摘要:

AbstractThe velocity for removal of particles adhering on a wall has been measured for polystyrene latex (PSL) and iron oxide particles at laminar and turbulent flow in a glass cell. The results indicate that larger particles detache at lower flow velocities and the width of the velocity range for removing adhering particles is wider when the particle size is smaller in the laminar flow regime. Both the viscous drag force for removing particles determined experimentally and the adhesive force obtained theoretically are proportional to the particle diameter, and the coefficients of friction were estimated to be 0.01–0.08 and 0.01–0.02 for PSL and iron oxide particles, respectively. The ranges of the viscous force, the adhesive force and the coefficient of friction are not so far from the values given byKanaokaet al.

ISSN:0934-0866    

DOI:10.1002/ppsc.19890060111

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractFor a field intercomparison of various widely used dust samplers, a reference instrument was needed. Based on a Wide Range Aerosol Classifier (WRAC), several improvements were introduced compared with the original design including mass flow control of the samplers and the plenum air, brushless threephase blowers, hyperbolic inlets and generally a more compact design, allowing for more comfortable operation. In addition, for measurement of small particle size distributions, a Hauke high‐volume, low‐pressure impactor (LPI 150/0.15) was included, so that size distribution information with cuts at 0.12, 0.30, 1.19, 3.14, 10.2, 20.4, 37.4 and 60 μm could be obtained. In addition, the aspiration efficiency was measured under in situconditions and parallel measurements were performed with the two reference samplers built so that the performance was well character

ISSN:0934-0866    

DOI:10.1002/ppsc.19890060112

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThis Committee stood under the banner of joint meetings with the Crystallization Committee. Further it was characterized by two aspects, namely technological innovation in connection with measurement methods and their (on‐line) application in engineering processes, whether for the sake of model formation or for process control or quality assurance in industr

ISSN:0934-0866    

DOI:10.1002/ppsc.19890060113

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractProblems connected with particle sizing with the use of radiation power measurement at a small angle (θ = 0.5° – 10°) where the Lorenz‐Mie theory is a mathematical model of the phenomenon are discussed. As an example, a computer program LICZ, allowing for the shortest calculation time, yet preserving satisfactory accuracy of calculations, is cons

ISSN:0934-0866    

DOI:10.1002/ppsc.19890060114

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0934-0866    

DOI:10.1002/ppsc.19890060115

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0934-0866    

DOI:10.1002/ppsc.19890060116

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThe sizing accuracy of a commercially available laser optical liquid‐borne particle counter is investigated. A calibration study, using aqueous suspensions of non‐absorbing, monodisperse, spherical polymer particles, and a study using suspensions of non‐spherical polydisperse, alumina particles are conducted. The experimental results from the spherical polymer study show an excellent agreement with the theoretical Mie light scattering calculations. The accuracy of the spherical polymer sizing is shown to be within 20% of the actual size. The alumina particle readings are compared to the readings of four different particle sizing instruments and to scanning electron microscope pictures. Although quantitative comparisons are difficult to make between the instruments, the results show a good agreement for the batch of particles with a narrower size distrib

ISSN:0934-0866    

DOI:10.1002/ppsc.19890060117

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractWhen measuring scattered light from single particles (as realized in various methods of scattered light‐particle size counting analysis) nonspherical particles and particles with inner structure produce different signal heights (scattered light intensities) when differently oriented in the measuring volume. To study the influence of the particle shape and structure, the representative spectrum of all signal heights reflecting all of the possible orientations of the particle in the measuring volume was recorded from individual particles of a definite material in each case. Additionally from every particle an equivalent diameter was determined.The measurements lead to a very precise calibration curve and to a transformation matrix, that describes the influence of shape and structure on scattered light‐counting analyses in case of the specific material. It is then possible tosimulatemeasurements to determine the loss in resolution caused by the influence of shape and structure and toeliminatethis effect from conventional scattered light analyses.The paper presents the concept together with results of simulation and elimination calculations for the material limestone and quartz. The corrected size distributions are compared with results by other methods. On the basis of this comparison it is discussed how successful the method is to recover a higher resolut

ISSN:0934-0866    

DOI:10.1002/ppsc.19890060118

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractAs part of the development of a light scattering instrument to detect fibres, scattered light from finite cylinders which are exposed to light at arbitrary orientation is studied using the Rayleigh – Gans – Debye approximation. Form anisotropy, which is crucial to the performance of the instrument, is allowed for by using the Shifrin modification in which the elemental volumes are considered to be prolate spheroids. For long cylinders this is compared with van de Hulst's model in which the rigorous theory for an infinite cylinder is modified by Fraunhofer diffraction on the length. For very short cylinders comparison is made with the Mie theory for sphe

ISSN:0934-0866    

DOI:10.1002/ppsc.19890060119

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractA single‐stage impactor has been used to calibrate a Polytec HC‐15/1 optical aerosol analyser so that this instrument can be used to study water droplets from approximately 1 to 20 μm aerodynamic diameter. The resulting calibration data were in good agreement with calculations based on Mie light scattering theory, and gave a conversion factor of 2.0 ± 0.2 between polystyrene latex microspheres and water droplets of the same aerodynamic diameter.Monodisperse water droplets were sampled by a Polytec HC‐70/2 analyser, calibrated using the conversion factor of 2.0. The measured count median diameter agreed closely with that predicted from the well‐defined operating conditions of the vibrating orifice aerosol generator. Size measurements of a polydisperse water‐droplet spray were also undertaken with both a Malvern laser diffractometer and a Polytec HC‐15 analyser; good agreement was achieved between the t

ISSN:0934-0866    

DOI:10.1002/ppsc.19890060120

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY