Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Engineering (4)
- Atomic, Molecular and Optical Physics (2)
- Biological and Chemical Physics (2)
- Aerospace Engineering (1)
- Applied Statistics (1)
-
- Astrophysics and Astronomy (1)
- Biochemistry, Biophysics, and Structural Biology (1)
- Biotechnology (1)
- Chemistry (1)
- Condensed Matter Physics (1)
- Electrical and Computer Engineering (1)
- Fluid Dynamics (1)
- Heat Transfer, Combustion (1)
- Life Sciences (1)
- Materials Science and Engineering (1)
- Mechanical Engineering (1)
- Metallurgy (1)
- Nanoscience and Nanotechnology (1)
- Other Physics (1)
- Statistics and Probability (1)
- Institution
- Publication Year
- Publication
- Publication Type
Articles 1 - 13 of 13
Full-Text Articles in Physics
Coil-To-Bridge Transitions Of Self-Assembled Water Chains Observed In A Nanoscopic Meniscus, Byung I. Kim, Ryan D. Boehm, Harrison Agrusa
Coil-To-Bridge Transitions Of Self-Assembled Water Chains Observed In A Nanoscopic Meniscus, Byung I. Kim, Ryan D. Boehm, Harrison Agrusa
Physics Faculty Publications and Presentations
Ten downward portions in the large oscillatory force–distance curve reported earlier are analyzed to understand a nanoscale water meniscus confined between a sharp probe and a flat substrate in air. The sigmoidal shape of each portion leads to the assumption that the meniscus is made up of n independent transitions of two states: one for a coil state and the other for a bridge state. The analysis reveals that each downward portion occurs due to a coil-to-bridge transition of n self-assembled water chains whose length ranges between 197 and 383 chain units. The transition provides novel insights into water’s unique …
Additive Modulation Of Dna-Dna Interactions By Interstitial Ions, Wei Meng, Raju Timsina, Abby Bull, Kurt Andresen, Xiangyun Qiu
Additive Modulation Of Dna-Dna Interactions By Interstitial Ions, Wei Meng, Raju Timsina, Abby Bull, Kurt Andresen, Xiangyun Qiu
Physics and Astronomy Faculty Publications
Quantitative understanding of biomolecular electrostatics, particularly involving multivalent ions and highly charged surfaces, remains lacking. Ion-modulated interactions between nucleic acids provide a model system in which electrostatics plays a dominant role. Using ordered DNA arrays neutralized by spherical cobalt3+ hexammine and Mg2+ ions, we investigate how the interstitial ions modulate DNA-DNA interactions. Using methods of ion counting, osmotic stress, and x-ray diffraction, we systematically determine thermodynamic quantities, including ion chemical potentials, ion partition, DNA osmotic pressure and force, and DNA-DNA spacing. Analyses of the multidimensional data provide quantitative insights into their interdependencies. The key finding of this study is that …
Application Of The Fisher Dimer Model To Dna Condensation, John C. Baker Iii
Application Of The Fisher Dimer Model To Dna Condensation, John C. Baker Iii
Theses and Dissertations
This paper considers the statistical mechanics occupation of the edge of a single helix of DNA by simple polymers. Using Fisher's exact closed form solution for dimers on a two-dimensional lattice, a one-dimensional lattice is created mathematically that is occupied by dimers, monomers, and holes. The free energy, entropy, average occupation, and total charge on the lattice are found through the usual statistical methods. The results demonstrate the charge inversion required for a DNA helix to undergo DNA condensation.
An Assessment Of The Validity Of The Kinetic Model For Liquid-Vapor Phase Change By Examining Cryogenic Propellants, Kishan Bellur
An Assessment Of The Validity Of The Kinetic Model For Liquid-Vapor Phase Change By Examining Cryogenic Propellants, Kishan Bellur
Dissertations, Master's Theses and Master's Reports
Evaporation is ubiquitous in nature and occurs even in a microgravity space envi- ronment. Long term space missions require storage of cryogenic propellents and an accurate prediction of phase change rates. Kinetic theory has been used to model and predict evaporation rates for over a century but the reported values of accommodation coefficients are highly inconsistent and no accurate data is available for cryogens. The proposed study involves a combined experimental and computational approach to ex- tract the accommodation coefficients. Neutron imaging is used as the visualization technique due to the difference in attenuation between the cryogen and the metallic …
Cosmic Background Radiation, Sree Ram Valluri, B G. Sidharth
Cosmic Background Radiation, Sree Ram Valluri, B G. Sidharth
Physics and Astronomy Publications
It is shown that a collection of photons with nearly the same frequency exhibits a “condensation” type of phenomenon corresponding to a peak intensity. The observed cosmic background radiation can be explained from this standpoint.We have obtained analogous results by extremization of the occupation number for photons with the use of the Lambert W function. Some of the interesting applications of this function are briefly discussed in the context of graphene which exhibits an interesting two dimensional structure with several characteristic properties and diverse practical applications.
Chiral Symmetry Breaking By Spatial Confinement In Tactoidal Droplets Of Lyotropic Chromonic Liquid Crystals, Luana Tortora, Oleg Lavrentovich
Chiral Symmetry Breaking By Spatial Confinement In Tactoidal Droplets Of Lyotropic Chromonic Liquid Crystals, Luana Tortora, Oleg Lavrentovich
Oleg Lavrentovich
In many colloidal systems, an orientationally ordered nematic (N) phase emerges fromthe isotropic (I) melt in the form of spindle-like birefringent tactoids. In cases studied so far, the tactoids always reveal a mirror-symmetric nonchiral structure, sometimes even when the building units are chiral. We report on chiral symmetry breaking in the nematic tactoids formed in molecularly nonchiral polymer-crowded aqueous solutions of low-molecular weight disodium cromoglycate. The parity is broken by twisted packing of self-assembled molecular aggregates within the tactoids as manifested by the observed optical activity. Fluorescent confocal microscopy reveals that the chiral N tactoids are located at the boundaries …
Ch₃Ch₂Od/D₂O Binary Condensation In A Supersonic Laval Nozzle: Presence Of Small Clusters Inferred From A Macroscopic Energy Balance, Shinobu Tanimura, Barbara E. Wyslouzil, Gerald Wilemski
Ch₃Ch₂Od/D₂O Binary Condensation In A Supersonic Laval Nozzle: Presence Of Small Clusters Inferred From A Macroscopic Energy Balance, Shinobu Tanimura, Barbara E. Wyslouzil, Gerald Wilemski
Physics Faculty Research & Creative Works
We determined the heat released in the condensing flow of a CH3 CH2 OD/ D2 O /carrier gas mixture (EtOD/ D2 O for brevity) through a supersonic Laval nozzle by integrating the equations for supersonic flow with condensation, using the static pressure, temperature, and mole fractions of EtOD and D2 O monomers [S. Tanimura, B. E. Wyslouzil, M. S. Zahniser, J. Chem. Phys. 127, 034305 (2007)] as inputs. by considering the depletion of the monomer species, the deviation of the pressure from the isentropic value, and the heat released, we estimated that ∼10% of the EtOD molecules are present as …
Condensation On (002) Graphite Of Liquid Bismuth Far Below Its Bulk Melting Point, M. K. Zayed, H. E. Elsayed-Ali
Condensation On (002) Graphite Of Liquid Bismuth Far Below Its Bulk Melting Point, M. K. Zayed, H. E. Elsayed-Ali
Electrical & Computer Engineering Faculty Publications
Condensation of thermally evaporated Bi on (002) graphite, at temperatures of 300-523K, was studied using in situ reflection high-energy electron diffraction (RHEED) and room temperature ex situ atomic force microscopy (AFM). For deposition at temperatures below 415±5K, transmission RHEED patterns of Bi appeared at an average thickness of ∼0.5 monolayer (ML). AFM images showed that the film consisted of crystallites in the shape of triangular step pyramids with step heights corresponding to single and double Bi layers in the [111] direction. This morphology indicates crystallization from the vapor. For deposition at higher temperatures, diffuse RHEED patterns appeared independent of the …
H2o–D2o Condensation In A Supersonic Nozzle, Christopher H. Heath, Kiril A. Streletzky, Barbara E. Wyslouzil, Judith Woelk, Reinhard Strey
H2o–D2o Condensation In A Supersonic Nozzle, Christopher H. Heath, Kiril A. Streletzky, Barbara E. Wyslouzil, Judith Woelk, Reinhard Strey
Physics Faculty Publications
We examined the condensation of H2O, D2O, and four intermediate mixtures (20, 40, 60, and 80 mol % D2O) in a supersonic nozzle. Because the physical and chemical properties of protonated and deuterated water are so similar, this system is ideal for studying the change in condensation behavior as a function of condensible composition. In our experiments dilute mixtures of condensible vapor in N2 are expanded from three different stagnation temperatures resulting in a broad range of onset temperatures (190–238 K) and pressures (27–787 kPa). For a fixed stagnation temperature, the partial pressure required to maintain the onset of condensation …
Binary Condensation In A Supersonic Nozzle, Barbara Ellen Wyslouzil, Christopher H. Heath, Janice L. Cheung, Gerald Wilemski
Binary Condensation In A Supersonic Nozzle, Barbara Ellen Wyslouzil, Christopher H. Heath, Janice L. Cheung, Gerald Wilemski
Physics Faculty Research & Creative Works
We present data from the first systematic studies of binary condensation in supersonic nozzles. The apparatus used to conduct the experiments is described in detail, and the important issues of stability and reproducibility of the experiments are discussed. Experiments were conducted with water, ethanol, propanol, and binary mixtures of these compounds. Onset was determined in the temperature range of 190-215 K, and for each mixture composition the pressures of the condensible species at an onset temperature of 207 K were determined. For the ideal ethanol-propanol mixtures, the onset pressures at constant temperature vary almost linearly between those of the pure …
Identification And Characterization Of The Iron-Zinc Intermetallics Formed In Galvanneal Steel, Richard Frederick George Grant
Identification And Characterization Of The Iron-Zinc Intermetallics Formed In Galvanneal Steel, Richard Frederick George Grant
Physics Theses & Dissertations
The demand to improve the corrosion resistance of steel sheet, particularly for use within the automotive industry, has led to a dramatic increase in the use of coated steels in place of cold-rolled sheet steel. Galvanneal steel results from the post annealing of the zinc-coated steel sheet, in which iron and zinc are interdiffused to form an iron-zinc alloy coating. Within this alloy coating, four main iron-zinc phases, Zeta, Delta, Gamma-1, and Gamma may be present. Manufacture of the most suitable coating requires identifying which phases form during the galvannealing process, an understanding of the properties of each phase and …
Effect Of Carrier Gas Pressure On Condensation In A Supersonic Nozzle, Barbara Ellen Wyslouzil, Gerald Wilemski, M. G. Beals, Michael B. Frish
Effect Of Carrier Gas Pressure On Condensation In A Supersonic Nozzle, Barbara Ellen Wyslouzil, Gerald Wilemski, M. G. Beals, Michael B. Frish
Physics Faculty Research & Creative Works
Supersonic nozzle experiments were performed with a fixed water or ethanol vapor pressure and varying amounts of nitrogen to test the hypothesis that carrier gas pressure affects the onset of condensation. Such an effect might occur if nonisothermal nucleation were important under conditions of excess carrier gas in the atmospheric pressure range, as has been suggested by Ford and Clement [J. Phys. A 22, 4007 (1989)]. Although a small increase was observed in the condensation onset temperature as the stagnation pressure was reduced from 3 to 0.5 atm, these changes cannot be attributed to any nonisothermal effects. The pulsed nozzle …
Measurement Of The Condensation Coefficient Of Water In The Umr Simulation Chamber, Daniel R. White, James L. Kassner, John C. Carstens, Donald E. Hagen, John L. Schmitt, Darryl J. Alofs, Alfred R. Hopkins, Max B. Trueblood, Max W. Alcorn, William L. Walker
Measurement Of The Condensation Coefficient Of Water In The Umr Simulation Chamber, Daniel R. White, James L. Kassner, John C. Carstens, Donald E. Hagen, John L. Schmitt, Darryl J. Alofs, Alfred R. Hopkins, Max B. Trueblood, Max W. Alcorn, William L. Walker
Physics Faculty Research & Creative Works
The UMR Cloud Simulation Facility is described. The facility is designed to provide a controlled environment simulating the conditions of natural atmospheric processes. It consists of two cooled-wall expansion cloud chambers and peripheral instrumentation for generation and characterization of aerosols used for cloud formation studies. Results of initial studies of the growth of warm cloud droplets and inferred measurements of the condensation coefficient are described.