Effect of preozonation on wastewater reclamation by the combination of ozonation and soil aquifer treatment

A series of column experiments and risk evaluation showed that preozonation was a better option to enhance the performance of soil aquifer treatment (SAT) than ozonation after SAT with respect to dissolved organic carbon, trace organic contaminants, and disinfection byproducts. This is a good example to show that upgrading pretreatments can be more effective than adding extra treatments after SAT, and that it is important to optimize a water reclamation system as a whole system

Osmotic potential, photosynthetic abilities and growth characters of oil palm (Elaeis guineensis Jacq.) seedlings in responses to polyethylene glycol-induced water deficit

The aim of the present study is to investigate the biochemical, physiological and morphological responses of oil palm seedlings when exposed to polyethylene glycol (PEG)-induced water deficit. Oil palm seedlings were photo-autotrophically grown in MS media and subsequently exposed to -0.23 (control), -0.42, -0.98 or -2.15 MPa PEG-induced water deficit. Osmotic potential (Ψs) in root and leaf tissues of oil palm seedlings grown under PEG-induced water deficit was decreased leading to chlorophyll degradation. Chlorophyll a (Chla), chlorophyll b (Chlb), total chlorophyll (TC), total carotenoids (Cx+c), maximum quantum yield of photosystem II (PSII) (Fv/Fm) and photon yield of PSII (ΦPSII) in the oil palm seedlings under water deficit conditions dropped significantly in comparison to the control group, leading to a reduction in net-photosynthetic rate (Pn) and growth. A positive correlation between physiological and growth parameters, including osmotic potential, photosynthetic pigments and water oxidation in photosystem II and Pn was demonstrated. These data provide the basis for the establishment of multivariate criteria for water deficit tolerance screening in oil palm breeding programs.Key words: Chlorophyll fluorescence, net-photosynthetic rate, pigment, water oxidation, water deficit stress

Dimuon production by laser-wakefield accelerated electrons

We analyze $\mu^+\mu^-$ pair production generated by high-energy electrons emerging from a laser-wakefield accelerator. The $\mu^+\mu^-$ pairs are created in a solid thick high-$Z$ target, following the electron accelerating plasma region. Numerical estimates are presented for electron beams obtained presently in the LBL TW laser experiment \cite{C2} and possible future developments. Reactions induced by the secondary bremsstrahlung photons dominate the dimuon production. According to our estimates, a 20 pC electron bunch with energy of 1 (10) GeV may create about 200 (6000) muon pairs. The produced $\mu^\pm$ can be used in studying various aspects of muon-related physics in table top installations. This may be considered as an important step towards the investigation of more complicated elementary processes induced by laser driven electrons.Comment: 14 pages, 5 figure

Nonaxisymmetric Magnetorotational Instability in Proto-Neutron Stars

We investigate the stability of differentially rotating proto-neutron stars (PNSs) with a toroidal magnetic field. Stability criteria for nonaxisymmetric MHD instabilities are derived using a local linear analysis. PNSs are expected to have much stronger radial shear in the rotation velocity compared to normal stars. We find that nonaxisymmetric magnetorotational instability (NMRI) with a large azimuthal wavenumber $m$ is dominant over the kink mode ($m=1$) in differentially rotating PNSs. The growth rate of the NMRI is of the order of the angular velocity $\Omega$ which is faster than that of the kink-type instability by several orders of magnitude. The stability criteria are analogous to those of the axisymmetric magnetorotational instability with a poloidal field, although the effects of leptonic gradients are considered in our analysis. The NMRI can grow even in convectively stable layers if the wavevectors of unstable modes are parallel to the restoring force by the Brunt-V\"ais\"al\"a oscillation. The nonlinear evolution of NMRI could amplify the magnetic fields and drive MHD turbulence in PNSs, which may lead to enhancement of the neutrino luminosity.Comment: 24pages, 7figures, Accepted for publication in the Astrophysical Journal (December 12, 2005

A review of astrophysics experiments on intense lasers

Astrophysics has traditionally been pursued at astronomical observatories and on theorists’ computers. Observations record images from space, and theoretical models are developed to explain the observations. A component often missing has been the ability to test theories and models in an experimental setting where the initial and final states are well characterized. Intense lasers are now being used to recreate aspects of astrophysical phenomena in the laboratory, allowing the creation of experimental testbeds where theory and modeling can be quantitatively tested against data. We describe here several areas of astrophysics—supernovae, supernova remnants, gamma-ray bursts, and giant planets—where laser experiments are under development to test our understanding of these phenomena. © 2000 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71013/2/PHPAEN-7-5-1641-1.pd

Characterization of electrostatic shock in laser-produced optically-thin plasma flows using optical diagnostics

We present a method for evaluating the properties of electrostatic shock in laser-produced plasmas by using optical diagnostics. A shock is formed by a collimated jet in counter-streaming plasmas in nearly collisionless condition, showing the steepening of the transition width in time. In the present experiment, a streaked optical pyrometry was applied to evaluate the electron density and temperatures in the upstream and downstream regions of the shock so that the shock conditions are satisfied, by assuming thermal bremsstrahlung emission in optically thin plasmas. The derived electron densities are nearly consistent with those estimated from interferometry

X-ray Astronomy in the Laboratory with a Miniature Compact Object Produced by Laser-Driven Implosion

Laboratory spectroscopy of non-thermal equilibrium plasmas photoionized by intense radiation is a key to understanding compact objects, such as black holes, based on astronomical observations. This paper describes an experiment to study photoionizing plasmas in laboratory under well-defined and genuine conditions. Photoionized plasma is here generated using a 0.5-keV Planckian x-ray source created by means of a laser-driven implosion. The measured x-ray spectrum from the photoionized silicon plasma resembles those observed from the binary stars Cygnus X-3 and Vela X-1 with the Chandra x-ray satellite. This demonstrates that an extreme radiation field was produced in the laboratory, however, the theoretical interpretation of the laboratory spectrum significantly contradicts the generally accepted explanations in x-ray astronomy. This model experiment offers a novel test bed for validation and verification of computational codes used in x-ray astronomy.Comment: 5 pages, 4 figures are included. This is the original submitted version of the manuscript to be published in Nature Physic