
Alexander MalmMalvern Panalytical
Alexander Malm
MPhys Physics, Doctor of Enterprise- Physics
Material characterization techniques, predominantly by light scattering
About
15
Publications
123,339
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Introduction
Development scientist with a background in optical physics and soft matter, with particular interest in the development of instruments to characterise colloidal systems and probe the rheology of materials.
Additional affiliations
September 2011 - September 2015
Publications
Publications (15)
Capillary Dynamic Light Scattering (DLS), has recently been introduced as a simple and enabling technique that increases the measurement range of traditional DLS analysis with minimized sample volumes (Ruseva et al., 2018). The previously published protocol for the preparation of samples for analysis within a capillary called for sealing of the cap...
Dynamic Light Scattering (DLS) is a ubiquitous and non-invasive measurement for the characterization of nano- and micro-scale particles in dispersion. The sixth power relationship between scattered intensity and particle radius is simultaneously a primary advantage whilst rendering the technique sensitive to unwanted size fractions from unclean lab...
Webinar discussing the challenges in interpreting particle size data from DLS, and how this can be aided by machine learning.
https://www.malvernpanalytical.com/en/learn/events-and-training/live-events/webinar-live/W192201WhenisaParticle.html
Dynamic light scattering (DLS) is a ubiquitous tool for the characterisation of hydrodynamic particle size in dispersion, relying on diffusive-only sample motion and exquisite thermal control of the sample viscosity. We demonstrate that the commonly assumed upper size limit for DLS due to gravitational settling should be significantly higher than p...
Webinar discussing the sensitivity of DLS measurements to contaminants and describing a new approach to solving this challenge.
https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W180913AdaptiveCorellation
Whilst being able to measure particles of below 1 nm size, DLS is preferentially sensitive to larger particles due to the 6th power relationship between particle radius and scattering intensity.
This means that sample preparation typically needs to be scrupulous, especially for low scattering samples such a proteins and biological molecules. The...
The flow instabilities of solutions of high molecular weight DNA in the entangled semi-dilute concentration regime were investigated using optical coherence tomography velocimetry, a technique that provides high spatial (probe volumes of 3.4 pL) and temporal resolution (sub μs) information on the flow behaviour of complex fluids in a rheometer. The...
Optical Coherence Tomography Velocimetry (OCTV) is a technique based on principals developed for medical imaging and is used to measure the velocity as a function of sample depth for a range of complex
fluid systems, revealing insight into rheological properties that are otherwise ignored by bulk rheometry methods. The technique fulfils the requir...
Optical coherence tomography velocimetry combined with a rheometer and optical modulation techniques provides increased sensitivity to the low shear rate motion of complex fluid systems. Optical modulation coupled with a new interferometer design yields improved signal to noise ratios and is demonstrated with optically opaque colloidal suspensions....
Optical Coherence Tomography (OCT) Velocimetry is a new technique for studying rheological systems that uses advances from medical imaging. It is a useful addition to the growing range of optical rheometry techniques [1].
Light is scattered off a sheared fluid and an interferometer with a low coherence infra-red light source allows
Doppler signal...
We present recent results obtained with an Optical Coherence Tomography Velocimetry technique. An optical interferometer measures the velocity of a sheared fluid at specific depths of the sample using the coherence length of the light source. The technique allows the dynamics of 3 pico liter volumes to be probed inside opaque complex fluids. In a s...
Questions
Questions (9)