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Determination of microcapsule physicochemical, structural, and mechanical properties

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Particuology 2016年第1期14卷 32-43页

作者： Andrew Gray Stefan Egan Serafim Bakalis Zhibing Zhang School of Chemical Engineering University of Birmingham Edgbaston Birmingham B15 2IT UK procter & gamble Newcastle-Upon-Tyne Innovation Centre Whitley Road Longbenton Newcastle-upon-Tyne NE12 9TS UK

Research into the fundamental properties of microcapsules and use of the results to develop a wide variety of products in industries such as printing, fast-moving consumer goods, construction, pharmaceuticals, and agrochemicals is a dynamic and ever-progressing field of study. For microcapsules to be effective in providing protection from harsh environments or delivering large payloads, it is essential to have a good understanding of their properties to enable quality control during formulation, storage, and applications. This review aims to outline the commonly used techniques for determining the physicochemical, struc- tural, and mechanical properties of microcapsules, and highlights the interlinked nature of these three areas with respect to the end-use industrial application. This review provides information on techniques that are well supported in the literature, and also examines microcapsule analytical techniques that will become more prevalent as a result of new technological developments or extensions from other areas of study.

关键词： Characterization Chemical composition Experimental technique Mechanical properties Microcapsule Physical structure

An experimental and numerical study of packing, compression, and caking behaviour of detergent powders

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Particuology 2014年第1期12卷 2-12页

作者： Subhash C.Thakur Hossein Ahmadian Jin Sun Jin Y.Ooi School of Engineering University of Edinburgh newcastle innovation centre Procter and Gamble Technical Centre Ltd

This paper presents an experimental and numerical study of the packing, compression, and caking behaviour of spray dried detergent （SDD） powders with a two-fold aim： an experimental process of observation and evaluation of the packing, compression and caking behaviour of SDD powders, and a numerical approach based on discrete element modelling （DEM）. The mechanical properties, including the stress-strain response and the corresponding porosity change as a function of consolidation stress in a confined cylinder, the stress-strain response during unconfined shearing and the cake strength as a func- tion of consolidation stress, were evaluated and compared for different SDD powders using an extended uniaxial tester （Edinburgh Powder Tester - EPT）. The experiments using EPT showed excellent repro- ducibility in the measurement of packing, compression and caking behaviour and were therefore very useful for describing the handling characteristics of these powdered products including screening new products and different formulations. It was found that the sample with higher moisture had lower bulk porosity but higher compressibility and cake strength. The porosity, compressibility and cake strength were found to vary across different size fractions of the same sample. The larger sieve-cut samples had higher initial bulk porosity, compressibility and cake strength. It is revealed that moisture plays a sig- nificant role in packing, compression, and shearing behaviour of the powder. Three-dimensional DEM modelling using a recently developed elasto-plastic adhesive-frictional contact model showed that the contact model is able to capture the detergent behaviour reasonably well and can be used to model complex processes involving these powders.

关键词： Discrete element methodPowder flowCohesive materialUniaxial testPlasticityContact model

Effects of laponite and silica nanoparticles on the cleaning performance of amylase towards starch soils

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Particuology 2009年第6期7卷 459-465页

作者： Wai Peng Lee Alberto Martinez Dan Xu Anju Brooker David W. York Yulong Ding Institute of Particle Science Engineering University of Leeds Leeds LS2 9IT UK procter gamble newcastle Technical centre Newcastle upon Tyne NE12 9TS UK

This work aims to understand the effect of nanoparticle-enzyme interactions and how such interactions affect starch based soil removal. Silica and laponite are used as the model nanoparticles, and s-amylase is employed as the model enzyme. The results show that, if the nanoparticles and enzyme are added simultaneously, laponite enhances the enzyme performance toward starch soil removal, whereas silica imposes a small effect on the enzymatic activity towards the same soil substrates. However, when nanoparticles are added first, the enzyme activity is not affected much by laponite but is hindered significantly by silica nanoparticles. Furthermore, sequential addition of the enzyme followed by silica nanoparticles improves soil removal. Electron microscopic analyses, measurements of the enzyme activity in suspen- sions of nanoparticles, and particle size characterisation suggest that dense coverage of soil surface by the silica nanoparticles be likely a mechanism for the experimentally observed hindrance of soil removal when silica nanoparticles are added before enzyme.

关键词： Enzyme Nanoparticles Laponite Silica Interaction Starch

ZnO nanofluids-A potential antibacterial agent

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Progress in Natural Science:Materials International 2008年第8期18卷 939-944页

作者： Malcolm Povey David York procter Department of Food Science University of Leeds Leeds LS2 9JT UK procter and gamble newcastle Technical centre Newcastle-upon-Tyne NE12 9TS UK

In this work, ZnO nanofluids were produced by a medium mill with a pH value of about 7.2 and characterized by Nano-Sizer and SEM. After milling, ZnO nanofluids were formed with an average particle size of 198.4 nm. The ZnO nanofluids used for testing were stored for different periods (1-, 90- and 120-day) and kept in different conditions (under the light and in the dark). The antibacterial activities of these ZnO nanofluids were evaluated by estimating the reduction ratio of the bacteria treated with ZnO. The results showed that the ZnO nanofluid stored for 120 days under the light had the best antibacterial behavior against Escherichia coli DH5a. SEM images suggest that an interaction between the ZnO particles and the E. coli bacteria cells caused by electrostatic forces might be a mechanism.

关键词： Antibacterial Nanofluids ZnO E. coli Photocatalysis

Numerical simulation of sedimentation of microparticles usingthe discrete particle method

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Particuology 2008年第1期6卷 38-49页

作者： Chane-Yuan Yang Yulong Ding Dave York Walter Broeckx Institute of Particle Science and Engineering University of LeedsLeeds LS2 9JTUK procter and gamble newcastle Technical centre Newcastle-upon-Tyne NE12 9TSUK

A mathematical model has been formulated based on the combined continuous and discrete particle method for investigating the sedimentation behaviour of microparticles in aqueous suspensions, by treating the fluid phase as continuous and the particles phase as discrete, thus allowing the behaviour of individual particles to be followed and the evolution of the structure of the particle phase to be investigated as a function of time. The model takes into account most of the prevailing forces acting on individual particles including van der Waals attractive, electrostatic repulsive, gravitational, Brownian, depletion, steric, contact and drag forces. A code has also been developed based on the model. This paper reports some preliminary modelling results of mono-dispersed microparticles settling in aqueous suspensions under various conditions. The results show the short time dynamics of the fluid phase, which has a similar order of magnitude to the particle phase. Such short time dynamics could bear significance to processes such as particle aggregation when their size becomes very small. Preliminary analyses of the results have also been carried out on the evolution of particle settling based on a newly proposed parameter, local normalised volume fraction （LNVF）.

关键词： Numerical modelling Combined continuous and discrete particle method Sedimentation Local normalised volume fraction lnterparticle interactions

Effect of carboxymethyl cellulose on dissolution kinetics of carboxymethyl cellulose-sodium carbonate two-component tablet

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Chinese Journal of Chemical Engineering 2017年第10期25卷 1545-1550页

作者： Changdong Li Carlos Amador Yulong Ding Institute of Particle Science and Engineering University of Leeds Leeds UK School of Engineering University of Warwick. Coventry. CV4 7AL UK procter & gamble newcastle-upon-tyne innovation centre Newcastle UK School of Chemical Engineering University of Birmingham Birmingham UK

Sodium carbonate and carboxymethyl cellulose powders are compressed into two-component tablets with three mass ratios,97%:3%,95%:5% and 93%:7%.The dissolution tests for two-component tablets and reference pure sodium carbonate tablets are carried out at various *** dissolution process of each tablet is measured by electrical conductivity tracking method and the concentration of dissolved sodium carbonate is quanti fied with calibrated conductivity-concentration converting equation of sodium *** quanti fied dissolution data is fitted with both surface reaction model and diffusion layer model and the results clearly show that surface reaction model is suggested as the appropriate dissolution model for all measured ***,it is determined that carboxymethyl cellulose is a stable element to remain the dissolution mechanism of tablet *** dissolution rate constant quanti fied with surface reaction model presents that carboxymethyl cellulose-sodium carbonate two-component tablets obtain signi ficant higher dissolution rate constant than pure sodium carbonate tablet and higher proportion of carboxymethyl cellulose leads to apparent higher dissolution rate *** results prove for the usage of carboxymethyl cellulose in most practical applications at a relative low-level,the effect of carboxymethyl cellulose is effective and positive for two-component tablet to enhance the dissolution process and improve dissolution rate constant and this effect is speculated coming from its dynamic physical transforming process in water including dilation and conglutination.

关键词： Carboxymethyl cellulose Sodium carbonate Electrical conductivity Temperature Surface reaction model Dissolution rate constant

CFD-DNS simulation of irregular-shaped particle dissolution

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Particuology 2020年第3期18卷 144-155页

作者： Hui Cao Xiaodong Jia Yongliang Li Carlos Amador Yulong Ding School of Chemical Engineering University of BirminghamB152TTUnited Kingdom School of Chemical and Process Engineering University of LeedsLS29JTUnited Kingdom Proctor&gamble newcastle innovation centre Newcastle Upon TyneNE129TSUnited Kingdom

A coupled approach between the conventional computational fluid dynamics platform COMSOL and an in-house-developed direct numerical simulation code DigiDiss is presented to study the dissolution kinetics of an irregular-shaped particle in a stirred *** complex flow dynamics from COMSOL were imported into DigiDiss as an initial flow condition.A digitised 3D particle structure scanned and reconstructed by X-ray micro-tomography was used in the dissolution simulation.A quantitative assessment of the simulation results was made using as a reference experimental data and a theoretical calculation based on the shrinking spherical model with different flow velocity profiles near the *** comprehensive agreement demonstrates the coherence of the simulation method in reproducing the experimental behaviour and is seen as a step closer towards developing a computer software design aide to help with formulation development.

关键词： Single particle dissolution Computational fluid dynamics Direct numerical simulation X-ray micro-tomography

Single droplet drying of detergents:Experimentation and modelling

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Particuology 2021年第5期19卷 35-47页

作者： Borja Hernandez Rosa Mondragon Mark A.Pintoa Leonor Hernandez J.Enrique Julia Juan Carlos Jarque Sergio Chiva Mariano Martin newcastle innovation centre Procter&Gamble R&DNewcastle upon TyneUK Departamento de Ingenieria Quimica y Textil.Universidad de Salamanca SalamancaSpain Departamento de Ingenieria Mecanica y Construccion Universitat Jaume ICastellon de la PlanaSpain Instituto de Tecnologia Ceramica Universitat Jaume ICastellon de la PlanaSpain

This study evaluates the single droplet drying(SDD)of *** data are used to validate a theoretical multistage *** experiments are carried out in an acoustic levitator analysing six different detergent formulations at 393 *** work is completed by developing a model based on conservation *** model is composed of the three stages observed in the drying *** the first stage,an external surface drying stage occurs until the surface is saturated and the crust is *** the next stage,the drying rate is governed by diffusion through the *** the same time,the particle heats up until boiling conditions are achieved in the core of the *** this point,the third stage *** the final stage,the droplet core is in boiling conditions which are governed by the pressure drop through the crust and the concentration of *** model has been evaluated for the different formulations being flexible to predict the drying of different mixtures with good accuracy.

关键词： Drying Single droplet Acoustic levitator Detergents

A Survey of the Experience and Impact of Acute Upper Respiratory Tract Infections on People in Six Countries in the 2011/2012 Common Cold and Flu Season

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Open Journal of Respiratory Diseases 2013年第4期3卷 175-187页

作者： John David Hull Ian Paul Barton Jennifer Torgersen Christine Marie McNeil Greater London innovation centre Procter & Gamble Egham UK Ipsos Marketing Cincinnati USA Mason Business centre Procter & Gamble Cincinnati USA

Introduction: Acute Upper Respiratory Tract Infections (URTIs) are the most common infectious diseases of humankind. While usually mild and self-limiting, they are characterized by a series of simultaneously occurring symptoms/ signs that are sufficiently disruptive to sufferers’ normal activities in which medication is frequently sought. While the literature has many examples of epidemiological studies on these infections, there are few reports on patient experience and impact. This study was designed to investigate these aspects of Common Cold/Flu across six countries. Methods: A minimum of 500 adults aged 18 and older were recruited in each of six countries (Brazil, China, Germany, India, Russia, and the US) using customary survey research sampling techniques. Single 30-minute (online) or 40-minute door-to-door quantitative questionnaires with c. 50 questions were completed with each participant by the global research firm Ipsos. Main Findings: Across countries, incidence and seasonality of infections reported to this study were consistent with published data. There appears to be a need for patient education on the causes and transmission routes of respiratory infections. Getting good quality sleep and being able to continue with daily activities as an infection resolves are significant drivers to therapy. The most common non-prescription therapies reported were multi-ingredient products in line with the simultaneously occurring multi-symptom nature of the condition(s). Conclusions: This study indicated that acute URTIs exert a significant deleterious effect on sufferers. Public health education, possibly best undertaken by Pharmacists has the potential to impact the extent of virus transmission by ensuring that people know the true cause of the infection, how it is transmitted and how best to combat this. The several simultaneously occurring symptoms encourage sufferers to seek multi-ingredient remedies to allow them to continue with normal activities as their i

关键词： Common Cold Upper Respiratory Tract Infections Common Cold Survey