bluuebunny/crossref_metadata_2025_split huggingface dataset:
A transcendental approximation for natural convection at small prandtl numbers
Authors: Cygan D. A. , Richardson P. D. 
Published: March 2009

AbstractAn improved method of approximation for natural convection at small Prandtl numbers is described. It involves simple transcendental functions for profile representation. The method utilizes a physically significant model of the velocity distribution in which regions of the thermal boundary layer and viscous boundary layer are distinguished. The shape of the velocity profile is allowed to vary with Prandtl number. The method is checked against known exact results for natural convection on a vertical flat plate and is used to obtain results for a horizontal cylinder.
Maximum spoutable bed depths of mixed particle‐size beds
Authors: Reddy K. V. S. , Fleming R. J. , Smith J. W. 
Published: March 2009

AbstractMaximum spoutable bed depths for mixed particle‐size beds of alundum, glass and polystyrene have been found experimentally to reach a peak at a critical particle Reynolds number of about 70. Using Becker's criterion that Vm f = Vmf and the correlations of Smith‐Reddy for V, and of Wen‐Yu for Vmf, the maximum spoutable bed depths Hmax were theoretically predicted to reach a maximum at a critical NRem = 68. The experimental maximum spoutable bed depts in a 6‐in. I. D. column fitted with a 60° cone were in good agreement with theoretical predictions.
Improved gas'liquid contacting in co‐current flow
Authors: Voyer R. D. , Miller A. I. 
Published: March 2009

AbstractA new method of increasing interfacial area for gas‐liquid contacting in co‐current flow using screen packings has been evaluated in a 51/2‐in. I. D. column using CO2 chemisortpion in sodium hydroxide solution and CO2 physical desorption from water.The study investigated the effect of gas velocity (0.3‐2.7‐ft/sec.), liquid velocity (0.018‐0.1‐ft/sec), and of column height (0.67‐7.8‐ft.) on the interfacial area, a, and the physical desorption liquid phase mass transfer coefficient, KL.The two types of screen packing tested produced interfacial areas of 2 to 4 times that generated in an unpacked column. KL showed no effect of gas velocity but increased with liquid velocity, a and KL decreased with increasing column height. Generally, photographic evaluation gave unrealistically high values of a.
The preparation and structure of electrodeposited sponge cadmium electrodes
Authors: Henderson I. H. S. , Ladan S. G. 
Published: March 2009

AbstractA method is described for preparing coherent sponge cadmium electrodes on cadmium‐plated substrates by electrodeposition from cadmium chloride solutions in the absence and presence of potassium chloride. The deposit morphology was shown to be a function of current density, pH, plating bath composition and temperature. Of the five main deposit types observed, only one, a sponge with very small crystallites, displayed high electrochemical activity when cycled in KOH solution and had sufficient coherence and adherence to its substrate to be considered suitable as a battery electrode. This material had a useful capacity approximately twice that of conventional electrodes, implying a net increase in battery capacity of at least 30% if conventional sintered plate positives were used. In addition, the elimination of the sintered nickel substrate and the possibility of continuous production methods promised a lower cost.In a separate series of experiments, ultramicrotome sections of the sponge deposits were examined by transmission electron microscopy. For specimens having a high electrochemical activity (more than 70% of the deposit being capable of reversible cycling in KOH solution) crystallite dimensions up to several microns in length and 0.5 to 1 micron in diameter appeared to predominate. This was consistent with measurements of the depth of oxidation observed on block cadmium electrodes and with the structure inferred from powder X‐ray diffraction examination.
Continuous and discrete time response analysis of the backflow cell model for linear interphase mass transfer on a distillation plate
Authors: Dickey B. R. , Durbin L. D. 
Published: March 2009

AbstractAn analysis of the backflow cell model of a distillation plate with linear interphase mass transfer is given. The steady state character is discussed in terms of liquid phase concentration profiles and plate efficiencies. The dynamics due to liquid and vapor phase concentration perturbations are derived for continuous time and discrete times based upon two point time difference methods of numerical solution. The moments of the discrete impulse response are related to those for continuous time. Stability and convergence are discussed. For the liquid on a valve plate, the backflow cell model outlet response due to a measured inlet response is compared to the monitored outlet response resulting from upstream salt tracer injection.
An experimental investigation of heat transfer to water in film flow Part I – non‐boiling runs with and without induced swirl
Authors: Herbert L. S. , Sterns V. J. 
Published: March 2009

AbstractLocal heat transfer coefficients have been measured in the range of Reynolds Numbers 3,000‐20,000 for non‐boiling heat transfer to water flowing down the inside of a copper tube. The tube was 0.948‐in. Inside diameter and 8‐ft long, heated in 15 sections 6‐in. long, by electrical resistance heaters wound on the outside of the tube. Thermocouples measured the wall temperature at the midpoint of each section. Coefficients obtained for downward, non‐swirling, full tube flow were correlated by the Dittus Boelter equation, with a correction for heat flux. An experimental correlation was obtained for the improved coefficients resulting from the use of a swirl generator in full tube flow. Non‐swirling falling film data were correlated by an equation:hLA = 3.9 ReLA0.05It is to be noted that the exponent on ReLS is higher than the value of 0.1‐0.33 found by previous workers. The effect of swirl on falling film heat transfer was complex; increased coefficients were noted at ReL below 10,000 but much reduced coefficients were obtained at RL above 15,000 in the lower parts of the tube.
An experimental investigation of heat transfer to water in film flow Part II – boiling runs with and without induced swirl
Authors: Herbert L. S. , Sterns V. J. 
Published: March 2009

AbstractIn the previous paper, (Part I)(1), the results were presented of an investigation of heat transfer to non‐boiling falling films of water in an electrically heated copper tube of 0.948‐in. i.d. and 8‐ft. long. Comparative measurements of heat transfer in full tube flow were also given, and the effect of a simple swirl‐type turbulence promoter was studied for both full tube and film‐type flow.The present paper presents the results of an investigation of boiling heat transfer in the same apparatus.
Reaction between two immiscible fluids in countercurrent flow in a series of stirred tanks: Design equations and optimum operations
Authors: Ahluwalia M. S. , Levenspiel Octave 
Published: March 2009

AbstractAn explicit expression is found for the conversion of two immiscible fluids reacting by a second order reaction while in countercurrent flow through a series of equal sized backmix reactors. It is also shown that the equal sized set‐up is always optimum in that it minimizes the total volume needed for any duty. Design charts are presented.
Heats of mixing for binary systems: n‐Alkanes + n‐Alcohols and n‐Alcohols
Authors: Ramalho R. S. , Ruel M. 
Published: March 2009

AbstractThe heats of mixingof 23 binary systems are reported at 20, 25 and 30°C. Of these systems, 14 binaries are mixtures of n‐alcohols + n‐alkanes and the remaining 9 systems are mixtures of n‐alcohols. The applicability of an extension of the principle of congruence to the data was investigated.
A steady'state capillary cell method for measuring gas‐liquid diffusion coefficients
Authors: Malik V. K. , Hayduk W. 
Published: March 2009

AbstractA simple method for measuring diffusion coefficients of gases in liquids using capillary cells has been shown to give accurate results for the diffusivities of carbon dioxide in water, methane in carbon tetrachloride, and carbon dioxide in ethanol when compared with reported values. Diffusivities were also measured at 30°C. for ethane in n‐hexane and ethane in n‐heptane, and at 40°C. for ethane in n‐heptane. The steady‐state capillary cell technique appears to be capable of giving reliable diffusivities for a large number of gas‐liquid systems.
Heats of mixing for ternary systems: n‐Alkanes + Two n‐Alcohols
Authors: Ramalho R. S. , Ruel M. 
Published: March 2009

AbstractHeats of mixing for 21 ternary systems of one n‐alkane + two n‐alcohols are reported at 25°C. Evaluation of four equations permitting the prediction of heats of mixing of ternary systems from binary data is made. Scatchard's modified equation for systems containing a polar component was found to be the most accurate.
An experimental study of the effect of dump packing on wall to fluidized bed heat transfer
Authors: Capes C. E. , Sutherland J. P. , Mcllhinney A. E. 
Published: March 2009

AbstractThe improvements in the performance of gas‐fluidized beds to be gained from the introduction of baffles or packing pieces have been discussed in the literature. These include higher conversions in chemical reactions(1), reduction of freeboard necessitated by fluctuations in bed height(2) and the possibility of operating with larger length to diameter ratios(3). In the case of wall‐to‐bed heat transfer, however, a preliminary investigation(4) into the effect of fixed packing in a 4‐in. column indicated that the rate of heat transfer was in most cases adversely affected by the presence of packing because of the restriction of particle movement within the bed. This was certainly true in the case of packings of closed structure such as solid spheres, although the data suggested(4) that heat transfer in beds containing screen mesh packings of open structure may exceed that in unpacked beds in some cases.The work described herein is a quite comprehensive experimental investigation of the effect of many types of dump packings on the rate of wall‐to‐bed heat transfer. Several commercially available packings as well as cylindrical screen packings produced in this laboratory were employed. A 12‐in. diameter bed was used so that the work would give an indication of the effects occurring in larger‐scale equipment.
Application of thermodynamics to the athabasca tar sands
Authors: Leja J. , Bowman C. W. 
Published: March 2009

AbstractSignificant changes in the interfacial areas often accompany transformations in highly dispersed systems containing oil, water, solid and gas phases. When such changes in area are considered, interfacial tension expressions diametrically opposed to the conventional criteria for oil spreading or de‐wetting may result. Further modifications in the energetics criteria are obtained when the electrical contributions to the free energy of the system (resulting from the adsorption of ionic surfactants) are included.
Electric field phenomena in fluidized and fixed beds
Authors: Katz Herbert , Sears John T. 
Published: March 2009

AbstractStabilization of a bed of dielectric particles against fluidization by an electric field (≥ 103 volts/cm) is described. Glass bead and silica gel particle beds have been observed to behave as packed beds with flow rates (and pressure drops) of the fluidizing gas up to 15 times the normal incipient fluidization rate. The pressure drop at the breakup of this fixed bed was dependent on the second power of voltage, the particular bed material, and geometry of the system. Under suitable conditions 100% bed expansion without diffusive particle motion or bubble formation was obtained using silica gel particles. Comparison with iron particle bed‐magnetic field effects are presented. Surface polarization charge effects are the simplest explanation of the phenomena. Several of the possible applications are suggested, such as precipitation enhancement in an aerosol filter or as a new tool for investigating aggregative fluidization.
Compressibility factors for the argon‐carbon dioxide system
Authors: Beer H. 
Published: March 2009

AbstractRedlich and Kwong's equation of state for compressible gases has been used for computing the compressibility factors for binary gaseous mixtures. The mean deviation between the experimental values of the factor and the values calculated from Redlich's equation is 2.2%. Data for CH4 ‐ CO2 and Ar ‐ CO2 mixtures up to pressures of 200 atm. and temperatures of 453°K in the whole range of composition have been obtained. The experimental error is estimated to be ± 0.74%.
Asymmetric, coupled transport of heat and mass in a duct
Authors: Chen T. S. , Sparrow E. M. 
Published: March 2009

AbstractMutually dependent heat and mass transfer for laminar gas flow in a parallel‐plate channel is investigated analytically. Sublimation occurs at one of the channel walls, while the other wall is nonsubliming. Both walls are thermally insulated from the external environment. The analysis of the problem requires simultaneous treatment of the energy and mass diffusion equations, with coupling provided by the boundary conditions. Mathematical expressions are derived and numerical results are presented for various quantities that characterize the heat and mass transfer processes. Comparisons are made with the case of symmetric transfer (i.e., both walls actively participating). In general, unsymmetric transfer is found to slow down the axial development of the temperature and mass fraction fields.
A method of prediction of the porosities of high‐pressure gaseous fluidization systems
Authors: Mogan J. P. , Taylor R. W. , Booth F. L. 
Published: March 2009

AbstractThe porosity of a fluidized bed at any superficial velocity may be calculated by Richardson and Zaki's method if the terminal velocity of a representative particle is known. This terminal velocity can be calculated under any operating conditions by Beranek's atmospheric elutriation criterion.Porosities were measured at 331 superficial velocities in fluidized beds of cracking catalyst, using hydrogen, nitrogen and argon at pressures of 300 to 800 p.s.i.g. as the fluidizing media. It was postulated that the “largest significant particle” was representative for beds fluidized with high‐pressure gases such as these.The porosities at these same velocities were calculated using Beranek terminal velocities of the “largest significant particles” in Richardson plots. A 16.6% standard deviation was found in the values of the calculated porosities when compared with the measured values.
Kinetics of catalytic ethane hydrogenolysis: Stirred reactor study of commercial nickel catalyst
Authors: Tajbl D. G. 
Published: March 2009

AbstractThe kinetics of ethane hydrogenolysis catalyzed by a commercial 58% nickel‐on‐kieselguhr catalyst were studied at 1 atm. and from 220° to 250°C. The kinetic data could be fit by a simple power rate equation that is a limiting case of a more general equation. The reaction rate of ethane was first order with respect to ethane and —2 order with respect to hydrogen. A possible reaction mechanism is discussed. The apparent activation energy was 46.4 kcal. Ethane/hydrogen ratios as high as 1:1 were studied without catalyst deactivation. Kinetic data were obtained in a novel stirred‐tank catalytic reactor.
Liquid phase oxidation of the light ketones
Authors: Rouchaud J. , Lutete B. 
Published: March 2009

AbstractAcetone, methyl ethylketone, methyl isopropylketone and toluene were oxidized separately in the liquid phase by oxygen at 140°C, under 15 atm partial pressure of oxygen with 1 wt % di‐ ter‐ butylperoxide. The main product is acetic acid. Acetone is much less reactive than the other two ketones. Cooxidations of binary mixtures composed of a ketone and toluene were performed under the same experimental conditions. In these cooxidation systems, the three ketones have similar reactivities. The discrepancy between the relative reactivities of the ketones oxidized alone or with toluene is interpreted by the theory of the branched chain oxidations, and indicates the great influence of the chain branching coefficients and the stability of the free peroxy radicals on the total rate of oxidation of the ketones.
Calibration of an argon plasma jet and preliminary application to production of oxygen by carbon dioxide reduction
Authors: Blanchet J. L. , Parent J. R. , Lavallee H. C. 
Published: March 2009

AbstractAn argon plasma jet generator hag been built and calibrated for various power inputs, arc gas flow rates, electrode gaps and anode materials. The gas enthalpy and its temperature, the heat losses, the impact pressure, the exit gas velocity and the heat flux have been calculated from the collected data. Comparisons with helium were also made.Injection of carbon dioxide into the plasma flame has yielded up to 3% of oxygen in the effluent gas. The reaction temperatures ranged from 3,000 to 11,000°K.
Recent experience with the spherical agglomeration process
Authors: Sirianni A. F. , Capes C. E. , Puddington J. E. 
Published: March 2009

AbstractThe process of removing particles from liquid suspension by selective wetting and agglomeration with a second immiscible liquid has many possible applications. Depending upon the amount of tthe second liquid used and the type of agitation to which the suspension is subjected, the particles to be separated are settled as flocs, as dense pellets or may simply be transferred to a continuous phase of the second liquid. This paper first describes the types of mixing equipment which have been used to carry out the process in its various forms and goes on to discuss a number of specific applications. These include the upgrading of coking coals by selective agglomeration, the pelletization of soluble salts, the formation of highly spherical bodies from various materials and the beneficiation of ores.
Hydrogen‐oxygen ion‐exchange membrane fuel cells
Authors: Foulkes F. R. , Graydon W. F. 
Published: March 2009

AbstractA hydrogen‐oxygen cationic ion‐exchange membrane fuel cell was operated at various temperatures, pressures, and electrolyte concentrations. The open circuit and discharge characteristics of the cell were explained in terms of the oxygen polyelectrode theory. Although discharge was limited by internal resistance, pressurization greatly reduced polarization.
Simulation and optimization of an existing ethylbenzene dehydrogenation reactor
Authors: Sheel J. G. P. , Crowe C. M. 
Published: March 2009

AbstractThe dehydrogenation of ethylbenzene to styrene in an ideal, adiabatic reactor has been modelled using side reactions in addition to the main one. The differential equations describing the process were integrated on an IBM 7040 digital computer.A profit function ($ gained/hour) was chosen and for various combinations of process variables, which were subject to constraints, the single bed reactor was optimized by the method of Rosenbrock(1,2). Studies of a proposed two‐bed reactor were also carried out. Catalyst deactivation during the reaction was not considered because of a lack of data.The results showed that the existing reactor could be operated more efficiently if the present plant constraints were removed. Two beds in series gave still better results.
Forced convection heat‐transfer from the heated downstream end of a cylinder placed in front of a similar, axially aligned, unheated cylinder
Authors: Babij G. B. , Godward R. 
Published: March 2009

AbstractExperiments, performed to obtain the average forced convection heat‐transfer coefficients from the heated downstream end of a cylinder, placed in front of a similar, axially aligned, unheated cylinder, produced the following results: (1) The Nusselt number can be correlated by an equation of the type NNuf = C NRebn, where C takes on values of 1.01 to 2.13 and n = 0.466 for the spacing between the two cylinders from ½‐in. to 6‐in. (2) In the range of Reynolds number from 3 × 104 to 5 × 105, the Nusselt number increases with the spacing between the two cylinders. At a spacing of 4‐in. a maximum Nusselt number is reached.
The shape of a fluid drop approaching an interface
Authors: Hartland Stanley 
Published: March 2009

AbstractThe shape of a fluid drop approaching an interface does not change appreciably with time and is very close to the equilibrium dimensions, in spite of the large pressure gradient which is present in the draining film. This is because the net vertical force due to the excess pressure in the draining film above that in the drop is identical with that for an equilibrium film being zero for a plane interface and —2Rσ sin2 ϕ for a deformable interface. Employing this result in a force balance around the drop which is independent of the bulk interface shows that the area A of the draining film between a fluid drop of volume V and a deformable fluid‐liquid interface is given by

where σ is the interfacial tension and Δρ the density difference between the drop and surrounding fluid, 1/b is the curvature at the top of the drop and h is the distance between this point and the edge of the draining film which is inclined to the horizontal at an angle ϕ. When the interface is a rigid plane the overall curvature 1/R of the draining film and the volume v enclosed by it, together with the angle ϕ are all zero.The limiting cases of the expression for very small and very large drops agree with those previously established for both deformable and rigid interfaces. An approximate expression which applies when cV2/3 (where c = Δρg/σ) is between 0.6 and 13.5 and which gives A to within ± e% is

where for a rigid plane interface

and for a deformable interface

When the densities of the drop and bulk heavy fluids are equal, but their respective interfacial tensions σ12 and σ23 with the light fluids are different, the expression becomes

which estimates A/V2/3 to within about ± 25% for σ12/σ23 in the range 0.11 to 9.0 and cV2/3 (where c = Δρg/σ12) between 0.6 and 13.5.
Pulsation error in a rotameter
Authors: Baird M. H. I. , Cheema M. A. 
Published: March 2009

AbstractThe effect of square‐wave pulsations in gas flow on the performance of a rotameter has been studied. The experimental variables were pulsation frequency (1–24 Hz), gas flow rate, gas density, float mass, and the gas volume between the pulse generator and the flowmeter. The fluctuation in float position was found to decrease with increasing frequency and this was in agreement with a simplified theoretical model. Pulsation caused the rotameter to over‐read by as much as 100% and in some cases the error was appreciable even when the float was almost stationary. The error decreased as the damping volume was increased.The factor of error was correlated empirically with the above variables. The results were also compared with other published data and theory, and with a numerical solution of the equations of motion of the float. The numerical solution was found to predict the error satisfactorily in cases where a damping chamber was used and where float bouncing did not occur.