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April 1990 - present
Malvern Instruments Inc
- Applications Manager
April 1990 - August 2016
Malvern Instruments Inc
- Applications Manager
September 1976 - November 1979
In a nutshell, the issues of nanomaterial characterization revolve around dealing with the difficulty of measuring what one cannot see. Nanomaterials have unique properties on account of their high surface area to mass ratio and their small size. Thus, a wide range of available and state-of-the-art techniques are needed to characterize such materia...
This article describes the routes used for the measurement of refractive index. It provides an applications focused perspective on the measurement of both the real and the imaginary parts of the refractive index. Modern and historic instruments are described together with methods and reasons for refractive index determination.
Nanoparticle zeta-potentials are relatively easy to measure, and have consistently been proposed in guidance documents as a particle property that must be included for complete nanoparticle characterization. There is also an increasing interest in integrating data collected on nanomaterial properties and behavior measured in different systems (e.g....
This paper deals the determination of the particle size distribution of a material nominally (and inadequately) described as “0 – 10 silica”. First, we will outline the routes to obtaining a stable set of light scattering data via wet and dry laser diffraction determination. These stable data are a prerequisite for the deconvolution to a particle s...
Like most things in life one gets out what one puts in and this is no truer than in modern instrumental particle size distribution techniques. The mantra of 'garbage in = garbage out' is meant to convey that the apparently complicated laser diffraction, dynamic light scattering, and electron microscopy techniques measure faithfully what they are gi...
The International Alliance for NanoEHS Harmonization (IANH) organises interlaboratory comparisons of methods used to study the potential biological impacts of nanomaterials. The aim of IANH is to identify and reduce or remove sources of variability and irreproducibility in existing protocols. Here, we present results of the first IANH round robin s...
15013320:2009, the newly released revised standard for laser diffraction particle size analysis has introduced key changes and provides tips for those seeking to optimize the use of the technique. The new standard indicates a number of changes to aspects of the measurement process, ranging from equipment selection to results analysis. A laser diffr...
Novel materials with single particle dimensions at the nano scale are submitted for analysis to our applications laboratory on a regular basis. These samples include nanotubes, buckyballs, quantum dots and various metal oxides. Determining the proper dispersion and test conditions to characterize nanomaterials is often challenging. This poster summ...
A two-day international workshop was convened recently in order to scope out and address the urgent need for standards to accurately characterize the physico-chemical and biological properties of engineered nanomaterials. These standards are needed by industry and regulatory bodies in order to meet requirements for the production, application and l...
Particle shape, size, and density play a fundamental role in determining both primary and bulk powder and suspension properties. For example, dissolution is related to the primary particle size in the system and rheological properties to the bulk particle size distribution (agglomerates and all). There are a large number of techniques both qualitat...
Basic physics that can help overcome technical challenges is discussed. These are potential killer mechanisms that lead to the proposal for a molecular approach to the design of high-performance ceramic materials rather than a top-down strategy. Chemical purity (including doping) and particle shape and size are key elements in the control of the su...
The difference in “diameter” from micron to nano is 103 which is 109 (a billion) times difference in volume or mass. This implies that the properties that we have intuitive feeling for at the micron scale are considerably modified at masses a billion times smaller. Indeed it is for this reason that “nano” materials have been exploited. For example,...
New patented technology, in combination with planned management of particle size and distribution, is providing Courtaulds Coatings with a competitive edge in successfully developing new powder coatings products for a range of increasingly demanding applications. Understanding the nature, behaviour and size distribution of the particulates involved...
The hydrogenation of isoprene (2-methyl-1,3-butadiene) proceeds at 273 K in EtOH solvent in the presence of Pd catalysts to give the three possible methylbutene isomers with high selectivity (≥ 98%): their proportions, which remain constant until all the isoprene has reacted, are approximately 2-methyl-2-butene, 50%; 3-methyl-1-butene and 2-methyl-...
The paint and pigment industry is only relatively recently becoming aware of the importance of controlling the particle size of its materials. Improved quality methods necessitate controlling paint performance at the manufacturing stage - a need that has stemmed from tighter tolerances and specifications from large paint consumers such as the autom...
I am seeing a number of ‘Discussions’ posted that are simply the synopsis of a published paper by the author (or one of the authors) of that paper. Often a response of ‘Impressive’ is seen in the Answers section. For example:
These seem to be of a similar theme and all from the same group at Nirma University.
Is this gaming the system when there is no discussion to be had or answers to be given?