68,599 research outputs found
Relative importance of crystal field versus bandwidth to the high pressure spin transition in transition metal monoxides
The crystal field splitting and d bandwidth of the 3d transition metal
monoxides MnO, FeO, CoO and NiO are analyzed as a function of pressure within
density functional theory. In all four cases the 3d bandwidth is significantly
larger than the crystal field splitting over a wide range of compressions. The
bandwidth actually increases more as pressure is increased than the crystal
field splitting. Therefore the role of increasing bandwidth must be considered
in any explanation of a possible spin collapse that these materials may exhibit
under pressure.Comment: 7 pages, 4 figure
High Performance Turboalternator and Associated Hardware. 1 - Design of Turboalternator
Performance of two stage axial flow turbogenerator with gas bearing rotor support syste
Study of transition temperatures in superconductors Final report, 11 Mar. 1968 - 10 Mar. 1970
Thermodynamic and electrical properties of niobium stannide and other superconductor
A Solution to Concerns over Public Access to Scientific Data
To balance the public need for accountability and better policy decision making with concerns regarding burdens on scientists and scientific progress, the authors propose that increased access be limited to data relevant in analyzing regulations that would have an annual economic impact of at least $100 million. They also recommend establishing an agency to replicate key findings used to support regulations before they are finalized.Regulatory Reform
Should Researchers Be Required to Share Data Used in Supporting Regulatory Decisions?
The scientific establishment is deeply concerned over a proposed regulation that would require data to be shared on projects that are federally funded. Specifically, the proposed amendment to OMB Circular A-110 would require data collected by researchers at universities, hospitals, and non-profit institutions to be shared with interested parties if (1) the data are produced as part of a grant or agreement funded by the federal government; (2) the data are used in a published study; and (3) the data or study is used in formulating a policy or rule. Parties could request the data under the Freedom of Information Act. The proposed rule responds to a provision by Senator Richard Shelby in the 1999 Omnibus Spending Bill that requires data generated under federal awards at universities and non-profit institutions to be available to the public. This regulatory analysis develops an economic framework for evaluating proposals to provide greater access to research data. Our analysis also offers specific recommendations for improving OMB Circular A-110 as well as the broader regulatory process. We argue that the economic analysis of sharing research findings can be separated into three parts: the impact of requiring public access on incentives to produce data, research, and innovation; the impact of that requirement on the quality of research; and the impact of required access on the efficiency and transparency of policy. The economic analysis demonstrates that the standard property-rights framework used to justify time-limited property rights for the use of data is not sufficient for addressing broader problems in which research and data could be used to help inform public policy decisions. The value of sharing data for public policy must also be considered. A second conclusion is that traditional peer review done by scientific journals is not adequate for purposes of relying on research for major public policy decisions. A third conclusion is that scientists who are reluctant to share their findings are more likely to have errors in their analysis than the average researcher. A fourth conclusion is that requiring the release of data could slow the development of data and delay the publication of results. Although substantial costs and uncertainty may be associated with greater public access to data, our analysis suggests that academic norms alone provide very limited access to scientific data. We recommend improving Circular A-110 by narrowing and clarifying the scope of the proposed regulation. The proposed regulation should apply to economically significant regulations that have an annual economic impact of at least $100 million. In addition, we recommend that Congress create an agency that would be charged with replicating the findings of regulatory agencies before such regulations could be implemented. The recommendations concerning replication would require additional legal authority. Taken together, our recommendations would help lay the foundation for a regulatory system that is more accountable and has more scientific integrity.
An Improved Procedure for Laboratory Rearing of the Corn Earworm, \u3ci\u3eHeliothis Zea\u3c/i\u3e (Lepidoptera: Noctuidae)
An improved method for the laboratory rearing of the corn earworm. Heliothis zea, described. The rearing medium is a modification of the commonly used wheat germ An oviposition chamber, a feeder for adults, and a simple and inexpensive contrnlled humidity chamber are described
First-principles investigation of 180-degree domain walls in BaTiO_3
We present a first-principles study of 180-degree ferroelectric domain walls
in tetragonal barium titanate. The theory is based on an effective Hamiltonian
that has previously been determined from first-principles
ultrasoft-pseudopotential calculations. Statistical properties are investigated
using Monte Carlo simulations. We compute the domain-wall energy, free energy,
and thickness, analyze the behavior of the ferroelectric order parameter in the
interior of the domain wall, and study its spatial fluctuations. An abrupt
reversal of the polarization is found, unlike the gradual rotation typical of
the ferromagnetic case.Comment: Revtex (preprint style, 13 pages) + 3 postscript figures. A version
in two-column article style with embedded figures is available at
http://electron.rutgers.edu/~dhv/preprints/index.html#pad_wal
Amplitudes Fitted to Experimental Data and to Roy's Equations
The scalar-isoscalar, scalar-isotensor and vector-isovector pi-pi amplitudes
are fitted simultaneously to experimental data and to Roy's equations. The
resulting amplitudes are compared with those fitted only to experimental data.
No additional constraints for the pi-pi threshold behaviour of the amplitudes
are imposed. Threshold parameters are calculated for the amplitudes in the
three waves. Spectrum of scalar mesons below 1.8 GeV is found from the analysis
of the analytical structure of the fitted amplitudes.Comment: 3 pages, 1 figure. Talk given at MESON 2004: 8th International
Workshop on Meson Production, Properties and Interactions, Cracow, Poland,
4-8 Jun 2004. Submitted to Int.J.Mod.Phys.
A novel method for the injection and manipulation of magnetic charge states in nanostructures
Realising the promise of next-generation magnetic nanotechnologies is
contingent on the development of novel methods for controlling magnetic states
at the nanoscale. There is currently demand for simple and flexible techniques
to access exotic magnetisation states without convoluted fabrication and
application processes. 360 degree domain walls (metastable twists in
magnetisation separating two domains with parallel magnetisation) are one such
state, which is currently of great interest in data storage and magnonics.
Here, we demonstrate a straightforward and powerful process whereby a moving
magnetic charge, provided experimentally by a magnetic force microscope tip,
can write and manipulate magnetic charge states in ferromagnetic nanowires. The
method is applicable to a wide range of nanowire architectures with
considerable benefits over existing techniques. We confirm the method's
efficacy via the injection and spatial manipulation of 360 degree domain walls
in Py and Co nanowires. Experimental results are supported by micromagnetic
simulations of the tip-nanowire interaction.Comment: in Scientific Reports (2016
- …