ORCID Profile
0000-0003-0472-6362
Current Organisation
University of Leeds
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Publisher: IOP Publishing
Date: 10-2019
DOI: 10.1088/1742-6596/1322/1/012006
Abstract: A statistical treatment is developed for the electrostatic transfer of particles from a powder bed to a pendent droplet during liquid marble and aggregate formation. The model uses Weibull statistics to calculate the probability of particle transfer events of a given size occurring, for the given electric field strength and geometry. This is used in Monte Carlo simulations of the transfer process. In this preliminary study, some of the most distinctive features of the experiments – transfer event size and spacing, scaling with driving potential – are well-captured using physically plausible parameter values. Other features, such as denuding of the particle bed, are less well reproduced, and require refinement.
Publisher: Springer Science and Business Media LLC
Date: 08-03-2021
DOI: 10.1038/S41598-021-84798-2
Abstract: Improving the heat tolerance of cotton is a major concern for breeding programs. To address this need, a fast and effect way of quantifying thermotolerant phenotypes is required. Triphenyl tetrazolium chloride (TTC) based enzyme viability testing following high-temperature stress can be used as a vegetative heat tolerance phenotype. This is because when live cells encounter a TTC solution, TTC undergoes a chemical reduction producing a visible, insoluble red product called triphenyl formazan, that can be quantified spectrophotometrically. However, existing TTC based cell viability assays cannot easily be deployed at the scale required in a crop improvement program. In this study, a heat stress assay (HSA) based on the use of TTC enzyme viability testing has been refined and improved for efficiency, reliability, and ease of use through four experiments. S ling factors that may influence assay results, such as leaf age, plant water status, and short-term cold storage, were also investigated. Experiments conducted in this study have successfully downscaled the assay and identified an optimal s ling regime, enabling measurement of large segregating populations for application in breeding programs. The improved HSA methodology is important as it is proposed that long-term improvements in cotton thermotolerance can be achieved through the concurrent selection of superior phenotypes based on the HSA and yield performance in hot environments. Additionally, a new way of interpreting both heat tolerance and heat resistance was developed, differentiating genotypes that perform well at the time of a heat stress event and those that maintain a similar performance level to a non-stressed control.
Publisher: Elsevier BV
Date: 06-2021
Publisher: American Chemical Society (ACS)
Date: 19-11-2020
Publisher: American Chemical Society (ACS)
Date: 30-12-2021
DOI: 10.1021/ACS.LANGMUIR.1C02507
Abstract: We report an unusually large spacing observed between microparticles after delivery to the surface of a pendent water droplet using a DC nonuniform electrostatic field, primarily via dielectrophoresis. The influence of particle properties was investigated using core particles, which were either coated or surface-modified to alter their wettability and conductivity. Particles that exhibited this spacing were both hydrophobic and possessed some dielectric material exposed to the external field, such as a coating or exposed dielectric core. The origin of this behavior is proposed to be the induced dipole-dipole repulsion between particles, which increases with particle size and decreases when the magnitude of the electric field is reduced. When the particles were no longer subjected to an external field, this large interparticle repulsion ceased and the particles settled to the bottom of the droplet under the force of gravity. We derive a simple model to predict this spacing, with the dipole-dipole repulsion balanced against particle weight. The external electric field was calculated using the existing electric field models. The spacing was found to be dependent on particle density and the induced dipole moment as well as the number of particles present on the droplet interface. As the number of particles increased, a decrease in interparticle spacing was observed.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0MA00670J
Abstract: A conductive coating is added to PET plates using a novel synthetic method and liquid marble manufactured using electrostatics forces.
Publisher: American Chemical Society (ACS)
Date: 14-04-2020
Publisher: Frontiers Media SA
Date: 10-07-2018
Publisher: Elsevier BV
Date: 04-2022
DOI: 10.1016/J.JCIS.2021.12.117
Abstract: Electrostatic extraction of particles from a bed to a pendent droplet to form liquid marbles has previously been investigated with respect to particle conductivity, size and shape, however, interparticle forces have not been specifically interrogated. If cohesion is the dominant force within the particle bed, then particles will be more readily extracted with reduced surface free energy. Glass particles were surface-modified using various alkyltrichlorosilanes. The surface free energy was measured for each s le using colloid probe atomic force microscopy (AFM) and sessile drop measurements on similarly modified glass slides. The ease of electrostatic particle extraction of each particle s le to a pendent droplet was compared by quantifying the electric field force required for successful extraction as a function of the measured surface free energy. Surface free energy calculated from sessile droplet measurements and AFM were not in agreement, as work of adhesion of a liquid droplet on a planar substrate is not representative of the contact between particles. Ease of electrostatic extraction of particles was observed to generally decrease as a function of AFM-derived surface free energy, confirming this is a critical factor in electrostatic delivery of particles to a pendent droplet. Roughness was also shown to inhibit particle extraction.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9SM01467E
Abstract: Larger particles are more readily extracted from an advancing bed of charged particles owing to decreased interparticle cohesion.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Benjamin Lobel.