5,209 research outputs found
TOWARD AN APPRAISAL OF THE FMHA FARM CREDIT PROGRAM: A CASE STUDY OF THE EFFICIENCY OF BORROWERS IN SOUTHERN ILLINOIS
A production frontier methodology is used to measure the overall efficiency of a sample of farms obtaining credit from the Farmers Home Administration (FmHA) compared to nonparticipants. The study did not find evidence that the efficiency of FmHA farms improved between 1981 and 1984. Results indicate that the overall efficiency of FmHA borrowers is associated with selected financial characteristics of the farms.Agricultural Finance,
Safety Critical Wide Area Network Performance Evaluation
The growing importance of real-time computing in numerous applications poses problems for network architectures, especially safety-critical Wide Area Networks (WANs). Assessing network performance in safety-critical real-time systems is difficult, and suggests the use of both human and technical performance criteria because of the importance of both dimensions in safety-critical settings. This research proposes a model that considers both technical and human performance in network evaluation
Prediction of process forces and stability of end mills with complex geometries
In order to optimize the cutting performance of end mills, the geometry of such cutters is optimized by toolmakers constantly. As a result of geometric changes, process forces can be reduced, i.e. by serrated end mills. Tools with unequal helix angles can lead to an increase of process stability. In this paper, a method to calculate the process forces of end mills with complex geometries is presented. The method for calculating the process forces is designed for the application for stability analysis of end mill cutters with complex geometries. A basic introduction of the method for the stability prediction of such tools is given. Cutting forces of end mills are analyzed at incremental axial depth of cuts to show the influence of the tool geometry on the process forces. The comparison with experimental data verifies this method and shows the influence of further effects on the process forces. Furthermore, stability charts obtained with the Semi-Discretization Method are presented to show the potential of end mills with complex geometries regarding stability improvement.Ministry for Science and Culture of Lower Saxony (MWK
Jacobi-Nijenhuis algebroids and their modular classes
Jacobi-Nijenhuis algebroids are defined as a natural generalization of
Poisson-Nijenhuis algebroids, in the case where there exists a Nijenhuis
operator on a Jacobi algebroid which is compatible with it. We study modular
classes of Jacobi and Jacobi-Nijenhuis algebroids
Decision Performance and Safety Performance: A Value-Focused Thinking Study in the Oil Industry
Considerable research has been performed to develop leading indicators of safety performance. We use value-focused thinking to understand the objectives and evaluation measures that frame a particular safety-related decision within an organization. These decisions are part of the safety culture. Our research partners were two oil shipping companies; we surveyed crewmembers on their tankers to evaluate performance in each decision objective on their vessel. We demonstrate that measurements of the achievement of these objectives are related to future safety performance and thus provide leading indicators of safety
A variational principle for volume-preserving dynamics
We provide a variational description of any Liouville (i.e. volume
preserving) autonomous vector fields on a smooth manifold. This is obtained via
a ``maximal degree'' variational principle; critical sections for this are
integral manifolds for the Liouville vector field. We work in coordinates and
provide explicit formulae
Trapping atoms on a transparent permanent-magnet atom chip
We describe experiments on trapping of atoms in microscopic magneto-optical
traps on an optically transparent permanent-magnet atom chip. The chip is made
of magnetically hard ferrite-garnet material deposited on a dielectric
substrate. The confining magnetic fields are produced by miniature magnetized
patterns recorded in the film by magneto-optical techniques. We trap Rb atoms
on these structures by applying three crossed pairs of counter-propagating
laser beams in the conventional magneto-optical trapping (MOT) geometry. We
demonstrate the flexibility of the concept in creation and in-situ modification
of the trapping geometries through several experiments.Comment: Modifications: A) Reference I. Barb et al., Eur. Phys. JD, 35, 75
(2005) added. B)Sentence rewritten: We routinely capture more than 10^6 atoms
in a micro-MOT on a magnetized pattern. C) The magnetic field strengths are
now given in Teslas. D) The second sentence in the fourth paragraph has been
rewritten in order to more clearly describe the geometry and purpose of the
compensation coils.E) In the seventh paragraph we have rewritten the sentence
about the creation of the external magnetic field for the magnetic-domain
patterning. F) In the ninth paragraph, we clarify the way to shift the trap
center. G) Caption of Fig. 4 changed. H) We have modified paragraph 12 to
improve the description on the guiding of the trap center along a toroidal
pattern. I) The last two sentences of the manuscript have been rewritte
Hubbard Models as Fusion Products of Free Fermions
A class of recently introduced su(n) `free-fermion' models has recently been
used to construct generalized Hubbard models. I derive an algebra defining the
`free-fermion' models and give new classes of solutions. I then introduce a
conjugation matrix and give a new and simple proof of the corresponding
decorated Yang-Baxter equation. This provides the algebraic tools required to
couple in an integrable way two copies of free-fermion models. Complete
integrability of the resulting Hubbard-like models is shown by exhibiting their
L and R matrices. Local symmetries of the models are discussed. The
diagonalization of the free-fermion models is carried out using the algebraic
Bethe Ansatz.Comment: 14 pages, LaTeX. Minor modification
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