9,089 research outputs found
Symbolic Reachability Analysis of B through ProB and LTSmin
We present a symbolic reachability analysis approach for B that can provide a
significant speedup over traditional explicit state model checking. The
symbolic analysis is implemented by linking ProB to LTSmin, a high-performance
language independent model checker. The link is achieved via LTSmin's PINS
interface, allowing ProB to benefit from LTSmin's analysis algorithms, while
only writing a few hundred lines of glue-code, along with a bridge between ProB
and C using ZeroMQ. ProB supports model checking of several formal
specification languages such as B, Event-B, Z and TLA. Our experiments are
based on a wide variety of B-Method and Event-B models to demonstrate the
efficiency of the new link. Among the tested categories are state space
generation and deadlock detection; but action detection and invariant checking
are also feasible in principle. In many cases we observe speedups of several
orders of magnitude. We also compare the results with other approaches for
improving model checking, such as partial order reduction or symmetry
reduction. We thus provide a new scalable, symbolic analysis algorithm for the
B-Method and Event-B, along with a platform to integrate other model checking
improvements via LTSmin in the future
Phase behaviour of binary mixtures of diamagnetic colloidal platelets in an external magnetic field
Using fundamental measure density functional theory we investigate
paranematic-nematic and nematic-nematic phase coexistence in binary mixtures of
circular platelets with vanishing thicknesses. An external magnetic field
induces uniaxial alignment and acts on the platelets with a strength that is
taken to scale with the platelet area. At particle diameter ratio lambda=1.5
the system displays paranematic-nematic coexistence. For lambda=2, demixing
into two nematic states with different compositions also occurs, between an
upper critical point and a paranematic-nematic-nematic triple point. Increasing
the field strength leads to shrinking of the coexistence regions. At high
enough field strength a closed loop of immiscibility is induced and phase
coexistence vanishes at a double critical point above which the system is
homogeneously nematic. For lambda=2.5, besides paranematic-nematic coexistence,
there is nematic-nematic coexistence which persists and hence does not end in a
critical point. The partial orientational order parameters along the binodals
vary strongly with composition and connect smoothly for each species when
closed loops of immiscibility are present in the corresponding phase diagram.Comment: 9 pages, to appear in J.Phys:Condensed Matte
Production of new neutron-rich isotopes of heavy elements in fragmentation reactions of U projectiles at 1 A GeV
The production of heavy neutron-rich nuclei has been investigated using cold
fragmentation reactions of U projectiles at relativistic energies. The
experiment performed at the high-resolving-power magnetic spectrometer FRS at
GSI allowed to identify 45 new heavy neutron-rich nuclei: Pt,
Au, Hg, Tl, Pb, Bi,
Po, At, Rn and Fr. The production
cross sections of these nuclei were also determined and used to benchmark
reaction codes that predict the production of nuclei far from stability.Comment: 5 pages, 2 figure
Kidney Transplantation and Diagnostic Imaging:The Early Days and Future Advancements of Transplant Surgery
The first steps for modern organ transplantation were taken by Emerich Ullmann (Vienne, Austria) in 1902, with a dog-to-dog kidney transplant, and ultimate success was achieved by Joseph Murray in 1954, with the Boston twin brothers. In the same time period, the ground-breaking work of Wilhelm C. Röntgen (1895) and Maria Sklodowska-Curie (1903), on X-rays and radioactivity, enabled the introduction of diagnostic imaging. In the years thereafter, kidney transplantation and diagnostic imaging followed a synergistic path for their development, with key discoveries in transplant rejection pathways, immunosuppressive therapies, and the integration of diagnostic imaging in transplant programs. The first image of a transplanted kidney, a urogram with intravenous contrast, was shown to the public in 1956, and the first recommendations for transplantation diagnostic imaging were published in 1958. Transplant surgeons were eager to use innovative diagnostic modalities, with renal scintigraphy in the 1960s, as well as ultrasound and computed tomography in the 1970s. The use of innovative diagnostic modalities has had a great impact on the reduction of post-operative complications in kidney transplantation, making it one of the key factors for successful transplantation. For the new generation of transplant surgeons, the historical alignment between transplant surgery and diagnostic imaging can be a motivator for future innovations
System For Data Acquisition From High Voltage Terminals
An inexpensive data acquisition system has been designed to provide high voltage isolation for data acquisition in analog, digital, and pulse modes. The telemetry system uses GaAs light sources, fiber optics, and phototransistors to accomplish the data transmission. Prewired logic boards have been adapted to accomplish the timing and logic functions. Seven decades of digital data are transmitted error free, pulse data can be transmitted at rates up to 1 MHz, and analog data are transmitted with 0.05% full scale accuracy. © 1972 The American Institute of Physics
Infinite Networks of Identical Capacitors
The capacitance between the origin and any other lattice site in an infinite
square lattice of identical capacitors is studied. The method is generalized to
infinite Simple Cubic (SC) lattice. We make use of the superposition principle
and the symmetry of the infinite gridComment: 16 pages, 5 figures, 2 table
Production of neutron-rich nuclei in fragmentation reactions of 132Sn projectiles at relativistic energies
The fragmentation of neutron-rich 132Sn nuclei produced in the fission of
238U projectiles at 950 MeV/u has been investigated at the FRagment Separator
(FRS) at GSI. This work represents the first investigation of fragmentation of
medium-mass radioactive projectiles with a large neutron excess. The measured
production cross sections of the residual nuclei are relevant for the possible
use of a two-stage reaction scheme (fission+fragmentation) for the production
of extremely neutron-rich medium-mass nuclei in future rare-ion-beam
facilities. Moreover, the new data will provide a better understanding of the
"memory" effect in fragmentation reactions.Comment: 5 pages, 3 figure
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