bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rorty's Neopragmatism and the Imperative of the Discourse of African Epistemology
Authors: Udefi Amaechi 
Published: March 2009

Rorty's Neopragmatism and the Imperative of the Discourse of African Epistemology
Pragmatism, as a philosophical movement, was a dominant orientation in the Anglo-American philosophical circles in the late nineteenth century and early twentieth century. Pragmatism, as expressed by its classical advocates, namely, Charles Sanders Peirce, William James and John Dewey, emphasized the primacy of practice or action over speculative thought and a priori reasoning. The central thesis of pragmatism (though there exist other variants) is the belief that the meaning of an idea or a proposition lies in its "observable practical consequences", And as a theory of truth, it diverges from the correspondence and coherence theories which see truth in terms of correspondence of a proposition to facts and coherence of propositions to other propositions within the web respectively, but instead contends that "truth is to be found in the process of verification". In other words, pragmatists would emphasize the practical utility or "cash value", as it were, of knowledge and ideas as instruments for understanding reality. Neopragmatism is used to refer to some contemporary thinkers whose views incorporate in a significant way, though with minor differences bordering on methodology and conceptual analysis, the insights of the classical pragmatists. Our intention in this paper is to explore Rorty's neopragmatism, particularly his critique of analytic philosophy and then argue that his views have potential for the establishment of African epistemology as an emerging discourse within the African philosophical tradition.
Two Dogmas of Rorty's Pragmatism
Authors: Vuorio Timo 
Published: March 2009

Two Dogmas of Rorty's Pragmatism
Here I discuss two controversial distinctions that have an essential role in Rorty's pragmatism: the distinction between descriptive and normative discourses, and the distinction between the private and public dimensions of human life. Neither of them is Rorty's novelty, but the way he stresses them is unique. The first is a central presupposition of his Philosophy and the Mirror of Nature (1979), while the other is the argumentative base of Contingency, Irony, and Solidarity (1989). I will argue that the distinctions provide metaphilosophical tools for Rorty's pragmatism, and that our stance towards the latter depends on the plausibility of them.
Baffle‐induced segregation in spouted beds
Authors: Rovero Giorgio 
Published: March 2009

AbstractSegregation of solid materials, differing in density, was detected at the surface of the annulus of a spouted bed when a baffle, preventing mixing with solids from the fountain, was placed above an overflow pipe. Concentrations higher than 90% by volume in the light material could be obtained in the continuous discharge stream from a well mixed bed having an overall light‐solids concentration as low as 3%. The gas velocity in the annulus, exceeding the minimum fluidization velocity of the light component, was shown to be the mechanistic explanation of the phenomenon.
Role of vapor‐liquid equilibrium in evaluation of coal liquefaction kinetics
Authors: Gopal J. S. , Shah Y. T. , Carr N. L. 
Published: March 2009

AbstractThe role of vapor liquid equilibrium in the coal liquefaction process and its effect on the process kinetics were studied. Available experimental data were analyzed by inclusion of vapor‐liquid equilibrium in an existing model to study its effect on the kinetics. The analysis showed that due to liquid vaporization, a significant increase in the slurry residence time occurs. In the range of operating variables investigated, the actual slurry residence time was observed to be higher by a factor of 1.14 to 1.41.Model simulations for some typical operating conditions (717‐737 K, 13.8‐20.7 MPa) showed the wt. fraction of liquid vaporized to be in the range of 0.1 to 0.3. This is seen to be in agreement with published data on the volatility of typical coal liquids. This study has shown that consideration of vapor‐liquid equilibrium in the kinetics and design of coal liquefaction process can be of importance, especially at high temperatures, where vaporization would be significant.
Fractionnement de deux bois tropicaux (eucalyptus et wapa) par traitement thermomécanique en phase aqueuse. Partie I: Conversion et profils de solubilisation
Authors: Carrasco F. , Chornet E. , Overend R. P. , Heitz M. 
Published: March 2009

AbstractLa conversion et les profils de solubilisation de deux bois tropicaux ont été étudiés par voie d'un traitement thermo‐mécanique en phase aqueuse. Une suspension de bois ayant une concentration en sol ides de 8% est préchauffée (cuisson à 135°C) et envoyée pneumatiquement à travers un capillaire à des vitesses comprises entre 50 et 115 m/s. A la sortie du capillaire, une détente soudaine (décompression flash) facilite la désagrégation du complexe hémicelluloses–lignine–cellulose. La séparation des hémicelluloses et de la lignine a été examinée en fonction de la sévérité thermique du traitement (150–230°C). Les résultats présentés permettent de conclure qu'un fractionnement sélectif de la lignine associée à la lamella composée (. mitoyenne plus la paroi primaire) et des hémicelluloses est possible pour les bois tropicaux considérés dans ce travail. Les conditions opératoires optimales sont discutées en fonction des observations expérimentales.
Low pressure drop gas distributors for packed distillation columns
Authors: Muir L. A. , Briens C. L. 
Published: March 2009

AbstractPacked distillation columns require gas distributors which provide uniform vapor distribution with a low pressure drop. Gas velocity profiles were measured for various gas distributors in a scale model of the gas distribution chamber of a packed distillation column.The most uniform gas distribution was obtained with two tangential inlets halfway up the distribution chamber and a deflector which induced a downward swirl to help collect any unvaporized liquid droplets. The insertion of a ring above the deflector further improved the vapor distribution.
Diffusional effects in wetproofed catalysts for isotopic exchange between hydrogen gas and water vapour
Authors: Suppiah S. , Chuang K. T. , Rolston J. H. 
Published: March 2009

AbstractDeuterium transfer rates between water vapour and hydrogen gas have been obtained for platinized carbon powder (Pt‐C) and Teflon wetproofed platinized carbon films. The pore diffusional resistance in the catalyst films was assessed by calculating the effectiveness factor, ϵ, from a mathematical model for simultaneous diffusion and first order reversible reaction kinetics. Wetproofing the Pt‐C catalyst with Teflon increased the intrinsic rate of reaction, but the effectiveness factor decreased with increasing catalyst layer thickness. Pore size and surface area distributions and water vapour adsorption isotherms of the Pt‐C/Teflon catalyst films were similar to those of the Pt‐C itself. Since Teflon had negligibly small surface area and very large pores compared to the carbon support, wetproofing did not cause significant changes to the physical characteristics of the platinized carbon.
Co‐processing of alberta subbituminous coal and bitumen in a semi‐continuous hot charge‐discharge unit
Authors: Kovacik G. , Özüm B. , Oguztöureli M. N. 
Published: March 2009

AbstractLiquefaction of an Alberta subbituminous coal (Highvale) with bitumen was studied using a semi‐continuous, two stage, hot charge‐discharge (HCD) unit. Experiments were performed using a CO/steam atmosphere in the first, and H2 atmosphere in the second stage. The second stage (hydrogenation) reactor input and output gas temperatures, compositions, reactor gas and liquid temperatures were measured during the reaction. In the numerical solutions of the mass and energy balance equations experimental data were used, and hydrogen consumption, heteroatom (O and S) removal, hydrocarbon gas production kinetic rate constants, and hydrogenation reaction enthalpy were determined.
Spouted bed hydrodynamics in a 0.91 m diameter vessel
Authors: Lim C. J. , Grace J. R. 
Published: March 2009

AbstractHydrodynamic measurements were obtained in a flat‐based half‐cylindrical column of diameter 0.91 m and inlet orifice diameters of 76 to 114 mm. Beds of 3.5 to 6.7 mm diameter particles with static depths of 0.53 to 1.83 m were spouted with air. In agreement with measurements by earlier workers in smaller columns, it was found necessary to operate with inlet orifice diameters less than about 30 times the mean particle diameter in order to be able to achieve stable spouting. Correlations for minimum spouting velocity developed on small vessels generally gave poor predictions for the large diameter vessel employed in this work and failed to predict the observed dependence of Ums on the static bed height. Substantial dead regions where particles were stagnant were observed in the lower outer portion of the vessel. Other aspects of behaviour studied, including spout diameters and shapes, fountain heights, pressure profiles and gas velocities in the annulus, were qualitatively similar to those in smaller columns, although equations developed for the smaller vessels did not always provide accurate predictions.
The deposition of haematite particles from flowing water
Authors: Williamson R. , Newson I. , Bott T. R. 
Published: March 2009

AbstractDeposition of 0.2 μ haematite (α – Fe2O3) particles from suspension in turbulently flowing water, Reynolds Number = 11000, onto metal tube surfaces has been studied with particular reference to the effect of pH. Measurements on stainless steel showed trivial deposition outside the pH range 5 to 8. Within this range deposition rose sharply to a peak at pH = 6.2. This is similar to the findings of Kuo and Matijevic (1980) who studied haematite particle deposition onto a packed bed of stainless steel beads under laminar flow conditions. This shows that particle/surface interactions govern deposition in this system and that hydrodynamic and geometric factors are secondary.
Properties of cold lake bitumen saturated with pure gases and gas mixtures
Authors: Mehrotra Anil K. , Svrcek William Y. 
Published: March 2009

AbstractThis paper presents new data for the viscosity, density and gas solubility of Cold Lake bitumen saturated with light gases and gas mixtures over a temperature range of 15 to 103°C at up to 10 MPa pressure. Specifically, the gases whose effects on the bitumen properties were measured are N2, CH4, CO2 and C2H6, and two mixtures of CO2 and CH4. With CO2 and C2H6, experiments were also performed in the liquid‐liquid region, and the results of these experiments generally agree with the previously published predictions.The viscosity of the gas‐free Cold Lake bitumen is comparable to that of a Marguerite Lake bitumen that was tested previously. Due to the large solubilities of C02 and C2H6, the reduction in gas‐saturated bitumen viscosity is quite dramatic. The density of the gas‐saturated bitumen decreases with increased amounts of the dissolved CH4 and C2H6 gases, but no such trends are evident for the N2 and CO2 gases. The results of the experiments with two binary gas mixtures (i.e., CO2 and CH4) indicate that the bitumen properties are affected largely by the major gas constituent.
Study of the transport disengaging height
Authors: Baron T. , Briens C. L. , Bergougnou M. A. 
Published: March 2009

AbstractThe trajectory of clusters ejected in the freeboard by gas bubbles bursting at the surface of fluidized beds is used to propose a new way to determine the transport disengaging height (TDH). As the effect of the drag force is negligible for the largest clusters, the maximum height they reach in the freeboard is directly proportional to the square of their ejection velocity. The maximum heights thus calculated are in good agreement with experimental TDH values from the literature. A procedure is given to compute the TDH from this simple expression.
Independent prediction of slip velocity and hold‐up in liquid/liquid extraction columns
Authors: Kumar Arun , Hartland Stanley 
Published: March 2009

AbstractThe correlation of slip velocity using a large bank of published data for pulsed perforated‐plate, Karr reciprocating‐plate, rotating disc and spray extraction columns is presented. Based on more than 3,700 data points with and without mass transfer, empirical equations not including hold‐up for each of the columns are suggested which reproduce the slip velocity data over a wide range of variables. Explicit correlations for hold‐up in both the loose and dense‐packed regions of operation in spray columns are also presented which do not involve slip velocity. The equations presented are more exact and simpler to use than previous empirical correlations; these often involve the characteristic velocity which is difficult to accurately predict.
Zncl2 catalyzed flash hydropyrolysis of +525°C pitch from cold lake bitumen
Authors: Pandey Raj N. , Ingard Eric , Ternan Marten 
Published: March 2009

AbstractFlash hydropyrolysis experiments have been performed on the vacuum bottoms fraction of Cold Lake bitumen, using zinc chloride as a catalyst. Milligram size samples of vacuum bottoms resid were heated rapidly (120–400°C/s) by passing a large electric current through the reactor tube. The variables studied included temperature, heating rate, catalyst/pitch ratio, vapour phase residence time and pressure. Temperature and catalyst/pitch ratio caused major changes in yields. In contrast pressure had little effect. It was found that high conversions could be obtained at hydrogen pressures which are much lower than those normally used in catalytically hydrocracking residual oils.
Four‐lump kinetic model for fluid catalytic cracking process
Authors: Lee Liang‐Sun , Chen Yu‐Wen , Huang Tsung‐Nien , Pan Wen‐Yen 
Published: March 2009

AbstractIn the fluid catalytic cracking reactor heavy gas oil is cracked into more valuable lighter hydrocarbon products. The reactor input is a mixture of hydrocarbons which makes the reaction kinetics very complicated due to the involved reactions. In this paper, a four‐lump model is proposed to describe the process. This model is different from others mainly in that the deposition rate of coke on catalyst can be predicted from gas oil conversion and isolated from the C1–C4 gas yield. This is important since coke supplies heat required for endothermic reactions occurring in the reactor. By this model we can also conclude that the C1–C4 gas yield increases with increasing reactor temperature, while production of gasoline and coke decreases.
Reaction kinetics of gasification of black liquor char
Authors: Li J. , Van Heiningen A. R. P. 
Published: March 2009

AbstractCO2 gasification of black liquor char, prepared from kraft spent pulping liquor is studied thermogravimetrically up to 775°C. The gasification rate is described by Langmuir‐Hinshelwood type kinetics and activation energy is similar to that found for alkali metal impregnated porous carbons. However the rate is about 20 times larger than that of coal char mixed with 10‐20% Na2 CO3. CO inhibition is relatively small and the rate is first order in carbon up to 80% conversion. The behavior is explained by a fine and three‐dimensional dispersion of sodium salts in the char. The rate is insensitive to pulping conditions over the range of industrial practice.
Modelling the transition to slug flow in horizontal conduit
Authors: Jepson W. P. 
Published: March 2009

AbstractA physical model for the prediction of transition to slug flow is presented. The model assumes that the slug is formed as a result of a hydraulic jump which is sufficient to just touch the top wall of the conduit. This, together with a ‘breaking dam’ assumption at the rear of the slug, gives necessary and sufficient conditions for the formation of a stable slug. The minimum liquid film thickness ahead of the slug, degree of aeration within the slug and slug translational velocity are predicted. The predictions agree very well with those of previous workers and with experimental data.
Droplet size characteristics for insecticide and herbicide spray atomizers
Authors: Picot J. J. C. , Vliet M. W. Van , Payne N. J. 
Published: March 2009

AbstractRotary atomizers and hydraulic nozzles used in forestry spraying were extensively tested with laser light scattering, laser light imaging, and photographic methods in a specially designed wind tunnel. Data on droplet size distribution and cumulative volume fraction versus droplet size are given. Correlations for reduced volume median diameter (Dv,0.5/d0) and reduced span ((Dv.0.9 – Dv.0.1)/d0) presented. Accuracy of prediction is of the order of 20% for hydraulic nozzle volume median diameter. Accuracy of prediction for high‐speed rotating wire mesh atomizers is of the order of 35% for the volume median diameter. When these accuracies are inadequate, a specific test of the device in question is recommended.
Separation of kinetics and mass‐transfer in a batch alkoxylation reaction
Authors: Hall C. A. , Agrawal P. K. 
Published: March 2009

AbstractThe quantitative aspects of the role of interfacial mass‐transfer and reaction kinetics in ethoxylation of lauryl alcohol were examined in a batch recirculation reactor. The liquid droplets falling through a gas column were obtained by utilizing a recirculation loop and a set of spray nozzles. The CO2/NaOH reaction was employed to characterize the interfacial area. The alkoxylation reaction was studied at temperatures between 124°C and 171°C, at catalyst levels between 0.09 and 0.50 weight percent and at ethylene oxide partial pressures between 68 kPa and 204 kPa.A model was developed which permits the prediction of reactor performance at various operating conditions. The mass‐transfer during free fall dominates the interfacial mass‐transfer and the contributions during the drop formation and coalescence stages are small. The rate of ethylene oxide (EO) addition to lauryl alcohol was constant during the batch run, indicating similar activity for the unreacted lauryl alcohol and the lauryl alcohol ethoxylated to varying extents. The rate of ethoxylation is first‐order in both catalyst and ethylene oxide concentrations. The liquid‐phase reaction kinetics and interfacial mass‐transfer occur in series, with kinetics dominating the overall ethoxylation rate. As expected, an increasing role of mass transfer is observed at higher temperatures, and/or higher catalyst concentrations where the kinetic rate becomes significantly high. The intrinsic activation energy for the ethoxylation of lauryl alcohol is 55.2 kJ/mole.
A simplified approach to the operation of a batch crystallizer
Authors: Rohani S. , Bourne J. R. 
Published: March 2009

AbstractA general model for a seeded cooling batch crystallizer based on first principles is developed, incorporating either size‐dependent or size‐independent growth rates. A simple approach is proposed to obtain temperature‐time trajectories at constant supersaturation or nucleation rate, without resorting to optimization techniques. Cooling curves at constant supersaturation, which lead to a substantial improvement (a smaller coefficient of variation and a larger mean size) of the terminal crystal size distribution, can be determined even in the absence of precise nucleation and growth kinetics, whereas properties related to the crystal size distribution are sensitive to such kinetics. Experimental results for the potassium sulfate‐water system, potash alum‐water system, and hexamethylenetetramine in ethanol, methanol, and 2‐propanol/water are predicted reasonably well by the model. Extension to any type of batch crystallization with super‐saturation induced by means other than cooling, such as reactive precipitation and salting out, is briefly discussed.
The prediction of transport parameters in filamentous fermentation broths based on results obtained in pseudoplastic polymer solutions
Authors: Allen D. Grant , Robinson Campbell W. 
Published: March 2009

AbstractTransport phenomena studies on single phase “model” fluids are of limited value in biochemical engineering if they cannot be translated to the heterogeneous systems encountered in real fermentation processes. In this paper we discuss the utility of polymer solutions as models of filamentous fermentation broths for evaluation of: pipeline friction factors and impeller power numbers (turbine and helical ribbon). To a first approximation, polymer solutions can serve as suitable models for the prediction of laminar flow pressure drop in pipelines and turbulent power consumption in stirred tanks. However, results obtained on polymer solutions do not directly apply to filamentous fermentation broths for predictions of laminar flow impeller power consumption and the transition point for turbulent flow in stirred tanks. These discrepancies are believed to result from the existence of a time dependent yield stress in filamentous fermentation broths.
Kinetics of, free radical modification of polyolefins in extruders – chain scission, crosslinking and grafting
Authors: Hamielec A. E. , Gloor P. E. , Zhu S. 
Published: March 2009

AbstractFree radical reactions, carried out in polymer melts, have become a popular method of chemically modifying polyolefins. The elementary free‐radical reactions which are relevant in the chemical modification of polyolefins at high temperatures in extruders, such as chain transfer to polymer via primary and polymer radicals, β‐scission, double bond addition and bimolecular termination, affect chain scission, long chain branching, crosslinking and grafting. This brief review will discuss some of the work focused on the kinetics and mathematical modelling of these reactions.
Hydrodynamics of disturbed flow and erosion—corrosion. Part I — Single‐phase flow study
Authors: Nešiĉ S. , Postlethwaite J. 
Published: March 2009

AbstractNumerical simulations of turbulent flow have been used to determine the flow structure in a sudden pipe expansion, in order to explain the effects of disturbed flow on mass transfer controlled erosion–corrosion. Previously determined rates of mass transfer through the liquid boundary layer have been directly related to the predicted levels of near‐wall turbulence. When rust films are present, the turbulent fluctuations affect both the mass transfer through the boundary layer and the removal of the film. The determining resistance to mass transfer, under the conditions examined, was that of the rust film.
Mechanism, onset and intensity of surface aeration in geometrically‐similar, sparged, agitated vessels
Authors: Veljković V. B. , Bicok K. M. , Simonović D. M. 
Published: March 2009

AbstractUnder sparged conditions surface aeration occurs by two mechanisms: first, the absorption of gas at the free surface and then its desorption at the gas bubbles‐liquid interfaces, and second, mechanical suction through the free surface; the latter is believed to occur via vortices formed on the free surface due to impeller action. The onset of gas entrainment is defined through the characteristic impeller speed above which mechanical suction rapidly increases. Gas entrainment intensity is correlated by the specific power input and the superficial sparge velocity and generally increases with increasing impeller speed and decreasing sparge gas flow rate.