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  • 1990-1994
  • 1985-1989  (30)
  • 1920-1924
  • 1820-1829
  • 1985  (30)
  • Industrial Chemistry and Chemical Engineering
  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 149-153 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: To investigate the influence of the stress history on the yield limit a shear tester was developed, in which stresses or strains in x- and y-direction can be applied independently of each other. Since there are no shear stresses on the boundary surfaces of the sample these stresses are principal stresses and the Mohr stress circles are known for each state of stress. First results from shear tests with limestone show a significant influence of the different ways of consolidation on the yield limit, i. e. the flow properties of a bulk solid will depend on the stress history. The flow function, however, which is essential for silo design, proves to be invariable of the stress history.
    Additional Material: 10 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 20-24 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In order to characterize flow separation and classification processes, particle size distributions must be measured in the airborne state without affecting the state of dispersion or disturbing the flow. Light scattering devices with an optically defined measuring volume are specially designed for this purpose. However the light scattering device must be calibrated using non-ideal particles which are present within the multiphase flow, preferably on an equivalent diameter based on settling rate. Such a calibration can be achieved by measuring with an optical particle counter before and after an impactor in droplet systems and a sampling cyclone in systems of solid particles. By measuring the calibration curves the size distribution of the investigated particles are also determined. This measuring technique allows the best use of the optical particle counter in industrially relevant cases which may have high particle concentrations, wide distributions, non-ideal particles and an undefined state of dispersion.
    Additional Material: 8 Ill.
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  • 3
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Disperse materials are often characterized by their particle-size distributions which can be determined by different measuring methods. Frequently the quantitative portions of the particle size classes obtained by way of experiment are considered insufficient and one strives for approximating the measured values by an analytic function. This can be reached, more or less satisfactorily, by power, exponential, or normal distribution functions which may include two, three, or four parameters.Publications as well as common practice have proved again and again that due to very rough or incorrect approximations wrong conclusions are derived from test and operating results, so that it appears expedient to investigate - when such an approximation would actually be advisable and - which function would be expedient in the specific case.Application of distriction functions will always be justified then when there is an actual need for utilizing the advantages connected with an approximation. Evaluation of a great number of measuring results revealed that the two-parameter functions in most cases only permit an utmost rough approximation which might give rise to wrong conclusions. Carefully classified products, however, mostly require three- or four-parameter functions for making an appropriate approximation.The functions, which appear appropriate for certain types of products, are set out in Table 1.In order to make the tabulated individual results accessible to a practical utilization a systematization was attempted. The outcome is a graph which is meant as an assistance for the practician and which presents the possibility of a quick selection of function type.
    Additional Material: 4 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 71-76 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In this paper a reciprocating shear cell, which has been developed to measure dynamic wall friction, is described. The cell has also been used to study the attrition behaviour of sand samples at the bounding wall. This attrition causes a considerable change in the angle of wall friction.
    Additional Material: 13 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 81-90 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Amongst the well known methods to measure surface area of particulate matter, preferably dry powders, only photometric methods can be used on-line.The basic equation for the photometric measurement of surface area is Lambert-Beer's law, which describes the attenuation of light (extinction) due to the presence of particles in a light beam. The attenuation being dependent not only on the size distribution of the particles in the light beam but also on their volume concentration. Since both effects alter the attenuation simultaneously the solids volume concentration has to be measured independently of the attenuation in a true on-line system. The instrument developed combines the extinction of white light with the absorption of γ-rays.Since the absorption of γ-rays demands more particles in the measuring zone than the attenuation of light, an aerosol stream of rectangular cross section has been used which allows the simultaneous measurement of extinction and γ-ray absorption.Apart from a brief description of the theoretical background of the instrument experimental evidence will be given of its suitability for on-line application [1, 2].
    Additional Material: 22 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 123-123 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: No. Abstract.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 133-136 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: High capacity preseparators are used to reduce bounce and blow-off of large particles in cascade impactors. In this paper, results are presented of a detailed analysis of the deposition of particles in two slightly different preseparators of the impactor-type which are used in connection with the Andersen Stack Sampler. The advantage of using any preseparator for aerosols mixed with large particles (x 10 μm) is clearly shown.A preseparator which is integrated into the impactor has the advantages of smaller overall size, accessible surfaces and, therefore, easier handling. The results of the study show that the reduction of unwanted particle losses is rather small when compared with a separate preseparator.
    Additional Material: 8 Ill.
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  • 8
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Inspection of the scattered light by two photodetectors makes it possible to investigate the velocities of droplets as well as their size in disperse systems and has some advantages against related methods. When this method is used, the size of the droplets can be derived from the phase difference of the signals from the first and the second photodetector.Special problems of this method are discussed in the paper. A system with fast signal processing facilities, working mostly digitally, was developed in order to solve these problems. This system derives several digital signals from the signals of high frequencies that are gained from the photodetectors. These digital signals are combined by digital circuits of the ECL-type. The resulting pulse series are fed into several digital counters. The data from the counters and from some other inputs are further processed by a real time computer that was developed for this special task, using an 8088 micro processor. This real time computer is connected to an ordinary personal computer by a parallel interface.
    Additional Material: 8 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 137-142 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A measurement method that approximates the spatial distribution of inhomogeneously distributed aerosols in a limited measurement plane is described. It is based on the evaluation of a comparably small number of infrared extinction measurements taken from the measurement plane boundary. The measured data are processed by means of computed tomography. The results are displayed on a monitor in a colour-coded picture of the aerosol-“density”-pattern. The basic design and the principal characteristics of the method are mathematically described and verified by simulation tests and practical results which are obtained from an experimental set up using smoldering wood as an aerosol source.
    Additional Material: 6 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 14-19 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Numerous methods have been reported in the literature for the measurement of (submicron) particle size distribution by turbidimetry. Attempts to apply some of these to coupler dispersions (oil-in-water emulsions of importance in the photographic industry) have not in general proved satisfactory, however, because small experimental errors lead to relatively large errors in the calculated distribution. In order to reduce this problem a turbidimetric technique involving measurements at two widely separated wavelengths, 400 nm and 2.22 μm, has been developed. Its accuracy has been demonstrated using polydisperse polystyrene latexes of known size distribution. With the aid of simple, purpose-built equipment, linked to a desktop computer, the technique has been largely automated so that it is suitable for use by an unskilled operator working in a factory environment.
    Additional Material: 7 Ill.
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  • 11
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 39-48 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Product quality is influenced by the properties of feedstocks and by production parameters. In contrast to gases and liquids, the quality of solids is also affected by the particle properties, such as size, specific surface area, structure and shape. These are the properties which are primarily changed in solids process engineering.The accuracy and cost of possible methods for the measurement of the particle properties of feedstocks, intermediates and end products are discussed. Examples of the methods discussed are laser diffraction spectrometry, quantitative image analysis and photon correlation spectroscopy.The measuring techniques required for monitoring production processes in solids process engineering are illustrated by simple examples. In the field of process control in particular, there is still room for improvement, since there is a lack of suitable sensors and models. Process monitoring is necessary in order to ensure that product quality meets requirements which are constantly increasing.
    Additional Material: 25 Ill.
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  • 12
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 77-78 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Aerosols or particles suspended in air are often filtered by pads of fibers. The particles collect on the surface of the fibers in chain-like structures called dendrites. An example scanning electron micrograph of 4.1 μm diameter particles captured on a 25-m̈m fiber was analyzed by a Richardson plot. The Richardson plot is the measured perimeter of an image as a function of the length of measure or stride length. Three distinct regions were identified. For long and short stride lengths, the linear fiber and spherical particles were Euclidean. In the intermediate stride length region, the dendrite was fractal with a dimension of 1.36. The fractal nature of dendrites results from the random position of particles approaching the fiber and the shadowing effect of collected particles. Fractal geometry is potentially a useful approach for describing the morphology of the dendritic structures.
    Additional Material: 2 Ill.
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  • 13
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Fineparticle Science is the study of the production and the behavior of finely divided material. In recent years the technology of fineparticle science has expanded rapidly. Many of the new innovations in that science have important applications in mineral processing. An important recent development in the mathematics of fineparticle science is the use of fractal descriptors to describe rugged boundries. In this communication the use of fractals to describe cracks in N dimensional space and potential applications of fractal descriptions in liberation kinetics are discussed. Fractals can also be used to describe the progress of a water front in a secondary oil recovery system. The use of divers to study concentration gradients in settling suspensions (tailing ponds) are described. New studies aimed at the optimization of on-line quality control of grinding circuits are reviewed.
    Additional Material: 8 Ill.
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  • 14
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The Activation of ultrafine particles as the condensation nuclei, or heterogeneous nucleation of ultrafine particles, has been observed in various supersaturated vapors. Monodisperse NaCl, ZnCl2, Ag and silicon oil particles, 5-15 mm in diameter, are used as the condensation nuclei and water, hexanol, dibutyl phthalate (DBP) and di-2-ethyl-hexyl sebacate (DEHS) are used as teh vapors. The supersaturated atmosphere is formed in the mixing type condensation nucleus counter (CNC) where a room temperature aerosol is mixed with warm air saturated by each vapor and the supersaturation ratio is controlled by changing the temperature of the saturated air. The number ratios of activated particles to total particles are observed at various supersaturation ratios. It is found that the activation of particles depends in a complicated manner on the combination of the substances of particles with condensing vapors, that is, activation in some particle-vapor systems is explained by the Kelvin effect but not in others.
    Additional Material: 9 Ill.
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  • 15
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 143-148 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A technique for measuring the fractal structure of the rugged boundaries exhibited by lunar dust and a cosmic dust fineparticle captured at the outer limits of earth's atmosphere are measured using a equipaced polygon construction measurement procedure. The measurement procedure is described and data illustrating the precision and accuracy of the method are presented. The technique can be automated using inexpensive equipment and is suitable for use in teaching laboratories. Comparative data is presented establishing that the equipaced polygon procedure generates data comparable to that generated by the structured walk exploration technique. It is suggested that the fractal structure of extra terrestrial fineparticles may be of interest not only to the cosmologist but to the mining engineer since lunar dust represents fractured material not subjected to attrition polishing. Models used to simulate the generation of soot in combustion processes are discussed and it is demonstrated that diffusion limited aggregation Monte Carlo routines generate an agglomerate that appears to have similar fractal structure to the cosmic dust fineparticle collected by Brownlee. The data presented also indicates that one should use caution when relating the fractal dimension of a projected perimeter profile in two dimensions to the three dimensional structure of a rugged fineparticle.
    Additional Material: 9 Ill.
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  • 16
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 160-165 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A dual gas flow chromatographic method is proposed. In this method, two different gas streams are introduced separately, one as the carrier gas and the other as the gas for creating the adsorption equilibrium. The thermodesorbed absorbate is eluted by a pure carrier gas. The complete curve of adsorption isotherm can be determined easily; therefore, both the specific area and the pore size distribution can be obtained at ordinary pressure. In addition, this method can be easily changed into the continuous flow method given by Nelsen and Eggertsen [1]. The relationship among R (rate) - V (volume) - A (area) - α (ratio) in elution chromatography are investigated, and the volume of desorbed gas can be obtained from Vd = KRAd directly with K = (αV)/(RA). The standardization for peak area is simplified and more convenient for the treatment by a microcomputer. Some results of specific surface area and pore size distribution by this method, and their comparison with those from other methods are given altogether, and the coincidence is good.
    Additional Material: 14 Ill.
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  • 17
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The rheological behaviour of a fluidised bed of alumina powder was determined using a specially designed form of rotating viscometer. Several different geometries of the inner and outer cylinder were tested. In the machine the two cylinders can be rotated independently, in either direction, which enables both their relative velocity and absolute velocity to be varied. Thus, the torque on the inner cylinder, strain-rate and the absolute velocity have been chosen as the consistency variables. Some examples of the derived consistency surface are given. The characteristics of these surfaces could be explained by assuming different states of structure, to which a certain mobility can be ascribed. It is proposed that any state of structure which can exist in the bed is an intermediate of two extremes the first being the immobile state which is elastic and has a yield value and the second being the dynamic state which behaves like a Newtonian fluid.
    Additional Material: 15 Ill.
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  • 18
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: There are three basic philosophies which may be taken towards the problem of calibrating particle size measuring techniques. The first is to assume a model of the process and that the technique is thus absolute. The second is to calibrate an instrument using the particles which are to be measured themselves. In this paper, these three approaches are compared and contrasted. As an example, the programme of certification of the BCR samples is cited and discussed. The paper then advocates the use of the equivalent volume diameter as the basic particle size characterization and its combination with other measurements as shape determinations. The representation of both size and shape in this way is conveniently presented in the form of orthogonal diagrams.
    Additional Material: 9 Ill.
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  • 19
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 25-30 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A modified drop-shatter test apparatus was used to study the primary breakage of particles of two solid fuels. In this apparatus many particles could be subjected to just one impact under known conditions.About 100000 particles of each fuel, sorted by size and shape into eight separate groups, were dropped from four different heights and the fragments thus formed were sifted to determine their size distributions, that is the experimental breakage functions.The interior of particles, of regular or irregular shape, fails under tension and the resulting fragmentation is due to stress-activated volume flaws which give rise to coarse fragments whose distribution can be represented by a theoretical breakage function of the form \documentclass{article}\pagestyle{empty}\begin{document}$$ B(z) = \mathop \Sigma \limits_{{\rm \gamma = 1}}^\infty \left[ {\frac{{\lambda \cdot e^{ - \lambda } }}{{{\rm \gamma !(1 - }e^{ - \lambda } )}} \cdot \left\{ {1 - (1 + {\rm \gamma }z^3 )(1 - z^3 )^{\rm \gamma } } \right\}} \right] $$\end{document} where z is the relative size of the fragments and γ is the number of stress-activated volume flaws per particle.The average values of γ, given by μγ = λ/(1 - e-λ), ranged from about one to five, corresponding to the formation of two to six coarse fragments per broken particle.The probability of breakage was log-normally related to μγ.
    Additional Material: 8 Ill.
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  • 20
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 67-70 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In any determination of the internal porosity (intra particle porosity) by mercury porosimetry, the penetration curve must be interpreted in such a way that the contribution of the interparticle porosity is deleted. In an earlier communication an experimental technique, known as the critical pressure technique, was developed to accomplish this goal. In this communication a hot stage microscopy image analysis technique is described for the determination of the intra particle porosity of PVC resins. This enables the validity of the critical pressure method to be independently tested. On 12 samples of PVC resin a 1 - 1 correlation between the two methods was found indicating the validity of the critical pressure technique. Another porosity determination technique described earlier, based on the uptake of wetting oil, is also discussed in the light of these findings. This work also illustrates that hot stage microscopy, combined with image analysis, can be used to determine the glass transition of polymers on samples as small as 1·10-8 grams.
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  • 21
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 56-61 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Fractal dimensions are numbers between the classical whole number dimensions which can be used to describe the ruggedness of a fineparticle boundary. This communication explores the utility of fractal dimensions between 1 and 2 for characterizing the ruggedness of fineparticle profiles. This type of fractal boundary is evaluated by estimating the perimeter of a profile of a fineparticle at various levels of scrutiny and then plotting a graph of the logarithm of the perimeter estimates against the logarithm of a unit representing the scale of scrutiny. Such a graph is known as a Richardson plot. Boundaries describable by fractal dimensions exhibit characteristic datalines on this type of graph.Aluminum shot fineparticles produced by the break up of turbulent jet of molten metal have irregular shapes because of the fluid turbulence in the regions where they solidify, but a smooth texture because of the effect of surface tension forces as the fineparticle solidifies. It is shown in this communication that the dataline on a Richardson plot of the estimated perimeter of an aluminum shot fineparticle consists of two regions. The first portion, at coarse levels of scrutiny, permits the calculation of a fractal dimension descriptor of the ruggedness of the profile. A second dataline at high resolution is parallel to the scrutiny axis indicating that at such levels of inspection the profile is effectively smooth and euclidean. Studies are reported of the changes in the ruggedness of an eroding aluminum shot fineparticle suspended in acid. It is shown that fractals can be used to describe the progress of corrosion and that, as corrosion proceeds, the euclidean portion of the Richardson plot of perimeter estimate recedes and disappears within the levels of scrutiny employed in these experiments.
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  • 22
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
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  • 23
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 104-112 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The forward-light scattering technique was compared with three other well known size analysis techniques in determining the size distribution of a crystalline adsorbent, Silicalite (1-10 μm) in a dilute aqueous suspension. The commercial light scattering equipment Malvern was found to produce size distributions within ± 10% agreement with those obtained by scanning electron microscopy (SEM), electronic image analysis (Quantimet) and the electrical sensing zone method (Coulter Counter).This rather surprising accuracy of the light scattering technique with crystal sizes quite close to the wavelength of the incident light is explained by considering the relative refractive index and the light absorbancy of the crystals in the “anamolous diffraction” regime. The theoretical analysis shows quite clearly that the calculation of a “unique” size distribution from a given set of scattering data is possible only when independently measured values of the optical properties are used.The commercial equipment (Malvern) which is currently in use does not require a priori knowledge of the optical properties. The exceptional accuracy obtained with Silicalite crystals using the Fraunhofer approximation in the anamolous diffraction regime is demonstrated with the aid of the light scattering theory to be due to a rather fortunate combination of the light absorptive nature and the polydispersity of the crystals.
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  • 24
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 125-132 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An aerosol sampling inlet has been developed to collect representative samples from the flowing gas stream. The inlet is referred to as the “Universal Aerosol Sampling Probe” because it is capable of efficient sampling over a wide range of free stream velocity without the need to change either the probe tip or sampling flow rate. It is a multi-nozzle device consisting of one or more outer nozzles to extract a sample isokinetically and decelerate it from the relatively high stream velocity to a relatively low velocity. An inner nozzle is then used to extract a representative particle sample for delivery to the impactor or other particle collectors placed downstream. The approach enables a representative particle sample to be extracted at a fixed flow rate, irrespective of the velocity of the gas stream in which the probe is placed. The theoretical considerations leading to the design of such a universal probe are described. It is followed by the description of an experimental evalution of a prototype device. Good agreement was found between the experimental results and the theoretical prediction.
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  • 25
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    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 31-37 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Practical procedures are described for a stereological method which determines the spatial distribution of particle orientation from the distribution observed on cross sections. First, the two dimensional distribution of needle-like particles is determined by counting the number of intersections with parallel probe lines. Next, the three dimensional distribution of needle-like particles is determined by counting the number of intersections with a cutting plane. Then, the three dimensional distribution of disklike particles is determined by counting the number of intersections with a probe line. Finally, the distribution of disklike particles is determined by measuring the total length of the cross sections on a cutting plane.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 26
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 62-66 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The need for particle shape characterization has been internationally recognised and has resulted in a number of publications proposing a variety of methods for particle shape analysis and shape description. Though very important in chemical engineering, correlations between shape parameters and bulk properties are still rare.This paper describes theoretical and experimental investigations of dynamic shape factors for use when calculating the settling velocity of a particle. For this purpose a study of the settling velocities of particles of various shapes has been made. A correlation is developed from the data with which to quantify the effect of shape on settling velocity for particles falling freely in a fluid in the laminar flow range.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 27
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 79-80 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 28
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 98-103 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper starts from the fact that the Fourier coefficients of the contour of a particle are commonly used to describe its shape, for example by Meloy's law of morphological coefficients. The authors point to the sensitivity of the Fourier coefficients of jump discontinuities of the contour or of one of its derivatives. Explicit formulae for this dependence are reported and are used to suggest a stochastic model, the sensitivity is demonstrated by two examples with calculated results.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 29
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 7-13 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: For several years the size distributions of particulate matter have increasingly been determined by using diffraction pattern analysis.In order to evaluate particle size distributions from the far field intensity distribution of light diffracted by a distribution of particles, a linear set of equations must be solved. Since, in many cases of application, conventional methods for solving linear sets of equations become unstable, the calculated particle size distribution may also be grossly in error. By applying special, known mathematical methods we succeeded in obtaining a parameterfree solution of the above problem.After a brief description of the mathematical method used, a diffraction pattern analyser will be presented as well as some experimental results obtained with it. The results obtained with aerosols and suspensions come from experiments performed with narrow-sized latexes and mono- and bi-modal particle size distributions of limestone and quartz.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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  • 30
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 2 (1985), S. 166-166 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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