The Department of Engineering is internationally renowned for the quality of its research. In the 2008 Research Assessment Exercise (RAE), the Department submitted over 90% of its academic staff. The quality profile, as judged by the RAE, showed that 90% of the research was internationally recognised, internationally excellent or world leading in terms of originality, significance, and rigour.

The Department of Engineering has six research groups:

- Bioengineering
- Control and Instrumentation
- Electrical Power and Power Electronics
- Mechanics of Materials
- Radio Systems
- Thermofluids and Environmental Engineering

The Department also hosts research in the following cross-disciplinary groupings:

- Advanced Microscopy Centre
- Energy Centre
- Centre for Analytical Excellence
- Systems Biology Lab
- Centre for Mathematical Modelling

When downloading papers please observe the normal copyright codes and conventions for their use.

### Recent Submissions

Increasing chip power densities allied to the continuous technology shrink is making emerging multiprocessor embedded systems more vulnerable to soft errors. Due the high cost and design time inherent to board-based fault injection approaches, more appropriate and efficient simulation-based fault injection frameworks become crucial to guarantee the adequate design exploration support at early design phase. In this scenario, this paper proposes a fast and flexible fault injector framework, cal...

Rosa, Felipe R.; Kastensmidt, Fernanda; Reis, Ricardo; Ost, Luciano

FinFET technology appears as an alternative solution to mitigate short-channel effects in traditional CMOS down-scaled technology. Emerging embedded systems are likely to employ FinFET and dynamic voltage scaling (DVS), aiming to improve system performance and energy-efficiency. This paper claims that the use of DVS increases the susceptibility of FinFET-based SRAM cells to soft errors under radiation effects. To investigate that, a methodology that allows determining the critical charge acco...

Rosa, F. R.; Brum, R. M.; Wirth, G.; Ost, Luciano; Reis, R.

This work investigates the effects of temperature and voltage scaling in neutron-induced bit-flip in SRAM memory cells. Proposed approach allows determining the critical charge according to the dynamic behavior of the temperature as a function of the voltage scaling. Experimental results show that both temperature and voltage scaling can increase in at least two times the susceptibility of SRAM cells to soft error rate (SER). In addition, a model for electrical simulation for soft error and d...

Rosa, F. R.; Brum, R. M.; Wirth, G.; Kastensmidt, F.; Ost, Luciano... et al.

The discharge of powders from hoppers usually takes place in open atmosphere. However, in powder pressing industries (e.g. manufacturing of pharmaceutical tablets, detergents, ceramics, powder metallurgy etc.) there are handling operations where powders are filled into closed cavities such as dies. During this process the air pressure is increased as powder is delivered into the die. At the same time typical tablet production equipment creates a suction effect. A critical orifice measurement ...

Sinka, Iosif Csaba; Baserinia, R.; Rajniak, P.

Progress is made in the validation and use of a shareable, royalty-free, non-commercial Computational AeroAcoustics (CAA) post-processor for predicting the far-field noise radiated by acoustically active transonic flows. Building upon past validation tests of this Ffowcs Williams and Hawkings CAA post-processor, which is part of the Antares software suite, predictions are obtained of a single isothermal Mach 0.9 jet at a Reynolds number of approximately half million. A more challenging applic...

Rona, Aldo; Di Stefano, Danilo; Hall, E.; Puigt, G.

This work addresses a research subject with a rich literature: task mapping in NoC-based systems. Task mapping is the process of selecting a processing element to execute a given task. The number of cores in many-core systems increases the complexity of the task mapping. The main concerns in task mapping in large systems include (i) scalability; (ii) dynamic workload; and (iii) reliability. It is necessary to distribute the mapping decision across the system to ensure scalability. The workloa...

Castilhos, G.; Mandelli, M.; Ost, Luciano; Moraes, F.

A wide-ranging taxonomy of turbomachinery types is given. The requirements of steam turbines and aircraft engines established a traditional approach to aerodynamic design analyzing orthogonal planes. Computers facilitated this and led to a greater reliance on Computational Fluid Dynamics, offering exciting developments in three dimensional modeling. A balance should be sought between analytical, computational and experimental work. In work on an axial flow pump rig photographic investigations...

Gostelow, Jonathan Paul; Rona, Aldo; Mahallati, A.

Areas where substantial research on planar turbine cascades is ongoing, or is still needed, are identified. Compressibility effects are particularly important and are addressed in the three main sections. The modeling of the shock-boundary layer interaction is not yet reliable. For supersonic speeds the agreement is excellent apart from the crucial region downstream of the shocks. At subsonic speeds the vortices were shed in a classical von Kármán vortex street. This resulted in strong base p...

Gostelow, Jonathan Paul; Mahallati, A.; Rona, Aldo

The crossed-magnetic-field effect on the demagnetization factor of stacked second generation (2G) high temperature superconducting tapes is presented. The superconducting sample was initially magnetized along the c-axis by the field cooling magnetization method and after achieving the magnetic relaxation of the sample, an extensive set of experimental measurements for different amplitudes of an applied ac magnetic field parallel to the ab-plane was performed. On the one hand, a striking reduc...

Baghdadi, M.; Ruiz, Harold Steven; Coombs, T. A.

A sector condition for two connected deadzone nonlinearities is provided. By introducing an additional non-square operator which exploits their connectivity, a more general set of sector-like matrix inequalities is obtained. This “non-square” matrix inequality condition is applied to an anti-windup (AW) problem in which the AW compensator is not activated until the unconstrained control signal reaches a well-defined level beyond that of the physical actuator limits. The non-square sector cond...

Turner, Matthew C.; Herrmann, G.

The stability and L2L2 performance analysis of systems consisting of an interconnection of a linear-time-invariant (LTI) system and a static nonlinear element which is Lipschitz, slope restricted and sector bounded is revisited. The main thrust of the paper is to improve and extend an existing result in the literature to enable (i) concise and correct conditions for asymptotic stability of the interconnection and (ii) reasonably tight bounds on the L2L2 gain between an exogenous input and a g...

Turner, Matthew C.; Kerr, M.

Absolute stability attracted much attention in the 1960s. Several stability conditions for loops with slope-restricted nonlinearities were developed. Results such as the Circle Criterion and the Popov Criterion form part of the core curriculum for students of control. Moreover, the equivalence of results obtained by different techniques, specifically Lyapunov and Popov׳s stability theories, led to one of the most important results in control engineering: the KYP Lemma. For Lurye1 systems t...

Turner, Matthew C.; Carrasco, J.; Heath, W. P.

State estimation for nonlinear systems with Gaussian or non-Gaussian noises, and with single and multiple sensors, is presented. The key purpose is to propose a derivative free estimator using concepts from the information filter, the H∞H∞ filter, and the cubature Kalman filter (CKF). The proposed estimator is called the cubature H∞H∞ information filter (CH∞IFCH∞IF); it has the capability to deal with highly nonlinear systems like the CKF, like the H∞H∞ filter it can estimate states with stoc...

Gu, Dawei; Chandra, K. P. B.; Postlethwaite, I.

Thixoforming is a type of semi-solid processing which is based on forming metals in the semi-solid state rather than fully liquid or solid state. There have been no reports of the thixoforming of nanocomposites in the literature. The incorporation of ceramic nanoparticles into liquid metals is a challenging task for the fabrication of metal matrix nanocomposites due to their large surface-to-volume ratio and poor wettability. Previous research work by a number of workers has highlighted the c...

Kandemir, S.; Atkinson, Helen V.; Weston, David P.; Hainsworth, Sarah V.

Renewable energy is high on international and national agendas. Currently, grid-connected photovoltaic (PV) systems are a popular technology to convert solar energy into electricity. Existing PV panels have a relatively low and varying output voltage so that the converter installed between the PVs and the grid should be equipped with high step-up and versatile control capabilities. In addition, the output current of PV systems is rich in harmonics which affect the power quality of the grid. I...

Hu, Y.; Cao, W.; Ji, Bing; Si, J.; Chen, X.

This study describes an optimised modulation strategy based on switching state sequences for the hybrid-clamped multilevel converter. Two key control variables defined as ‘phase shift angle’ and ‘switching state change’ for a five-level hybrid-clamped inverter are proposed to improve all switches’ operation, and by changing their values, different control methods can be obtained for modulation optimisation purposes. Two example methods can solve the voltage imbalance problem of the dc-link ca...

Ma, M.; He, X.; Cao, W.; Song, X.; Ji, Bing

This paper proposes an LMI-based approach for studying the stability of feedback interconnections of a finite dimensional LTI system and a nonlinear element that consists of several identical scalar nonlinearities that have restrictions on their sector and slope. The results are based on the integral quadratic constraint stability analysis framework and other recent results that give a sharp characterisation of stability multipliers for monotone, repeated scalar nonlinearities. Several exampl...

Turner, Matthew Christopher; Kerr, M. L.; Sofrony, J.

This paper addresses the antiwindup problem for linear systems equipped with the zero-phase repetitive controller (ZPRC). The antiwindup compensator is designed using a coprime factorization technique and conditions to characterize the sets of admissible references and disturbances are proposed. A numerical example illustrates the application and potentialities of the proposed methodology.

Flores, J. V.; Gomes da Silva, J. M.; Sbarbaro, D.; Turner, Matthew Christopher; Salton, A. T.

In semi-solid processing, the liquid fraction vs temperature is commonly used to define the process window. Conventionally, it is assumed that a freezing range is required for semi-solid processing but recently both high-purity aluminum and binary Al-Si eutectic alloy have been rheo-processed. Here, the kinetics during melting and solidification of pure metal are analyzed, and a comparison between the liquid fraction vs temperature and the liquid fraction vs time is presented. It is found tha...

Zhang, Duyao; Dong, Hongbiao; Atkinson, Helen V.

In the various forms of semisolid processing such as thixoforming and thixoforging, the entry into the die occurs in a fraction of a second so it is the transient rheological behavior which governs the initial stages of flow. In experiments in the literature, this rheological behavior is probed through applying rapid transitions in shear rate under isothermal conditions. There is contradictory evidence as to whether the behavior during these transitions is shear thinning or shear thickening, ...

Atkinson, Helen Valerie; Favier, V.

### Filter

- 129 Science & Technology
- 102 Technology
- 51 Engineering
- 44 Physical Sciences
- 35 Humans
- 29 Automation & Control Systems
- 22 Neurons
- 21 Models
- 19 Animals
- 19 Physics
- . next >

- 439 2010 - 2016
- 725 2000 - 2009
- 131 1990 - 1999
- 38 1980 - 1989
- 52 1970 - 1979
- 9 1966 - 1969