8,465 research outputs found

    Co- and counter-helicity interaction between two adjacent laboratory prominences

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    The interaction between two side-by-side solar prominence-like plasmas has been studied using a four-electrode magnetized plasma source that can impose a wide variety of surface boundary conditions. When the source is arranged to create two prominences with the same helicity (co-helicity), it is observed that helicity transfer from one prominence to the other causes the receiving prominence to erupt sooner and faster than the transmitting prominence. When the source is arranged to create two prominences with opposite helicity (counter-helicity), it is observed that upon merging, prominences wrap around each other to form closely spaced, writhing turns of plasma. This is followed by appearance of a distinct bright region in the middle and order of magnitude higher emission of soft x rays. The four-electrode device has also been used to change the angle of the neutral line and so form more pronounced S-shapes

    Search for d^* Dibaryon by Double-radiative Capture on Pionic Deuterium

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    We report a search for d^* dibaryon production by double-radiative capture on pionic deuterium. The experiment was conducted at the TRIUMF cyclotron using the RMC cylindrical pair spectrometer, and detected gamma-ray coincidences following pion stops in liquid deuterium. We found no evidence for narrow dibaryons, and obtained a branching ratio upper limit, BR < 6.7 times 10^{-6} (90% C.L.), for narrow d^* production in the mass range from 1920 to 1980 MeV. Replaced with Physics Letter B accepted version and corrected normalization.Comment: 9 pages, 4 figure

    Laboratory simulations of astrophysical jets and solar coronal loops: new results

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    An experimental program underway at Caltech has produced plasmas where the shape is neither fixed by the vacuum chamber nor fixed by an external coil set, but instead is determined by self-organization. The plasma dynamics is highly reproducible and so can be studied in considerable detail even though the morphology of the plasma is both complex and time-dependent. A surprising result has been the observation that self-collimating MHD-driven plasma jets are ubiquitous and play a fundamental role in the self-organization. The jets can be considered lab-scale simulations of astrophysical jets and in addition are intimately related to solar coronal loops. The jets are driven by the combination of the axial component of the J×B force and the axial pressure gradient resulting from the non-uniform pinch force associated with the flared axial current density. Behavior is consistent with a model showing that collimation results from axial non-uniformity of the jet velocity. In particular, flow stagnation in the jet frame compresses frozen-in azimuthal magnetic flux, squeezes together toroidal magnetic field lines, thereby amplifying the embedded toroidal magnetic field, enhancing the pinch force, and hence causing collimation of the jet

    Test of isospin symmetry via low energy 1^1H(π\pi^-,πo\pi^o)nn charge exchange

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    We report measurements of the πpπon\pi^- p \to \pi^o n differential cross sections at six momenta (104-143 MeV/c) and four angles (0-40 deg) by detection of γ\gamma-ray pairs from πoγγ\pi^o \to \gamma \gamma decays using the TRIUMF RMC spectrometer. This region exhibits a vanishing zero-degree cross section from destructive interference between s-- and p--waves, thus yielding special sensitivity to pion-nucleon dynamics and isospin symmetry breaking. Our data and previous data do not agree, with important implications for earlier claims of large isospin violating effects in low energy pion-nucleon interactions.Comment: 5 pages, 3 figures, submitted to Physical Review Letter

    Ortho-para transition rate in μ\mu-molecular hydrogen and the proton's induced pseudoscalar coupling gpg_p

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    We report a measurement of the ortho-para transition rate in the pμ\mup molecule. The experiment was conducted at TRIUMF via the measurement of the time dependence of the 5.2 MeV neutrons from muon capture in liquid hydrogen. The measurement yielded an ortho-para rate Λop=(11.1±1.7±0.60.9)×104\Lambda_{op} = (11.1 \pm 1.7 \pm^{0.9}_{0.6}) \times 10^4 s1^{-1} that is substantially larger than the earlier result of Bardin {\it et al.} We discuss the striking implications for the proton's induced pseudoscalar coupling gpg_p.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let

    Biodegradation of organo-metallic pollutants in distillery wastewater employing bioaugmentation process

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    This objective of this work was to study the potential of a constructed bacterial consortium (comprising strains of Stenotrophomonas maltophilia, Bacillus cereus, and Bacillus thuringiensis) to treat distillery wastewater via the bioaugmentation process. The discharged wastewater showed elevated total ammonium nitrogen (195.0 ± 1.24 mg L-1), total dissolved solids (25980.6 ± 8.09 mg L-1), chemical oxygen demand (20534.5 ± 3.12 mg L-1), and biological oxygen demand (20534.5 ± 3.12 mg L-1). High concentration of heavy metals, phenolic and organo-metallic compounds were also detected. Results showed that growing the bacterial consortium in the distillery wastewater at 37 ºC supplemented with 1% glucose achieved the best colour reduction (up to 90 %) in 144 h. The physico-chemical quality of the treated wastewater also improved by 50-70 %. Furthermore, many of the major organic pollutants present in the distillery wastewater were degraded by the constructed consortium to below detection limit via active biotransformation and biodegradation. Heavy metals were biosorbed by the bacterial consortium, and the ligninolytic enzymes such as Lip and MnP played an important role in the degradation of the organo-metallic pollutants. The constructed bacterial consortia therefore offered a sustainable and effective solution to treat distiller wastewater
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