The Experts below are selected from a list of 225 Experts worldwide ranked by ideXlab platform
Claus Bernhardt - One of the best experts on this subject based on the ideXlab platform.
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Preparation of suspensions for Particle Size Analysis. Methodical recommendations, liquids and dispersing agents
Advances in Colloid and Interface Science, 2003Co-Authors: Claus BernhardtAbstract:Abstract One of the most important preconditions for numerous methods of Particle Size Analysis is the preparation of suspensions of the defined state of dispersion. This problem is dealt with in the present paper, taking into account measuring problems as encountered in actual practice. The first part deals with a number of physico-chemical fundamentals as the basis for the preparation of a sufficiently well dispersed and stable suspension. The mechanical methods of pretreatment are described from the literature as well as methods to determine the state of dispersion. At the end of the text, the author's opinion is given on the applicability of the methods described.
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Encyclopedia of Analytical Chemistry - Sedimentation in Particle Size Analysis
Encyclopedia of Analytical Chemistry, 2000Co-Authors: Claus BernhardtAbstract:Particle Size Analysis by sedimentation is one of the most important techniques of Analysis. The principle is based on the fact that it is possible to draw conclusions about the geometrical dimensions (Size) of the Particles from the speed of their movement in a fluid. In the past many different apparatuses were developed. Nowadays, methods that allow quick, automatic measurement are most popular. This article consists of two general sections valid for all methods: the first concerns the undisturbed and disturbed movement of Particles in a fluid at rest, and the second concerns the dispersion of solids in liquids. The methods described are divided in gravitational methods and methods used in a centrifugal field, respectively. Finally, the appendix gives a list of liquids and dispersing agents valid for measurement.
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Particle Size Analysis—Problems and Possibilities in the Fine and Ultrafine Range
Journal of Materials Synthesis and Processing, 2000Co-Authors: Claus BernhardtAbstract:The paper discusses some experiences in the field of Particle Size Analysis and is restricted to the off-line techniques measuring the Particle Size distributions of solids. A survey concerning the developments of methods and instruments is followed by a representation of some actual problems (sampling procedure, coincidence, distance between Particles, and interaction forces).
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Position, tasks and structure of Particle Size Analysis
Particle Size Analysis, 1994Co-Authors: Claus BernhardtAbstract:Today the concept of Particle Size Analysis is that of a special field of Particle measurement technology, which in turn is part of particulate technology. This classification has developed over the last 20 years; it is the result of a scientific integration process taking place in many industrialized countries of the world.
S Chandra - One of the best experts on this subject based on the ideXlab platform.
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adequacy of laser diffraction for soil Particle Size Analysis
PLOS ONE, 2017Co-Authors: Peter Fisher, C Aumann, Kohleth Chia, Nick Ohalloran, S ChandraAbstract:Sedimentation has been a standard methodology for Particle Size Analysis since the early 1900s. In recent years laser diffraction is beginning to replace sedimentation as the prefered technique in some industries, such as marine sediment Analysis. However, for the Particle Size Analysis of soils, which have a diverse range of both Particle Size and shape, laser diffraction still requires evaluation of its reliability. In this study, the sedimentation based sieve plummet balance method and the laser diffraction method were used to measure the Particle Size distribution of 22 soil samples representing four contrasting Australian Soil Orders. Initially, a precise wet riffling methodology was developed capable of obtaining representative samples within the recommended obscuration range for laser diffraction. It was found that repeatable results were obtained even if measurements were made at the extreme ends of the manufacturer’s recommended obscuration range. Results from statistical Analysis suggested that the use of sample pretreatment to remove soil organic carbon (and possible traces of calcium-carbonate content) made minor differences to the laser diffraction Particle Size distributions compared to no pretreatment. These differences were found to be marginally statistically significant in the Podosol topsoil and Vertosol subsoil. There are well known reasons why sedimentation methods may be considered to ‘overestimate’ plate-like clay Particles, while laser diffraction will ‘underestimate’ the proportion of clay Particles. In this study we used Lin’s concordance correlation coefficient to determine the equivalence of laser diffraction and sieve plummet balance results. The results suggested that the laser diffraction equivalent thresholds corresponding to the sieve plummet balance cumulative Particle Sizes of < 2 μm, < 20 μm, and < 200 μm, were < 9 μm, < 26 μm, < 275 μm respectively. The many advantages of laser diffraction for soil Particle Size Analysis, and the empirical results of this study, suggest that deployment of laser diffraction as a standard test procedure can provide reliable results, provided consistent sample preparation is used.
Klaus Reichardt - One of the best experts on this subject based on the ideXlab platform.
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Alternative soil Particle-Size Analysis by gamma-ray attenuation
Soil & Tillage Research, 1999Co-Authors: E.a. Elias, Osny Oliveira Santos Bacchi, Klaus ReichardtAbstract:In 1992 a new method of soil Particle-Size Analysis was introduced, which coupled sedimentation to gamma-ray attenuation. The theoretical possibility of an alternative for this method is here presented, which includes the necessity of sieving soil samples, but simplifies the gamma-ray measurements. Advantages and disadvantages of this alternative are discussed.
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improved soil Particle Size Analysis by gamma ray attenuation
Soil Science Society of America Journal, 1997Co-Authors: J C M Oliveira, Klaus Reichardt, D SwartzendruberAbstract:The Size distribution of Particles is useful for physical characterization of soil. This study was conducted to determine whether a new method of soil Particle-Size Analysis by gamma-ray attenuation could be further improved by changing the depth and time of measurement of the suspended Particle concentration during sedimentation. In addition to the advantage of nondestructive, undisturbed measurement by gamma-ray attenuation, as compared with conventional pipette or hydrometer methods, the modifications here suggested and employed do substantially decrease the total time for Analysis, and will also facilitate total automation and generalize the method for other sedimentation studies. Experimental results are presented for three different Brazilian soil materials, and illustrate the nature of the fine detail provided in the cumulative Particle-Size distribution as given by measurements obtained during the relatively short time period of 28 min.
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Improved Soil Particle‐Size Analysis by Gamma‐Ray Attenuation
Soil Science Society of America Journal, 1997Co-Authors: J C M Oliveira, Klaus Reichardt, D SwartzendruberAbstract:The Size distribution of Particles is useful for physical characterization of soil. This study was conducted to determine whether a new method of soil Particle-Size Analysis by gamma-ray attenuation could be further improved by changing the depth and time of measurement of the suspended Particle concentration during sedimentation. In addition to the advantage of nondestructive, undisturbed measurement by gamma-ray attenuation, as compared with conventional pipette or hydrometer methods, the modifications here suggested and employed do substantially decrease the total time for Analysis, and will also facilitate total automation and generalize the method for other sedimentation studies. Experimental results are presented for three different Brazilian soil materials, and illustrate the nature of the fine detail provided in the cumulative Particle-Size distribution as given by measurements obtained during the relatively short time period of 28 min.
Albert H L Chow - One of the best experts on this subject based on the ideXlab platform.
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Particle Size Analysis in pharmaceutics principles methods and applications
Pharmaceutical Research, 2007Co-Authors: Boris Y. Shekunov, Pratibhash Chattopadhyay, Henry H.y. Tong, Albert H L ChowAbstract:Abstract Physicochemical and biopharmaceutical properties of drug substances and dosage forms can be highly affected by the Particle Size, a critical process parameter in pharmaceutical production. The fundamental issue with Particle Size Analysis is the variety of equivalent Particle diameters generated by different methods, which is largely ascribable to the Particle shape and Particle dispersion mechanism involved. Thus, to enable selection of the most appropriate or optimal sizing technique, cross-correlation between different techniques may be required. This review offers an in-depth discussion on Particle Size Analysis pertaining to specific pharmaceutical applications and regulatory aspects, fundamental principles and terminology, instrumentation types, data presentation and interpretation, in-line and process analytical technology. For illustration purposes, special consideration is given to the Analysis of aerosols using time-of-flight and cascade impactor measurements, which is supported by a computational Analysis conducted for this review.
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Particle Size Analysis in pharmaceutics: Principles, methods and applications
Pharmaceutical Research, 2007Co-Authors: Boris Y. Shekunov, Pratibhash Chattopadhyay, Henry H.y. Tong, Albert H L ChowAbstract:Physicochemical and biopharmaceutical properties of drug substances and dosage forms can be highly affected by the Particle Size, a critical process parameter in pharmaceutical production. The fundamental issue with Particle Size Analysis is the variety of equivalent Particle diameters generated by different methods, which is largely ascribable to the Particle shape and Particle dispersion mechanism involved. Thus, to enable selection of the most appropriate or optimal sizing technique, cross-correlation between different techniques may be required. This review offers an in-depth discussion on Particle Size Analysis pertaining to specific pharmaceutical applications and regulatory aspects, fundamental principles and terminology, instrumentation types, data presentation and interpretation, in-line and process analytical technology. For illustration purposes, special consideration is given to the Analysis of aerosols using time-of-flight and cascade impactor measurements, which is supported by a computational Analysis conducted for this review. © 2006 Springer Science+Business Media, Inc.
Peter Fisher - One of the best experts on this subject based on the ideXlab platform.
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adequacy of laser diffraction for soil Particle Size Analysis
PLOS ONE, 2017Co-Authors: Peter Fisher, C Aumann, Kohleth Chia, Nick Ohalloran, S ChandraAbstract:Sedimentation has been a standard methodology for Particle Size Analysis since the early 1900s. In recent years laser diffraction is beginning to replace sedimentation as the prefered technique in some industries, such as marine sediment Analysis. However, for the Particle Size Analysis of soils, which have a diverse range of both Particle Size and shape, laser diffraction still requires evaluation of its reliability. In this study, the sedimentation based sieve plummet balance method and the laser diffraction method were used to measure the Particle Size distribution of 22 soil samples representing four contrasting Australian Soil Orders. Initially, a precise wet riffling methodology was developed capable of obtaining representative samples within the recommended obscuration range for laser diffraction. It was found that repeatable results were obtained even if measurements were made at the extreme ends of the manufacturer’s recommended obscuration range. Results from statistical Analysis suggested that the use of sample pretreatment to remove soil organic carbon (and possible traces of calcium-carbonate content) made minor differences to the laser diffraction Particle Size distributions compared to no pretreatment. These differences were found to be marginally statistically significant in the Podosol topsoil and Vertosol subsoil. There are well known reasons why sedimentation methods may be considered to ‘overestimate’ plate-like clay Particles, while laser diffraction will ‘underestimate’ the proportion of clay Particles. In this study we used Lin’s concordance correlation coefficient to determine the equivalence of laser diffraction and sieve plummet balance results. The results suggested that the laser diffraction equivalent thresholds corresponding to the sieve plummet balance cumulative Particle Sizes of < 2 μm, < 20 μm, and < 200 μm, were < 9 μm, < 26 μm, < 275 μm respectively. The many advantages of laser diffraction for soil Particle Size Analysis, and the empirical results of this study, suggest that deployment of laser diffraction as a standard test procedure can provide reliable results, provided consistent sample preparation is used.