Wessex Institute of Technology

Ashurst, United Kingdom

Wessex Institute of Technology

Ashurst, United Kingdom
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Ooi E.H.,Wessex Institute of Technology | Popov V.,Wessex Institute of Technology | Dogan H.,Wessex Institute of Technology
Applied Mathematics and Computation | Year: 2012

The radial basis integral equations method (RBIEM) has been applied for solution of threedimensional (3D) acoustic and transport problems. The acoustic problem is often described using the Helmholtz equation, while the transport problems are usually described using the Laplace equation (diffusion only), the Poisson equation (diffusion with sources/sinks) and the convection-diffusion equation. The accuracy of the numerical scheme employing the first and second order Duchon splines augmented by first and second order polynomials, respectively, was examined. The effect of the number of interpolation points used in the radial basis function approximation on the condition number of the system was investigated. Numerical results obtained for the convection-diffusion equation were compared with the solutions obtained using the multi-domain dual reciprocity boundary element method (DRM-MD). The RBIEM formulation was found to be more accurate than the DRM-MD formulation. The implementation does not involve discretization over the boundaries of the subdomains used in the RBIEM formulation when evaluating the integrals. © 2012 Elsevier Inc. All rights reserved.


Grant
Agency: European Commission | Branch: FP7 | Program: CP-IP | Phase: NMP-2008-1.2-1 | Award Amount: 12.04M | Year: 2009

Hospital-acquired (nosocomial) infections are a major financial issue in the European healthcare system. The financial impact of these infections counteract medical advances and expensive medical treatments by increasing the length of hospital stay by at least 8 days on average per affected patient, hence adding more than 10 millions patient days in hospitals in Europe per year. The statistics on patient safety in the EU show alarming tendencies : - 1 in 10 patients are affected by hospital-acquired infections - 3 million deaths are caused by hospital-acquired infections An active infection control program of patients and personnel and hygiene measures, have proven to significantly reduce both the number of infections and hospitalisation costs . The SONO project directly addresses the above problems by developing a pilot line for the production of medical antibacterial textiles. The pilot line will be based on the scale-up of a sonochemical process developed and patented at BIU laboratories. The pilot line will use a sonochemical technique to produce and deposit inorganic, antimicrobial nanoparticles on medical textiles, e.g. hospital sheets, medical coats and bandages. Sonicators are used industrially for heavy and light duty cleaning, for water disinfection and for sewage treatment. It is also used in the food industry for emulsification and drying. The proposed concept based on one step sonochemical process to produce nanoparticles and impregnate them as antibacterial factors on textile is novel and does not exist on an industrial scale. The concept has already been proven (and patented ) on a lab scale where sonochemistry was applied to impregnate nanoparticles in a single-step process. It was demonstrated that due to the special properties of the sonochemical method the antibacterial nanoparticles are adsorbed permanently on the fibres even after 70 laundry cycles. The sonochemical impregnation process is a one-step procedure in which the nanopa


Garcia-Maraver A.,University of Granada | Popov V.,Wessex Institute of Technology | Zamorano M.,University of Granada
Renewable Energy | Year: 2011

The quality of pellets is directly related to their physical, chemical, and mechanical properties. It affects the emissions resulting from their combustion and also their use in stoves and boilers. Certain European countries have developed standards specifying control parameters and guidelines with a view to guaranteeing the effective and environmentally-friendly combustion of pellets. This paper presents a comparative study of regulations and standards created by government authorities in Austria, Sweden, Germany, Italy, and France. Also considered are the guidelines of the European Standard Committee CEN/TC 335 for densified biomass fuels. The comparison of these standards provides evidence of significant differences in the quality parameters and guidelines for the manufacture and use of pellets in Europe. The results obtained could be used as a technical reference for all issues related to the production, sale and research on pellets. © 2011 Elsevier Ltd.


Ooi E.H.,Wessex Institute of Technology | Popov V.,Wessex Institute of Technology
Computational Mechanics | Year: 2013

A simplified approach for imposing the boundary conditions in the local boundary integral equation (LBIE) method is presented. The proposed approach employs an integral equation derived using the fundamental solution and the Green's second identity when the collocation node is at the boundary of the solution domain (global boundary). The subdomains for the nodes placed at the global boundary preserve their circular shapes; avoiding in this way any integration over the global boundary. Consequently, the difficulties related to evaluation of singular integrals and determination of intersection points between the global and local circular boundaries are avoided. So far, attempts to avoid these issues have focused on using schemes based on meshless approximations. The downside of such schemes is that the weak formulation is abandoned. In this study the interpolation of field variables over the boundaries of the subdomains is carried out using the radial basis function approximation. Numerical examples show that the proposed approach despite its simplicity, achieves comparable accuracy to the classical treatment of the boundary conditions in the LBIE. © 2012 Springer-Verlag.


Saeed R.A.,Wessex Institute of Technology | Galybin A.N.,Wessex Institute of Technology | Galybin A.N.,Institute of Physics of the Earth | Popov V.,Wessex Institute of Technology
Mechanical Systems and Signal Processing | Year: 2013

This paper discusses condition monitoring and fault diagnosis in Francis turbine based on integration of numerical modelling with several different artificial intelligence (AI) techniques. In this study, a numerical approach for fluid-structure (turbine runner) analysis is presented. The results of numerical analysis provide frequency response functions (FRFs) data sets along x-, y- and z-directions under different operating load and different position and size of faults in the structure. To extract features and reduce the dimensionality of the obtained FRF data, the principal component analysis (PCA) has been applied. Subsequently, the extracted features are formulated and fed into multiple artificial neural networks (ANN) and multiple adaptive neuro-fuzzy inference systems (ANFIS) in order to identify the size and position of the damage in the runner and estimate the turbine operating conditions. The results demonstrated the effectiveness of this approach and provide satisfactory accuracy even when the input data are corrupted with certain level of noise. © 2012 Elsevier Ltd.


Popov V.,Wessex Institute of Technology | Thanh Bui T.,Wessex Institute of Technology
Engineering Analysis with Boundary Elements | Year: 2010

An integral equation domain decomposition method has been implemented in a meshless fashion. The method exploits the advantage of placing the source point always in the centre of circular sub-domains in order to avoid singular or near-singular integrals. Three equations for two-dimensional (2D) or four for three-dimensional (3D) potential problems are required at each node. The first equation is the integral equation arising from the application of the Green's identities and the remaining equations are the derivatives of the first equation in respect to space coordinates. Radial basis function interpolation is applied in order to obtain the values of the field variable and partial derivatives at the boundary of the circular sub-domains, providing this way the boundary conditions for solution of the integral equations at the nodes (centres of circles). Dual reciprocity method (DRM) has been applied to convert the domain integrals into boundary integrals, though the approach is general and can be applied without the DRM. The accuracy and robustness of the method has been tested on a convection-diffusion problem. The results obtained using the current approach have been compared with previously reported results obtained using the finite element method (FEM), and the DRM multi-domain approach (DRM-MD) showing similar level of accuracy. © 2010 Elsevier Ltd. All rights reserved.


Ooi E.H.,Wessex Institute of Technology | Popov V.,Wessex Institute of Technology
International Journal of Thermal Sciences | Year: 2013

The natural convection flow of the Cu-water nanofluid inside a square cavity is simulated by using the radial basis integral equation (RBIE) method. The RBIE is a meshless method and it has the benefit of solving at each node for the velocity and its spatial gradients via integral equations. The effects of the spherical and spheroidal nanoparticles (NPs) on the natural convection flow of the nanofluids are examined. The different NPs shapes and sizes were found to affect differently the thermal conductivity and the viscosity of the nanofluids. Numerical results showed that the oblate spheroid with aspect ratio of 10 produced the largest enhancement of the overall heat transfer characteristic. © 2012 Elsevier Masson SAS. All rights reserved.


Fu Z.,Wessex Institute of Technology | Popov V.,Wessex Institute of Technology
Ultrasonics Sonochemistry | Year: 2014

The bubble cavitation along a solid wall is investigated with a three-dimensional model based on the indirect boundary element method. Kinetic energy and Kelvin impulse are calculated in order to quantify the strength of cavitation. The influences of acoustic wave amplitude and frequency and liquid properties on the strength of cavitation are investigated. This study was carried out in order to better understand the relation between microscale processes and macroscale parameters in a sonochemical reactor used for impregnation of fabrics with nanoparticles. © 2013 Elsevier B.V. All rights reserved.


Ooi E.H.,Wessex Institute of Technology | Popov V.,Wessex Institute of Technology
Engineering Analysis with Boundary Elements | Year: 2012

An efficient and accurate implementation of the meshless radial basis integral equation method (RBIEM) is proposed. The proposed implementation does not involve discretization of the subdomains' boundaries. By avoiding the boundary discretization, it was hypothesised that a significant source of error in the numerical scheme is avoided. The proposed numerical scheme was tested on two problems governed by the Poisson and Helmholtz equations. The test problems were selected such that the spatial gradients of the solutions were high to examine the robustness of the numerical scheme. The dual reciprocity method (DRM) and the cell integration technique were used to treat the domain integrals arising from the source terms in the partial differential equations. The results showed that the proposed implementation is more accurate and more robust than the previously suggested implementation of the RBIEM. Though the CPU time usage of the proposed scheme is lower, the difference to the previously proposed scheme is not significant. The proposed scheme is easier to implement, since the task of keeping track of boundary elements and boundary nodes is not needed. The proposed implementation of the RBIEM is promising and opens up possibilities for efficient implementation in three-dimensional problems. This is currently under investigation. © 2011 Elsevier Ltd. All rights reserved.


Mambretti S.,Wessex Institute of Technology
WIT Transactions on Ecology and the Environment | Year: 2011

In the paper a method for the optimization of water distributions networks is developed and applied to the case of the water supply network of Milano. This network is very complex and has no suspended reservoirs as the hydraulic head is maintained by the action of 31 pumping stations. Starting from real data, the operations of the entire network and pumping station, with the actual scheduling, are simulated with software using EPANET engine which was developed to this purpose. Afterwards, the operation of the pumping stations is optimized through the use of a simple Genetic Algorithm, in order to reduce the energy consumption maintaining a good service. Results show a significant improvement with the new working logics, thus justifying the study. Site tests show that the assumptions made in building the model are reliable, but they will probably require some adjustments following this research. © 2011 WIT Press.

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