1,651 research outputs found
The use of orbitals and full spectra to identify misalignment
In this paper, a SpectraQuest demonstrator is used to introduce misalignment in a rotating set-up. The vibrations caused by misalignment is measured with both accelerometers on the bearings and eddy current probes on the shaft itself. A comparison is made between the classical spectral analysis, orbitals and full spectra. Orbitals are used to explain the physical interpretation of the vibration caused by misalignment. Full spectra allow to distinguish unbalance from misalignment by looking at the forward and reversed phenomena. This analysis is done for different kinds of misalignment, couplings, excitation forces and combined machinery faults
A Sustainable Learning Environment based on an Open-Source Content Management System
This paper presents our approach for supporting face-to-face courses with software components for e-learning based on a general-purpose content management system (CMS). These components—collectively named eduComponents—can be combined with other modules to create tailormade, sustainable learning environments, which help to make teaching and learning more efficient and effective. We give a short overview of these components, and we report on our practical experiences with the software in our courses
Proof without Words: On Sums of Squares and Triangles
author's final draft post-referee and pre-publication copySummary. We visually display a relationship between sums of squares and the sum of an even number of triangular numbers. Connections to some proofs without words appearing in the literature are briefly discussed.Ye
PCIExpress Communication Layer for ATCA-based Linear Accelerator Control System
PCIExpress architecture is widely used communication bus designed, among other things, for industrial application. Additionally, according to PICMG 3.4 specification it is part of an ATCA architecture. For that reason PCIExpress was used as communication interface for data transmission between ATCA carrier boards and AMC modules for the new control system for XFEL linear accelerator. In this paper authors present general overview of this system, describe communication protocols designed to exchange data with external user application and show results of performance test
Coalitions in the quantum Minority game: classical cheats and quantum bullies
In a one-off Minority game, when a group of players agree to collaborate they
gain an advantage over the remaining players. We consider the advantage
obtained in a quantum Minority game by a coalition sharing an initially
entangled state versus that obtained by a coalition that uses classical
communication to arrive at an optimal group strategy. In a model of the quantum
Minority game where the final measurement basis is randomized, quantum
coalitions outperform classical ones when carried out by up to four players,
but an unrestricted amount of classical communication is better for larger
coalition sizes.Comment: 12 pages, 1 figur
Recommended from our members
Synchronous Deglacial Overturning and Water Mass Source Changes
Understanding changes in ocean circulation during the last deglaciation is crucial to unraveling the dynamics of glacial-interglacial and millennial climate shifts. We used neodymium isotope measurements on postdepositional iron-manganese oxide coatings precipitated on planktonic foraminifera to reconstruct changes in the bottom water source of the deep western North Atlantic at the Bermuda Rise. Comparison of our deep water source record with overturning strength proxies shows that both the deep water mass source and the overturning rate shifted rapidly and synchronously during the last deglacial transition. In contrast, any freshwater perturbation caused by Heinrich event 1 could have only affected shallow overturning. These findings show how changes in upper-ocean overturning associated with millennial-scale events differ from those associated with whole-ocean deglacial climate events
Short Communication: The potential of portable near infrared spectroscopy for assuring quality and authenticity in the food chain, using Iberian hams as an example
This communication assesses the use of a portable near infrared (NIR) instrument to measure quantitative (fatty acid profile) properties and qualitative (‘Premium’ and ‘Non-premium’) categories of individual Iberian pork carcasses at the slaughterhouse. Acorn-fed Iberian pigs have more unsaturated fats than pigs fed conventional compound feed. Recent advances in miniaturisation have led to a number of handheld NIR devices being developed, allowing processing decisions to be made earlier, significantly reducing time and costs. The most common methods used for assessing quality and authenticity of Iberian hams are analysis of the fatty acid composition of subcutaneous fat using gas chromatography and DNA analysis. In this study, NIR calibrations for fatty acids and classification as premium or non-premium ham, based on carcass fat measured in situ, were developed using a portable NIR spectrometer. The accuracy of the quantitative equations was evaluated through the standard error of cross validation or standard error of prediction of 0.84 for palmitic acid (C16:0), 0.94 for stearic acid (C18:0), 1.47 for oleic acid (C18:1) and 0.58 for linoleic acid (C18:2). Qualitative calibrations provided acceptable results, with up to 98% of samples (n = 234) correctly classified with probabilities ⩾0.9. Results indicated a portable NIR instrument has the potential to be used to measure quality and authenticity of Iberian pork carcasses
Strontium optical lattice clocks for practical realization of the metre and secondary representation of the second
We present a system of two independent strontium optical lattice standards
probed with a single shared ultra-narrow laser. The absolute frequency of the
clocks can be verified by the use of Er:fiber optical frequency comb with the
GPS-disciplined Rb frequency standard. We report hertz-level spectroscopy of
the clock line and measurements of frequency stability of the two strontium
optical lattice clocks.Comment: This is an author-created, un-copyedited version of an article
accepted for publication in Meas. Sci. Technol. The publisher is not
responsible for any errors or omissions in this version of the manuscript or
any version derived from it. The Version of Record is available online at
doi:10.1088/0957-0233/26/7/07520
An Analysis of the Quantum Penny Flip Game using Geometric Algebra
We analyze the quantum penny flip game using geometric algebra and so
determine all possible unitary transformations which enable the player Q to
implement a winning strategy. Geometric algebra provides a clear visual picture
of the quantum game and its strategies, as well as providing a simple and
direct derivation of the winning transformation, which we demonstrate can be
parametrized by two angles. For comparison we derive the same general winning
strategy by conventional means using density matrices.Comment: 8 Pages, 1 Figure, accepted for publication in the Journal of
Physical Society of Japa
- …