6,385 research outputs found
Noise-based logic: Binary, multi-valued, or fuzzy, with optional superposition of logic states
A new type of deterministic (non-probabilistic) computer logic system
inspired by the stochasticity of brain signals is shown. The distinct values
are represented by independent stochastic processes: independent voltage (or
current) noises. The orthogonality of these processes provides a natural way to
construct binary or multi-valued logic circuitry with arbitrary number N of
logic values by using analog circuitry. Moreover, the logic values on a single
wire can be made a (weighted) superposition of the N distinct logic values.
Fuzzy logic is also naturally represented by a two-component superposition
within the binary case (N=2). Error propagation and accumulation are
suppressed. Other relevant advantages are reduced energy dissipation and
leakage current problems, and robustness against circuit noise and background
noises such as 1/f, Johnson, shot and crosstalk noise. Variability problems are
also nonexistent because the logic value is an AC signal. A similar logic
system can be built with orthogonal sinusoidal signals (different frequency or
orthogonal phase) however that has an extra 1/N type slowdown compared to the
noise-based logic system with increasing number of N furthermore it is less
robust against time delay effects than the noise-based counterpart.Comment: Accepted for publication by Physics Letters A, on December 23, 200
The role of the alloy structure in the magnetic behavior of granular systems
The effect of grain size, easy magnetization axis and anisotropy constant
distributions in the irreversible magnetic behavior of granular alloys is
considered. A simulated granular alloy is used to provide a realistic grain
structure for the Monte Carlo simulation of the ZFC-FC curves. The effect of
annealing and external field is also studied. The simulation curves are in good
agreement with the FC and ZFC magnetization curves measured on melt spun Cu-Co
ribbons.Comment: 13 pages, 10 figures, submitted to PR
How Can Progress Toward Ending the Human Immunodeficiency Virus Epidemic in the United States Be Monitored?
The plan for Ending the HIV (human immunodeficiency virus) Epidemic (EHE) in the United States aims to reduce new infections by 75% by 2025 and by 90% by 2030. For EHE to be successful, it is important to accurately measure changes in numbers of new HIV infections after 5 and 10 years (to determine whether the EHE goals have been achieved) but also over shorter timescales (to monitor progress and intensify prevention efforts if required). In this viewpoint, we aim to demonstrate why the method used to monitor progress toward the EHE goals must be carefully considered. We briefly describe and discuss different methods to estimate numbers of new HIV infections based on longitudinal cohort studies, cross-sectional incidence surveys, and routine surveillance data. We particularly focus on identifying conditions under which unadjusted and adjusted estimates based on routine surveillance data can be used to estimate changes in new HIV infections
Deformed one-quasiparticle states in covariant density functional theory
Systematic investigation of the accuracy of the description of the energies
of deformed one-quasiparticle states has been performed in covariant density
functional theory in actinide and rare-earth mass regions. The sources of the
discrepancies between theory and experiment are analyzed. Although some
improvements in the description of ground state configurations and
one-quasiparticle spectra can be achieved by better parametrization of the
relativistic mean field Lagrangian, the analysis suggests that spectroscopic
quality of their description can be achieved only in theoretical framework
which takes into account particle-vibration coupling.Comment: 7 pages, 4 figure
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Re‐evaluation of stannous chloride (E 512) as food additive
The Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re‐evaluating the safety of stannous chloride and stannous chloride dihydrate (E 512) as food additives. The Panel considered that adequate exposure and toxicity data were available. Stannous chloride is only permitted as food additives in one food category and no reply on the actual use level of stannous chloride (E 512) as a food additive and on its concentration in food was provided by any interested party. According to the Mintel's Global New Products Database (GNPD), stannous chloride was not labelled on any products in the EU nor in Norway. The regulatory maximum level exposure assessment scenario is based on the maximum permitted levels (MPLs) for stannous chloride (E 512), which is 25 mg Sn/kg. The mean exposure to stannous chloride (E 512) from its use as a food additive was below 1.3 μg Sn/kg body weight (bw) per day for all age groups. The 95th percentile of exposure to stannous chloride (E 512) ranged from 0.0 μg Sn/kg bw per day in all groups to 11.2 μg Sn/kg bw per day in adults. Absorption of stannous chloride from the gastrointestinal tract is low there is no concern with respect to carcinogenicity and genotoxicity. Gastrointestinal irritation was reported in humans after ingestion of a bolus dose of 40 mg Sn. The Panel concluded that stannous chloride (E 512) is of no safety concern in this current authorised use and use levels
Morphology and magnetism of multifunctional nanostructured -FeO films: Simulation and experiments
This paper introduces a new approach for simulating magnetic properties of
nanocomposites comprising magnetic particles embedded in a non-magnetic matrix,
taking into account the 3D structure of the system in which particles'
positions correctly mimic real samples. The proposed approach develops a
multistage simulation procedure in which the size and distribution of particles
within the hosting matrix is firstly attained by means of the Cell Dynamic
System (CDS) model. The 3D structure provided by the CDS step is further
employed in a Monte Carlo (MC) simulation of zero-field-cooled/field-cooled
(ZFC/FC) and magnetic hysteresis loops ( curves) for the system.
Simulations are aimed to draw a realistic picture of the as-produced ultra-thin
films comprising maghemite nanoparticles dispersed in polyaniline. Comparison
(ZFC/FC and curves) between experiments and simulations regarding
the maximum of the ZFC curve (), remanence () and
coercivity () revealed the great accuracy of the multistage approach
proposed here while providing information about the system's morphology and
magnetic properties. For a typical sample the value we found experimentally for
(54 K) was very close to the value provided by the
simulation (53 K). For the parameters depending on the nanoparticle clustering
the experimental values were consistently lower ( = 0.32 and =
210 Oe) than the values we found in the simulation ( = 0.53 and
= 274 Oe). Indeed, the approach introduced here is very promising for the
design of real magnetic nanocomposite samples with optimized features.Comment: 19 pages (one column), 5 figure
Investigation of process parameter effect on anisotropic properties of 3D printed sand molds
The development of sand mold three-dimensional printing technologies enables the manufacturing of molds without the use of a physical model. However, the effects of the three-dimensional printing process parameters on the mold permeability and strength are not well known, leading the industries to keep old settings until castings have recurring defects. In the present work, the influence of these parameters was experimentally investigated to understand their effect on the mold strength and permeability. Cylindrical and barshaped test specimens were printed to perform, respectively, permeability and bending strength measurements. Experiments were designed to statistically quantify the individual and combined effect of these process parameters. While the binder quantity only affects the mold strength, increasing the recoater speed leads to both greater permeability and reduced strength due to the reduced sand compaction. Recommendations for optimizing some 3D printer settings are proposed to attain predefined mold properties and minimize the anisotropic behavior of the sand mold in regard to both the orientation and the position in the job box
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