2,569 research outputs found

    Yang-Yang thermodynamics on an atom chip

    Get PDF
    We investigate the behavior of a weakly interacting nearly one-dimensional (1D) trapped Bose gas at finite temperature. We perform in situ measurements of spatial density profiles and show that they are very well described by a model based on exact solutions obtained using the Yang-Yang thermodynamic formalism, in a regime where other, approximate theoretical approaches fail. We use Bose-gas focusing [Shvarchuck etal., Phys. Rev. Lett. 89, 270404 (2002)] to probe the axial momentum distribution of the gas, and find good agreement with the in situ results.Comment: extended introduction and conclusions, and minor changes throughout; accepted for publication in Phys. Rev. Let

    Yang-Yang thermodynamics on an atom chip

    Get PDF
    We investigate the behavior of a weakly interacting nearly one-dimensional (1D) trapped Bose gas at finite temperature. We perform in situ measurements of spatial density profiles and show that they are very well described by a model based on exact solutions obtained using the Yang-Yang thermodynamic formalism, in a regime where other, approximate theoretical approaches fail. We use Bose-gas focusing [Shvarchuck etal., Phys. Rev. Lett. 89, 270404 (2002)] to probe the axial momentum distribution of the gas, and find good agreement with the in situ results.Comment: extended introduction and conclusions, and minor changes throughout; accepted for publication in Phys. Rev. Let

    Stability and electronic structure of the complex K2_2PtCl6_6 structure-type hydrides

    Full text link
    The stability and bonding of the ternary complex K2_2PtCl6_6 structure hydrides is discussed using first principles density functional calculations. The cohesion is dominated by ionic contributions, but ligand field effects are important, and are responsible for the 18-electron rule. Similarities to oxides are discussed in terms of the electronic structure. However, phonon calculations for Sr2_2RuH6_6 also show differences, particularly in the polarizability of the RuH6_6 octahedra. Nevertheless, the yet to be made compounds Pb2_2RuH6_6 and Be2_2FeH6_6 are possible ferroelectrics. The electronic structure and magnetic properties of the decomposition product, FeBe2_2 are reported. Implications of the results for H storage are discussed

    THE CORRELATION OF MUSCLE FIBER AND PERIMYSIUM THICKNESS TO THE QUALITY OF TURKEY BREAST MEAT

    Get PDF
    Turkey meat is one kind of poultry meat which gives contribute for consumer meat demand. Germany as a second exporter of turkey meat has always improving the quality of turkey meat. One of the important attribute which play main role in meat quality is tenderness. The objectives of the research were to measure of muscle fiber and perimysium of two male turkeys in particular amount then makes comparison of the measurement between them. Tracing identifying factors which have strong influence to the tenderness of turkey meat also was done. The data also supported by the values from pH, EC, color, drip loss, grill loss, and shear force. Hybrid XL and Big 6 as two lines of genetically turkeys was used in this study. They lines have different weight in part of carcass where Hybrid XL is bigger than Big 6. Concerning to the diameter of muscle fiber, Hybrid XL has smaller diameter than Big 6. The type of muscle fiber in turkey meat is II B. The analysis of the data was used software Statistic 10.0 ed. The results showed that pH value gives influences to the meat colour. L* would be increasing when pH value was decreasing and meat color turning pale. L* determined by amount of myoglobin inside of meat. The other factors were influenced each other concerning the tenderness of turkey meat. Big 6 breast meat has better tenderness quality and Hybrid XL meat was more profitable because they have heavier part of carcass. Diameter of muscle fiber has strongest factors than others

    Current and future technical, economic and environmental feasibility of maize and wheat residues supply for biomass energy application:Illustrated for South Africa

    Get PDF
    AbstractThis study assessed the feasibility of mobilising maize and wheat residues for large-scale bioenergy applications in South Africa by establishing sustainable residue removal rates and cost of supply based on different production regions. A key objective was to refine the methodology for estimating crop residue harvesting for bioenergy use, while maintaining soil productivity and avoiding displacement of competing residue uses. At current conditions, the sustainable bioenergy potential from maize and wheat residues was estimated to be about 104 PJ. There is potential to increase the amount of crop residues to 238 PJ through measures such as no till cultivation and adopting improved cropping systems. These estimates were based on minimum residues requirements of 2 t ha−1 for soil erosion control and additional residue amounts to maintain 2% SOC level.At the farm gate, crop residues cost between 0.9 and 1.7 GJ−1.About96 GJ−1. About 96% of these residues are available below 1.5 GJ−1. In the improved scenario, up to 85% of the biomass is below 1.3 GJ−1.Forbiomassdeliveriesattheconversionplant,about36 GJ−1. For biomass deliveries at the conversion plant, about 36% is below 5 GJ−1 while in the optimised scenario, about 87% is delivered below 5$ GJ−1. Co-firing residues with coal results in lower cost of electricity compared to other renewables and significant GHG (CO2 eq) emissions reduction (up to 0.72 tons MWh−1). Establishing sustainable crop residue supply systems in South Africa could start by utilising the existing agricultural infrastructure to secure supply and develop a functional market. It would then be necessary to incentivise improvements across the value chain

    Box traps on an atom chip for one-dimensional quantum gases

    Get PDF
    We present the implementation of tailored trapping potentials for ultracold gases on an atom chip. We realize highly elongated traps with box-like confinement along the long, axial direction combined with conventional harmonic confinement along the two radial directions. The design, fabrication and characterization of the atom chip and the box traps is described. We load ultracold (≲1μ\lesssim1 \muK) clouds of 87^{87}Rb in a box trap, and demonstrate Bose-gas focusing as a means to characterize these atomic clouds in arbitrarily shaped potentials. Our results show that box-like axial potentials on atom chips are very promising for studies of one-dimensional quantum gases.Comment: 9 pages 4 figure

    Continuous selections of multivalued mappings

    Full text link
    This survey covers in our opinion the most important results in the theory of continuous selections of multivalued mappings (approximately) from 2002 through 2012. It extends and continues our previous such survey which appeared in Recent Progress in General Topology, II, which was published in 2002. In comparison, our present survey considers more restricted and specific areas of mathematics. Note that we do not consider the theory of selectors (i.e. continuous choices of elements from subsets of topological spaces) since this topics is covered by another survey in this volume

    The dynamics and prethermalization of one dimensional quantum systems probed through the full distributions of quantum noise

    Get PDF
    Quantum noise correlations have been employed in several areas in physics including condensed matter, quantum optics and ultracold atom to reveal non-classical states of the systems. So far, such analysis mostly focused on systems in equilibrium. In this paper, we show that quantum noise is also a useful tool to characterize and study the non-equilibrium dynamics of one dimensional system. We consider the Ramsey sequence of one dimensional, two-component bosons, and obtain simple, analytical expressions of time evolutions of the full distribution functions for this strongly-correlated, many-body system. The analysis can also be directly applied to the evolution of interference patterns between two one dimensional quasi-condensates created from a single condensate through splitting. Using the tools developed in this paper, we demonstrate that one dimensional dynamics in these systems exhibits the phenomenon known as "prethermalization", where the observables of {\it non-equilibrium}, long-time transient states become indistinguishable from those of thermal {\it equilibrium} states.Comment: 22 pages, 11 figures+appendi

    Precision measurements of the top quark mass from the Tevatron in the pre-LHC era

    Full text link
    The top quark is the heaviest of the six quarks of the Standard Model. Precise knowledge of its mass is important for imposing constraints on a number of physics processes, including interactions of the as yet unobserved Higgs boson. The Higgs boson is the only missing particle of the Standard Model, central to the electroweak symmetry breaking mechanism and generation of particle masses. In this Review, experimental measurements of the top quark mass accomplished at the Tevatron, a proton-antiproton collider located at the Fermi National Accelerator Laboratory, are described. Topologies of top quark events and methods used to separate signal events from background sources are discussed. Data analysis techniques used to extract information about the top mass value are reviewed. The combination of several most precise measurements performed with the two Tevatron particle detectors, CDF and \D0, yields a value of \Mt = 173.2 \pm 0.9 GeV/c2c^2.Comment: This version contains the most up-to-date top quark mass averag

    Colour reconnections in Herwig++

    Get PDF
    We describe the implementation details of the colour reconnection model in the event generator Herwig++. We study the impact on final-state observables in detail and confirm the model idea from colour preconfinement on the basis of studies within the cluster hadronization model. Moreover, we show that the description of minimum bias and underlying event data at the LHC is improved with this model and present results of a tune to available data.Comment: 19 pages, 21 figures, 2 tables. Matches with published versio
    • …
    corecore