• Measuring the ranking capability of SWA system

      Shurrab, O.; Awan, Irfan U. (2015)
      The analysts need timely and accurate information to conduct proactive action over complex situations. Typically, there are thousands of reported activities in real time operation, although, to direct the analysts attentions to the most important one, researchers have designed multiple levels of situational awareness (SWA). Each process lends itself to ranking the most important activities into a predetermined order. According to our best knowledge, less attention has been given to the performance evaluation with regards to the prioritisation stage. Specifically, the performance metric, "The Activity of Interest Scores" has not considered corner cases of different situational assessments needs and configurations. Originally, it had not been designed for measuring the capability of the SWA system. In this paper, we have proposed a new performance metric, as well as a guidance case study for measuring the ranking capability of SWA systems. Our initial result shows that, The Ranking Capability Score has provided an appropriate scoring scheme for different ranking capabilities of SWA systems.
    • Mechanical and microstructural characterization of geopolymers from assorted construction and demolition waste-based masonry and glass

      Ulugöl, H.; Kul, A.; Yildirim, G.; Şahmaran, M.; Aldemir, A.; Figueira, D.; Ashour, Ashraf F. (2021-01)
      Geopolymers are mostly produced with main-stream precursors such as fly ash and slag. These precursors are successfully used and competitively demanded by the cement industry. Development of geopolymers from alternative precursors is appealing. The main aim of this work is the development of geopolymers with construction and demolition waste-based precursors including masonry units (red clay brick, roof tile, hollow brick) and glass. Different curing temperatures (50, 65, 75, 85, 95, 105, 115, 125 oC), curing periods (24, 48, 72 h), and Na concentrations (10, 12, 15%) of alkaline activator (NaOH) were employed. Compressive strength testing and microstructural investigations were performed including X-ray diffraction, thermogravimetry and scanning electron microscopy with energy-dispersive X-ray spectroscopy. Results showed that depending on the type of precursor (hollow brick), curing temperature/period (115 oC/24 h) and concentration of alkaline activator (12%), it is possible to obtain compressive strength results more than 45 MPa. Hollow brick is the most successful precursor resulting in higher compressive strength results thanks to a more compact microstructure. The strength performance of red clay brick and roof tile is similar. The compressive strength results of geopolymers with glass precursor are lower, most probably due to significantly coarser particles of glass used. The main reaction products of red clay brick-, roof tile- and hollow brick-based geopolymers are sodium aluminosilicate hydrate (N-A-S-H) gels with zeolite-like structures while they are sodium silicate gels in the case of glass-based geopolymers. Our findings showed that CDW-based materials can be used successfully in producing geopolymers. Current research is believed to help raise awareness in novel routes for the effective utilization of such wastes which are realistically troublesome and attract further research on the utilization of CDW-based materials in geopolymer production.
    • Mechanical durability of hydrophobic surfaces fabricated by injection moulding of laser-induced textures

      Romano, J.-M.; Gülçür, Mert; Garcia-Giron, A.; Martinez-Solanas, E.; Whiteside, Benjamin R.; Dimov, S.S. (2019-05-15)
      The paper reports an investigation on the mechanical durability of textured thermoplastic surfaces together with their respective wetting properties. A range of laser-induced topographies with different aspect ratios from micro to nanoscale were fabricated on tool steel inserts using an ultrashort pulsed near infrared laser. Then, through micro-injection moulding the topographies were replicated onto polypropylene surfaces and their durability was studied systematically. In particular, the evolution of topographies on textured thermoplastic surfaces together with their wetting properties were investigated after undergoing a controlled mechanical abrasion, i.e. reciprocating dry and wet cleaning cycles. The obtained empirical data was used both to study the effects of cleaning cycles and also to identify cleaning procedures with a minimal impact on textured thermoplastic surfaces and their respective wetting properties. In addition, the use of 3D areal parameters that are standardised and could be obtained readily with any state-of-the-art surface characterisation system are discussed for monitoring the surfaces' functional response.
    • Mechanical failure analysis in a virtual reality environment

      Li, Jian-Ping; Thompson, Glen P. (2009-07-20)
      This paper is part of a research theme to develop methods that enhance risk assessment studies by the use of 'automated' failure analysis. The paper presents an approach to mechanical failure analysis and introduces a mechanical failure analysis module that can be used in a virtual reality (VR) environment. The module is used to analyse and predict failures in mechanical assemblies; it considers stress related failures within components, as well as failures due to component interactions. Mechanical failures are divided into two categories in this paper: material failures and interference failures. The former occur in components and the latter happen at the interface between components. Individual component failures can be analysed readily; a contribution of the mechanical failure analysis module is to predict interference failures. A mechanical failure analysis system that analyses and visualizes mechanical failures in a virtual environment has been developed. Two case studies demonstrate how the system carries out failure analysis and visualization as design parameters are changed.
    • Mechanical Investigations on Agar Gels Using Atomic Force Microscopy: Effect of Deuteration.

      Grant, Colin A.; Twigg, Peter C.; Savage, M.D.; Woon, W.H.; Greig, D. (25/08/2011)
      The isotopic effect of exchanging deuterium with hydrogen on the mechanical and surface properties of agar gel is examined. The elastic modulus of the D2O gels obtained by AFM nanoindentation is significantly higher (factor of 1.5¿2) than the modulus found in H2O agar gels. Furthermore, the modulus is independent of loading rate. Surface imaging reveals that the surface roughness gets progressively smaller with increasing agar concentration. All these data suggest that the isotopic replacement of deuterium enhances the mechanical properties of the agar gel, with significant advantages in its use as a biphasic scaffold.
    • Mechanism analysis for concrete breakout capacity of single anchors in tension

      Yang, Keun-Hyeok; Ashour, Ashraf F. (2008)
      A numerical technique based on the theory of plasticity is developed to predict an optimum failure surface generatrix and concrete breakout capacity of single anchors away from edges under tensile loads. Concrete is regarded as a rigid, perfectly plastic material obeying a modified coulomb failure criteria with effective compressive and tensile strengths. The failure mode is idealized as an assemblage of two rigid blocks separated by failure surfaces of displacement discontinuity. Minimization of the collapse load predicted by the energy equation produces the optimum shape of the failure surface generatrix. A simplified solution is also developed by approximating the failure surface as two straight lines. The effect of different parameters on the concrete breakout capacity of anchors is reviewed using the developed mechanism analysis, ACI 318-05, and test results of 501 cast-in-place and 442 post-installed anchor specimens. The shape of failure surface and concrete breakout capacity of anchors predicted by the mechanism analysis are significantly affected by the ratio between effective tensile and compressive strengths of concrete. For anchors installed in concrete having a low ratio between effective tensile and compressive strengths, a much larger horizontal extent of failure planes in concrete surface is predicted by the mechanism analysis than recommended by ACI 318-05, similar to test results. Experimental concrete breakout capacity of anchors is closer to the prediction obtained from the mechanism analysis than ACI 318-05. ACI 318-05 provisions for anchors sharply underestimate the breakout capacity of cast-in-place and post-installed anchors having effective embedment depths exceeding 200 and 80 mm (7.87 to 3.15 in.), respectively, installed in concrete of compressive strength larger than 50 MPa (7250 psi).
    • Mechanism for Polymorphic Transformation of Artemisinin during High Temperature Extrusion

      Kulkarni, Chaitrali S.; Kelly, Adrian L.; Kendrick, John; Gough, Timothy D.; Paradkar, Anant R. (2013)
      A novel, green, and continuous method for solid-state polymorphic transformation of artemisinin by high temperature extrusion has recently been demonstrated. This communication describes attempts to understand the mechanisms causing phase transformation during the extrusion process. Polymorphic transformation was investigated using hot stage microscopy and a model shear cell. At high temperature, phase transformation from orthorhombic to the triclinic crystals was observed through a vapor phase. Under mechanical stress, the crystalline structure was disrupted continuously, exposing new surfaces and accelerating the transformation process.
    • Medical image classification based on artificial intelligence approaches: A practical study on normal and abnormal confocal corneal images

      Qahwaji, Rami S.R.; Ipson, Stanley S.; Sharif, Mhd Saeed; Brahma, A. (2015-11)
      Corneal images can be acquired using confocal microscopes which provide detailed images of the different layers inside the cornea. Most corneal problems and diseases occur in one or more of the main corneal layers: the epithelium, stroma and endothelium. Consequently, for automatically extracting clinical information associated with corneal diseases, or evaluating the normal cornea, it is important also to be able to automatically recognise these layers easily. Artificial intelligence (AI) approaches can provide improved accuracy over the conventional processing techniques and save a useful amount of time over the manual analysis time required by clinical experts. Artificial neural networks (ANN) and adaptive neuro fuzzy inference systems (ANFIS), are powerful AI techniques, which have the capability to accurately classify the main layers of the cornea. The use of an ANFIS approach to analyse corneal layers is described for the first time in this paper, and statistical features have been also employed in the identification of the corneal abnormality. An ANN approach is then added to form a combined committee machine with improved performance which achieves an accuracy of 100% for some classes in the processed data sets. Three normal data sets of whole corneas, comprising a total of 356 images, and seven abnormal corneal images associated with diseases have been investigated in the proposed system. The resulting system is able to pre-process (quality enhancement, noise removal), classify (whole data sets, not just samples of the images as mentioned in the previous studies), and identify abnormalities in the analysed data sets. The system output is visually mapped and the main corneal layers are displayed. 3D volume visualisation for the processed corneal images as well as for each individual corneal cell is also achieved through this system. Corneal clinicians have verified and approved the clinical usefulness of the developed system especially in terms of underpinning the expertise of ophthalmologists and its applicability in patient care.
    • Meeting the Fixed Water Demand of MSF Desalination using Scheduling in gPROMS

      Sowgath, Md Tanvir; Mujtaba, Iqbal M. (2015)
      Multi-Stage Flash (MSF) desalination process has been used for decades for making fresh water from seawater and is the largest sector in desalination industries. In this work, dynamic optimisation of MSF desalination is carried out using powerful and robust dynamic simulation and optimisation software called gPROMS model builder. For a fixed freshwater demand, a number of optimal combinations of the factors such as heat transfer area, brine flow rate, cooling water flow rate, steam flow in brine heater, Top Brine Temperature, the number of stages, etc. are determined with the objective of maximising the performance ratio of the process (defined as the amount of fresh water produced per unit of energy input) considering the seasonal variations. An attempt has been made to develop an operational schedule for a particular day using dynamic optimisation.
    • Melt temperature consistency during polymer extrusion

      Abeykoon, Chamil; Martin, P.J.; Kelly, Adrian L.; Li, K.; Brown, Elaine C.; Coates, Philip D. (2014)
    • Melt temperature field measurement in single screw extrusion using thermocouple meshes.

      Brown, Elaine C.; Kelly, Adrian L.; Coates, Philip D. (2004)
      The development and validation of a sensor for extrusion melt temperature field measurement is described. A grid of opposing thermocouple wires was constructed and held in position by a supporting frame. Wires were joined together at crossing points to form thermocouple junctions, which were computer monitored. The mesh was used to monitor melt temperature fields during single screw extrusion at the die entrance. Design and construction of the mesh is described in addition to experimental optimization of wire diameter and junction forming. Calibration of the sensor and potential measurement errors including shear heating effects are discussed. Initial results from single screw extrusion are presented for a commercial grade of low density polyethylene using five- and seven-junction thermocouple meshes. The dependence of melt temperature profile on screw speed is illustrated. At low screw speeds melt temperature profiles were flat in shape and higher than set wall temperatures. At higher screw speeds the profiles became more pointed in shape. Use of higher resolution sensors exposed more complex temperature profiles with shoulder regions.
    • The meshing of timing belt teeth in pulley grooves

      Childs, T.H.C.; Dalgarno, K.W.; Hojjati, M.H.; Tutt, M.J.; Day, Andrew J. (1997)
      The work described here has been carried out to obtain a better understanding of the tooth root cracking failure mode of timing belts. Previous work has demonstrated the close dependence of this on the tooth deflections of fully meshed teeth, generated by torque transmission, but has not considered the additional distortions generated in the partially meshed conditions at entry to and exit from a pulley groove. Approximate compatibility and constitutive equations are combined with a rigorous consideration of tooth equilibrium in partial meshing to show how bending moments are generated at both exit from a driven pulley and entry to a driving pulley. Experimentally determined belt lives correlate very well with a combined measure of fully meshed tooth strain and strain due to bending at entry or exit. The analysis also shows that this strain measure reduces with increasing belt tooth stiffness, confirming the importance of a high tooth stiffness for a long belt life. Tooth force variations through the partial meshing cycle have also been predicted and compared with measurements obtained from a special strain gauge instrumented pulley. A greater pulley rotation than is predicted is required for a belt tooth to seat in a pulley groove. There is room for improvement in the modelling
    • A meta-analysis of the factors affecting eWOM providing behaviour

      Ismagilova, Elvira; Rana, Nripendra P.; Slade, E.; Dwivedi, Y.K. (2020-11-25)
      Purpose- Numerous studies have examined factors influencing eWOM providing behaviour. The volume of extant research and inconsistency in some of the findings makes it useful to develop an all-encompassing model synthesising results. Therefore, the aim of this study is to synthesise findings from existing studies on eWOM by employing meta-analysis, which will help to reconcile conflicting findings of factors affecting consumers’ intention to engage in eWOM communications. Design/methodology/approach- The findings from 51 studies were used for meta-analysis, which was undertaken using Comprehensive Meta-Analysis software. Findings- Factors affecting eWOM providing behaviour were divided into four groups: personal conditions, social conditions, perceptual conditions, and consumption-based conditions. The results of meta-analysis showed that out of 20 identified relationships, 16 were found to be significant (opinion seeking, information usefulness, trust in web eWOM services, economic incentive, customer satisfaction, loyalty, brand attitude, altruism, affective commitment, normative commitment, opinion leadership, self-enhancement, information influence, tie strength, homophily, and community identity). Originality/value- Applying meta-analysis helped reconciliation of conflicting findings, enabled investigation of the strengths of the relationships between motivations and eWOM providing behaviour, and offered a consolidated view. The results of this study facilitate the advancement of current knowledge of information dissemination on the Internet, which can influence consumer purchase intention and loyalty.
    • Meta-Surface Wall Suppression of Mutual Coupling between Microstrip Patch Antenna Arrays for THz-Band Applications

      Alibakhshikenari, M.; See, Chan H.; Virdee, B.S.; Abd-Alhameed, Raed A. (2018)
      This paper presents a novel 2D meta-surface wall to increase the isolation between microstrip patch radiators in an antenna array that is operating in the teraherz (THz) band of 139–141 GHz for applications including communications, medical and security screening systems. The metasurface unit-cell comprises conjoined twin ‘Y-shape’ microstrip structures, which are inter-digitally interleaved together to create the meta-surface wall. The proposed meta-surface wall is free of via holes and defected ground-plane hence easing its fabrication. The meta-surface wall is inserted tightly between the radiating elements to reduce surface wave mutual coupling. For best isolation performance the wall is oriented orthogonal to the patch antennas. The antenna array exhibits a gain of 9.0 dBi with high isolation level of less than −63 dB between transmit and receive antennas in the specified THz-band. The proposed technique achieves mutual coupling suppression of more than 10 dB over a much wider frequency bandwidth (2 GHz) than achieved to date. With the proposed technique the edge-to-edge gap between the transmit and receive patch antennas can be reduced to 2.5 mm. Dimensions of the transmit and receive patch antennas are 5 × 5 mm2 with ground-plane size of 9 × 4.25 mm2 when being constructed on a conventional lossy substrate with thickness of 1.6 mm.
    • Metamodel-based collaborative optimization framework

      Zadeh, Parviz M.; Toropov, V.V.; Wood, Alastair S. (2009)
      This paper focuses on the metamodel-based collaborative optimization (CO). The objective is to improve the computational efficiency of CO in order to handle multidisciplinary design optimization problems utilising high fidelity models. To address these issues, two levels of metamodel building techniques are proposed: metamodels in the disciplinary optimization are based on multi-fidelity modelling (the interaction of low and high fidelity models) and for the system level optimization a combination of a global metamodel based on the moving least squares method and trust region strategy is introduced. The proposed method is demonstrated on a continuous fiber-reinforced composite beam test problem. Results show that methods introduced in this paper provide an effective way of improving computational efficiency of CO based on high fidelity simulation models.
    • Method and Apparatus for Supporting Ad-Hoc Networking over UMTS (Universal Mobile Telecommunications System) Protocol.

      Barnawi, A.; Gardiner, John G. (2007)
      A method and apparatus are provided for ad hoc networking over a universal mobile telecommunications system (UMTS) . In the method, if user equipment (40A) (such as a mobile phone) is not within normal cell coverage (20) , then in an uplink procedure a message which would normally have not be able to be transmitted directly from the User Equipment (40A) to a Base Station (10) is instead forwarded towards the Base Station (10) via one or more intermediate User Equipments (40B) . In the method, the user equipment (40A) is arranged to synchronise itself with the Base Station (10) to acquire timeslot and frame synchronisations and thence perform probing activities to build up a list of neighbouring User Equipments. From this list and power and signal to interference calculations the user equipment (40A) is able to work out the relative positions of its neighbours with respect to the Base Station and itself and come to a routing decision for forwarding its message towards the Base Station.
    • A method for location based search for enhancing facial feature design

      Al-Dahoud, A.; Ugail, Hassan (2016-09)
      In this paper we present a new method for accurate real-time facial feature detection. Our method is based on local feature detection and enhancement. Previous work in this area, such as that of Viola and Jones, require looking at the face as a whole. Consequently, such approaches have increased chances of reporting negative hits. Furthermore, such algorithms require greater processing power and hence they are especially not attractive for real-time applications. Through our recent work, we have devised a method to identify the face from real-time images and divide it into regions of interest (ROI). Firstly, based on a face detection algorithm, we identify the face and divide it into four main regions. Then, we undertake a local search within those ROI, looking for specific facial features. This enables us to locate the desired facial features more efficiently and accurately. We have tested our approach using the Cohn-Kanade’s Extended Facial Expression (CK+) database. The results show that applying the ROI has a relatively low false positive rate as well as provides a marked gain in the overall computational efficiency. In particular, we show that our method has a 4-fold increase in accuracy when compared to existing algorithms for facial feature detection.
    • A method for predicting geometric characteristics of polymer deposition during fused-filament-fabrication

      Hebda, Michael; McIlroy, C.; Whiteside, Benjamin R.; Caton-Rose, Philip D.; Coates, Philip D. (2019-05)
      In recent years 3D printing has gained popularity amongst industry professionals and hobbyists alike, with many new types of Fused Filament Fabrication (FFF) apparatus types becoming available on the market. A massively overlooked component of FFF is the requirement for a simple method to calculate the geometries of polymer depositions extruded during the FFF process. Manufacturers have so far achieved adequate methods to calculate tool-paths through so called slicer software packages which calculate the required velocities of extrusion from prior knowledge and data. Presented here is a method for obtaining a series of equations for predicting height, width and cross-sectional area values for given processing parameters within the FFF process for initial laydown on to a glass surface.
    • A method for temporal fault tree analysis using intuitionistic fuzzy set and expert elicitation

      Kabir, Sohag; Goek, T.K.; Kumar, M.; Yazdi, M.; Hossain, F. (2020)
      Temporal fault trees (TFTs), an extension of classical Boolean fault trees, can model time-dependent failure behaviour of dynamic systems. The methodologies used for quantitative analysis of TFTs include algebraic solutions, Petri nets (PN), and Bayesian networks (BN). In these approaches, precise failure data of components are usually used to calculate the probability of the top event of a TFT. However, it can be problematic to obtain these precise data due to the imprecise and incomplete information about the components of a system. In this paper, we propose a framework that combines intuitionistic fuzzy set theory and expert elicitation to enable quantitative analysis of TFTs of dynamic systems with uncertain data. Experts’ opinions are taken into account to compute the failure probability of the basic events of the TFT as intuitionistic fuzzy numbers. Subsequently, for the algebraic approach, the intuitionistic fuzzy operators for the logic gates of TFT are defined to quantify the TFT. On the other hand, for the quantification of TFTs via PN and BN-based approaches, the intuitionistic fuzzy numbers are defuzzified to be used in these approaches. As a result, the framework can be used with all the currently available TFT analysis approaches. The effectiveness of the proposed framework is illustrated via application to a practical system and through a comparison of the results of each approach.
    • Method of boundary based smooth shape design

      Ugail, Hassan (2005)
      The discussion in this paper focuses on how boundary based smooth shape design can be carried out. For this we treat surface generation as a mathematical boundary-value problem. In particular, we utilize elliptic Partial Differential Equations (PDEs) of arbitrary order. Using the methodology outlined here a designer can therefore generate the geometry of shapes satisfying an arbitrary set of boundary conditions. The boundary conditions for the chosen PDE can be specified as curves in 3-space defining the profile geometry of the shape. We show how a compact analytic solution for the chosen arbitrary order PDE can be formulated enabling complex shapes to be designed and manipulated in real time. This solution scheme, although analytic, satisfies exactly, even in the case of general boundary conditions, where the resulting surface has a closed form representation allowing real time shape manipulation. In order to enable users to appreciate the powerful shape design and manipulation capability of the method, we present a set of practical examples