Diagnostic analysis of RO desalting treated waste water

Diagnostic analysis of reverse osmosis membranes that were fed with Western treatment plant (WTP) recycled water was investigated by both thermodynamic calculations and laboratory experiments in order to predict the feasibility of RO desalting for WTP. The thermodynamic calculations suggested that RO recoveries of 80–85% were feasible with careful control of feed water pH and the use of chemical additives such as antiscalants and chelating agents, it also predicted the major minerals of concern to be silica, calcium fluoride, calcium carbonate, and calcium phosphate. Following the thermodynamic simulations, diagnostic laboratory experiments were undertaken. The experiments showed that the major contributor to scale formation was indeed calcium phosphate and possibly another calcium based compound, which was strongly suspected to be calcium carbonate. Based on previously published literature that indicated anti-scalants did not substantially decrease the scaling effect of calcium phosphate and laboratory tests that indicated controlling the pH to 6.4 in the feed water dramatically reduced scaling formation, it was suggested that the feed water could be controlled by pH adjustments only. Inter-stage pH correction was suggested as an optional technique to enhance the overall water recovery to above 95%

The art of coaching: Addressing mobile technology integration in a complex hospital school environment

This qualitative study examined the effects of a coaching program as part of a professional development effort to support integration of mobile technologies in a hospital school setting. The professional development consisted of two components: (a) the researchers introduced pedagogical models for incorporating mobile technology in education and (b) a technological expert (the iCoach) provided one-on-one and small-group personalized coaching. After studying the contextual challenges and teachers’ needs over a period of 12 months, an effective coaching model emerged. This was a personalized model geared to each teacher and tailored to the unique features of this hospital context. An integral part of the model was a reflection strategy, which encouraged teachers to question their teaching with the purposeful use of technology. Data collection involved teachers’ reflections, iCoach reflections, and semi-structured interviews. Many themes emerged from the data analysis; the two main ones were the uniqueness of the setting and the multiplicity of demands on the teachers and the iCoach. The study developed a set of guidelines to help teachers use technology in an integrated pedagogical way

Soft interaction model and the LHC data

Most models for soft interactions which were proposed prior to the measurements at the LHC, are only marginally compatible with LHC data, our GLM model has the same deficiency. In this paper we investigate possible causes of the problem, by considering separate fits to the high energy ($W > 500\, GeV$), and low energy ($W < 500\, GeV$) data. Our new results are moderately higher than our previous predictions. Our results for total and elastic cross sections are systematically lower that the recent Totem and Alice published values, while our results for the inelastic and forward slope agree with the data. If with additional experimental data, the errors are reduced, while the central cross section values remain unchanged, we will need to reconsider the physics on which our model is built.Comment: 12 pp, 12 figures in .eps file

The Synthesis and Origin of the Pectic Polysaccharide Rhamnogalacturonan II – Insights from Nucleotide Sugar Formation and Diversity

There is compelling evidence showing that the structurally complex pectic polysaccharide rhamnogalacturonan II (RG-II) exists in the primary cell wall as a borate cross-linked dimer and that this dimer is required for the assembly of a functional wall and for normal plant growth and development. The results of several studies have also established that RG-II structure and cross-linking is conserved in vascular plants and that RG-II likely appeared early in the evolution of land plants. Two features that distinguish RG-II from other plant polysaccharides are that RG-II is composed of 13 different glycoses linked to each other by up to 22 different glycosidic linkages and that RG-II is the only polysaccharide known to contain both apiose and aceric acid. Thus, one key event in land plant evolution was the emergence of genes encoding nucleotide sugar biosynthetic enzymes that generate the activated forms of apiose and aceric acid required for RG-II synthesis. Many of the genes involved in the generation of the nucleotide sugars used for RG-II synthesis have been functionally characterized. By contrast, only one glycosyltransferase involved in the assembly of RG-II has been identified. Here we provide an overview of the formation of the activated sugars required for RG-II synthesis and point to the possible cellular and metabolic processes that could be involved in assembling and controlling the formation of a borate cross-linked RG-II molecule. We discuss how nucleotide sugar synthesis is compartmentalized and how this may control the flux of precursors to facilitate and regulate the formation of RG-II

Evolution of density perturbations in double exponential quintessence models

In this work we investigate the evolution of matter density perturbations for quintessence models with a self-interaction potential that is a combination of exponentials. One of the models is based on the Einstein theory of gravity, while the other is based on the Brans-Dicke scalar tensor theory. We constrain the parameter space of the models using the determinations for the growth rate of perturbations derived from data of the 2-degree Field Galaxy Redshift Survey.Comment: 5 pages, 3 eps figure

Distances in inhomogeneous quintessence cosmology

We investigate the properties of cosmological distances in locally inhomogeneous universes with pressureless matter and dark energy (quintessence), with constant equation of state. We give exact solutions for angular diameter distances in theempty beam approximation. In this hypothesis, the distance-redshift equation is derived fron the multiple lens-plane theory. The case of a flat universe is considered with particular attention. We show how this general scheme makes distances degenerate with respect to w_X and the smoothness parameters, alpha, accounting for the homogeneously distributed fraction of energy of the i-components. We analyse how this degeneracy influences the critical redshift where the angular diameter distance takes its maximum, and put in evidence future prospects for measuring the smoothness parameter of the pressureless matter, alpha_M.Comment: 24 pages, 9 ps figure

Testing the black disk limit in pppp collisions at very high energy

We use geometric scaling invariant quantities to measure the approach, or not, of the imaginary and real parts of the elastic scattering amplitude, to the black disk limit, in $pp$ collisions at very high energy.Comment: 11 pages, 4 figure

Supernovae and the Nature of the Dark Energy

The use of Type Ia supernovae as calibrated standard candles is one of the most powerful tools to study the expansion history of the universe and thereby its energy components. While the analysis of some ~50 supernovae at redshifts around z~0.5 have provided strong evidence for an energy component with negative pressure, ``dark energy'', more data is needed to enable an accurate estimate of the amount and nature of this energy. This might be accomplished by a dedicated space telescope, the SuperNova / Acceleration Probe (2000; SNAP), which aims at collecting a large number of supernovae with z<2. In this paper we assess the ability of the SNAP mission to determine various properties of the ``dark energy.'' To exemplify, we expect SNAP, if operated for three years to study Type Ia supernovae, to be able to determine the parameters in a linear equation of state w(z)=w0 + w1 z to within a statistical uncertainty of +-0.04 for w0 and +0.15,-0.17 for w1 assuming that the universe is known to be flat and an independent high precision (sigma_{Omega_m}=0.015) measurement of the mass density Omega_m, is used to constrain the fit. An additional improvement can be obtained if a large number of low-z, as well as high-z, supernovae are included in the sample.Comment: 13 pages, submitted to A&

Quantized Non-Abelian Monopoles on S^3

A possible electric-magnetic duality suggests that the confinement of non-Abelian electric charges manifests itself as a perturbative quantum effect for the dual magnetic charges. Motivated by this possibility, we study vacuum fluctuations around a non-Abelian monopole-antimonopole pair treated as point objects with charges g=\pm n/2 (n=1,2,...), and placed on the antipodes of a three sphere of radius R. We explicitly find all the fluctuation modes by linearizing and solving the Yang-Mills equations about this background field on a three sphere. We recover, generalize and extend earlier results, including those on the stability analysis of non-Abelian magnetic monopoles. We find that for g \ge 1 monopoles there is an unstable mode that tends to squeeze magnetic flux in the angular directions. We sum the vacuum energy contributions of the fluctuation modes for the g=1/2 case and find oscillatory dependence on the cutoff scale. Subject to certain assumptions, we find that the contribution of the fluctuation modes to the quantum zero point energy behaves as -R^{-2/3} and hence decays more slowly than the classical -R^{-1} Coulomb potential for large R. However, this correction to the zero point energy does not agree with the linear growth expected if the monopoles are confined.Comment: 18 pages, 5 figures. Minor changes, reference list update

Constraining slow-roll inflation with WMAP and 2dF

We constrain slow-roll inflationary models using the recent WMAP data combined with data from the VSA, CBI, ACBAR and 2dF experiments. We find the slow-roll parameters to be $0 < \epsilon_1 < 0.032$ and $\epsilon_2 + 5.0 \epsilon_1 = 0.036 \pm 0.025$. For inflation models $V \propto \phi^{\alpha}$ we find that $\alpha< 3.9, 4.3$ at the 2$\sigma$ and $3\sigma$ levels, indicating that the $\lambda\phi^4$ model is under very strong pressure from observations. We define a convergence criterion to judge the necessity of introducing further power spectrum parameters such as the spectral index and running of the spectral index. This criterion is typically violated by models with large negative running that fit the data, indicating that the running cannot be reliably measured with present data.Comment: 8 pages RevTeX4 file with six figures incorporate