bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Droplet Vaporization Model for Spray Calculations
Authors: Renksizbulut Metin , Bussmann Markus , Li Xianguo 
Published: June 2005

AbstractA semi‐analytical model of multi‐component droplet vaporization in a convective environment is formulated. The model includes many important physical effects such as variable properties, non‐unity Lewis number, transient liquid phase heat and mass transport, and the blowing effect of evaporation on heat, mass and momentum transfer. The liquid phase heating is calculated from a Nusselt number model which incorporate heat transfer enhancement due to internal circulation. The model predictions are in good agreement with detailed numerical results for droplets vaporizing in various ambient conditions. The behavior of droplets in simultaneously changing concentration, temperature and velocity fields, is also examined.
Light Scattering Applied to LDA and PDA Measurements part 2: Computational results and their discussion
Authors: Naqwi Amir A. , Durst Franz 
Published: June 2005

AbstractA general procedure for the design of a phase Doppler system is presented, which includes computations based on the computer codes described previously. The utility of Mie computations is demonstrated through six examples pertaining to sizing of large particles; in particular, new considerations in bubble sizing are pointed out. Through additional examples, it is shown that the phase Doppler technique may be used for sizing of submicron particles as well as large particles. Recognition of particle material, in addition to the measurement of diameter, is also made possible.
Monte Carlo Studies of the Effect of Spatial Coincidence Errors on the accuracy of the size characterization of respirable dust
Authors: Kaye Brian H. , Clark Garry G. 
Published: June 2005

AbstractThe effect of coincidence errors on the accuracy of fineparticle profile characterization of respirable dust hazard by Image Analysis procedures is discussed. Monte Carlo routines are used to characterize the level of clustering that can occur in a field of view from random chance. The effectiveness of some image processing strategies used to separate touching components of visible clusters are discussed. Monte Carlo routines are also used to explore at what level of space occupancy a monosized population of dust fineparticles being deposited at random has no significant level of stochastic clustering. These studies demonstrate that if reliable information on dust hazards is to be forthcoming from image analysis studies of the deposited dust deposition, measurement routines must change radically from those in current use. It is also pointed out that interpretive uncertainties associated with many previous studies of dust levels to which industrial workers have been exposed may invalidate experimental data reported from the workplace.
A Comparison of Image Analysis With Other Methods of particle size measurement for general purpose PVC resins
Authors: Davidson John A. , Etter A. A. , Thomas M. , Butler R. S. 
Published: June 2005

AbstractOf all methods of particle size analysis determination only microscopy and subsequent image analysis enables accurate, geometrically determined size parameters to be measured. For this reason image analysis is a convenient referee or umpire method against which to compare other techniques.In this study, a series of seven poly(vinyl) chloride (PVC) resins were characterized by optical microscopy and image analysis, sieves, HIAC and Coulter counter. It was not found possible to perform the image analysis measurements without operator intervention with a light pen to separate agglomerates. The PVC particles were far too irregular to enable this task to be performed by erosion and dialation techniques. The errors at 90% confidence associated with the image analysis study were: calibration ± 1.7%, counting statistics ± 1% (max) with a focus and algorithms error which ranged from ½‐3% depending upon the quantity being measured. These numbers gave a total error of ± 2% (ca. one pixel) for equivalent circular diameter (ECD) and ± 4% (ca. two pixels) for object breadth. In general the agreement between the various techniques was quite good suggesting that the object breadth (OB) as measured by sieves was nearly identical to equivalent spherical diameter (ECD) as measured by the HIAC and Coulter counter for the samples investigates.A study of the image analysis data alone confirmed that OB and ECD were nearly identical with ECD running about 6.1 m̈m above OB.Mass resin samples, which are prone to electrostatic charging effects, tended to give slightly higher results in those methods which measured the resin in the dry state (HIAC and sieves). Finally, it should be suggested that many of the classical concepts of resolution and depth of focus which are used to place limits upon the performance of the optical microscope do not necessarily apply to particle size determination by image analysis. If the chord through the particle which describes its diameter can be considered an approximation to a square wave then it is the fundamental frequency of the Fourier components of that square wave that contains the size information. This should be true for microscopic objects which are absorbing of light and non‐retarding in nature.Once this fundamental frequency can be identified then sizing accuracy is dependent chiefly on the signal to noise ratio of the system.
The electromagnetic scattering problem of Laser‐Doppler Anemometry. Part I: Fluid investigation
Authors: Raszillier Hans , Durst Franz 
Published: June 2005

AbstractLight scattering by moving particles as used in laser‐Doppler anemometry (LDA) is reviewed. This first part of the review describes the situation where the scattering particles play the role of tracers of fluid flow. In this situation only general properties of the scattering process are of relevance. No special knowledge of the specific scattering mechanism is needed, provided that a detectable signal intensity is obtained. The velocity of the particle in a direction determined by the two laser beams of an LDA measuring device can be derived exclusively from the modulation frequency of the signal. In the second part of the review a description of specific properties of the scattering process will be given with the purpose of gaining information on the particles themselves.
Interaction Between the Motion of particles and their turbulent carrier fluid flow
Authors: Ebert Fritz 
Published: June 2005

AbstractThe turbulence occurring in the flow of the carrier fluid exerts a substantial influence on the motion of suspended particles or droplets. This influence is obvious, e.g. if fine particles are dispersed in free flows or deposited on free surfaces, bluff obstacles or channel walls. With application in aerosol science in mind, the interaction between dispersed phase and carrier fluid is described in terms of turbulence intensities, energy spectra, turbulence time scales and eddy diffusivities. Experimental results obtained for different important flow types are reviewed and compared with theoretical predictions. With regard to the latter, the different methods of treating theoretically turbulent two‐phase flows of low concentration are discussed.
Particle Sizing by Photon Correlation Spectroscopy. Part III: Mono and bimodal distributions and data analysis
Authors: Finsy Robert , de Jaeger Nicolas , Sneyers Rik , Geladé Eric 
Published: June 2005

AbstractThe possibilities and limitations of photon correlation spectroscopy (PCS) as a practical tool for particle sizing are reviewed. In this part the most frequently used methods of data analysis are briefly surveyed. The practical performances for the determination of particle size distributions were evaluated by a comparative study with different kinds of users (industrial and academic research groups and manufacturers). The PCS results were also compared with electron microscopy (EM) and static light scattering (SLS) results. Thereby it was confirmed that the amount of reliable information that can be obtained by PCS about particle size distributions with measuring times of the order of minutes is limited by the ill‐conditioning of the data inversion procedure, among other factors. Nevertheless, the information obtained from the PCS measurements agrees essentially with the EM and SLS results.
Relevance of Light Scattering Theory in Photon correlation spectroscopic experiments
Authors: van der Meeren Paul , Bogaert Herwig , Vanderdeelen Jan , Baert Leon 
Published: June 2005

AbstractSince photon correlation spectroscopy (PCS) is essentially a light scattering technique, it estimates the intensity‐weighted particle size distribution. Using the Mie theory, some consequences were demonstrated. First, argon ion lasers were shown to be superior for particle sizing of very small particles. In addition, multiple scattering was shown to be largely dependent on the scattering angle and the state of polarization of the light source. Owing to this disturbing phenomenon, sizing of supermicron particles becomes troublesome. The estimated intensity distribution of polydisperse samples could be greatly influenced by the observation angle. The use of simplified light scattering theories such as the Rayleigh and the Debye‐Gans theory was shown to be limited to small particles, especially in the case of high refractive indices. Finally, it was shown that the smoothing effect of PCS data analysis software may give rise to artificial bimodal number‐ or weight distributions, even when the Mie theory is considered.
Localized Approximation of Generalized Lorenz‐Mie Theory: Faster algorithm for computations of beam shape coefficients, g
Authors: Ren Kuan F. , Gréhan Gérard , Gouesbet Gérard 
Published: June 2005

AbstractBeam shape coefficients, g, are at the core of the generalized Lorenz‐Mie theory describing the scattering of a shaped beam by spheres. A decrease in computation times is essential for systematic applications of the theory. This paper introduces a new formulation to compute beam shape coefficients, g, in the framework of the localized approximation and discusses symmetry relations between the coefficients. The new formulation permits computation times to be decreased by one to two orders of magnitude.
Characteristics of Particle Sizes produced by suspension polymerization of styrene
Authors: Stamatoudis Michael , Apostolidou Christina 
Published: June 2005

AbstractExperiments on the suspension polymerization of styrene were conducted at various stabilizer concentrations, dispersed phase hold‐up fractions, impeller types and impeller speeds. The experimental final particle size distributions obtained were almost always described by the upper limit number distribution. Plots of the maximum diameter, amax, and the mean diameters, a21 and a10, vs. the Sauter mean diameter, a32, gave straight lines with slopes of 1.24, 0.99 and 0.97, respectively.
Computer Aided Image Analysis Procedures for Characterizing the stochastic structure of chaotically assembled pigmented coatings
Authors: Kaye Brian H. , Clark Garry G. 
Published: June 2005

AbstractNew techniques for studying stochastic (random) clustering in paint films and composite materials are discussed. The interpretation of measured levels of clustering from the perspective of percolation theory of fractal systems is discussed. The possibility of increasing the optical efficiency of pigments by interfering with stochastic clustering by means of extender pigment and/or microencapsulation is discussed. The use of intertrack measurements on a section through a paint film to study pigment dispersion efficiency is explored by Monte Carlo Routines and illustrative measurements made on a section through a carbonblack dispersion. The design of an intelligent machine to monitor pigment dispersion in real films is discussed.
The Effect of Suspension Medium Refractive index on the particle size analysis of quartz by laser diffraction
Authors: Hitchen Christopher J. 
Published: June 2005

AbstractThe size distributions of four samples of quartz dust, suspended in liquids of different refractive index (RI), were determined using a Malvern 2600 laser particle sizing instrument. As the relative RI, between particle and suspension media, approached unity the instrument over‐estimated the mean particle size for the three finest quartz samples. An under‐estimated mean particle size was recorded for the largest quartz sample indicating the complex nature of light scattering by small particles under conditions of low relative RI.A regime of relative refractive index is determined within which particle size analysis using laser diffraction, invoking anomalous diffraction theory, becomes prone to large errors and this range is compared with the van de Hulst criterion.
Phase‐Doppler Sizing of Optically Absorbing Liquid Droplets: Comparison between mie theory and experiment
Authors: Manasse Uwe , Wriedt Thomas , Bauckhage Klaus 
Published: June 2005

AbstractPhase‐Doppler experiments applied to optically absorbent (homogeneous and inhomogeneous) liquids are described. Simultaneous size and velocity measurements of single droplets were executed at three off‐axis angles ψ. These angles were found to be suitable for the evaluation of the phase‐Doppler technique by Mie theory. Both the sizes of the monodisperse droplets and their absorption properties were varied. At least with respect to homogeneous liquids, comparison of the droplet diameters obtained by phase‐Doppler measurement and by photography (reference technique) showed good agreement. Concerning the optical properties of inhomogeneous liquids, additional phase‐Doppler measurements were carried out using an alternative device based on a laser diode and photodiodes. The longer wavelength λ (830 nm instead of 488 nm) reduced the influence of the inhomogeneities on the droplets' scattering behaviour and thereby improved significantly the phase‐Doppler results. It is concluded that phase‐Doppler anemometry is suitable for the sizing of optically absorbent droplets of real process fluids. Such droplets result from atomization processes often used in various branches, such as the chemical, pharmaceutical and food industries (production of powders and granules, "spray drying"), automotive engineering (dispersing fuels for combustion) and agriculture (crop spraying). Mie scattering theory is a powerful aid for describing the scattering behaviour of dispersed droplets of real process fluids with more complicated optical properties compared with water, i.e. the behaviour of optically absorbent homogeneous liquids, and for determining the necessary parameters of the optical set‐up.
The electromagnetic scattering problem of Laser‐Doppler Anemometry. Part II: Particle investigation
Authors: Raszillier Hans , Durst Franz 
Published: June 2005

AbstractThe second part of this review concentrates on the situation where the moving particles that scatter light are themselves an essential part of the flow under investigation. In order to obtain information also on their nature und their shape, their quantitative characterization by light scattering is needed. This characterization is codified in the magnitude which describes scattering, the scattering amplitude. It becomes transparent for very small and very large particles, because their scattering mechanisms can be interpreted in terms of electromagnetic multipoles and of geometrical optics, respectively. Scatterers of the simplest composition and shape, homogeneous spheres, are considered in detail; they are characterized optically by their radius and index of refraction. It is shown that phase measurements of the modulated scattering signal (phase Doppler anemometry, PDA) can provide, with suitably located detectors, information on these quantities.
On the Prediction of Droplet Size and Velocity distributions in sprays through maximum entropy principle
Authors: Li Xianguo , Tankin Richard S. 
Published: June 2005

AbstractBased on the conservation laws of mass, momentum and energy, the droplet size and velocity distributions in liquid sprays are formulated through the maximum entropy principle, without taking into account the details of liquid atomization processes such as the characteristics of disturbances and behavior of liquid bulk preceding the droplet formation. The joint probability distribution function in size and velocity of the droplets can be predicted from the atomization conditions which are represented by the Weber number and the source terms in the formulation. The model prediction agrees well with the experimental data measured by a phase Doppler particle analyzer.
Characterizing the Fractal Structure of Fineparticle Profiles using the concepts of geometrical probability
Authors: Kaye Brian H. , Trottier Remi A. , Clark Garry G. 
Published: June 2005

AbstractSeveral theorems exist in the subject of geometrical probability with regard to the intersection frequency in two‐dimensional space of stochastic sets of Euclidean line systems of various length and structure. When some of the intersecting lines are fractal in nature, these theories can be modified to deduce the fractal dimensions of the line system, including fineparticle profiles, from observed intersection frequency of the stochastically distributed line system using search grids of known length Analytical procedures based upon such measurements are particulary useful for quality control measurements of a product in which structural changes lie within a relatively restricted range. The theory of the procedures are presented along with experimental data demonstrating the usefulness and efficiency of the procedures.
Sizing Particles by Optical Microscopy through criteria developed by the analysis of image profiles
Authors: Davidson John A. , Butler R. S. 
Published: June 2005

AbstractModern image analysis equipment has now made it possible to obtain detailed intensity profile information about objects imaged under the optical microscope. If the object contrast is generated by light absorption alone then the image profile of the object is a square wave and the size information is contained in the fundamental frequency of the Fourier components of that square wave. The period of the fundamental frequency lies very close to the intensity midpoint of the image profile. As long as the microscope objective numerical aperture (NA) is high enough to pass this fundamental the object can be sized to an accuracy which is chiefly dependent upon the signal to noise ratio of the system and independent of classical notions of microscope resolution.Thus for latex particle metal replicas it was possible to determine the diameter to a precision which was typically on the order of 13% of the classical Sparrow limit of resolution for the objective employed.By sizing the same particle replica with objectives of different NA it was demonstrated that the size obtained was independent of the objective NA used as long as the replica diameter was above the Sparrow limit. This is in accordance with optical theory.About mid‐summer the Goldstein "Zernike" program became available to us through the kindness of Dr. Goldstein. With this program it was possible to model the effect of optical path difference. Unlike particle replicas, most real objects generate object profiles that are a function of refractive index difference and thickness or path difference in addition to object size and transmittance. Although the "Zernike" program can accommodate path differences, it assumes that the object has negligible thickness‐an assumption not merited by most real microscopic objects.Although exact quantitative agreement could not always be obtained with reasonable assumptions, the predictions of the "Zernike" program nevertheless could help to define sample preparation conditions which enabled high accuracy sizing to be performed.This work thus demonstrates that an extremely high degree of accuracy and precision in particle sizing is available from the optical microscope which is independent of classical notions of microscope "resolution". The major requirements are that the objective NA be sufficiently high enough to pass the Fourier components which contain the size information and that features in the image can be identified which contain the size information.
The Effect of Particle Shape on the Amplitude of scattered light for a sizing instrument
Authors: Orfanoudakis Nicholas G. , Taylor Alexander M. K. P. 
Published: June 2005

AbstractThe relationship between size and intensity of laser light scattered from coal particles, glass beads and calibration pinholes in the size ranges 10–140 m̈m, 17–240 m̈m and 5–200 m̈m respectively has been measured. The purposes were to determine the effect of shape of non‐spherical particles and beads by varying three parameters in the collection optics.These were: the angle, θc, between the axis of the collection optics and that of the incident laser beam; the aperture of the f/3.66 collection lens; and the diameter of the spatial filter on the photodetector. A spatial filter diameter of 0.5 mm was used on the detector as a compromise between image vignetting and reducing the size of the effective measuring volume of the instrument. Due to refraction, and particularly for diameters larger than about 80 m̈m, the beads scattered more light than the pinholes or the coal particles. A mask, introduced to limit the collection lens aperture to angles less than 5.3°, reduced the intensity collected from the beads, while the response curves for the pinholes and coal particles were unaffected. Non‐spherical beads larger than about 60 m̈m with aspect ratios up to 1.8 resulted in departure from the response curve, established from the calibration pinholes, by up to a factor of two. The aspect ratio was defined by the maximum and minimum projected lengths of the image of the scatterer. The response curves for beads and coal particles approached that of the pinholes as θc was changed from 2.5° to 1.4° and as the angular position of the mask limiting the aperture of the collection lens nearest to the incident beam axis, θi, was reduced from 2.9° to 0.9°. The best results were obtained for θi and θc equal to 0.9° and 1.4° respectively, for which the precision and accuracy were 9 m̈m and + 5 m̈m for nominally spherical glass beads and 5 m̈m and −1 m̈m for the coal particles for diameters up to 60 m̈m and aspect ratio up to 2.5.
Information Potential of the Method of pulsed recording of light‐scattering particles
Authors: Oshchepkov Sergey L. 
Published: June 2005

AbstractThe topical problem of pulsed recording of light‐scattering particles in a flux has been studied. Along with the determination of the sizes of particles, this problem involves the simultaneous evaluation of their material composition. Such a task arises in analysing multi‐component disperse systems. It is shown that it can easily be realized if the particle materials differ appreciably in absorption coefficients and closeness of their refractive indices to that of the dispersion medium. This is connected with the significant difference of the spatial distribution of the scattered light. A simple method for solving such a problem has been designed with regard to the peculiarities of recording weak light fluxes and the necessity for real‐time optical measurement processing.