1,932 research outputs found

    A Proposal for a Three Detector Short-Baseline Neutrino Oscillation Program in the Fermilab Booster Neutrino Beam

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    A Short-Baseline Neutrino (SBN) physics program of three LAr-TPC detectors located along the Booster Neutrino Beam (BNB) at Fermilab is presented. This new SBN Program will deliver a rich and compelling physics opportunity, including the ability to resolve a class of experimental anomalies in neutrino physics and to perform the most sensitive search to date for sterile neutrinos at the eV mass-scale through both appearance and disappearance oscillation channels. Using data sets of 6.6e20 protons on target (P.O.T.) in the LAr1-ND and ICARUS T600 detectors plus 13.2e20 P.O.T. in the MicroBooNE detector, we estimate that a search for muon neutrino to electron neutrino appearance can be performed with ~5 sigma sensitivity for the LSND allowed (99% C.L.) parameter region. In this proposal for the SBN Program, we describe the physics analysis, the conceptual design of the LAr1-ND detector, the design and refurbishment of the T600 detector, the necessary infrastructure required to execute the program, and a possible reconfiguration of the BNB target and horn system to improve its performance for oscillation searches.Comment: 209 pages, 129 figure

    Incorporation of feed-network and circuit modeling into the time-domain finite element analysis of antenna arrays and microwave circuits

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    In this dissertation, accurate and efficient numerical algorithms are developed to incorporate the feed-network and circuit modeling into the time-domain finite element analysis of antenna arrays and microwave circuits. First, simulation of an antenna system requires accurate modeling of interactions between the radiating elements and the associated feeding network. In this work, a feed network is represented in terms of its scattering matrix in a rational function form in the frequency domain that enables its interfacing with the time-domain finite element modeling of the antenna elements through a fast recursive time-convolution algorithm. The exchange of information between the antenna elements and the feed network occurs through the incident and reflected modal voltages/currents at properly defined port interfaces. The proposed numerical scheme allows a full utilization of the advanced antenna simulation techniques, and significantly extends the current antenna modeling capability to the system level. Second, a hybrid field-circuit solver that combines the capabilities of the time-domain finite element method and a lumped circuit analysis is developed for accurate and efficient characterization of complicated microwave circuits that include both distributive and lumped-circuit components. The distributive portion of the device is modeled by the time-domain finite element method to generate a finite element subsystem, while the lumped circuits are analyzed by a SPICE-like circuit solver to generate a circuit subsystem. A global system for both the finite-element and circuit unknowns is established by combining the two subsystems through coupling matrices to model their interactions. For simulations of even more complicated mixed-scale circuit systems that contain pre-characterized blocks of discrete circuit elements, the hybrid field-circuit analysis implemented a systematic and efficient algorithm to incorporate multiport lumped networks in terms of frequency-dependent admittance matrices. Other advanced features in the hybrid field-circuit solver include application of the tree-cotree splitting algorithm and introduction of a flexible time-stepping scheme. Various numerical examples are presented to validate the implementation and demonstrate the accuracy, efficiency, and applications of the proposed numerical algorithms

    Healthy and open phase PMaSynRM model based on virtual reluctance concept

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    © 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The trend in the industrial power electronics electrical drives is to reach high power density and high efficiency in variable load conditions at cost-effective unwasteful designs. Currently, motors with permanent magnets (such as IPMSM and PMaSynRM) are of great interest because of compactness, low losses, and high torque capability. The performance of a drive system can be predicted with a motor electromagnetic authentic nonlinear model. In this paper, a novel, fast, and precise motor model of PMaSynRM based on virtual reluctance (VR) is proposed. It takes into account the cross saturation, winding distribution, space harmonics, slotting effect, and stepped skewing. The virtual reluctances are identified by finite element analysis (FEA) and implemented in the time-stepping simulation. The flux inversion is not required. The proposed concept is useful in the rotating field or phase quantities (for open phase simulation). The model is also discretized for SiL and HiL applications. Finally, the validation in FEA and experimental setup was performed.This work was supported in part by Spanish Ministry of Economy and Competitiveness under TRA2016-80472-R Research Project and Secretaria d’Universitats i Recerca del Departament d’Empresa i Coneixement de la Generalitat de Catalunya under 2017SGR967.Peer ReviewedPostprint (author's final draft

    High-resolution broadband spectroscopy using externally dispersed interferometry at the Hale telescope: part 2, photon noise theory

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    High-resolution broadband spectroscopy at near-infrared (NIR) wavelengths (950 to 2450 nm) has been performed using externally dispersed interferometry (EDI) at the Hale telescope at Mt. Palomar, with the TEDI interferometer mounted within the central hole of the 200-in. primary mirror in series with the comounted TripleSpec NIR echelle spectrograph. These are the first multidelay EDI demonstrations on starlight. We demonstrated very high (10×) resolution boost and dramatic (20× or more) robustness to point spread function wavelength drifts in the native spectrograph. Data analysis, results, and instrument noise are described in a companion paper (part 1). This part 2 describes theoretical photon limited and readout noise limited behaviors, using simulated spectra and instrument model with noise added at the detector. We show that a single interferometer delay can be used to reduce the high frequency noise at the original resolution (1× boost case), and that except for delays much smaller than the native response peak half width, the fringing and nonfringing noises act uncorrelated and add in quadrature. This is due to the frequency shifting of the noise due to the heterodyning effect. We find a sum rule for the noise variance for multiple delays. The multiple delay EDI using a Gaussian distribution of exposure times has noise-to-signal ratio for photon-limited noise similar to a classical spectrograph with reduced slitwidth and reduced flux, proportional to the square root of resolution boost achieved, but without the focal spot limitation and pixel spacing Nyquist limitations. At low boost (∼1×) EDI has ∼1.4× smaller noise than conventional, and at >10× boost, EDI has ∼1.4× larger noise than conventional. Readout noise is minimized by the use of three or four steps instead of 10 of TEDI. Net noise grows as step phases change from symmetrical arrangement with wavenumber across the band. For three (or four) steps, we calculate a multiplicative bandwidth of 1.8:1 (2.3:1), sufficient to handle the visible band (400 to 700 nm, 1.8:1) and most of TripleSpec (2.6:1)

    Full-field vibrometry by high-speed digital holography for middle-ear mechanics

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    Hearing loss affects approximately 1 in 10 people in the world and this percentage is increasing every year. Some of the most common causes of hearing loss are disorders of the middle-ear. Early detection and diagnosis of hearing loss as well as research to understand the hearing processes depend on medical and research tools for quantification of hearing capabilities and the function of the middle-ear in the complex acousto-mechanical transformation of environmental sounds into vibrations of the middle-ear, particular of the human tympanic membrane (TM or eardrum). Current ear exams assess the state of a patient’s hearing capabilities mainly based on qualitative evaluation of the healthiness of the TM. Existing quantitative clinical methods for description of the motion of the TM are limited to either average acoustic estimates (admittance or reflectance) or single-point displacement measurements. Such methods could leave examiners and researchers blind to the complex spatio-temporal response of the nanometer scale displacements of the entire TM. Current state-of-the-art medical research tools provide full-field nanometer displacement measurements of the surface of the human TM excited by steady state (tonal) stimuli. However, to fully understand the mechanics of hearing, and the complex acousto-mechanical characteristics of TM in particular, new tools are needed for full-field high-speed characterization of the nanometer scale displacements of the human TM subjected to impulse (wideband) acoustic excitation. This Dissertation reports the development of a new high-speed holographic system (HHS) for full-field nanometer transient (i.e., \u3e 10 kHz) displacement measurement of the human middle-ear and the tympanic membrane, in particular. The HHS allows spatial (i.e., \u3e500k data points) and temporal (i.e., \u3e 40 kHz) resolutions that enable the study of the acoustical and mechanical characteristics of the middle-ear at a level of detail that have never been reached before. The realization of the HHS includes the development and implementation of novel phase sampling and acquisition approaches that allow the use of state-of-the-art high-resolution (i.e., \u3e5 MP) and high-speed (\u3e 80,000 fps) cameras through modular and expandable control architectures. The development of novel acquisition approaches allows the use of conventional speed (i.e., \u3c20 fps) cameras to realize high-temporal resolutions (i.e., \u3c15 us) at equivalent sampling rates of \u3e 50,000 fps with minimum hardware cost and modifications. The design and implementation of novel spatio-temporal phase sampling methods utilize the high temporal resolution (i.e., \u3c 5 us exposure) and frame rate (i.e., \u3e80,000 fps) of high-speed cameras without imposing constraints on their spatial resolution (i.e., \u3e20 um pixel size). Additionally, the research and in-vivo applications capabilities of the HHS are extended through the development and implementation of a holographic otoscope head (OH) and a mechatronic otoscope positioner (MOP). The large (i.e., \u3e 1 GB with \u3e 8x10^9 parameters) spatio-temporal data sets of the HHS measurements are automatically processed by custom parallel data mining and interpretation (PDMI) methods, which allow automatic quantification of medically relevant motion parameters (MRMPs), such as modal frequencies, time constants, and acoustic delays. Such capabilities could allow inferring local material properties across the surface of the TM. The HHS is a new medical tool that enables otologists to improve the quality of diagnosis and treatments as well as provides researchers with spatio-temporal information of the hearing process at a level of detail never reached before

    One-sided smoothness-increasing accuracy-conserving filtering for enhanced streamline integration through discontinuous fields

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    The discontinuous Galerkin (DG) method continues to maintain heightened levels of interest within the simulation community because of the discretization flexibility it provides. One of the fundamental properties of the DG methodology and arguably its most powerful property is the ability to combine high-order discretizations on an inter-element level while allowing discontinuities between elements. This flexibility, however, generates a plethora of difficulties when one attempts to use DG fields for feature extraction and visualization, as most post-processing schemes are not designed for handling explicitly discontinuous fields. This work introduces a new method of applying smoothness-increasing, accuracy-conserving filtering on discontinuous Galerkin vector fields for the purpose of enhancing streamline integration. The filtering discussed in this paper enhances the smoothness of the field and eliminates the discontinuity between elements, thus resulting in more accurate streamlines. Furthermore, as a means of minimizing the computational cost of the method, the filtering is done in a one-dimensional manner along the streamline.United States. Army Research Office (Grant no. W911NF-05-1-0395)National Science Foundation (U.S.) (Career Award NSF-CCF0347791

    Development of convective reflow-projection moire warpage measurement system and prediction of solder bump reliability on board assemblies affected by warpage

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    Out-of-plane displacement (warpage) is one of the major thermomechanical reliability concerns for board-level electronic packaging. Printed wiring board (PWB) and component warpage results from CTE mismatch among the materials that make up the PWB assembly (PWBA). Warpage occurring during surface-mount assembly reflow processes and normal operations may cause serious reliability problems. In this research, a convective reflow and projection moire warpage measurement system was developed. The system is the first real-time, non-contact, and full-field measurement system capable of measuring PWB/PWBA/chip package warpage with the projection moire technique during different thermal reflow processes. In order to accurately simulate the reflow process and to achieve the ideal heating rate, a convective heating system was designed and integrated with the projection moire system. An advanced feedback controller was implemented to obtain the optimum heating responses. The developed system has the advantages of simulating different types of reflow processes, and reducing the temperature gradients through the PWBA thickness to ensure that the projection moire system can provide more accurate measurements. Automatic package detection and segmentation algorithms were developed for the projection moire system. The algorithms are used for automatic segmentation of the PWB and assembled packages so that the warpage of the PWB and chip packages can be determined individually. The effect of initial PWB warpage on the fatigue reliability of solder bumps on board assemblies was investigated using finite element modeling (FEM) and the projection moire system. The 3-D models of PWBAs with varying board warpage were used to estimate the solder bump fatigue life for different chip packages mounted on PWBs. The simulation results were validated and correlated with the experimental results obtained using the projection moire system and accelerated thermal cycling tests. Design of experiments and an advanced prediction model were generated to predict solder bump fatigue life based on the initial PWB warpage, package dimensions and locations, and solder bump materials. This study led to a better understanding of the correlation between PWB warpage and solder bump thermomechanical reliability on board assemblies.Ph.D.Committee Chair: Dr. Ume, I. Charles; Committee Member: Dr. Book, Wayne; Committee Member: Dr. Kim, Yeong; Committee Member: Dr. Pan, Jiahui; Committee Member: Dr. Sitaraman, Suresh; Committee Member: Dr. Wu, C. F. Jef

    Examination of nanosecond laser melting thresholds in refractory metals by shear wave acoustics

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    Nanosecond laser pulse-induced melting thresholds in refractory (Nb, Mo, Ta and W) metals are measured using detected laser-generated acoustic shear waves. Obtained melting threshold values were found to be scaled with corresponding melting point temperatures of investigated materials displaying dissimilar shearing behavior. The experiments were conducted with motorized control of the incident laser pulse energies with small and uniform energy increments to reach high measurement accuracy and real-time monitoring of the epicentral acoustic waveforms from the opposite side of irradiated sample plates. Measured results were found to be in good agreement with numerical finite element model solving coupled elastodynamic and thermal conduction governing equations on structured quadrilateral mesh. Solid-melt phase transition was handled by means of apparent heat capacity method. The onset of melting was attributed to vanished shear modulus and rapid radial molten pool propagation within laser-heated metal leading to preferential generation of transverse acoustic waves from sources surrounding the molten mass resulting in the delay of shear wave transit times. Developed laser-based technique aims for applications involving remote examination of rapid melting processes of materials present in harsh environment (e.g. spent nuclear fuels) with high spatio-temporal resolution. © 2017 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). [http://dx.doi.org/10.1063/1.4993591
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