Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 9 of 9
Full-Text Articles in Physics
Overlap Statistics Of Cumuliform Boundary-Layer Cloud Fields In Large-Eddy Simulations, Roel A.J. Neggers, Thijs Heus, A. Pier Siebesma
Overlap Statistics Of Cumuliform Boundary-Layer Cloud Fields In Large-Eddy Simulations, Roel A.J. Neggers, Thijs Heus, A. Pier Siebesma
Physics Faculty Publications
Overlap statistics of cumuliform boundary-layer clouds are studied using large-eddy simulations at high resolutions. The cloud overlap is found to be highly inefficient, due to the typical irregularity of cumuliform clouds over a wide range of scales. The detection of such inefficient overlap is enabled in this study by i) applying fine enough discretizations and ii) by limiting the analysis to exclusively cumuliform boundary-layer cloud fields. It is argued that these two factors explain the differences with some previous studies on cloud overlap. In contrast, good agreement exists with previously reported observations of cloud overlap as derived from lidar measurements …
Equation Of State From The Potts-Percolation Model Of A Solid, Miron Kaufman
Equation Of State From The Potts-Percolation Model Of A Solid, Miron Kaufman
Physics Faculty Publications
We expand the Potts-percolation model of a solid to include stress and strain. Neighboring atoms are connected by bonds. We set the energy of a bond to be given by the Lennard-Jones potential. If the energy is larger than a threshold the bond is more likely to fail, whereas if the energy is lower than the threshold, the bond is more likely to be alive. In two dimensions we compute the equation of state: stress as a function of interatomic distance and temperature by using renormalization-group and Monte Carlo simulations. The phase diagram, the equation of state, and the isothermal …
Chronic Fluid Flow Is An Environmental Modifier Of Renal Epithelial Function, Andrew Resnick
Chronic Fluid Flow Is An Environmental Modifier Of Renal Epithelial Function, Andrew Resnick
Physics Faculty Publications
Although solitary or sensory cilia are present in most cells of the body and their existence has been known since the sixties, very little is been known about their functions. One suspected function is fluid flow sensing- physical bending of cilia produces an influx of Ca++, which can then result in a variety of activated signaling pathways. Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a progressive disease, typically appearing in the 5th decade of life and is one of the most common monogenetic inherited human diseases, affecting approximately 600,000 people in the United States. Because ADPKD is a slowly progressing …
Glitter And Glints On Water, David K. Lynch, David S. P. Dearborn, James A. Lock
Glitter And Glints On Water, David K. Lynch, David S. P. Dearborn, James A. Lock
Physics Faculty Publications
We present new observations of glitter and glints using short and long time exposure photographs and high frame rate videos. Using the sun and moon as light sources to illuminate the ocean and laboratory water basins, we found that (1) most glitter takes place on capillary waves rather than on gravity waves, (2) certain aspects of glitter morphology depend on the presence or absence of thin clouds between the light source and the water, and (3) bent glitter paths are caused by asymmetric wave slope distributions We present computer simulations that are able to reproduce the observations and make predictions …
Magnetic Properties Of Monolayer Co Islands On Ir(111) Probed By Spin-Resolved Scanning Tunneling Microscopy, Jessica E. Bickel, Focko Meier, Jens Brede, André Kubetzka, Kirsten Von Bergmann, Roland Wiesendanger
Magnetic Properties Of Monolayer Co Islands On Ir(111) Probed By Spin-Resolved Scanning Tunneling Microscopy, Jessica E. Bickel, Focko Meier, Jens Brede, André Kubetzka, Kirsten Von Bergmann, Roland Wiesendanger
Physics Faculty Publications
As the characteristic length scale of devices continues to decrease, it is essential to understand the fundamental magnetic properties of reduced dimension structures. This paper examines the electronic and magnetic properties of two-dimensional nanoscale Co islands on an Ir(111) surface using spin-polarized scanning tunneling microscopy. The pseudomorphic Co islands investigated are ferromagnetic and single domain, with the magnetic easy axis normal to the sample surface. Remarkably, the coercivity of these islands is greater than 4 T and magnetic saturation of the islands requires an applied field of at least 5 T.
Mie Scattering In The Time Domain. Part I. The Role Of Surface Waves, James A. Lock, Philip Laven
Mie Scattering In The Time Domain. Part I. The Role Of Surface Waves, James A. Lock, Philip Laven
Physics Faculty Publications
We computed the Debye series p = 1 and p = 2 terms of the Mie scattered intensity as a function of scattering angle and delay time for a linearly polarized plane wave pulse incident on a spherical dielectric particle and physically interpreted the resulting numerical data. Radiation shed by electromagnetic surface waves plays a prominent role in the scattered intensity. We determined the surface wave phase and damping rate and studied the structure of the p = 1, 2 surface wave glory in the time domain. (C) 2011 Optical Society of America
Mie Scattering In The Time Domain. Part Ii. The Role Of Diffraction, James A. Lock, Philip Laven
Mie Scattering In The Time Domain. Part Ii. The Role Of Diffraction, James A. Lock, Philip Laven
Physics Faculty Publications
The p = 0 term of the Mie-Debye scattering amplitude contains the effects of external reflection and diffraction. We computed the reflected intensity in the time domain as a function of the scattering angle and delay time for a short electromagnetic pulse incident on a spherical particle and compared it to the predicted behavior in the forward-focusing region, the specular reflection region, and the glory region. We examined the physical consequences of three different approaches to the exact diffraction amplitude, and determined the signature of diffraction in the time domain. The external reflection surface wave amplitude gradually replaces the diffraction …
Radial Motion In A Central Potential For Singular Mass Densities, Ulrich Zürcher, Miron Kaufman
Radial Motion In A Central Potential For Singular Mass Densities, Ulrich Zürcher, Miron Kaufman
Physics Faculty Publications
We study the radial motion of an object in the gravitational field produced by an isotropic mass density that is singular at the origin. This problem applies to elliptical galaxies and can be used to illustrate motion in a central field appropriate for an intermediate-level mechanics course.
Torque Around The Center Of Mass: Dynamic Stability During Quadrupedal Arboreal Locomotion In The Siberian Chipmunk (Tamias Sibiricus), Andrew R. Lammers, Ulrich Zurcher
Torque Around The Center Of Mass: Dynamic Stability During Quadrupedal Arboreal Locomotion In The Siberian Chipmunk (Tamias Sibiricus), Andrew R. Lammers, Ulrich Zurcher
Physics Faculty Publications
When animals travel on tree branches, avoiding falls is of paramount importance. Animals swiftly running on a narrow branch must rely on movement to create stability rather than on static methods. We examined how Siberian chipmunks (Tamias sibiricus) remain stable while running on a narrow tree branch trackway. We examined the pitch, yaw, and rolling torques around the center of mass, and hypothesized that within a stride, any angular impulse (torque during step time) acting on the center of mass would be canceled out by an equal and opposite angular impulse. Three chipmunks were videotaped while running on a 2 …