1,305 research outputs found
Recommended from our members
Molecular dynamics simulation of high frequency (1010 to 10 12 Hz) dielectric absorption in the Hollandite Nax(Ti 8-xCrx)O16
The charge-compensating sodium ions that reside interstitially in the one-dimensional tunnels of the hollandite Nax(Ti8-xCrx)O16 are used as a simple model for a fluid. Molecular dynamics are used to calculate the motions of the ions at a range of temperatures between 200 K and 373 K. The polarization response of the system to a step-up electric field is calculated for field strengths between 7.43 MV/m and 74.3 GV/m, and converted to an ac susceptibility. A resonance absorption is found,peaking at frequencies between 4.5x1010 and 8.8x1010 Hz at 297K. The origin of the response is shown to be the anharmonically coupled ion vibrations damped by ion hopping to neighbouring sites. The relationship of the result to the experimentally observed Poley absorption is explored, and a brief comparison of the calculated dynamics to previous theoretical models is made
Studies on the condition of water in plant systems and of the influence of the major solid constituents
No abstract available.No abstract available
Creatio Ex Amore Dei: Creation out of Nothing and God’s Relational Nature
The opinion of many feminist thinkers and process theologians has been that Christianity needs to shed its allegiance to a God conceived in terms of omnipotent sovereignty. As an alternative, many of them have envisioned God in more relational categories, focusing on the metaphysically “limited” nature of God, with the first step along this path often being a refutation of the traditional doctrine of creatio ex nihilo. This essay summarizes such critiques before proceeding to argue that a robust understanding of creatio ex nihilo, viewed through the lens of kenosis, can actually speak more effectively to God’s relational nature and sacrificial love
Growth of a Richtmyer-Meshkov turbulent layer after reshock
This paper presents a numerical study of a reshocked turbulent mixing layer using high-order accurate Implicit Large-Eddy-Simulations (ILES). Existing theoretical approaches are discussed, and the theory of Youngs (detailed in Ref. 1) is extended to predict the behaviour of a reshocked mixing layer formed initially from a shock interacting with a broadband instability. The theory of Mikaelian2 is also extended to account for molecular mixing in the single-shocked layer prior to reshock. Simulations are conducted for broadband and narrowband initial perturbations and results for the growth rate of the reshocked layer and the decay rate of turbulent kinetic energy show excellent agreement with the extended theoretical approach. Reshock causes a marginal decrease in mixing parameters for the narrowband layer, but a significant increase for the broadband initial perturbation. The layer properties are observed to be very similar post-reshock, however, the growth rate exponent for the mixing layer width is higher in the broadband case, indicating that the reshocked layer still has a dependence (although weakened) on the initial conditions. These results have important implications for Unsteady Reynolds Averaged Navier Stokes modelling of such instabilities
Lorentz force metamaterial with giant optical magnetoelectric response
We demonstrate the first reconfigurable photonic metamaterial controlled by electrical currents and magnetic fields, providing first practically useful solutions for sub-megahertz and high contrast modulation of metamaterial optical properties
Organometallic Polymeric Conductors
For aerospace applications, the use of polymers can result in tremendous weight savings over metals. Suitable polymeric materials for some applications like EMI shielding, spacecraft grounding, and charge dissipation must combine high electrical conductivity with long-term environmental stability, good processability, and good mechanical properties. Recently, other investigators have reported hybrid films made from an electrically conductive polymer combined with insulating polymers. In all of these instances, the films were prepared by infiltrating an insulating polymer with a precursor for a conductive polymer (either polypyrrole or polythiophene), and oxidatively polymerizing the precursor in situ. The resulting composite films have good electrical conductivity, while overcoming the brittleness inherent in most conductive polymers. Many aerospace applications require a combination of properties. Thus, hybrid films made from polyimides or other engineering resins are of primary interest, but only if conductivities on the same order as those obtained with a polystyrene base could be obtained. Hence, a series of experiments was performed to optimize the conductivity of polyimide-based composite films. The polyimide base chosen for this study was Kapton. 3-MethylThiophene (3MT) was used for the conductive phase. Three processing variables were identified for producing these composite films, namely time, temperature, and oxidant concentration for the in situ oxidation. Statistically designed experiments were used to examine the effects of these variables and synergistic/interactive effects among variables on the electrical conductivity and mechanical strength of the films. Multiple linear regression analysis of the tensile data revealed that temperature and time have the greatest effect on maximum stress. The response surface of maximum stress vs. temperature and time (for oxidant concentration at 1.2 M) is shown. Conductivity of the composite films was measured for over 150 days in air at ambient temperature. The conductivity of the films dropped only half an order of magnitude in that time. Films aged under vacuum at ambient temperature diminished slightly in conductivity in the first day, but did not change thereafter. An experimental design approach will be applied to maximize the efficiency of the laboratory effort. The material properties (initial and long term) will also be monitored and assessed. The experimental results will add to the existing database for electrically conductive polymer materials. Attachments: 1) Synthesis Crystal Structure, and Polymerization of 1,2:5,6:9,10-Tribenzo-3,7,11,13-tetradehydro(14) annulene. 2) Reinvestigation of the Photocyclization of 1,4-Phenylene Bis(phenylmaleic anhydride): Preparation and Structure of (5)Helicene 5,6:9,10-Dianhydride. 3) Preparation and Structure Charecterization of a Platinum Catecholate Complex Containing Two 3-Ethynyltheophone Groups. and 4) Rigid-Rod Polymers Based on Noncoplanar 4,4'-Biphenyldiamines: A Review of Polymer Properties vs Configuration of Diamines
Crystal structure of 9-methacryloylanthracene
The authors would like to thank the Graduate College and Chemistry Department at Cleveland State University for support, the Ohio Supercomputing Center for a grant of computer time, and the National Science Foundation (CHE-0840446) for funds used to purchase the Bruker APEXII DUO X-ray diffractometer used in this research.Peer reviewedPublisher PD
Offenders' Crime Narratives across Different Types of Crimes
The current study explores the roles offenders see themselves playing during an offence and their relationship to different crime types. One hundred and twenty incarcerated offenders indicated the narrative roles they acted out whilst committing a specific crime they remembered well. The data were subjected to Smallest Space Analysis (SSA) and four
themes were identified: Hero, Professional, Revenger and Victim in line with the recent theoretical framework posited for Narrative Offence Roles (Youngs & Canter, 2012). Further analysis showed that different subsets of crimes were more like to be associated with different narrative offence roles. Hero and Professional were found to be associated with property offences (theft, burglary and shoplifting), drug offences and robbery and Revenger
and Victim were found to be associated with violence, sexual offences and murder. The theoretical implications for understanding crime on the basis of offenders' narrative roles as well as practical implications are discussed
The Shape of Cas A
Based on optical, IR and X-ray studies of Cas A, we propose a geometry for
the remnant based on a "jet-induced" scenario with significant systematic
departures from axial symmetry. In this model, the main jet axis is oriented in
the direction of strong blue-shifted motion at an angle of 110 - 120 degrees
East of North and about 40 - 50 degrees to the East of the line of sight.
Normal to this axis would be an expanding torus as predicted by jet-induced
models. In the proposed geometry, iron-peak elements in the main jet-like flow
could appear "beyond" the portions of the remnant rich in silicon by projection
effects, not the effect of mixing. In the context of the proposed geometry, the
displacement of the compact object from the kinematic center of the remnant at
a position angle of ~169 degrees can be accommodated if the motion of the
compact object is near to, but slightly off from, the direction of the main
"jet" axis by of order 30 degrees. In this model, the classical NE "jet," the
SW "counter-jet" and other protrusions, particularly the "hole" in the North,
are non-asymmetric flows approximately in the equatorial plane, e.g., out
through the perimeter of the expanding torus, rather than being associated with
the main jet. We explore the spoke-like flow in the equatorial plane in terms
of Rayleigh-Taylor, Richtmyer-Meshkov and Kelvin-Helmholz instabilities and
illustrate these instabilities with a jet-induced simulation.Comment: 25 pages, 4 figures. Accepted for publication in the Astrophysical
Journa
- …