459 research outputs found

    ORGANIZATIONAL DESIGN, ORGANIZATIONAL LEARNING, AND THE MARKET VALUE OF THE FIRM

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    We compare market returns associated with firms' creation of new units focused on e-business. Two aspects of organization design - governance and leadership - are considered with regard to exploitation - and exploration-oriented organization learning. We find that exploitation in governance (high centralization) is associated with a lower mean and variance in returns; that exploitation in leadership (appointment of outsiders) is associated with the same mean yet higher variance; and, among units exhibiting both modes of learning, the variance of returns are not equal

    The effect of cationic surfactants on improving natural clinoptilolite for the flotation of cesium - Dataset

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    In this study, flotation was investigated as a rapid separation technique to dewater powdered clinoptilolite ion-exchange resins by utilising cationic surfactant collectors, for the decontamination of radioactive cesium ions (Cs+) from nuclear waste effluent streams. The zeta potential of clinoptilolite with different concentrations of cesium is included in the datafile entitled "Zetapotential". Adsorption equilibrium and kinetics of cesium on clinoptilolite is given in the datafile entitled "AdsorptionKin". The particle size distribution of Cs-contaminated clinoptilolite with different surfactant concentrations of EHDa-Br and CPC, is given in the datafile called "Particlesized". Equilibrium air-water surface tension of EHDA-Br and CPC surfactants is given in the datafile "SurfaceTensio". This datafile also contains the surface tension of mixed surfactant-clinoptilolite systems and the resulting adsorption coefficient distribution. The total amount of remobilised Cs+ in ppm and percentage terms, of a 5 ppm dose from adsorption of surfactant onto clinoptilolite, is given in the datafile "AASsurfactant". Lastly, in the datafile called "Flotation", is given both the clinoptilolite recovery and water reduction ratio as surfactant concentration is varied for a) EHDA-Br and b) CPC ; including the effect of MIBC concentration and the effect of cesium concentration changes. Overall, this study highlighted the great viability of flotation to separate and concentrate the contaminated powder in the froth phase

    From dilute polyelectrolyte solutions to entangled polyelectrolyte networks: a study of sodium carboxymethyl cellulose in water by light scattering and rheology

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    Sodium carboxymethyl cellulose (Na CMC) is widely used in industry for its thickening and swelling properties. Applications are very broad and include pharmaceutical, food, home and personal care products as well as the paper industry, water treatment and mineral processing. Na CMC is a linear negatively charged water-soluble polymer derived from cellulose. Its behaviour in water is known to be very complex and a function of several parameters including the characteristics of the polymer itself [1] such as molecular weight and degree of substitution as well as the solution concentration and dissolution conditions [2] (e.g. addition order of the system components) [3]. While Dynamic Light Scattering (DLS) has been widely used to study the behaviour of polyelectrolytes, relatively few DLS studies have been conducted on Na CMC and, to our knowledge, none in pure water; this is most likely due to the difficulty of preparing salt-free Na CMC solutions of DLS grade. Indeed, the presence of even a few poorly substituted Na CMC fibres suffices to prevent proper DLS data from being collected. The aim of the present study was to investigate the behaviour of Na CMC (Mw = 700,000 g/mol; DS = 0.9) in pure water using both DLS and rheology measurements. A method was developed to prepare samples of appropriate quality for DLS measurements, which could then be successfully run over a wide range of concentrations. Rheology measurements were run in parallel to identify the different concentration regimes, facilitating comparisons to the behaviour typically found for polyelectrolytes (see Figure 1). Both DLS and rheology measurements were combined to look at the relationships between the structure of the Na CMC solutions and their rheological properties. Please click Additional Files below to see the full abstract

    Characterisation of multiple hindered settling regimes in aggregated mineral suspensions

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    Aqueous suspensions of magnesium hydroxide are shown to exhibit low ζ-potential behavior and highly complex settling dynamics. Two distinct regimes of hindered settling behavior are observed on either side of a threshold concentration, ϕ*, of 2.38% v/v, which is considerably below the gel point, ϕg, observed at 5.4 ± 1.6% v/v. The low-concentration regime was characterized by a very large Richardson and Zaki exponent of 146, a factor of 10 larger than that of the high-concentration regime. Michaels and Bolger analysis of the low-concentration regime implies settling governed by large, low-density macroaggregates of 138–147 μm diameter and low intraaggregate packing fractions on the order of 0.05, which is in good agreement with in situ particle characterization undertaken using particle vision and measurement (PVM) and focused-beam reflectance measurements (FBRM). The large macroaggregates must undergo some shear densification within the higher-concentration hindered settling regime in order for the suspension to gel at a concentration of 5.4% v/v. Consequently, fluid flow past small, shear-resistant primary agglomerates, observed within the aggregates using scanning electron microscopy and flow particle image analysis, during aggregate densification may represent the limiting step for dewatering within the high-concentration regime

    Synthesis of nuclear waste simulants by reaction precipitation: formation of caesium phosphomolybdate, zirconium molybdate and morphology modification with citratomolybdate complex

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    Caesium phosphomolybdate (CsPMoO·xHO) and zirconium molybdate ([ZrMoO(OH)]·2HO) solids are known to precipitate out from highly active liquors (HAL) during reprocessing of spent nuclear fuel. Here, a new synthesis for these simulants is reported; with the initial step producing spherical ceasium phosphomolybdate particles, which can then be converted into cubic Zirconium molybdate. Additionally, the addition of citric acid prior to the formation of the zirconium salt is investigated. In this case, a citratomolybdate complex is generated, leading to the synthesis of elongated cuboidal zirconium citratomolybdate ([ZrMoO(OH)]·2HO·[(MoO)O(cit)]). A key focus of this study is to explore the optimisation of reaction conditions to create a controlled environment for the particles to form with high conversion rates and with desired shape properties. Elemental and structural characterisation of the particles at various points during the synthesis, as well as post-synthesis, was undertaken to provide further insights. Ultimately, it is of importance to determine the mechanism of how these simulants are formed within the components in HAL. Establishing the influence of particle properties on HAL behaviour is key for current processing, post operational clean out (POCO) and life-time assessment of the nuclear waste facilities

    Measurements of Submicron Particle Adsorption and Particle Film Elasticity at Oil-Water Interfaces

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    The influence of particle adsorption on liquid/liquid interfacial tension is not well understood, and much previous research has suggested conflicting behaviors. In this paper we investigate the surface activity and adsorption kinetics of charge stabilized and pH-responsive polymer stabilized colloids at oil/water interfaces using two tensiometry techniques: (i) pendant drop and (ii) microtensiometer. We found, using both techniques, that charge stabilized particles had little or no influence on the (dynamic) interfacial tension, although dense silica particles affected the "apparent" measured tension in the pendent drop, due to gravity driven elongation of the droplet profile. Nevertheless, this apparent change additionally allowed the study of adsorption kinetics, which was related qualitatively between particle systems by estimated diffusion coefficients. Significant and real interfacial tension responses were measured using ∼53 nm core-shell latex particles with a pH-responsive polymer stabilizer of poly(methyl methacrylate)-b-poly(2-(dimethylamino)ethyl methacrylate) (pMMA-b-pDMAEMA) diblock copolymer. At pH 2, where the polymer is strongly charged, behavior was similar to that of the bare charge-stabilized particles, showing little change in the interfacial tension. At pH 10, where the polymer is discharged and poorly soluble in water, a significant decrease in the measured interfacial tension commensurate with strong adsorption at the oil-water interface was seen, which was similar in magnitude to the surface activity of the free polymer. These results were both confirmed through droplet profile and microtensiometry experiments. Dilational elasticity measurements were also performed by oscillation of the droplet; again, changes in interfacial tension with droplet oscillation were only seen with the responsive particles at pH 10. Frequency sweeps were performed to ascertain the dilational elasticity modulus, with measured values being significantly higher than previously reported for nanoparticle and surfactant systems, and similar in magnitude to protein stabilized droplets.</p

    KSU Chamber Singers, A Litany for Courage and the Seasons

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    Kennesaw State University Chamber Singers present David Maslanka\u27s A Litany for Courage and the Seasons, six songs for chorus, clarinet and vibraphone on poems of Richard Beale at the 2013 National Collegiate Choral Organization 5th National Conference in Charleston, South Carolina, October 31 - November 2.https://digitalcommons.kennesaw.edu/musicprograms/1268/thumbnail.jp

    KSU Chamber Singers and Men\u27s Ensemble

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    KSU School of Music presents KSU Chamber Singers and Men\u27s Ensemble.https://digitalcommons.kennesaw.edu/musicprograms/1294/thumbnail.jp

    Particle concentration measurement and flow regime identification in multiphase pipe flow using a generalised dual-frequency inversion method

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    An acoustic particle concentration measurement method, originally developed for marine sediment, in which the backscattered energy received by emitter-receiver transducers in the megahertz range is used to construct concentration profiles in suspensions of solid particles in a carrier fluid is applied to suspensions of general engineering interest. Four particle species with range of densities and sizes are used. Concentration profiles in horizontal, turbulent pipe flow at a Reynolds number of 50,000 and three nominal volume fractions are presented for each particle species, using experimentally determined acoustic coefficients, in order to isolate the influence of particle size and density on transport and settling in solid-liquid multiphase flows. It is clear from the results that the method allows the degree of segregation in real suspensions and slurries to be measured, and has a range of potential applications in the nuclear and minerals processing industries, for example. Lastly, the limiting conditions of the method are explored through the concept of an acoustic penetration depth

    Masses, radii, and orbits of small Kepler planets : The transition from gaseous to rocky planets

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    We report on the masses, sizes, and orbits of the planets orbiting 22 Kepler stars. There are 49 planet candidates around these stars, including 42 detected through transits and 7 revealed by precise Doppler measurements of the host stars. Based on an analysis of the Kepler brightness measurements, along with high-resolution imaging and spectroscopy, Doppler spectroscopy, and (for 11 stars) asteroseismology, we establish low false-positive probabilities (FPPs) for all of the transiting planets (41 of 42 have an FPP under 1%), and we constrain their sizes and masses. Most of the transiting planets are smaller than three times the size of Earth. For 16 planets, the Doppler signal was securely detected, providing a direct measurement of the planet's mass. For the other 26 planets we provide either marginal mass measurements or upper limits to their masses and densities; in many cases we can rule out a rocky composition. We identify six planets with densities above 5 g cm-3, suggesting a mostly rocky interior for them. Indeed, the only planets that are compatible with a purely rocky composition are smaller than 2 R ⊕. Larger planets evidently contain a larger fraction of low-density material (H, He, and H2O).Peer reviewedFinal Accepted Versio
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