Malcolm R. Mackley

Malcolm R. Mackley
University of Cambridge | Cam · Department of Chemical Engineering and Biotechnology

BSc, MSc, PhD

About

272
Publications
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Publications

Publications (272)
Article
Full-text available
This paper is concerned with the mechanical compressive and tensile behaviour of polyethylene microcapillary monoliths (MCMs). MCMs are a voided polyethylene microstructure with two dimensional arrays of microcapillaries and where the polymer monolith is fabricated by the heat melding of microcapillary films (MCFs). MCFs are plastic films that rese...
Article
This paper reports a new design of experimental double piston filament stretching apparatus that can stretch fluids to very high extensional strain rates. Using high speed photography, filament deformation and breakup profiles of a strategically selected range of fluids including low and higher viscosity Newtonian liquids together with a viscoelast...
Article
Cover Legend This figure shows an artistic representation of UVC inactivation of virus particles in a plastic fluoropolymer microcapillary film. The plastic microcapillary film has a refractive index similar to water and is very transparent to UVC light, consisting of a number of parallel microcapillaries embedded in a flat film. The inner diameter...
Article
Full-text available
Despite the availability of elaborate varieties of nanoparticles, their assembly into regular superstructures and photonic materials remains challenging. Here we show how flexible films of stacked polymer nanoparticles can be directly assembled in a roll-to-roll process using a bending-induced oscillatory shear (BIOS) technique. For sub-micron sphe...
Article
Full-text available
It has long been established that UVC light is a very effective method for inactivating pathogens in a fluid, yet the application of UVC irradiation to modern biotechnological processes is limited by the intrinsic short penetration distance of UVC light in optically dense protein solutions. This experimental and numerical study establishes that irr...
Article
Full-text available
Polymer processing involves three thermo-mechanical stages: Plastication of solid polymer granules or powder to an homogeneous fluid which is shaped under pressure in moulds or dies and finally cooled and eventually drawn to obtain the final plastic part. Physical properties of polymers (high viscosity, non-linear rheology, low thermal diffusivity)...
Article
Full-text available
It has long been established that UVC light is a very effective method for inactivating pathogens in a fluid, yet the application of UVC irradiation to modern biotechnological processes is limited by the intrinsic short penetration distance of UVC light in optically dense protein solutions. This experimental and numerical study establishes that irr...
Chapter
This chapter is concerned with developing an understanding of the way inkjet fluid properties can be characterized. Inkjet processing involves forcing an inkjet fluid through very small nozzles. The whole jetting process is extremely delicate and sensitive to many variables. The viscosity and viscoelasticity of inkjet fluids are not easy to measure...
Article
This paper gives a personal view on the state of art in relation to the modelling of polymer melt processing. The paper briefly reviews both industrial, laboratory and modelling developments over the last forty years and highlights the key aspects now required for realistic modelling of polymer melt processing. The paper summarizes elements relatin...
Article
Dissolution of CO2 in water was studied for a batch vertical multiorifice baffled column (MOBC) with varying orifice diameters (d0) of 6.430 mm and baffle open area (a) of 1542%. Bubble size distributions (BSDs) and the overall volumetric CO2 mass transfer coefficient (KLa) were experimentally evaluated for very low superficial gas velocities, UG o...
Conference Paper
Full-text available
We have previously studied DoD jetting of complex model fluids based on dilute polymer solutions, resulting in the identification of a new regime of polymer jetting and some basic rules for predicting the limiting polymeric concentrations under real conditions such as print head nozzle diameter, jetting speed, solvent quality and polymer molecular...
Conference Paper
Full-text available
This work reports the first systematic survey of colloidal suspension jetting [1], as opposed to dripping liquids containing particles [2], and it complements a previous survey of the jetting of complex fluids [3]. Colloidal suspensions of stabilised polystyrene particles in water/ethylene glycol were formulated for maximum stable loadings (vol%) a...
Article
Pulmonary inhalation is increasingly being selected as a preferred route for the delivery of both small and large drug macromolecules for the treatment of a range of pathologies. The direct crystallization of micronized powders, in particular, paracetamol, remains difficult, as it requires the ability to work in high solution supersaturations where...
Article
Full-text available
This paper is concerned with the rheology and processing of solvent-free core shell “polymer opals” that consist of a soft outer shell grafted to hard colloidal polymer core particles. Strong iridescent colors can be produced by shearing the material in a certain way that causes the initially disordered spheres to rearrange into ordered crystalline...
Article
The addition of a starch or gum-based thickener to patient fluids with dysphagia is commonly carried out, but the mechanism behind the efficacy of this treatment is not fully understood. This paper describes the rheological behavior of two commercially available thickening powders and an additional xanthan gum solution with a view to explaining the...
Article
Links of Science & Technology The Scientific and Technological Route to the Manufacture of High-Modulus Polyethylene • Article author query • mackley m [Google Scholar] Malcolm Mackley Polyethylene has been manufactured commercially for over sixty years. However recently a high-modulus variant has become available. This article describes the bac...
Article
This paper is concerned with the way interfacial coalescence of a single drop of biodiesel or glycerol occurs at a glycerol/biodiesel interface. Two stages of interfacial coalescence were studied: the thinning of the trapped liquid film between the rising or falling droplet and bulk fluid interface, and the retraction of the film after the film had...
Article
Full-text available
Recent results from a number of UK academic inkjet research studies advance the understanding of complex fluid jetting behavior and may be of interest to the wider digital fabrication community for the enhancement of inkjet printing applications. (C) 2013 Society for Imaging Science and Technology.
Article
This paper describes numerical simulation and matching experimental results for oscillatory flow within a baffled tube containing tri-orifice baffles. The numerical simulation implemented a non-standard approach based on Implicit Large Eddy Simulation (ILES) to predict the flow in a situation where complex eddy formation occurs due to periodic sepa...
Article
Singlet oxygen, a reactive oxygen species, has been a basic synthetic tool in the laboratory for many years. It can be generated either through a chemical process or most commonly via a photochemical process mediated by a sensitizing dye. The relative paucity of singlet oxygen employment in fine chemical industrial settings can be attributed to man...
Article
This paper reports the miniaturisation of sandwich enzyme-linked immunosorbent assays (ELISA) using a meltextruded fluoropolymer MicroCapillary Film (MCF). A prototype 8-channel*10-microcapillaries device was used for quantitative detection a range of human biomarkers in 30 mm long fluoropolymer MCF strips. This represents a novel combination of ul...
Article
This paper describes an efficient method for the functionalizing of multi-walled carbon nanotubes (MWCNT) using oscillatory flow mixing (OFM). A 3 l batch oscillatory flow reactor (OFR) was designed and constructed for pilot scale functionalization of MWCNT in order to potentially improve their compatibility within a thermoplastic polyphenylene sul...
Article
This paper is concerned with a direct experimental and modeling comparison of the rheology of carbon black (CB) and multiwalled carbon nanotube (CNT) suspensions within a Newtonian epoxy matrix. Experimental observations of the effect of shear on CB and CNT microstructure are reported for a range of CB and CNT suspension concentrations. Steady shea...
Article
Full-text available
This paper is concerned with the comparison of two numerical viscoelastic strategies for predicting the fast filament stretching, relaxation, and break up of low viscosity, weakly elastic polymeric fluids. Experimental data on stretch, relaxation, and breakup were obtained using a Cambridge Trimaster for a Newtonian solvent (diethyl phthalate) and...
Article
This paper presents both experimental measurements and numerical modelling on the separation of glycerol from biodiesel. Glycerol is a natural by-product of biodiesel production and removal of glycerol droplets from biodiesel is required to attain fuel quality standards. Experimental observations on the separation kinetics for sedimentation and cre...
Article
Full-text available
This paper is concerned with the rheology of algae suspensions relevant to algae biofuel processing for a range of concentrations up to 15 vol. % using mostly a piezoaxial vibrator (PAV) rheometer as a method of measuring rheological properties. Linear viscoelastic (LVE) measurements of a Scenedesmus obliquus [culture collection of algae and protoz...
Article
Full-text available
This paper develops a model for fast filament stretching, thinning, and break-up for Newtonian and non-Newtonian fluids, and the results are compared against experimental data where fast filament relaxation occurs. A 1D approximation was coupled with the arbitrary Lagrangian Eulerian (ALE) formulation to perform simulations that captured both filam...
Article
Full-text available
We present a simple device for multiplex quantitative enzyme-linked immunosorbant assays (ELISA) made from a novel melt-extruded microcapillary film (MCF) containing a parallel array of 200 μm capillaries along its length. To make ELISA devices different protein antigens or antibodies were immobilised inside individual microcapillaries within long...
Conference Paper
Full-text available
This work presents recent results on the way linear and non linear viscoelastic properties of the fluids affect the jetting mechanism. Recent progress on quantitative characterising both high frequency linear (LVE) and non-linear (NLVE) viscoelasticity of fluids allows fluids to be assessed for their jettability before using such materials in a DoD...
Article
The effect of flow-boundary curvature on the principal stress difference (PSD) profiles observed through a contraction–expansion (CE) slit flow is evaluated for three different polyethylenes exhibiting increasing levels of branching. Studies were performed using both experimental optical techniques and computational simulations, in the latter case...
Article
Full-text available
Stress-optical measurements at a flow stagnation point in confined geometries such as the cross-slot provide an elegant way to perform extensional testing for polymer melts. This technique is especially useful for samples which have a steady-state that cannot be reached (easily) in standard elongational rheometry, for example, highly branched polym...
Article
This review describes the development and application of the multipass rheometer; a servo hydraulically driven two piston device that enables rheology and precise processing measurements to be carried out within an enclosed volume. The apparatus development and then specific application areas are highlighted. In particular, application to rheology,...
Article
This paper describes experiments and related modelling on a new method for separating aqueous phase slugs from the surrounding organic matrix phase in segmented two phase flow in a plastic microcapillary film (MCF). Kerosene or paraffin oil was metered through a plastic capillary of 630 microns diameter and aqueous phase slugs were generated within...
Article
A novel disposable adsorbent material for fast cation-exchange separation of proteins was developed based on plastic microcapillary films (MCFs). A MCF containing 19 parallel microcapillaries, each with a mean internal diameter of 142 μm, was prepared using a melt extrusion process from an ethylene-vinyl alcohol copolymer (EVOH). The MCF was surfac...
Article
a b s t r a c t Extrudate swell is a common phenomenon observed in the polymer extrusion industry. Accurate predic-tion of the dimensions of an extrudate is important for appropriate design of dies for profile extrusion applications. Prediction of extrudate swell has been challenging due to (i) difficulties associated with accu-rate representation...
Article
This paper reports the experimental results for the processing of micro-capillary film (MCF) membranes. MCFs are films with embedded multiple hollow capillaries and can be considered as a hybrid geometry between flat sheet and hollow fibres. Compared to the conventional membrane geometries, MCFs potentially provide a higher surface area per unit vo...
Article
The present work deals with the study of drop formation of polymeric fluids with the objective of providing a correlation between fluid printability and its rheological properties. An innovative approach combining together many experiments and numerical simulations of free surface flows is proposed. Viscoelasticify of fluids is probed using experim...
Article
Full-text available
This paper presents process characteristics and proof of concept reactions for a newly developed microreactor system, termed the Cambridge Disc Microreactor (CDM), using plastic Microcapillary Flow Discs (MFDs). These flat reactor discs were constructed from a flexible, temperature resilient, solvent resistant fluoropolymer Microcapillary Film (MCF...
Article
This paper is concerned with the rheological modelling of untreated Carbon Nanotubes (CNTs) suspended within an epoxy resin and its application in nanocomposites forming processes. The untreated CNT suspensions exhibited significant steady shear-thinning and contained optically resolvable aggregate structures. A simple orientation model, based on a...
Article
Herein we describe the preparation of a novel continuous flow multi-channel microreactor in which the internal surface has been functionalised with a palladium coating, enabling its use in catalytic heterogeneous liquid-phase reactions. Simple chemical deposition techniques were used to immobilise palladium(0) on the channel wall surface of a polym...
Article
This paper reports experimental data from, and numerical modelling of, plastic solar collectors fabricated from a novel thermoplastic extrudate. The extrudate, termed as microcapillary film (MCF), consists of an extruded flexible, plastic, film with a parallel array of hollow capillaries running along the film’s length. Experimental investigations...
Article
This paper is concerned with the experimental ability to measure viscoelasticity of low viscosity ink jet fluids and demonstrates the capability of both a piezo axial vibrator and torsion resonator rheometer to capture high frequency rheological data for both model and commercial ink jet fluids. Results are presented for polymer and particle laden...
Article
Full-text available
This paper is based on a presentation given at the de Gennes discussion meeting held at Chamonix in February 2009. The paper gives a personal review of the way developments relating to the stretching of polymer chains has taken place over the last 40years. de Gennes was very influential in relation to chain dynamics concepts at the University of Br...
Article
This research investigates the dynamics of mechanical and structural transformations of styrene–butadiene–styreneblock copolymer, known as RCM1, which has cylindrical mesophase morphology. The polymer was processed using a Multipass Rheometer (MPR) with simultaneous X-ray observation. The method allowed investigation of the dynamics with 1 second t...
Article
This paper presents process characteristics and proof of concept reactions for a newly developed microreactor system, termed the Cambridge Disc Microreactor (CDM), using plastic microcapillary flow discs (MFDs). These flat reactor discs were constructed from a flexible, temperature resilient, solvent resistant fluoropolymer microcapillary film (MCF...
Article
Full-text available
This paper describes the design and initial results from the “Cambridge Trimaster,” a recently developed high speed filament stretch and break-up device that can be used for viscoelastic fluids with shear viscosities as low as 10 mPa s . Extensional viscosity and filament break-up behavior were studied optically using a high speed camera and extens...
Article
Full-text available
This paper is concerned with matching a fully three-dimensional (3D) viscoelastic numerical simulation with experimental results obtained using a multi-pass rheometer for both an entry-exit slit flow and a cross-slot geometry. The 3D code simulates the time evolution of steady flows using a multi-mode Rolie-Poly constitutive equation. A test polydi...
Article
Full-text available
Optical scattering spectra are recorded in situ on flowing colloidal polymeric nanocomposites which are sheared into photonic crystals at 150 degrees C using a high-pressure quartz-cell multipass rheometer. Broadband spectroscopy of the resonant Bragg scattering peak allows the direct observation of crystal formation and melting of monodisperse cor...
Article
This paper reports an experimental study of the formation of a two-phase liquid mixture in a circular capillary tube of 0.74 mm diameter. Organic liquid, the continuous phase, flowed through the capillary. Aqueous liquid, the dispersed phase, was injected through a hypodermic entering the side of the capillary and a stream of aqueous droplets was f...
Article
Full-text available
This paper is concerned with the effect of protein–precipitant interfaces and externally applied shear on the nucleation and growth kinetics of hen egg-white lysozyme crystals. The early stages of microbatch crystallization of lysozyme were explored using both optical and confocal fluorescence microscopy imaging. Initially, an antisolvent (precipit...
Article
Full-text available
This paper describes the simultaneous application of time-sequenced laser-induced fluorescence imaging of OH radicals and stereoscopic particle image velocimetry for measurements of the flame front dynamics in lean and premixed LP turbulent flames. The studied flames could be acoustically driven, to simulate phenomena important in LP combustion tec...
Article
Residence time distributions (RTDs) for a thermoplastic microreactor system were experimentally measured using fibre optic probes and step change concentration inputs. The distributions were then compared to models assuming plug flow superimposed by axial dispersion. The disc-shaped plastic microreactors contained microcapillary arrays of up to 19...
Article
Full-text available
Composites materials reinforced using nano-particles or carbon nano-tubes (CNTs) are more and more used in industry and their modeling is one of the most active research topics in this area. As in usual processes involving composite materials, the main objective is to understand the induced properties (electrical, thermal, mechanical …) and obvious...
Article
Flow-induced crystallization (FIC) behavior of a high-density polyethylene melt in two entry-exit flow geometries was investigated by direct optical observation using a multi-pass rheometer and the results compared with a viscoelasticflow simulation. A set of experiments was performed at several piston speeds using a sharp and a rounded entry-exit...
Article
Full-text available
This article links measurements of ink jetting performance in drop-on-demand printing with the high-frequency rheologi-cal properties of model viscoelastic fluids containing linear polymers with various molecular weights. Jet formation and evolution were studied for solutions of polystyrene in diethyl phthalate. Ligament length, initial jet ejectio...
Article
This paper is concerned with the fabrication of voided polyethylene microstructures by heat melding of plastic microcapillary films (MCFs) to form microcapillary monoliths (MCMs), which are consolidated layers of MCFs forming in two-dimensional arrays of microcapillaries. MCMs were manufactured by heat melding multiple layers of low-voidage MCFs or...
Article
The sensitivity of the principal stress difference (PSD) profile to molecular architecture is demonstrated for flow in a cross-slot geometry. For materials with low levels of branching, the pattern along the outlet centre line exhibited “single cusps”, while an increase in molecular branching was found to lead to “W cusps”. The formation of these W...
Article
The behaviour of a number of mono and polydisperse polystyrenes are probed experimentally in complex extensional flow within a Cross-Slot geometry using flow-induced birefringence. Polystyrenes with similar molecular weight (M w) and increasing polydispersity (PD) illustrated the effect of PD on the principal stress difference (PSD) pattern in exte...
Article
Superparamagnetic nanoparticles were synthesised and their in-flow magnetic capture behaviour studied within transparent plastic microcapillary arrays (MicroCapillary Film or MCF). This system represents an in vitro analogue of capillary vasculature and facilitates easy optical observation of capture phenomenon. A dispersion of nanoparticles was de...
Article
Full-text available
This paper reports recent experimental findings and rheological modeling on chemically treated single-walled carbon nanotubes (CNTs) suspended within an epoxy resin. When a CNT suspension was subject to a steady shear flow, it exhibited a shear-thinning characteristic, which was subsequently modeled by a Fokker-Planck (FP) based orientation model....
Article
This short communication reviews the past, current and future state of rheology within the UK. It is a personal view that predicts in the future there will be significant changes in UK rheology, mainly because of the way universities, industry and most of all funding agencies have changed their priorities in the area of science and engineering.
Article
This paper presents an experimental study on the formation of a polymer flow instability seen in a range of polystyrene melts flowing through contraction–expansion slit geometries. Seen for both monodisperse and polydisperse materials, it took the form of an oscillation in the principal stress difference (PSD) and velocity field perpendicular to th...
Article
This paper is concerned with the rheological modeling of untreated Carbon Nanotubes (CNTs) suspended within an epoxy resin and its application in nanocomposites forming processes. A new model named the "Aggregation/ Orientation" (AO) model was developed to describe the experimental findings. However, it predicts an "affine" orientation of the tubes...
Article
This proceeding describes the development of two apparatus used to characterise ink-jet fluids. In term of Linear Viscoelasticity (LVE), the recently developed Piezo Axial Vibrator (PAV) was used to characterize the high frequency response of model ink-jet fluids. Two series of model ink-jet fluids were investigated. The first series was a mixture...
Chapter
This paper provides an overview of recent experiments and modelling carried out in relation to the foaming kinetics of molten potato starch containing an adjusted water content of 30 wt%. The paper describes the experimental protocol necessary to form a clear, optically transparent starch melt held within a confined volume between two hydraulically...
Article
This paper reports experimental observations on the way polypropylene (PP) and high-density polyethylene (HDPE) can crystallise during flow. Both a deep and a shallow slit geometry were chosen for the rheo-optical study. Preliminary linear viscoelastic rheological tests enabled the temperature window for quiescent crystallisation to be established....
Article
Full-text available
This paper is concerned with the rheological modeling of untreated carbon nanotubes (CNTs) suspended within an epoxy resin. The untreated CNT suspensions exhibited significant steady shear thinning and contained optically resolvable aggregate structures. A simple orientation model, based on a Fokker-Planck advection-diffusion description, failed to...
Article
This paper reports an experimental investigation into the heat transfer response of plastic microcapillary films (MCFs). The first section presents experimental determination of temperature profiles and heat transfer coefficients for an MCF-based micro-heat exchanger. The next section presents two case studies: the first concerns cooling an electri...
Article
The sensitivity of the principal stress difference (PSD) profiles to material viscoelasticity is demonstrated for two flow geometries using three different polyethylenes. Studies were performed using both experimental optical techniques and computational simulations, in the latter case to evaluate the ability to model these complex flows. The mater...
Article
Full-text available
The present review is concerned with the way that the incorporation of carbon nanotubes (CNTs) into a fluid matrix can modify the microstructure and rheology of the resulting suspensions. Some background to CNT manufacture and in particular methods of dispersing them into a suspension is presented for a range of different systems, where effective d...
Article
The magnetic field mediated capture of 10 nm diameter superparamagnetic nanoparticles, in the form of agglomerates of mean diameter 330 and 580 nm, from microcapillary flows has been observed and modelled. The steady state thickness of the captured layer in microcapillaries of diameter 400– could be predicted for both the 330 and the 580 nm diamete...
Article
This paper describes how both capillary diameter and voidage can be manipulated by downstream mechanical processing of plastic microcapillary films (MCFs). MCFs are a novel thermoplastic extrudate that have been manufactured by the entrainment of gas within nozzles positioned in an extrusion die; the film resembles a plastic tape but contains an ar...