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1,531 full-text articles. Page 54 of 61.

Charge-Magnetic Interference Resonant Scattering Studies Of Ferromagnetic Crystals And Thin Films, D. Haskel, E. Kravtsov, Y. Choi, J. C. Lang, Z. Islam, G. Srajer, J. S. Jiang, S. D. Bader, Paul C. Canfield 2012 Argonne National Laboratory

Charge-Magnetic Interference Resonant Scattering Studies Of Ferromagnetic Crystals And Thin Films, D. Haskel, E. Kravtsov, Y. Choi, J. C. Lang, Z. Islam, G. Srajer, J. S. Jiang, S. D. Bader, Paul C. Canfield

Physics and Astronomy Publications

The element- and site-specificity of X-ray resonant magnetic scattering (XRMS) makes it an ideal tool for furthering our understanding of complex magnetic systems. In the hard X-rays, XRMS is readily applied to most antiferromagnets where the relatively weak resonant magnetic scattering (10−2–10−6 I c ) is separated in reciprocal space from the stronger, Bragg charge scattered intensity, I c . In ferro(ferri)magnetic materials, however, such separation does not occur and measurements of resonant magnetic scattering in the presence of strong charge scattering are quite challenging. We discuss the use of charge-magnetic interference resonant scattering for studies of ...


Development Of A Pyrotechnic Shock Simulation Apparatus For Spacecraft Applications, Joseph Binder, Matthew McCarty, Chris Rasmussen 2012 California Polytechnic State University, San Luis Obispo

Development Of A Pyrotechnic Shock Simulation Apparatus For Spacecraft Applications, Joseph Binder, Matthew Mccarty, Chris Rasmussen

Aerospace Engineering

This report details the research, design, construction, and testing of a pyrotechnic shock simulation apparatus for spacecraft applications. The apparatus was developed to be used in the Space Environments Lab at California Polytechnic State University. It will be used for testing spacecraft components with dimensions up to 24”x12”x12” as well as CubeSats. Additionally, it may be used as an instructional or demonstrational tool in the Aerospace Department’s space environments course. The apparatus functions by way of mechanical impact of an approximately 20 lb stainless steel swinging hammer. Tests were performed to verify the simulator’s functionality. Suggestions ...


Inductive Metal Identification, Paul Maggi 2012 California Polytechnic State University - San Luis Obispo

Inductive Metal Identification, Paul Maggi

Electrical Engineering

This project focuses on creating a device to differentiate between various types of metals via magnetic induction. Magnetic induction is used because it is both non-optical and non-contact. It achieves this by generating a varying magnetic field, which induces eddy currents in the metal. These eddy currents produce small disturbances in the surrounding magnetic field, which can be sensed with Hall Effect Sensors (HES). The primary challenge in this project was generating a sufficiently strong magnetic field to detectable disturbances. In order to achieve better results, a stronger magnetic field must be used as well as more sensitive Hall Effect ...


Analysis Of Focal-Plane Measurements For Veritas Telescopes, William Hemmo Schuur 2012 California Polytechnic State University - San Luis Obispo

Analysis Of Focal-Plane Measurements For Veritas Telescopes, William Hemmo Schuur

Physics

In this experiment we measured the Point Spread Function (PSF) of the telescope at different image locations using a python GUI and servo motors to automate a screen along the focal axis of the telescope. Our results show that the telescope T4 has a well-defined image distance at each elevation, but this distance shifts as the telescope is lowered. Additionally, off-axis telescope orientations are degraded by aberrations and at low elevation possibly some structural warping of the mirror. The VERITAS Telescopes are located in Southern Arizona at the Fred Lawrence Whipple Observatory.


Agent-Based Modeling Of Emergency Building Evacuation, Vi Q. Ha 2012 University of Connecticut - Storrs

Agent-Based Modeling Of Emergency Building Evacuation, Vi Q. Ha

Master's Theses

Panic during emergency building evacuation can cause crowd stampede, resulting in serious injuries and casualties. Agent-based methods have been successfully employed to investigate the collective human behavior during emergency evacuation in cases where the configurational space is extremely simple - usually one rectangular room - but not in evacuations of multi-room or multi-floor buildings. This implies that the effect of the complexity of building architecture on the collective behavior of the agents during evacuation has not been fully investigated. Here, we employ a system of self-moving particles whose motion is governed by the social-force model to investigate the effect of complex building ...


A Method To Measure The Detective Quantum Efficiency Of Radiographic Systems In Clinical Setting, Michael C. McDonald 2012 The University of Western Ontario

A Method To Measure The Detective Quantum Efficiency Of Radiographic Systems In Clinical Setting, Michael C. Mcdonald

Electronic Thesis and Dissertation Repository

The risks associated with exposure to radiation make it critical that digital imaging systems give the best possible images for a given dose to the patient. The DQE is the most widely accepted measure of performance and dose efficiency for digital radiography systems, however it is not commonly measured in a clinical environment as part of routine quality assurance. The primary reason for this is that the data provided to the user by clinical systems has typically undergone image processing and therefore may have a non-linear characteristic response. This is a problem because the Fourier metrics of the DQE require ...


Breaking Glass: Exploring The Relationship Between Kinetic Energy And Radial Fracturing In Plate Glass, Andrea Hulman 2012 Scripps College

Breaking Glass: Exploring The Relationship Between Kinetic Energy And Radial Fracturing In Plate Glass, Andrea Hulman

Scripps Senior Theses

When glass breaks from the impact of an object, it exhibits a distinctive shattering pattern comprised of two different regions. This pattern was investigated using experimental impacts and predicted using Young’s Modulus. Results were not as expected, and it is likely that there exists error in some measurements. Further investigation of this topic is recommended.


The Discrete Yang-Fourier Transforms In Fractal Space, Yang Xiao-Jun 2012 China University of Mining & Technology

The Discrete Yang-Fourier Transforms In Fractal Space, Yang Xiao-Jun

Xiao-Jun Yang

The Yang-Fourier transform (YFT) in fractal space is a generation of Fourier transform based on the local fractional calculus. The discrete Yang-Fourier transform (DYFT) is a specific kind of the approximation of discrete transform, used in Yang-Fourier transform in fractal space. This paper points out new standard forms of discrete Yang-Fourier transforms (DYFT) of fractal signals, and both properties and theorems are investigated in detail.


Expression Of Generalized Newton Iteration Method Via Generalized Local Fractional Taylor Series, Yang Xiao-Jun 2012 China University of Mining & Technology

Expression Of Generalized Newton Iteration Method Via Generalized Local Fractional Taylor Series, Yang Xiao-Jun

Xiao-Jun Yang

Local fractional derivative and integrals are revealed as one of useful tools to deal with everywhere continuous but nowhere differentiable functions in fractal areas ranging from fundamental science to engineering. In this paper, a generalized Newton iteration method derived from the generalized local fractional Taylor series with the local fractional derivatives is reviewed. Operators on real line numbers on a fractal space are induced from Cantor set to fractional set. Existence for a generalized fixed point on generalized metric spaces may take place.


Structural Properties And Relative Stability Of (Meta)Stable Ordered, Partially Ordered, And Disordered Al-Li Alloy Phases, Aftab Alam, Duane D. Johnson 2012 Ames Laboratory

Structural Properties And Relative Stability Of (Meta)Stable Ordered, Partially Ordered, And Disordered Al-Li Alloy Phases, Aftab Alam, Duane D. Johnson

Ames Laboratory Publications

We resolve issues that have plagued reliable prediction of relative phase stability for solid solutions and compounds. Due to its commercially important phase diagram, we showcase the Al-Li system because historically density-functional theory (DFT) results show large scatter and limited success in predicting the structural properties and stability of solid solutions relative to ordered compounds. Using recent advances in an optimal basis-set representation of the topology of electronic charge density (and, hence, atomic size), we present DFT results that agree reasonably well with all known experimental data for the structural properties and formation energies of ordered, off-stoichiometric partially ordered, and ...


Low-Loss Meta-Atom For Improved Resonance Response, Derrick Langley, Ronald Coutu Jr., Peter J. Collins 2012 Air Force Institute of Technology

Low-Loss Meta-Atom For Improved Resonance Response, Derrick Langley, Ronald Coutu Jr., Peter J. Collins

Faculty Publications

Measurements of a meta-atom integrated with a low noise amplifier into the split-ring resonator are presented. A comparison is made between baseline meta-atoms and one integrated with a GaAs low noise amplifier. S-parameter measurements in a RF strip-line show the resonant frequency location. The resonance null is more prominent for the integrated meta-atom. Biasing the low noise amplifier from 0 to 7 VDC showed that the resonant null improved with biasing voltage. As the biasing voltage increases, the transmission null reduced from -11.82 to -23.21 dB for biases from 0 to 7 VDC at resonant frequency.


Cesium Absorption Spectrum Perturbed By Argon: Observation Of Non-Lorentzian Far Wings, Gordon E. Lott 2012 Air Force Institute of Technology

Cesium Absorption Spectrum Perturbed By Argon: Observation Of Non-Lorentzian Far Wings, Gordon E. Lott

Theses and Dissertations

The purpose of this research was to observe the core and far wing absorption spectra of the D1 and D2 lines of cesium (Cs) perturbed by argon (Ar). A 1.33 m scanning monochromator with a PMT detector was used to measure the spectra from 8300 Å to 9100 Å. A heat pipe was used to control the Cs concentration and Ar pressure allowing for a broad range of spectra to be collected. Spectra were collected for heat pipe temperatures of 50, 75, 100, 125, 150 and 175 °C, corresponding to Cs concentrations of approximately 6×1011 ...


Advances In Ultrafast Time Resolved Fluorescence Physics For Cancer Detection In Optical Biopsy, R. R. Alfano 2012 CUNY City College

Advances In Ultrafast Time Resolved Fluorescence Physics For Cancer Detection In Optical Biopsy, R. R. Alfano

Publications and Research

We discuss the use of time resolved fluorescence spectroscopy to extract fundamental kinetic information on molecular species in tissues. The temporal profiles reveal the lifetime and amplitudes associated with key active molecules distinguishing the local spectral environment of tissues. The femtosecond laser pulses at 310 nm excite the tissue. The emission profile at 340 nm from tryptophan is non-exponential due to the micro-environment. The slow and fast amplitudes and lifetimes of emission profiles reveal that cancer and normal states can be distinguished. Time resolved optical methods offer a new cancer diagnostic modality for the medical community.


The Zero-Mass Renormalization Group Differential Equations And Limit Cycles In Non-Smooth Initial Value Problems, Yang Xiaojun 2012 China University of Mining & Technology

The Zero-Mass Renormalization Group Differential Equations And Limit Cycles In Non-Smooth Initial Value Problems, Yang Xiaojun

Xiao-Jun Yang

In the present paper, using the equation transform in fractal space, we point out the zero-mass renormalization group equations. Under limit cycles in the non-smooth initial value, we devote to the analytical technique of the local fractional Fourier series for treating zero-mass renormalization group equations, and investigate local fractional Fourier series solutions.


A Novel Approach To Processing Fractal Dynamical Systems Using The Yang-Fourier Transforms, Yang Xiaojun 2012 China University of Mining & Technology

A Novel Approach To Processing Fractal Dynamical Systems Using The Yang-Fourier Transforms, Yang Xiaojun

Xiao-Jun Yang

In the present paper, local fractional continuous non-differentiable functions in fractal space are investigated, and the control method for processing dynamic systems in fractal space are proposed using the Yang-Fourier transform based on the local fractional calculus. Two illustrative paradigms for control problems in fractal space are given to elaborate the accuracy and reliable results.


Insights Into The Power Law Relationships That Describe Mass Deposition Rates During Electrospinning, Jonathan J. Stanger, Nick Tucker, Simon Fullick, Mathieu Sellier, Mark P. Staiger 2012 SelectedWorks

Insights Into The Power Law Relationships That Describe Mass Deposition Rates During Electrospinning, Jonathan J. Stanger, Nick Tucker, Simon Fullick, Mathieu Sellier, Mark P. Staiger

Jonathan J Stanger

This work explores how in electrospinning, mass deposition rate and electric current relate to applied voltage and electrode separation, factors give a range of applied electric fields. Mass deposition rate was measured by quantifying the rate of dry fibre deposited over time. Electric current was measured using a current feedback from the high voltage supply. The deposition of fibre was observed to occur at a constant rate for deposition times of up to 30 min. Both the mass deposition rate and electric current were found to vary with the applied voltage according to a power law. The relationship between the ...


Manipulation Of Electrospun Fibres In Flight: The Principle Of Superposition Of Electric Fields As A Control Method, Nurfaizey A. Hamid, Jonathan J. Stanger, Nick Tucker, Andrew Wallace, Mark P. Staiger 2012 SelectedWorks

Manipulation Of Electrospun Fibres In Flight: The Principle Of Superposition Of Electric Fields As A Control Method, Nurfaizey A. Hamid, Jonathan J. Stanger, Nick Tucker, Andrew Wallace, Mark P. Staiger

Jonathan J Stanger

This study investigates the magnitude of movement of the area of deposition of electrospun fibres in response to an applied auxiliary electric field. The auxiliary field is generated by two pairs of rod electrodes positioned adjacent and parallel to the line of flight of the spun fibre. The changes in shape of the deposition area and the degree of movement of the deposition area are quantified by optical scanning and image analysis. A linear response was observed between the magnitude of movement of the deposition area and voltage difference between the auxiliary and deposition electrodes. A squeezing effect which changed ...


Theory And Applications Of Local Fractional Fourier Analysis, Yang Xiaojun 2012 China University of Mining & Technology

Theory And Applications Of Local Fractional Fourier Analysis, Yang Xiaojun

Xiao-Jun Yang

Local fractional Fourier analysis is a generalized Fourier analysis in fractal space. The local fractional calculus is one of useful tools to process the local fractional continuously non-differentiable functions (fractal functions). Based on the local fractional derivative and integration, the present work is devoted to the theory and applications of local fractional Fourier analysis in generalized Hilbert space. We investigate the local fractional Fourier series, the Yang-Fourier transform, the generalized Yang-Fourier transform, the discrete Yang-Fourier transform and fast Yang-Fourier transform.


Heat Transfer In Discontinuous Media, Yang Xiaojun 2012 China University of Mining & Technology

Heat Transfer In Discontinuous Media, Yang Xiaojun

Xiao-Jun Yang

From the fractal geometry point of view, the interpretations of local fractional derivative and local fractional integration are pointed out in this paper. It is devoted to heat transfer in discontinuous media derived from local fractional derivative. We investigate the Fourier law and heat conduction equation (also local fractional instantaneous heat conduct equation) in fractal orthogonal system based on cantor set, and extent them. These fractional differential equations are described in local fractional derivative sense. The results are efficiently developed in discontinuous media.


A Short Note On Local Fractional Calculus Of Function Of One Variable, Yang Xiaojun 2012 China University of Mining & Technology

A Short Note On Local Fractional Calculus Of Function Of One Variable, Yang Xiaojun

Xiao-Jun Yang

Local fractional calculus (LFC) handles everywhere continuous but nowhere differentiable functions in fractal space. This note investigates the theory of local fractional derivative and integral of function of one variable. We first introduce the theory of local fractional continuity of function and history of local fractional calculus. We then consider the basic theory of local fractional derivative and integral, containing the local fractional Rolle’s theorem, L’Hospital’s rule, mean value theorem, anti-differentiation and related theorems, integration by parts and Taylor’ theorem. Finally, we study the efficient application of local fractional derivative to local fractional extreme value of non-differentiable ...


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