 15 kW/m2. Companion computational experiments were performed that allowed the determination of axially resolved Nusselt number distributions, the first of their kind for vortex tube flows. A notable finding is that the vast majority of heat added to the vortex tube flow remains within the hot stream; i.e., the cold stream experiences relatively little temperature rise due to the heat addition. For example, even when only 30% of the flow exits the hot side of the tube, it retains more than 80% of the heat added to the flow. Additionally, a modified swirl number was also defined that was found to scale the Nusselt number augmentation across the two different total flowrates examined presently
Design Considerations for the Use of the Julia Programming Language in Future Quantum Networking Simulation Software
Get PDFGiven the prevalence of Python-based packages in the existing quantum network simulation ecosystem, we attempt to assess what might be realistically gained by switching to Julia. We focus our experimental activities on three areas: 1) surveying the characteristics of Julia as they tie into robust framework development, 2) presenting benchmarks that compare Julia and Python with respect to elements of possible simulation workloads, and 3) producing a tangible lightweight Julia architecture for modeling components in a manner similar to SeQUeNCe. Our analysis suggests that while Julia does o.er performance advantages over Python over certain workloads, knowing the reasons for why and when it does not deliver necessitates an understanding of the at-times complex dance between type-stability and code generality