Dry coating of powders and grains by high shear mixing

Dry coating of powders and grains (host) by much finer particles (guest) is widely used in food, pharmaceutical and battering manufacturing technologies to impart desirable functional characteristics, such as controlling bulk cohesion and thereby improving flowability and tabletting, controlling drug release in dry powder inhalers and flavouring of crisps. The operation is currently an art and the practicing engineer relies heavily on past experience and new experimentation. Process optimisation is often very costly and time consuming, due to the diversity of material characteristics, lack of understanding of what goes on inside the equipment during processing, interactions of the materials with the environment, process dynamics and scale-up. Dry coating depends on many factors, in particular particle size, shape, density, interparticle adhesion and medium fluid drag. This project aims to put the operation of dry coating by high-shear mixing on a firm scientific base by a two-pronged approach: modelling by the Discreet Element Method and experimentation by characterising single particle adhesion and bulk mixing. Interparticle adhesion will be characterised by the Drop Test Method developed at the University of Leeds. Bulk mixing will be studied using three types of mixing equipment, tumbler, impeller-driven mixer and intense high shear mixer. The systems to be investigated will have a dual focus: one on the fundamental engineering science of dry coating by high shear mixing and the other on its application to powders of interest to the industrial partner. Fundamental research involves the use of surface-modified glass beads (by acid-washing to make it hydrophilic, and silanisation to make it hydrophobic), and the use of both hydrophilic and hydrophobic glidants such as fumed silica (e.g. AEROSIL®) calcium carbonate and zeolite. Specific applications are to be defined by the industrial partner.

<p style="margin-bottom:11px">Further info about the group’s research activities can be found at <a href="https://ghadiri-group.leeds.ac.uk/">https://ghadiri-group.leeds.ac.uk/</a></p> <p style="margin-bottom:11px"><strong>Please note that this project is part of a wider competition for funding, therefore, the funding is not guaranteed.</strong></p>

<p>Formal applications for research degree study should be made online through the <a href="https://www.leeds.ac.uk/research-applying/doc/applying-research-degrees">University's website</a>. Please state clearly in the Planned Course of Study section that you are applying for <em><strong>PHD Chemical and Process Engineering FT</strong></em>, in the research information section that the research degree you wish to be considered for is <em><strong>Dry coating of powders and grains by high shear mixing</strong></em> as well as <a href="https://eps.leeds.ac.uk/chemical-engineering/staff/201/dr-xiaodong-jia">Dr Xiaodong Jia</a> as your proposed supervisor.</p> <p>If English is not your first language, you must provide evidence that you meet the University's minimum English language requirements (below).</p> <p><em>As an international research-intensive university, we welcome students from all walks of life and from across the world. We foster an inclusive environment where all can flourish and prosper, and we are proud of our strong commitment to student education. Across all Faculties we are dedicated to diversifying our community and we welcome the unique contributions that individuals can bring, and particularly encourage applications from, but not limited to Black, Asian, people who belong to a minority ethnic community, people who identify as LGBT+ and people with disabilities. Applicants will always be selected based on merit and ability.</em></p> <p style="margin-bottom:11px">Applications will be considered on an ongoing basis.  Potential applicants are strongly encouraged to contact the supervisors for an informal discussion before making a formal application.  We also advise that you apply at the earliest opportunity as the application and selection process may close early, should we receive a sufficient number of applications or that a suitable candidate is appointed.</p> <p>Please note that you must provide the following documents in support of your application by the closing date of Friday 15 November 2024:</p> <ul> <li>Full Transcripts of all degree study or if in final year of study, full transcripts to date</li> <li>Personal Statement outlining your interest in the project</li> <li>CV</li> </ul>

Applicants to research degree programmes should normally have at least a first class or an upper second class British Bachelors Honours degree (or equivalent) in an appropriate discipline. The criteria for entry for some research degrees may be higher, for example, several faculties, also require a Masters degree. Applicants are advised to check with the relevant School prior to making an application. Applicants who are uncertain about the requirements for a particular research degree are advised to contact the School or Graduate School prior to making an application.

The minimum English language entry requirement for research postgraduate research study is an IELTS of 6.0 overall with at least 5.5 in each component (reading, writing, listening and speaking) or equivalent. The test must be dated within two years of the start date of the course in order to be valid. Some schools and faculties have a higher requirement.

<p class="MsoNoSpacing">A highly competitive External Partner Studentship, providing the award of full academic fees, together with a tax-free maintenance grant at the standard UKRI rate (£19,237 in academic session 2024/25) for 3.5 years. There are no additional allowances for travel, research expenses, conference attendance or any other costs.</p> <p>You will be responsible for paying the overtime fee in full in your writing up/overtime year (£320 in Session 2024/25), but the scholarship maintenance allowance will continue to be paid for up to 6 months in the final year of award.</p> <p><strong>Important:</strong> Please note that that the award does <em><strong>not</strong></em> cover the costs associated with moving to the UK.  All such costs (<a href="https://www.leeds.ac.uk/international-visas-immigration/doc/applying-student-visa">visa, Immigration Health Surcharge</a>, flights etc) would have to be met by yourself, or you will need to find an alternative funding source. </p> <p>Please refer to the <a href="https://www.ukcisa.org.uk/">UKCISA</a> website for information regarding Fee Status for Non-UK Nationals.</p>

<p>For further information about this project, please contact Dr Xiaodong Jia by email to <a href="mailto:X.Jia@leeds.ac.uk">X.Jia@leeds.ac.uk</a></p> <p>For further information about your application, please contact PGR Admissions by email to <a href="mailto:phd@engineering.leeds.ac.uk">phd@engineering.leeds.ac.uk</a></p>