568 research outputs found
Improving methane production from digested manure biofibers by mechanical and thermal alkaline pretreatment
Standard-model prediction for direct CP violation in decay
We report the first lattice QCD calculation of the complex kaon decay
amplitude with physical kinematics, using a lattice
volume and a single lattice spacing , with GeV. We find
Re GeV and Im GeV, where the first error is statistical
and the second systematic. The first value is in approximate agreement with the
experimental result: Re GeV while the second
can be used to compute the direct CP violating ratio
Re, which is
below the experimental value . The real
part of is CP conserving and serves as a test of our method while the
result for Re provides a new test of the
standard-model theory of CP violation, one which can be made more accurate with
increasing computer capability.Comment: 9 pages, 3 figures. Updated to match published versio
Domain wall QCD with physical quark masses
We present results for several light hadronic quantities (, ,
, , , , ) obtained from simulations of 2+1
flavor domain wall lattice QCD with large physical volumes and nearly-physical
pion masses at two lattice spacings. We perform a short, O(3)%, extrapolation
in pion mass to the physical values by combining our new data in a simultaneous
chiral/continuum `global fit' with a number of other ensembles with heavier
pion masses. We use the physical values of , and to
determine the two quark masses and the scale - all other quantities are outputs
from our simulations. We obtain results with sub-percent statistical errors and
negligible chiral and finite-volume systematics for these light hadronic
quantities, including: = 130.2(9) MeV; = 155.5(8) MeV; the
average up/down quark mass and strange quark mass in the scheme
at 3 GeV, 2.997(49) and 81.64(1.17) MeV respectively; and the neutral kaon
mixing parameter, , in the RGI scheme, 0.750(15) and the
scheme at 3 GeV, 0.530(11).Comment: 131 pages, 30 figures. Updated to match published versio
Experimental quantum tossing of a single coin
The cryptographic protocol of coin tossing consists of two parties, Alice and
Bob, that do not trust each other, but want to generate a random bit. If the
parties use a classical communication channel and have unlimited computational
resources, one of them can always cheat perfectly. Here we analyze in detail
how the performance of a quantum coin tossing experiment should be compared to
classical protocols, taking into account the inevitable experimental
imperfections. We then report an all-optical fiber experiment in which a single
coin is tossed whose randomness is higher than achievable by any classical
protocol and present some easily realisable cheating strategies by Alice and
Bob.Comment: 13 page
γ-Cyclodextrin Metal-Organic Frameworks: Do Solvents Make a Difference?
Conventionally, methanol is the solvent of choice in the synthesis of gamma-cyclodextrin metal-organic frameworks (γ-CD-MOFs), but using ethanol as a replacement could allow for a more food-grade synthesis condition. Therefore, the aim of the study was to compare the γ-CD-MOFs synthesised with both methanol and ethanol. The γ-CD-MOFs were characterised by scanning electron microscopy (SEM), surface area and pore measurement, Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffraction (PXRD). The encapsulation efficiency (EE) and loading capacity (LC) of the γ-CD-MOFs were also determined for curcumin, using methanol, ethanol and a mixture of the two as encapsulation solvent. It was found that γ-CD-MOFs synthesised by methanol and ethanol do not differ greatly, the most significant difference being the larger crystal size of γ-CD-MOFs crystallised from ethanol. However, the change in solvent significantly influenced the EE and LC of the crystals. The higher solubility of curcumin in ethanol reduced interactions with the γ-CD-MOFs and resulted in lowered EE and LC. This suggests that different solvents should be used to deliberately manipulate the EE and LC of target compounds for better use of γ-CD-MOFs as their encapsulating and delivery agents
Electromagnetic levitation containerless processing of metallic materials in microgravity: thermophysical properties
Transitions from the liquid to the solid state of matter are omnipresent. They form a crucial step in the industrial solidification of
metallic alloy melts and are greatly influenced by the thermophysical properties of the melt. Knowledge of the thermophysical
properties of liquid metallic alloys is necessary in order to gain a tight control over the solidification pathway, and over the obtained
material structure of the solid. Measurements of thermophysical properties on ground are often difficult, or even impossible, since
liquids are strongly influenced by earth’s gravity. Another problem is the reactivity of melts with container materials, especially at
high temperature. Finally, deep undercooling, necessary to understand nucleus formation and equilibrium as well as nonequilibrium solidification, can only be achieved in a containerless environment. Containerless experiments in microgravity allow
precise benchmark measurements of thermophysical properties. The electromagnetic levitator ISS-EML on the International Space
Station (ISS) offers perfect conditions for such experiments. This way, data for process simulations is obtained, and a deeper
understanding of nucleation, crystal growth, microstructural evolution, and other details of the transformation from liquid to solid
can be gained. Here, we address the scientific questions in detail, show highlights of recent achievements, and give an outlook on
future work
Ab-initio Determination of Light Hadron Masses
More than 99% of the mass of the visible universe is made up of protons and
neutrons. Both particles are much heavier than their quark and gluon
constituents, and the Standard Model of particle physics should explain this
difference. We present a full ab-initio calculation of the masses of protons,
neutrons and other light hadrons, using lattice quantum chromodynamics. Pion
masses down to 190 mega electronvolts are used to extrapolate to the physical
point with lattice sizes of approximately four times the inverse pion mass.
Three lattice spacings are used for a continuum extrapolation. Our results
completely agree with experimental observations and represent a quantitative
confirmation of this aspect of the Standard Model with fully controlled
uncertainties.Comment: 22 pages, 3 Tables, 8 Figures. Published in Science (21 November
2008) with Supporting Online Material. Submission to arXiv has been delayed
by 6 months to respect the journal's embargo polic
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