Other Physics Commons^™

Utilizing Computed To Mography Image Features To Advance Prediction Of Radiation Pneumonitis, Shane P. Krafft

Dissertations and Theses (Open Access)

Improving outcomes for non-small-cell lung cancer patients treated with radiation therapy (RT) requires optimizing the balance between local tumor control and risk of normal tissue toxicity. In approximately 20% of patients, severe acute symptomatic lung toxicity, termed radiation pneumonitis (RP), still occurs. Identifying the individuals at risk of RP prior to or early during treatment offers tremendous potential to improve RT by providing the physician with information to assist in making clinical decisions that enhance therapy. Our central goal for this work was to demonstrate the potential gain in predictive accuracy of normal tissue complication probability models for RP by …

Measurement Of The Electron Return Effect Using Presage Dosimeter, Gye Won Choi

Dissertations and Theses (Open Access)

MR-guided radiation therapy (MRgRT) provides benefits such as superior soft tissue contrast, no imaging dose, and functional imaging capacities, but it also has concerns to be addressed. The electron return effect (ERE) refers to dose enhancement at the interface between different media, caused when radiation is delivered in the magnetic field. The ERE poses clinical concerns in MRgRT because it significantly enhances the dose at interfaces, and the intensity and pattern of the dose enhancement depends on many factors. The ERE results in a complex pattern of dose enhancement over a three-dimensional (3D) volume around tissue interfaces inside the patient …

Spica: Stereographic Projection For Interactive Crystallographic Analysis, Xingzhong Li

Nebraska Center for Materials and Nanoscience: Faculty Publications

In numerous research fields, especially the applications of electron and X-ray diffraction, stereographic projection represents a powerful tool for researchers. SPICA is a new computer program for stereographic projection in interactive crystallographic analysis, which inherits features from the previous JECP/SP and includes more functions for extensive crystallographic analysis. SPICA provides fully interactive options for users to plot stereograms of crystal directions and crystal planes, traces, and Kikuchi maps for an arbitrary crystal structure; it can be used to explore the orientation relationships between two crystalline phases with a composite stereogram; it is also used to predict the tilt angles of …

Phase Gradient Algorithm Method For 3-D Holographic Ladar Imaging, Jason W. Stafford, Bradley D. Duncan, David J. Rabb

Electro-Optics and Photonics Faculty Publications

3-D holographic ladar uses digital holography with frequency diversity to add the ability to resolve targets in range. A key challenge is that since individual frequency samples are not recorded simultaneously, differential phase aberrations may exist between them making it difficult to achieve range compression. We describe steps specific to this modality so that phase gradient algorithms (PGA) can be applied to 3-D holographic ladar data for phase corrections across multiple temporal frequency samples. Substantial improvement of range compression is demonstrated with a laboratory experiment where our modified PGA technique is applied. Additionally, the PGA estimator is demonstrated to be …

Model For The Electrolysis Of Water And Its Use For Optimization, Roger Lascorz, Javier E. Hasbun Dr

Georgia Journal of Science

The goal of this research was to study the optimization of the electrolysis of water both theoretically and experimentally. For accuracy, 3 hr experiments were made with measurements recorded every 15 min. The results show that a better model than the classical one is needed for water electrolysis. A new model that fits experimental data better is proposed. The results of this new model not only predict hydrogen production in electrolysis of water better, but show a way to predict gas production of any liquid as well as what voltage to use to optimize it.

Lrs Bianchi Type-Ii Cosmological Model With String Bulk Viscous Fluid And Magnetic Field In Barber’S Second Self Creation Theory, M. S. Borkar, N. K. Ashtankar

Applications and Applied Mathematics: An International Journal (AAM)

We present a solution of LRS Bianchi type-II space-time with string viscous fluid and magnetic field by solving the Barber’s field equations of self-creation theory of gravitation and it is seen that Barber scalar function 𝜙 affects the other physical parameters of the model and contributes a very high matter density, with high particle density at early stage of the universe and also it contributes the negative role of bulk viscous fluid in the evolution. Other geometrical and physical aspects of the model are also studied.

Enhancement Of Heat Transfer In Elastico-Viscous Fluid Due To Nanoparticles, Where The Fluid Is Impinging Obliquely To The Stretchable Surface: A Numerical Study, Tariq Javed, Abuzar Ghaffari, Tasawar Hayat

Applications and Applied Mathematics: An International Journal (AAM)

This article addresses the two-dimensional oblique stagnation point flow of non-Newtonian fluid in the presence of nanoparticles. Constitutive equations of Walter-B fluid are employed in the mathematical development of the relevant problems. Mathematical formulation includes the Brownian motion and thermophoresis effects. The resulting nonlinear system of equations are analyzed through Chebyshev Spectral Newton Iterative Scheme (CSNIS). A comparative study of present results through tabular values has been made with the previous results in a limiting sense and an excellent agreement is noted. It is also found that in near stagnation point region, the heat transfer rate and mass diffusion flux …

Lrs Bianchi Type-I Cosmology With Gamma Law Eos In F(R; T) Gravity, Pratishtha Shukla, Amritha Jayadev

Applications and Applied Mathematics: An International Journal (AAM)

We have studied the locally rotationally symmetric (LRS) Bianchi type-I line element in f(R; T) (R is the Ricci scalar and T is the trace of the stress energy tensor) theory of gravity in presence of EoS parameter. The simplest case of f(R; T) gravity, i.e. first choice, is considered. The “gamma-law” equations of state are considered to explore the role of particle creation in the early universe. The exact solutions of the field equations are obtained using the scalar expansion proportional to the shear. The physical and kinematical properties of the model are studied.

Effect Of Fluid Suction On An Oscillatory Mhd Channel Flow With Heat Transfer, N. Ahmed, A. H. Sheikh, D. P. Barua

Applications and Applied Mathematics: An International Journal (AAM)

Magnetohydrodynamics (MHD) is generally concerned with the study of the magnetic properties (behaviour) of electrically conducting fluids (plasmas, liquid metals etc.) moving in an electromagnetic field. The importance of the concept of MHD in various fields such as astrophysics, bio-medical research, missile technology and geophysics motivates the modelling and investigation of MHD flow and transport problems. The role of fluid suction is paramount in laminar flow control and has wide applications in fields such as aeronautical engineering, automobile engineering and rocket science. This fact inspires the study of the effects of fluid suction in flow and transport models. Time dependent …

Thermal Vibration Of Magnetostrictive Functionally Graded Material Shells With The Transverse Shear Deformation Effects, C. C. Hong

Applications and Applied Mathematics: An International Journal (AAM)

The transverse shear deformation effect on the functionally graded material (FGM) circular cylindrical shells with mounted magnetostrictive layer under thermal vibration is investigated by using the generalized differential quadrature (GDQ) method. In the time dependent of displacement field, the first order shear deformation theory (FSDT) is used. The dynamic equilibrium differential equations with displacements and shear rotations of FGM shells under the magnetostrictive load and thermal load are normalized into the dynamic discrete equations. The computational solutions for thermal stresses and center deflections of magnetostrictive FGM circular cylindrical shells with four edges in simply supported boundary conditions are obtained. Some …

On The Global Existence And Boundedness Of Solutions Of Nonlinear Vector Differential Equations Of Third Order, Timur Ayhan, Cemil Tunç

Applications and Applied Mathematics: An International Journal (AAM)

In this paper, we give some criteria to ensure the global existence and boundedness of solutions to a kind of third order nonlinear vector differential equations. By using the Lyapunov's direct method, we obtain a new result on the topic and give an example for the illustrations. Our result includes, completes and improves some earlier results in the literature.

Bianchi Type-I Hyperbolic Models With Perfect Fluid And Dark Energy In Bimetric Theory Of Gravitation, M. S. Borkar, S. S. Charjan, V. V. Lepse

Applications and Applied Mathematics: An International Journal (AAM)

Three different Bianchi type-I cosmological models as related to perfect fluid, with quintessence and with Chaplygin gas, in bimetric theory of gravitation have been deduced. The perfect fluid model has hyperbolic geometry and all its physical parameters are also hyperbolic in nature and therefore they have been studied from hyperbolic geometric view point. All these models are isotropize and shear-less. Other geometrical and physical behaviors of the models have also been studied. The hyperbolic geometric view point of the models will be helpful to the people who use observational data to search for such type of geometry.

Magnetic Reconnection In Small And Large Scales On The Sun, Xin Chen

Dissertations

Almost all solar activities observed are related to the solar magnetic field, especially the topological restructuring of magnetic fields, the so-called magnetic reconnection in solar physics. They are occurring at different scales related to various phenomena, during minimum or maximum of the solar cycle, from the photosphere to the solar corona.

For small-scale activities, type II spicules which display high velocity upflows observed at the limb, have the most possible underlying driving mechanism of magnetic reconnection. A set of tools is developed for detecting small-scale solar magnetic cancellations and the disk counterpart of type II spicules (the so-called Rapid Blueshifted …

New Facet Of Solar Activities Revealed By High-Resolution Imaging At He I 10830 Å, Zhicheng Zeng

Dissertations

Major solar activities such as major flares and associated coronal mass ejections (CMEs), have a great impact on space weather, which requires us to develop the ability to predict them. Despite the extensive studies already made, however, many basic processes, such as energy accumulation processes in solar active regions and the triggering mechanism of solar activities, are still not well understood.

One reason why the basic processes are hard to be understood is that the large-scale activities are complicated, involving many small-scale energy releases, making it hard to understand the basic picture of the events. Small-scale solar activities, such as …

Radiative Properties Of Silicon Related Materials, Scott Sanowitz

Theses

The objective of this thesis is to study the optical properties of silicon, as a function of temperature, in the infrared range of wavelengths. The wavelength range, considered in this study, is between 1 micron and 20 microns. The temperature range observed is from 50 degrees Celsius to 1000 degrees Celsius. Varying wafer thickness and doping are taken into account. The thickness of the native oxide, silicon dioxide, must be taken into account as well as its orientation (front side versus back side). The effect of layering wafers one onto another is investigated. It is shown that all these parameters …

Automated Sea State Classification From Parameterization Of Survey Observations And Wave-Generated Displacement Data, Jason A. Teichman

LSU New Orleans Theses and Dissertations

Sea state is a subjective quantity whose accuracy depends on an observer’s ability to translate local wind waves into numerical scales. It provides an analytical tool for estimating the impact of the sea on data quality and operational safety. Tasks dependent on the characteristics of local sea surface conditions often require accurate and immediate assessment. An attempt to automate sea state classification using eleven years of ship motion and sea state observation data is made using parametric modeling of distribution-based confidence and tolerance intervals and a probabilistic model using sea state frequencies. Models utilizing distribution intervals are not able to …

The Millikan Oil Drop Experiment: A Simulation Suitable For Classroom Use, Benjamin Hogan, Javier E. Hasbun

Georgia Journal of Science

Due to advancements in computing techniques it has become possible to extend the accessibility of physics experiments across the physics curriculum by means of computational simulations. The widespread availability of computers in modern classrooms provides virtual access to hands-on physics, chemistry, and biology experiments, among others. Here, specifically, we consider Robert Millikan’s famous oil drop experiment. This experiment requires equipment that can be dangerous and expensive. A more practical approach is achieved via a computer simulation, a useful and a universally available alternative. The goal is to encourage scientific thinking, literacy, and innovation while promoting a free network of academic …

A Cylindrically Symmetric “Micro-Mott” Electron Polarimeter, Nathan B. Clayburn, Evan M. Brunkow, S. J. Burtwistle, George H. Rutherford, Timothy J. Gay

Timothy J. Gay Publications

A small, novel, cylindrically symmetric Mott electron polarimeter is described. The effective Sherman function, S_eff , or analyzing power, for 20 kV Au target bias with a 1.3 keV energy loss window is 0.16 ± 0.01, where uncertainty in the measurement is due primarily to uncertainty in the incident electron polarization. For an energy loss window of 0.5 keV, S_eff reaches its maximum value of 0.24 ± 0.02. The device’s maximum efficiency, I/I_o, defined as the detected count rate divided by the incident particle rate, is 3.7 ± 0.2 × 10^{− …}

Particle Image Velocimetry Design & Installation, Zach Ritchie

Mechanical Engineering Undergraduate Honors Theses

This work will mainly focus on the design, construction, and installation of the Particle Image Velocimetry (PIV) system in the Chemical Hazards Research Center wind tunnel. The PIV system utilizes a Class IV (double pulsed) laser, optics to produce a light sheet, timing circuitry, and a high-resolution camera (with buffered output) to measure a system’s velocity (two-dimensional) field by determining the displacement of particles over the time between laser pulses. For maximum mobility and functionality, the PIV system was installed in the center of the tunnel on a moveable cart with the laser and camera mounted to an adjustable support. …

The Singing Cymbal: Is It Really Photon Momentum?, Thomas R. Moore, Samantha Collin, Nikki Etchenique

Student-Faculty Collaborative Research Publications

A simple demonstration that is occasionally used in the classroom to show that light carries momentum involves making an orchestral cymbal audibly ring using light from a common photoflash. A metal plate or a piece of foil can also be used, however, it appears that many people use a cymbal because the sound is easily heard at a reasonable distance. It is such an impressive example of the effects attributable to photon momentum that it is posted on the CERN website for educational under the name “singing cymbal.” Although it is an impressive demonstration, a series of simple classroom experiments …