5,628 Matching Results

Search Results

Advanced search parameters have been applied.

The effect of solvent dynamics on the low frequency collectivemotions of DNA in solution and unoriented films

Description: Infrared spectroscopy is used to probe the dynamics of invitro samples of DNA prepared as solutions and as solid unoriented films.The lowest frequency DNA mode identified in the far-infrared spectra ofthe DNA samples is found to shift in frequency when the solvent influencein the hydration shell is altered. The lowest frequency mode also hascharacteristics that are similar to beta - relaxations identified inother glass forming polymers.
Date: April 20, 2006
Creator: Woods, K.N.; Lee, S.A.; Holman, H.-Y.N. & Wiedemann, H.
Partner: UNT Libraries Government Documents Department

Random Iteration of Rational Functions

Description: It is a theorem of Denker and Urbański that if T:ℂ→ℂ is a rational map of degree at least two and if ϕ:ℂ→ℝ is Hölder continuous and satisfies the “thermodynamic expanding” condition P(T,ϕ) > sup(ϕ), then there exists exactly one equilibrium state μ for T and ϕ, and furthermore (ℂ,T,μ) is metrically exact. We extend these results to the case of a holomorphic random dynamical system on ℂ, using the concepts of relative pressure and relative entropy of such a system, and the variational principle of Bogenschütz. Specifically, if (T,Ω,P,θ) is a holomorphic random dynamical system on ℂ and ϕ:Ω→ ℋα(ℂ) is a Hölder continuous random potential function satisfying one of several sets of technical but reasonable hypotheses, then there exists a unique equilibrium state of (X,P,ϕ) over (Ω,Ρ,θ).
Date: May 2012
Creator: Simmons, David
Partner: UNT Libraries

A Technique for Delineating Subsurface Fracture Zones Resulting from High-Yield Detonations

Description: From summary: Site investigations were conducted at two locations, the sites of the DUGOUT and CHARLIE events, at the Nevada Test Site for the purpose of evaluating the dynamic in situ technique as a means of determining the boundaries of craters produced by explosive detonations.
Date: February 1967
Creator: Ballard, Robert F., Jr.
Partner: UNT Libraries Government Documents Department

Fluidization in Tapered Beds

Description: Abstract: The concept of a tapered fluidized bed is explored briefly. Data are given showing that in bench scale apparatus a tapered bed gives better fluidization with some materials that are difficult to fluidize in a conventional cylindrical bed.
Date: February 14, 1958
Creator: Rossmassler, W. R. & Harris, R. L.
Partner: UNT Libraries Government Documents Department

On the Formation of Shock Waves in Subsonic Flows With Local Supersonic Velocities

Description: In the flow about a body with large subsonic velocity if the velocity of the approaching flow is sufficiently large, regions of local supersonic velocities are formed about the body. It is known from experiment that these regions downstream of the flow are always bounded by shock waves; a continuous transition of the supersonic velocity to the subsonic under the conditions indicated has never been observed. A similar phenomenon occurs in pipes. If at two cross sections of the pipe the velocity is subsonic and between these sections regions of local supersonic velocity are formed without completely occupying a single cross section, these regions are always bounded by shock waves.
Date: April 1950
Creator: Frankl, F. I.
Partner: UNT Libraries Government Documents Department

General considerations on the flow of compressible fluids

Description: This paper presents an introduction to the subject of the flow of compressible media. Information regarding steady potential flow, flows with "subsonic" velocities, higher approximations of subsonic velocities, flow with supersonic velocities, an approximate method for general two-dimensional supersonic flow, passage through the velocity of sound, and the application to airfoils is provided. Historical development and hydraulics are omitted.
Date: October 1936
Creator: Prandtl, L.
Partner: UNT Libraries Government Documents Department

A Classification of Lattice Rules Using the Reciprocal Lattice Generator Matrix

Description: The search for cost-effective lattice rules is a time-consuming and difficult process. After a brief overview of some of the lattice theory relevant to these rules, a new approach to this search is suggested. This -approach is based on a classification of lattice rules using "the upper triangular lattice form" of the reciprocal lattice generator matrix.
Date: June 1989
Creator: Lyness, James N.
Partner: UNT Libraries Government Documents Department

Flow and Drag Formulas for Simple Quadrics

Description: This report gives the pressure distribution and resistance found by theory and experiment for simple quadrics fixed in an infinite uniform stream of practically incompressible fluid. The experimental values pertain to air and some liquids, especially water; the theoretical refer sometimes to perfect, again to viscid fluids. For the cases treated the concordance of theory and measurement is so close as to make a resume of results desirable. Incidentally formulas for the velocity at all points of the flow field are given, some being new forms for ready use derived in a previous paper. (author).
Date: 1927
Creator: Zahm, A. F.
Partner: UNT Libraries Government Documents Department

Theories of flow similitude

Description: The laws of comparison of dynamically similar fluid motions are derived by three different methods based on the same principle and yielding the same or equivalent formulas. This report outlines the three current methods of comparing dynamically similar motions, more especially of fluids, initiated respectively by Newton, Stokes (or Helmholtz), and Rayleigh. These three methods, viz., the integral, the differential, and the dimensional, are enough alike to be studied profitably together. They are treated in succession then compared. (author).
Date: May 7, 1928
Creator: Zahm, A. F.
Partner: UNT Libraries Government Documents Department

Location of Detached Shock Wave in Front of a Body Moving at Supersonic Speeds

Description: It is shown that for velocities slightly in excess of sonic, the position of detached shock wave located in front of a given body at zero angle of attack may be estimated theoretically to a reasonable degree of accuracy. In case of bodies of revolution the result was simple, but for two-dimensional bodies, pressure coefficient varies with Mach number, and slight difficulty appears. Theory developed compares favorably with available experimental data.
Date: May 6, 1947
Creator: Laitone, Edmund V. & Pardee, Otway O'M.
Partner: UNT Libraries Government Documents Department

The decay of a simple eddy

Description: The principal result obtained in this report is a generalization of Taylor's formula for a simple eddy. The discussion of the properties of the eddy indicates that there is a slight analogy between the theory of eddies in a viscous fluid and the quantum theory of radiation. Another exact solution of the equations of motion of viscous fluid yields a result which reminds one of the well-known condition for instability in the case of a horizontally stratified atmosphere.
Date: 1923
Creator: Bateman, H.
Partner: UNT Libraries Government Documents Department

A theory of unstaggered airfoil cascades in compressible flow

Description: By use of the methods of thin airfoil theory, which include effects of compressibility, relations are developed which permit the rapid determination of the pressure distribution over an unstaggered cascade of airfoils of a given profile, and the determination of the profile shape necessary to yield a given pressure distribution for small chord/gap ratios. For incompressible flow the results of the theory are compared with available examples obtained by the more exact method of conformal transformation. Although the theory is developed for small chord/gap ratios, these comparisons show that it may be extended to chord/gap ratios of order unity, at least for low-speed flows. Choking cascades, a phenomenon of particular importance in compressor design, is considered.
Date: September 1947
Creator: Spurr, Robert A. & Allen, H. Julian
Partner: UNT Libraries Government Documents Department

Translational motion of bodies under the free surface of a heavy fluid of finite depth

Description: In the present paper, the two-dimensional problem of the wave motion produced in a heavy fluid of finite depth by the horizontal rectilinear and uniform motion of a solid body of arbitrary shape immersed under the surface of the fluid is considered by the method of N. E. Kochin.
Date: June 1952
Creator: Haskind, M. D.
Partner: UNT Libraries Government Documents Department

Turbulent flow

Description: Report presenting some information and potential areas of study of turbulent flow and turbulence.
Date: October 1927
Creator: Prandtl, L.
Partner: UNT Libraries Government Documents Department

Motion of fluids with very little viscosity

Description: Report presenting a discussion of the laws of motion of a fluid with very low viscosity. Mathematical formulas that have been created in order to compensate for this lack of viscosity and the circumstances under which viscosity can be disregarded are provided.
Date: March 1928
Creator: Prandtl, L.
Partner: UNT Libraries Government Documents Department

Some effects of fluid in pylon-mounted tanks on flutter

Description: Report presenting fluid-dynamics studies of a tank of fineness ratio 7.0 which was pylon mounted on a simplified two-dimensional flutter model in order to determine the effects of the fluid on flutter. The flutter speed was determined for three cases: with various amounts of water in the tank, with weights with the same mass and moment of inertia as the fluid considered to be a frozen solid, and with weights with the same mass and moment of inertia as the actual fluid. Results regarding the flutter speed, effects of inertia on flutter, and amplitude of flutter are provided.
Date: July 19, 1955
Creator: Reese, James R.
Partner: UNT Libraries Government Documents Department