Development of a slurry continuous flow reactor for photocatalytic treatment of industrial waste water

The water treatment capability of a novel photocatalytic slurry reactor was investigated using methylene blue (MB) as a model pollutant in an aqueous suspension. A pellet TiO ₂ catalyst was employed and this freed the system from the need of filtration of catalyst following photocatalysis. This configuration combines the high surface area contact of catalyst with pollutant of the slurry reactor and also offers a high illumination of catalyst by its unique array of weir-like baffles. In this work, the batch adsorption of MB from aqueous solution (10μM) onto the TiO ₂ catalyst was studied, adsorption isotherms and kinetics were determined from the experimental data. Complete degradation of MB was achieved within 60 min illumination with various loadings of catalyst (30-200 g L ^-1). A modest catalyst loading (30 g L ^-1) achieved 98% degradation within 60 min of irradiation. Experimental results indicate that this novel reactor configuration has a high effective mass transfer rate and UV light penetration characteristics. 

Photocatalytic reactors for environmental remediation: A review

Research in the field of photocatalytic reactors in the past three decades has been an area of extensive and diverse activity with an extensive range of suspended and fixed film photocatalyst configurations being reported. The key considerations for photocatalytic reactors, however, remain the same; effective mass transfer of pollutants to the photocatalyst surface and effective deployments and illumination of the photocatalyst. Photocatalytic reactors have the potential versatility to be applied to the remediation of a range of water and gaseous effluents. Furthermore they have also been applied to the treatment of potable waters. The scale-up of photocatalytic reactors for waste and potable water treatment plants has also been demonstrated. Systems for the reduction of carbon dioxide to fuel products have also been reported. This paper considers the main photocatalytic reactor configurations that have been reported to date. 

Effective monitoring for ractopamine residues in samples of animal origin by SPR biosensor and mass spectrometry

Ractopamine (RCT) is a member of the beta-2-agonist (beta-agonist) family. It is licensed for use as an animal growth promoter in more than 20 countries worldwide, including the United States and Canada, but is either not licensed or prohibited by over 150 others, including those within the European Union. The issue of the use of RCT in livestock bound for human consumption has risen to prominence recently following the decision by The People's Republic of China to ban the import of pork from a number of processing plants after finding traces of RCT in shipments from the U.S.A.

Radiative rates, collision strengths and effective collision strengths for transitions in Mo XXXIV

Radiative rates for electric dipole (E I), electric quadrupole (E2), magnetic dipole (M1), and magnetic quadrupole (M2) transitions among the lowest 60 fine-structure levels of the (1s(2)) 2S(2)2p(5), 2s2p(6), and 2S(2)2p(4)3l configurations of F-like Mo XXXIV have been calculated using the fully relativistic GRASP code. Additionally, collision strengths for transitions among these levels have been computed over a wide energy range below 3200Ry, using the Dirac Atomic R-matrix Code. Resonances have been resolved in a fine energy mesh in order to calculate the effective collision strengths. Results for radiative rates and excitation rates are presented for all transitions, and for collision strengths for transitions from the lowest three levels to the higher lying levels. The accuracy of the present data is assessed to be similar to 20%.

Effective collision strengths for transitions within the ground configuration of Fe XXI

Effective collision strengths for transitions among the energetically lowest 46 fine-structure levels belonging to the (1s(2)) 2S(2) 2p(2), 2s2p(3), 2p(4), 2S(2)2p3s, 2s(2)2p3p and 2S(2)2p3d configurations of Fe XXI are computed, over an electron temperature range of 5.6 less than or equal to log T-e less than or equal to 7.4 K, using the recent Dirac Atomic R- matrix Code (DARC) of Norrington and Grant. Results are presented for transitions within the ground configuration only, and are compared with earlier R matrix calculations. Large discrepancies are observed for many transitions, especially at lower temperatures.

Radiative rates, collision strengths and effective collision strengths for transitions in Gd XXXVII

Energy levels and radiative rates for transitions among 107 fine-structure levels belonging to the (1s(2)2S(2)p(6)) 3S(2)3p(6)3d(10), 3S(2)3p(6)3d(9)4e. 3S(2)3p(5)3d(10)4e. and 3s3p(6)3d(10)4e configurations of Ni-like Gd XXXVII have been calculated using the fully relativistic GRASP code. Radiative rates and oscillator strengths are tabulated for all allowed transitions among these levels. Additionally. collision strengths for transitions among the lowest 59 levels have been computed using the Dirac Atomic R-matrix Code. Resonances in the threshold region have been delineated, but results for collision strengths are tabulated only at energies above thresholds in the range 120

Effective collision strengths for transitions among the 3s(2), 3s3p and 3p(2) configurations of Fe xv

Effective collision strengths for transitions among the ten energetically lowest fine-structure levels belonging to the (1s(2)2s(2)2p(6))3s(2), 3s3p and 3p(2) configurations of Fe xv have been calculated in the electron temperature range of 10(5)-10(7) K, using the recent Dirac atomic R-matrix code of Norrington and Grant. The results are compared with the other recently available independent Breit-Pauli R-matrix calculations of Eissner et al (Eissner W, Galavis M E, Mendoza C and Zeippen C J 1999 Astron. Astrophys. Suppl. 137 165) and Griffin et al (Griffin DC, Badnell N R, Pindzola M S and Shaw J A 1999 J. Phys. B: At. Mol. Opt. Phys. 32 2139, 4129). Large differences are observed for many transitions over almost the entire temperature range. These differences are analysed and discussed, and the accuracy of the calculations is assessed.

Effective collision strengths for electron impact excitation of Si VIII

Effective collision strengths for electron-impact excitation of the nitrogen-like ion Si VIII are presented over the wide range of electron temperatures log T(K) = 4.0-6.5. All 231 fine- structure transitions among the 22 fine-structure levels arising from the lowest 11 LS target states (2s(2)2p(3), 2s2p(4), 2p(5), and 2s(2)2p(2)3s) are considered in the tabulation. The collision strengths are evaluated in a multi- channel R-matrix approach, and the corresponding effective collision strengths are obtained by averaging these over a Maxwellian distribution of electron velocities. Comparisons are made with recent distorted-wave results at high incident electron energies. Differences of up to 20% are found, particularly for some allowed transitions. (C) 2003 Elsevier Inc. All rights reserved.

Dynamical and steady-state requirements for effective entanglement transfer

Entanglement transfer processes from a continuous-variable (CV) to a qubit system have primary importance in quantum information processing due to some practical implications in the realization of a quantum network. A CV system can propagate entanglement while a qubit system is easy to manipulate. We study conditions to entangle two atomic qubits with a two-mode squeezed field driving two cavities containing the atoms.

The VLT-FLAMES survey of massive stars: mass loss and rotation of early-type stars in the SMC

We have studied the optical spectra of a sample of 31 O- and early B-type stars in the Small Magellanic Cloud, 21 of which are associated with the young massive cluster NGC 346. Stellar parameters are determined using an automated fitting method (Mokiem et al. 2005, A&A, 441, 711), which combines the stellar atmosphere code FASTWIND (Puls et al. 2005, A&A, 435, 669) with the genetic algorithm based optimisation routine PIKAIA (Charbonneau 1995, ApJS, 101, 309). Comparison with predictions of stellar evolution that account for stellar rotation does not result in a unique age, though most stars are best represented by an age of 1-3 Myr. The automated method allows for a detailed determination of the projected rotational velocities. The present day v(r) sin i distribution of the 21 dwarf stars in our sample is consistent with an underlying rotational velocity (v(r)) distribution that can be characterised by a mean velocity of about 160-190 km s(-1) and an effective half width of 100-150 km s(-1). The vr distribution must include a small percentage of slowly rotating stars. If predictions of the time evolution of the equatorial velocity for massive stars within the environment of the SMC are correct (Maeder & Meynet 2001, A&A, 373, 555), the young age of the cluster implies that this underlying distribution is representative for the initial rotational velocity distribution. The location in the Hertzsprung-Russell diagram of the stars showing helium enrichment is in qualitative agreement with evolutionary tracks accounting for rotation, but not for those ignoring vr. The mass loss rates of the SMC objects having luminosities of log L-star/L-circle dot greater than or similar to 5.4 are in excellent agreement with predictions by Vink et al. (2001, A&A, 369, 574). However, for lower luminosity stars the winds are too weak to determine. M accurately from the optical spectrum. Three targets were classified as Vz stars, two of which are located close to the theoretical zero-age main sequence. Three lower luminosity targets that were not classified as Vz stars are also found to lie near the ZAMS. We argue that this is related to a temperature effect inhibiting cooler from displaying the spectral features required for the Vz luminosity class.

Geometry- and diffraction-independent ionization probabilities in intense laser fields: Probing atomic ionization mechanisms with effective intensity matching

We report an experimental technique for the comparison of ionization processes in ultrafast laser pulses irrespective of pulse ellipticity. Multiple ionization of xenon by 50 fs 790 nm, linearly and circularly polarized laser pulses is observed over the intensity range 10 TW/cm(2) to 10 PW/cm(2) using effective intensity matching (EIM), which is coupled with intensity selective scanning (ISS) to recover the geometry-independent probability of ionization. Such measurements, made possible by quantifying diffraction effects in the laser focus, are compared directly to theoretical predictions of multiphoton, tunnel and field ionization, and a remarkable agreement demonstrated. EIM-ISS allows the straightforward quantification of the probability of recollision ionization in a linearly polarized laser pulse. Furthermore, the probability of ionization is discussed in terms of the Keldysh adiabaticity parameter gamma, and the influence of the precursor ionic states present in recollision ionization is observed.

Enrichment and analysis of nonenzymatically glycated peptides: Boronate affinity chromatography coupled with electron-transfer dissociation mass spectrometry

Nonenzymatic glycation of peptides and proteins by D-glucose has important implications in the pathogenesis of diabetes mellitus, particularly in the development of diabetic complications. However, no effective high-throughput methods exist for identifying proteins containing this low-abundance posttranslational modification in bottom-up proteomic studies. In this report, phenylboronate affinity chromatography was used in a two-step enrichment scheme to selectively isolate first glycated proteins and then glycated, tryptic peptides from human serum glycated in vitro. Enriched peptides were subsequently analyzed by alternating electron-transfer dissociation (ETD) and collision induced dissociation ( CID) tandem mass spectrometry. ETD fragmentation mode permitted identification of a significantly higher number of glycated peptides (87.6% of all identified peptides) versus CID mode (17.0% of all identified peptides), when utilizing enrichment on first the protein and then the peptide level. This study illustrates that phenylboronate affinity chromatography coupled with LC-MS/MS and using ETD as the fragmentation mode is an efficient approach for analysis of glycated proteins and may have broad application in studies of diabetes mellitus.

Effective collision strengths for inner shell transitions of Fe XVI

Collision strengths for transitions among the energetically lowest 134 levels of the (1s(2)2s(2)) 2p(6)3l, 2p(5)3s(2), 2p(5)3s3p, 2p(5)3s3d, 2p(5)3p3d and 2p(5)3d(2) configurations of Fe XVI are computed, over an electron energy range below 570 Ryd, using the Dirac atomic R-matrix code (DARC) and the flexible atomic code (FAC). All partial waves with J

Measurements of the XUV mass absorption coefficient of an overdense liquid metal

The increase in the XUV mass absorption coefficient of liquid aluminium, produced by high-power-laser shock-compression, is measured using XUV laser radiography. At a photon energy of 63 eV a change in the mass absorption coefficient by up to a factor of similar to2.2 is determined at densities close to twice that of solid and electron temperatures of the order of 1 eV. Comparison with hydrodynamic simulations indicate that the absorption coefficient scales with density as rho (1.3 +/-0.2).