Search Results

Advanced search parameters have been applied.
open access

Technique for Estimating the Magnitude and Frequency of Floods in Texas

Description: Abstract: Drainage area, slope, and mean annual precipitation were the only factors that were statistically significant at the 95-percent confidence level when the characteristics of the drainage basins were used as independent variables in a multiple-regression flood-frequency analysis of natural, unregulated streams in Texas. The State was divided into six regions on the basis of the distribution of the residuals from a single statewide regression of the 10-year flood. Equations were develope… more
Date: 1977
Creator: Schroeder, E. E & Massey, B. C.
Partner: UNT Libraries Government Documents Department
open access

Techniques for Estimating Magnitude and Frequency of Floods in South Carolina

Description: Information is presented for estimating the magnitude and frequency of floods on streams in South Carolina. Flood-frequency characteristics for 151 gaging stations were related to basin characteristics by multiple regression techniques for each of four physiographic provinces. Equations were derived to estimate flood magnitudes at recurrence intervals ranging from 2 to 100 years on streams with drainage areas greater than 1.0 square mile. Examples demonstrate the procedure for computing flood-f… more
Date: February 1982
Creator: Whetstone, Benjamin H.
Partner: UNT Libraries Government Documents Department
open access

A New Principle of Sound Frequency Analysis

Description: "In connection with the study of aircraft and propeller noises, the National Advisory Committee for Aeronautics has developed an instrument for sound-frequency analysis which differs fundamentally from previous types, and which, owing to its simplicity of principle, construction, and operation, has proved to be of value in this investigation. The method is based on the well-known fact that the Ohmic loss in an electrical resistance is equal to the sum of the losses of the harmonic components of… more
Date: March 23, 1931
Creator: Theodorsen, Theodore
Partner: UNT Libraries Government Documents Department
open access

Magnitude and Frequency of Floods in Small Drainage Basins in Idaho

Description: Abstract: A method which relates basin characteristics with peak flow characteristics is presented for determining magnitude and frequency of floods on streams with drainage areas between 0.5 and 200 square miles. Regression equations for each of eight regions are presented for determination of the 10-year flood. Peak flows for the 25- and 50-year floods can then be estimated from ratios developed for each region. Regression equations are not developed because of poor definitions for several ar… more
Date: April 1973
Creator: Thomas, C. A.; Harenberg, W. A. & Anderson, J. M.
Partner: UNT Libraries Government Documents Department
open access

Stream Reconnaissance for Nutrients and Other Water-Quality Parameters, Greater Pittsburgh Region, Pennsylvania

Description: Abstract: Eighty-five stream sites in and near the six-county Greater Pittsburgh Region were sampled in mid-June 1971 and again in mid-October 1972. Concentrations of inorganic nitrogen, organic carbon, or phosphorus were high enough to indicate potential problems at about a quarter of the sampling sites. Temperature, dissolved oxygen, and pH values indicated a generally favorable capacity for recovery from degradation, although a number of streams east of the Allegheny and Monongahela Rivers a… more
Date: February 1975
Creator: Beall, Robert M.
Partner: UNT Libraries Government Documents Department
open access

Techniques for Estimating Magnitude and Frequency of Floods on Rural Unregulated Streams in New York State Excluding Long Island

Description: Abstract: Techniques are presented for estimating the magnitude and frequency of floods at ungaged sites on unregulated rural streams in New York, excluding Long Island. Discharge-frequency data and basin characteristics of 220 gaging stations in New York and adjacent states were used in multiple linear regression analysis to develop equations for floods that range in recurrence interval from 2 to 100 years. Separate equations were developed for northern, southeastern, and western regions of Ne… more
Date: July 1979
Creator: Zembrzuski, Thomas J., Jr. & Dunn, Bernard
Partner: UNT Libraries Government Documents Department
open access

XAPiir: A recursive digital filtering package

Description: XAPiir is a basic recursive digital filtering package, containing both design and implementation subroutines. XAPiir was developed for the experimental array processor (XAP) software package, and is written in FORTRAN. However, it is intended to be incorporated into any general- or special-purpose signal analysis program. It replaces the older package RECFIL, offering several enhancements. RECFIL is used in several large analysis programs developed at LLNL, including the seismic analysis packag… more
Date: September 21, 1990
Creator: Harris, David
Partner: UNT Libraries Government Documents Department
open access

Evaluation of Tektronix (2 gigasample/second) Digital Signal Analyzer DSA 602

Description: The results of evaluating the Tektronix (2 gigasample/second) Digital Analyzer DSA 602 is discussed. Evaluations were done using both the 11A52 and 11A72 amplifier modules. Effective bits tests were run from 2 MHz to 1 GHz. Timing tests were done to verify repeatability of triggering. Baseline data were taken to determine noise levels. Pulse testing was done to determine overdrive recoverability. The stability of the internal calibration was verified. TDR tests were done to determine what refle… more
Date: January 1, 1990
Creator: Graves, Tom
Partner: UNT Libraries Government Documents Department
open access

Finding Cryptography in Object Code

Description: Finding and identifying Cryptography is a growing concern in the malware analysis community. In this paper, a heuristic method for determining the likelihood that a given function contains a cryptographic algorithm is discussed and the results of applying this method in various environments is shown. The algorithm is based on frequency analysis of opcodes that make up each function within a binary.
Date: October 1, 2008
Creator: Wright, Jason L.
Partner: UNT Libraries Government Documents Department
open access

Lg excitation, attenuation, and source spectral scaling in central and eastern North America

Description: Seismic moments and corner frequencies were obtained for many earthquakes in the central and eastern United States, and for a few events in the western United States, using the Lg phase and a recently developed inversion algorithm. Additionally, Q values for the Lg phase along paths to individual stations were obtained simultaneously with the source parameters. Both corner frequencies and magnitudes were found to vary systematically with moment. For moments between 0.15 and 400 x 10{sup 15} N-m… more
Date: October 1, 1997
Creator: Mitchell, B.J.; Xie, J. & Baqer, S.
Partner: UNT Libraries Government Documents Department
open access

Femtosecond Coherent Spectroscopy at 800nm: MI-FROG Measures High-Field Ionization Rates in Gases

Description: The authors report the first quantitative phase-sensitive measurement of ultrafast ionization rates in gases using Multi-phase Interferometric Frequency-Resolved Optical Gating. Ultrafast probe depletion via frequency mixing in the ionization front is observed.
Date: May 24, 1999
Creator: Siders, C. W.; Siders, J. L. W. & Taylor, A. J.
Partner: UNT Libraries Government Documents Department
open access

Statistical damage identification techniques applied to the I-40 bridge over the Rio Grande River

Description: The statistical significance of vibration-based damage identification parameters is studied via application to the data from the tests performed on the Interstate 40 highway bridge in Albuquerque, New Mexico. A test of statistical significance is applied to the mean and confidence interval estimates of the modal properties and the corresponding damage indicators. The damage indicator used in this study is the change in the measured flexibility matrix. Previously presented deterministic results … more
Date: March 1, 1998
Creator: Doebling, S.W. & Farrar, C.R.
Partner: UNT Libraries Government Documents Department
open access

Stability analysis of a variable-speed wind turbine

Description: This paper examines the elastomechanical stability of a four-bladed wind turbine over a specific rotor speed range. Stability modes, frequencies, and dampings are extracted using a specialized modal processor developed at NREL that post-processes the response data generated by the ADAMS simulation code. The processor can analyze a turbine with an arbitrary number of rotor blades and offers a novel capability of isolating stability modes that become locked at a single frequency. Results indicate… more
Date: October 1, 1996
Creator: Bir, G. S.; Wright, A. D. & Butterfield, C. P.
Partner: UNT Libraries Government Documents Department
open access

Application of frequency map analysis to the ALS

Description: Frequency map analysis is a numerical method based on Fourier techniques which provides a clear representation of the global dynamics of many multi-dimensional systems, and which is particularly useful for systems of 3 degrees of freedom and more. The frequency dependence with time also allows refined estimates of the diffusion of the orbits. Here are presented the theoretical foundation of the method, and some applications to the Advanced Light Source, demonstrating how frequency map analysis … more
Date: January 1, 1996
Creator: Laskar, J. & Robin, D.
Partner: UNT Libraries Government Documents Department
open access

Measurement of Non-Linearities Using Spectrum Analysis of Driven Betatron Oscillation

Description: Resonance driving terms can be derived from the frequency analysis of turn-by-turn betatron oscillation data. This paper demonstrates that the same information can also be drawn from the spectral analysis of a driven oscillation adiabatically excited by an rf dipole. The advantage of this method is that a large betatron oscillation amplitude can be sustained without loosing the coherence signal. The frequency spectrum of the driven oscillation is composed of multiples of the rf dipole modulatio… more
Date: June 18, 2001
Creator: Bai, M.; Blaskiewicz, M.; Lehrach, A.; Roser, T.; Schmidt, F. & Van Asselt, W.
Partner: UNT Libraries Government Documents Department
open access

Choppertron II

Description: We present experimental results of a version of the Choppertron microwave generator designed to work with the high emittance beam of the Advanced Test Accelerator (ATA). Simulations showed that a 800-A, 120 {pi} cm-mrad beam (typical of ATA), could produce 800 MW of rf (11.4 GHz) power using two 12-cell, traveling-wave output structures. Funding contraints prevented final tuning of the modulator system and limited the experiment to 530 MW in narrow pulses. Over 400 MW were extracted from a sing… more
Date: April 25, 1995
Creator: Houck, T.L.; Westenskow, G.A.; Haimson, J. & Mecklenburg, B.
Partner: UNT Libraries Government Documents Department
open access

Center for Extended Magnetohydrodynamic Modeling (CEMM) University of Utah SAPP 2007 Final Status Report

Description: During the third and final period of this grant, our goal was to refine the algorithmic approaches used to detect and visualize magnetic islands and their corresponding null points within both the NIMROD and M3D data sets. We refined our geometric approach, which gave a greater confidence in the accuracy of the Poincareplots created. The final results are best demonstrated through Figures 2-6 attached to the report. Technical details this work was reported in both the Physics and Visualization … more
Date: December 4, 2007
Creator: Sanderson, Allen R. & Johnson, Christopher R.
Partner: UNT Libraries Government Documents Department
open access

Nonlinear frequency analysis of porous Bi directional functionally graded beams utilizing reddy shear deformation theory

Description: Article describes how the nonlinear frequency response of bi-directional functionally graded porous beams experienced range of various end conditions is investigated in this work. The findings are presented to aid in future research into the effects of various gradient indices, vibration amplitude ratios, porosity coefficients, shear and elastic substrate parameters, boundary conditions, and vibration frequencies on the bi-directional functionally graded beams.
Date: September 3, 2023
Creator: Forghani, Mohammadamin; Bazarganlari, Yousef; Zahedinejad, Parham & Kazemzadeh-Parsi, Mohammad Javad
Partner: UNT College of Science
open access

IEMDC-In-Line Electric Motor Driven Compressor Quarterly Report

Description: Considerable effort was put forth on the mechanical design of the compressor section of the IEMDC. These efforts focused on the main compressor case design and included an evaluation of the motor-compressor interface. The initial mechanical evaluation of the compressor motor interface indicates that the integration of an electric motor and compressor can be made successfully. All mechanical design efforts resulted in considerable progress being made towards the completion of the mechanical desi… more
Date: January 1, 2004
Creator: Crowley, Michael J.; Bansal, Prem N. & Tessaro, John E.
Partner: UNT Libraries Government Documents Department
open access

Impact induced response spectrum for the safety evaluation of the high flux isotope reactor

Description: The dynamic impact to the nearby HFIR reactor vessel caused by heavy load drop is analyzed. The impact calculation is carried out by applying the ABAQUS computer code. An impact-induced response spectrum is constructed in order to evaluate whether the HFIR vessel and the shutdown mechanism may be disabled. For the frequency range less than 10 Hz, the maximum spectral velocity of impact is approximately equal to that of the HFIR seismic design-basis spectrum. For the frequency range greater than… more
Date: May 1, 1997
Creator: Chang, S.J.
Partner: UNT Libraries Government Documents Department
open access

Hazards and accident analyses, an integrated approach, for the Plutonium Facility at Los Alamos National Laboratory

Description: This paper describes an integrated approach to perform hazards and accident analyses for the Plutonium Facility at Los Alamos National Laboratory. A comprehensive hazards analysis methodology was developed that extends the scope of the preliminary/process hazard analysis methods described in the AIChE Guidelines for Hazard Evaluations. Results fro the semi-quantitative approach constitute a full spectrum of hazards. For each accident scenario identified, there is a binning assigned for the even… more
Date: July 1, 1995
Creator: Pan, P. Y.; Goen, L. K.; Letellier, B. C. & Sasser, M. K.
Partner: UNT Libraries Government Documents Department
open access

Application of nonlinear wave modulation spectroscopy to discern material damage

Description: Materials containing structural damage have a far greater nonlinear elastic response than materials with no structural damage. This is the basis for nonlinear wave diagnostics of damage, methods which are remarkably sensitive to the detection and progression of damage in materials. Here the authors describe one nonlinear method, the application of harmonics and sum and difference frequency to discern damage in materials. The method is termed Nonlinear Wave Modulation Spectroscopy (NWMS). It con… more
Date: April 1999
Creator: Johnson, Paul A.; Sutin, Alexander & Van Den Abeele, Koen E.-A.
Partner: UNT Libraries Government Documents Department
open access

An Introduction to Wavelet Theory and Analysis

Description: This report reviews the history, theory and mathematics of wavelet analysis. Examination of the Fourier Transform and Short-time Fourier Transform methods provides tiormation about the evolution of the wavelet analysis technique. This overview is intended to provide readers with a basic understanding of wavelet analysis, define common wavelet terminology and describe wavelet amdysis algorithms. The most common algorithms for performing efficient, discrete wavelet transforms for signal analysis … more
Date: October 1, 1998
Creator: Miner, N.E.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen