Rheological properties of municipal sludge during hydrothermal processing

Project code:  ENG015


Hydrothermal processing technologies provide significant benefits and improvements to existing sludge treatment methods. It has been used as a pre-treatment prior to conventional anaerobic digestion.

Progress and quality analyses of hydrothermal processing are generally done by discrete chemical methods such as chromatography and elemental analysis. These methods are suitable for laboratory scale analysis. However, some of the draw backs are high cost, extensive sample preparation and no real time indication. Direct monitoring of hydrothermal treatments has always been a challenge due to the complexity of sludge and different steps involved in the reaction mechanism. Therefore, an easy and feasible option needs to be found in order to monitor the progress of the reactions.

The aim of this project is to study the variations in rheological properties of municipal wastewater treatment sludge during hydrothermal processing.  This will help to develop a continuous monitoring technique based on the rheological property as an indicator to describe progression of hydrothermal processing.

Rheological properties of municipal sludge

3D-microhistopathology of the cartilage-bone junction

Project code:  ENG016



The initiation of osteoarthritis (OA) remains a mystery. Recently we have found evidence that both mechanical and structural changes in the cartilage-bone junction (a soft-hard tissue interface) indicate the early onset of OA. In this project, the student will explore these changes and create a three dimensional ‘mechano-structural’ map of early tissue degeneration.
This project will require a student who is up to the challenge of carrying out complex experimental lab-based work.

In doing so, the student will learn to use state-of-the-art microscopic and micromechanical testing techniques, as well as some (limited) computer modelling.

Related Literature

1: Hargrave-Thomas E, van Sloun F, Dickinson M, Broom N, Thambyah A. Multi-scalar mechanical testing of the calcified cartilage and subchondral bone comparing healthy vs early degenerative states. Osteoarthritis Cartilage. 2015 23(10):1755-62.

2: Thambyah A, Broom N. On new bone formation in the pre-osteoarthritic joint. Osteoarthritis Cartilage. 2009 Apr;17(4):456-63.

3: Thambyah A, Broom N. On how degeneration influences load-bearing in the cartilage-bone system: a microstructural and micromechanical study. Osteoarthritis Cartilage. 2007 15(12):1410-23.


Develop efficient heating and cooling for electric cars

Project code:  ENG017

Plug in electric cars are becoming very popular for many reasons. The cabinet of petrol and diesel cars is heated using the waste heat produced form the engine, which is not available for electric cars. Using the battery for this purpose could reduce the mileage by 50%. The project will look into recent developments made in this area and build an innovative storage system, which could be charged while the car battery is charged. Most of the facilities needed for building such system and testing it are available in our laboratories.  


An investigation on how instability from bilateral pars defects can influence intervertebral disc structural integrity in ovine spine

Project code:  ENG018


  • Prof Neil Broom
  • A/Prof Ashvin Thambyah
  • Surgeon Collaborator - Dr Peter Robertson

Defects or fractures in the pars interarticularis has been shown to cause vertebral instability and linked to disc degeneration [1, 2]. What remains unknown is how such instability may lead to the degenerative process. The disc degenerative process involves a progressive structural failure that is initiated, among other influences, by mechanical factors [3].


In this study, ovine lumbar spines will undergo mechanical testing in its intact state, and then following a fracture of the pars interarticularis, after which the disc will be carefully examined for any microstructural damage, using novel micro-imaging techniques developed in this lab [4,5].


1.     Dai LY. Disc degeneration in patients with lumbar spondylolysis. J Spinal Disord. 2000;13:478–486.

2.     Mihara H, Onari K, Cheng BC, David SM, Zdeblick TA. The biomechanical effects of spondylolysis and its treatment. Spine 2003 28(3):235-8.

3.     Adams MA, Roughley PJ. What is intervertebral disc degeneration, and what causes it? Spine 2006;31: 2151–2161.

4.     Wade KR, Schollum ML, Robertson PA, Thambyah A, Broom ND. Vibration Really Does Disrupt the Disc- A Microanatomical Investigation. Spine (Phila Pa 1976).2016 Mar 31. [Epub ahead of print] PubMed PMID: 27043193.

Veres SP, Robertson PA, Broom ND. ISSLS prize winner: microstructure and mechanical disruption of the lumbar disc annulus: part II: how the annulus fails under hydrostatic pressure. Spine 2008 33(25):2711-20.


Synthesis, microstructure and ionic conductivity of garnet-type oxide electrolytes

Project code:  ENG019

The oxide electrolytes (Li7La3Zr2O12 based) powders will be synthesized first, and then sintered into bulk ceramics for conductivity properties measurement. The student is expected to be self-motivated, and be familiar with XRD and SEM analyses.


Synthesis and photoluminescent (PL) properties of phosphate phosphors

Project code:  ENG020

A series of phosphate powders with different concentrations of dopants (Eu2+/Ce3+) will be synthesized, then the PL properties will be assessed. The student is expected to be self-motivated, and be familiar with structure chemistry and XRD analysis.


Investigation of fatigue properties of 3D printed NiTi shape memory alloys

Project code:  ENG021

Student will be asked to undertake fatigue testing on the NiTi shape memory alloy samples made by electron beam melting. He or she is expected to have basic knowledge of mechanical testing and materials characterisation.


Nanopatterning using block copolymers

Project code:  ENG022


Jenny Malmstrom

In this summer scholarship you will work with a fascinating family of macromolecules called block copolymers. Block copolymers consist of two chemically different blocks linked together by a covalent bond. If the two blocks are different enough, the polymers will spontaneously form nanostructured materials. This project will be focussed on improving the formation of ordered films from block copolymers, through optimising deposition and annealing protocols. Since the formed structures are small, the imaging of the films will be done using Atomic Force Microscopy. This project suits an ambitious student with an interest in surface science or nanotechnology.


Nanostructured Composite Coatings

Project code:  ENG023


Professor Wei Gao

Surface science and engineering are a very important area in Materials Research Society.  Coating and surface technology play a critical role in modern industries and our everyday life.  Electrochemical technologies including electroplating, eletroless deposition and surface anodising are popular surface treatment methods due to their simple processes and high effectiveness.  These methods can significantly improve the mechanical strength, hardness, wear and corrosion resistance of machine parts, extending the service life of components and equipment.

This group has been working on surface science and technologies for more than two decades, and recently developed several new techniques.  Some patented technologies such as sol-introduced nano-particle composite-alloy coatings, electroless deposition on anodised substrate, and double-layered nanostructured coatings showed significantly improved micro-hardness and wear resistance.  There are many new systems and technical innovation that the group is keen to explore.  The final year project will be planned to work on a new coating system or new/improved method.

This is a typical materials project, consisting of processing/treatment technique, electrochemistry theory, microstructure characterisation and property optimisation research.  The student is expected to work on an independent topic supported by postdoctoral fellow(s) and senior PhD student(s).  There are also industrial support from two local companies in Auckland.


Nanostructured photocatalysts and their environmental applications

Project code:  ENG024


Professor Wei Gao

Environmental problems are a big challenge human being facing in the 21st Century.  At the same time, water shortage is getting worse in many countries that require serious attention.  Our group has extensive studies on using nano-structured materials with combination of membrane materials to treat wastewater.  There are several topics on this area including decomposing organic pollutants, selective absorption/desorption, and valuable materials recovery.

This project studies the nanostructure and catalytic properties of materials, including (1) transition metals oxides such as ZnO, TiO2 and V2O5, (2) polymer membrane, (3) porous materials and (4) their combinations.  Research is focused on study selective absorption and desorption properties of these materials.  The potential applications of these materials are (a) to clean up city and farming wastewater, (b) to selectively absorb various dyes, and (c) to extract valuable materials such as noble metals Ag and Cu from wastewater from metallurgical industry.

This research needs combined knowledge and expertise of Materials Science and Chemical Engineering/Processes.  Both chemical reaction systems and materials characterisation knowledge will be used in the research.  We have a number of active projects in this area.  Students will have their own focused projects, and supported by senior PhD students.  One of the topics will be collaborated with another group. 


Nanostructure engineering of semiconducting transition metal oxides

Project code:  ENG025


Professor Wei Gao

Materials energy applications are another extremely hot area.  In order to reduce fuel consumption and environmental pollution, use of renewable energy especially solar energy is a global research focus.  Semiconducting oxides are a relatively new group of materials that exhibit their special properties.  Their wide electron energy band-gap can absorb UV radiation.  Unfortunately, there is only ~5% UV from the solar radiation spectrum.  In order to harvest more energy from the solar radiation, engineering wide energy-gap transition metal oxides has attracted much attention.

We have recently developed a technology to introduce micro- nano-structural defects in wide band-gap semiconductors such as TiO2 and ZnO.  For instance, oxygen deficient TiO2-x has a narrow band gap that allows it to harvest full spectrum of solar radiation instead of only UV light.  Photo-catalytic reaction tests showed a much higher efficiency with black titania than ordinary TiO2.  Our current work include (1) further study on how to control the defect structure of black titania to obtain desirable properties, (2) how to convert the absorbed solar energy (or microwave energy) to useful electricity, and (3) explore a wide range of other transition metal oxides to see if they can obtain useful properties for energy applications.

This project will have materials processing (anodising and thermal treatment, nanostructure characterisation and electronic property studies, is a true frontier research in materials science and engineering.


Long-lived plastic solar cells through the optical characterization of polymer composites

Project code:  ENG026


Alisyn Nedoma

Plastic solar cells are inexpensive, flexible, and their efficiencies have quadrupled during the last 15 years [1]. Device lifetimes remain untenably short due to the evolution of micron-sized crystals during operation of the solar cell.

This project seeks to understand the fundamental behavior of polymer composites by examining the structures that form in thin films and the kinetics of their formation. Optical microscopy will be used to map the behavior of polymer composites and determine the best formulations for stable, smooth polymer films. The analysis of microscopic features, using Finite Fourier Transforms and particle sizing, will be used to quantify the growth of crystals and thereby control their dimensions.

[1] National Renewable Energy Laboratory. Best Research-cell Efficiencies (20 April 2016).


Design of a continuous production line for plastic electronic nanomaterials

Project code:  ENG027


Alisyn Nedoma

Plastic electronics, such as OLEDs, transistors, thermoelectrics, and photovoltaics, combine the multifunctionality of nanoscale structure with low-cost materials and manufacturing. The commercialization of these products is largely unrealized because their scale-up is an ongoing challenge.

This project seeks to design a bench-scale process for continuously automating the deposition of polymer composites. Using motors, pulleys, pumps, and nozzles, a student will design and test a prototype manufacturing line for the liquid-phase deposition of plastic electronic materials. Particular emphasis will be placed on developing methods to quickly dry the liquid formulation, a necessity for attaining the high polymer crystallinity that enables plastic electronics to function.


Measuring crystallinity in plastic electronic composites

Project code:  ENG028


Alisyn Nedoma

Crystallinity is essential for providing mechanical stability and conductivity to plastic electronic composites. When both the polymer and its filler are crystallizable, a range of structures are possible based on the kinetics of crystallization and phase separation.

This project will use differential scanning calorimetry, possibly in conjunction with x-ray diffraction, to monitor crystal formation and kinetics in polymer composites. Direct measurements of the enthalpy of crystallization will be used to calculate the total amount of crystalline material, whilst isothermal crystallization experiments will be used to extract the Avrami kinetic parameters for crystallization. These data will be used to design thermal protocols that precisely control crystal formation.


Microencapsulation of hydrated salts as phase change materials

Project code:  ENG032

Phase change materials are used for thermal storage in wide range of applications. However they must be encapsulated to prevent their leaking when melted. We have developed efficient microencapsulation and used it to encapsulate paraffin. Hydrated salts have higher storage density and much cheaper than paraffin. In this project we aim to develop a technique for encapsulating hydrated salts. All the facilities needed for emulsification and encapsulation are available in our laboratories.


Innovative thermal insulation

Project code:  ENG114

There have been significant developments in thermal insulation including those used for buildings. However, for light weight constructions, insulation by itself is not enough since there is a need to increase thermal mass of these buildings. This could be achieved through the use of phase change materials microcapsules embedded within common insulation. This is a new product development. We have the facilities to prepare the PCM microcapsules and all the facilities required for thermal testing of the product using advanced thermal cycling.