Two-axis bend measurement with Bragg gratings in multicore optical fiber

We describe what is to our knowledge the first use of fiber Bragg gratings written into three separate cores of a multicore fiber for two-axis curvature measurement. The gratings act as independent, but isothermal, fiber strain gauges for which local curvature determines the difference in strain between cores, permitting temperature-independent bend measurement. (C) 2003 Optical Society of America

EQUILIBRIUM MODE DISTRIBUTION IN W-TYPE GLASS OPTICAL FIBERS

Power flow equation is used to calculate equilibrium mode distribution in W-type glass optical fibers. It has been shown how the coupling length for achieving the equilibrium mode distribution in W-type glass optical fibers varies with the depth and width of the intermediate layer and coupling strength for different widths of launch beam distribution. W-type optical fibers have shown effectiveness in reducing modal dispersion and bending loss.Power flow equation is used to calculate equilibrium mode distribution in W-type glass optical fibers. It has been shown how the coupling length for achieving the equilibrium mode distribution in W-type glass optical fibers varies with the depth and width of the intermediate layer and coupling strength for different widths of launch beam distribution. W-type optical fibers have shown effectiveness in reducing modal dispersion and bending loss

Plastic Optical Fiber Displacement Sensor Based on Dual Cycling Bending

In this study, a high sensitivity and easy fabricated plastic optical fiber (POF) displacement sensor is proposed. A POF specimen subjected to dual cyclic bending is used to improve the sensitivity of the POF displacement sensor. The effects of interval between rollers, relative displacement and number of rollers on the sensitivity of the displacement sensor are analyzed both experimentally and numerically. A good agreement between the experimental measurements and numerical calculations is obtained. The results show that the interval between rollers affects sensitivity most significantly than the other design parameters. Based on the experimental data, a linear equation is derived to estimate the relationship between the power loss and the relative displacement. The difference between the estimated results and the experimental results is found to be less than 8%. The results also show that the proposed POF displacement sensor based on dual cyclic bending can be used to detect displacement accurately

Phenomenological description of the microwave surface impedance and complex conductivity of high-TcT_c single crystals

Measurements of the microwave surface impedance $Z_s(T)=R_s(T)+iX_s(T)$ and of the complex conductivity $\sigma_s(T)$ of high-quality, high-$T_c$ single crystals of YBCO, BSCCO, TBCCO, and TBCO are analyzed. Experimental data of $Z_s(T)$ and $\sigma_s(T)$ are compared with calculations based on a modified two-fluid model which includes temperature-dependent quasiparticle scattering and a unique temperature variation of the density of superconducting carriers. We elucidate agreement as well as disagreement of our analysis with the salient features of the experimental data. Existing microscopic models are reviewed which are based on unconventional symmetry types of the order parameter and on novel mechanisms of quasiparticle relaxation.Comment: 15 pages, 17 figures, 1 tabl

LDRD project final report : hybrid AI/cognitive tactical behavior framework for LVC.

This Lab-Directed Research and Development (LDRD) sought to develop technology that enhances scenario construction speed, entity behavior robustness, and scalability in Live-Virtual-Constructive (LVC) simulation. We investigated issues in both simulation architecture and behavior modeling. We developed path-planning technology that improves the ability to express intent in the planning task while still permitting an efficient search algorithm. An LVC simulation demonstrated how this enables 'one-click' layout of squad tactical paths, as well as dynamic re-planning for simulated squads and for real and simulated mobile robots. We identified human response latencies that can be exploited in parallel/distributed architectures. We did an experimental study to determine where parallelization would be productive in Umbra-based force-on-force (FOF) simulations. We developed and implemented a data-driven simulation composition approach that solves entity class hierarchy issues and supports assurance of simulation fairness. Finally, we proposed a flexible framework to enable integration of multiple behavior modeling components that model working memory phenomena with different degrees of sophistication

Understanding communication in counterterrorism crisis management.

This report describes the purpose and results of the two-year, Sandia-sponsored Laboratory Directed Research and Development (LDRD) project entitled Understanding Communication in Counterterrorism Crisis Management The purpose of this project was to facilitate the capture of key communications among team members in simulated training exercises, and to learn how to improve communication in that domain. The first section of this document details the scenario development aspects of the simulation. The second section covers the new communication technologies that were developed and incorporated into the Weapons of Mass Destruction Decision Analysis Center (WMD-DAC) suite of decision support tools. The third section provides an overview of the features of the simulation and highlights its communication aspects. The fourth section describes the Team Communication Study processes and methodologies. The fifth section discusses future directions and areas in which to apply the new technologies and study results obtained as a result of this LDRD

Investigations on the Mechanical Properties of Conducting Polymer Coating-Substrate Structures and Their Influencing Factors

This review covers recent advances and work on the microstructure features, mechanical properties and cracking processes of conducting polymer film/coating- substrate structures under different testing conditions. An attempt is made to characterize and quantify the relationships between mechanical properties and microstructure features. In addition, the film cracking mechanism on the micro scale and some influencing factors that play a significant role in the service of the film-substrate structure are presented. These investigations cover the conducting polymer film/coating nucleation process, microstructure-fracture characterization, translation of brittle-ductile fractures, and cracking processes near the largest inherent macromolecule defects under thermal-mechanical loadings, and were carried out using in situ scanning electron microscopy (SEM) observations, as a novel method for evaluation of interface strength and critical failure stress

Tool for Planetary Probe Payload Sensor System Integration

This presentation was part of the session : Poster SessionsSixth International Planetary Probe WorkshopDetermination of instrumentation for interplanetary science mission is an involved, complex procedure. A final design solution is achieved at the end of this often lengthy process. The analysis methodology performed within this work investigates mission requirements and generates a mission sensor package using design engineering relations. Given the broad science goals for an interplanetary science mission, the specific scientific measurements required can be determined. From the objectives the required measurements flow down, leading to an overall mission design. The mission design drives the instrumentation requirements and influences the selection of components for the mission. Components are chosen to meet mission requirements, creating an initial sensor package design. Trade studies are performed at component levels. Designs iterate on initial concepts and options are evaluated until a final design is determined. A tool for in-situ measurements is developed using systems engineering design relations to deliver a sensor payload configuration starting from the initial mission concept and the specific measurement objectives. Design of the sensor payload package for any mission is a combination of different aspects. The final design is a result of individual case studies at the component level and design engineering studies at a system level. Human decision elements are included in the design process, and final selection between competing components is made. The decision to use one flight hardware component over another can arise from many factors - functionality, heritage, Technology Readiness Level (TRL), compatibility, etc. The objective of this work is to combine selection techniques for mission hardware, based on optimization studies with engineering judgment, into a single tool that can be used to generate a preliminary sensor package configuration for planetary missions. A tool for in-situ measurements is developed using systems engineering design relations to deliver a sensor payload configuration starting from the initial mission objectives and the specific measurement types. The In-Situ Sensor Payload Optimization Tool (ISSPO) consists of a number of individual sensor modules, based on commercially available and space-rated components, and programs to determine the required components. Information on the desired mission location and types of science data to be returned, along with payload limits, are entered into the main program. For each sensor type available within the database, a corresponding module is executed and supplied information on the planetary location and additional sensor requirements. Selection of the final sensor is made based on operational ranges and required performance limits. Logic checks determine whether the sensor package meets or exceeds the mission limits, or if another combination of components would provide a viable solution with some requirement tradeoff. The resulting sensor package represents a preliminary sensor package capable of answering the mission's science requirements