Recent Submissions

  • Stray alternating current (AC) induced corrosion of steel fibre reinforced concrete

    Tang, Kangkang (Elsevier, 2019-12-31)
    This paper primarily discusses the assessment of stray DC and AC-induced corrosion phenomena on steel fibres and the analysis of the main influencing parameters. Instrumental methods in electrochemistry including Tafel polarization, Cyclic Potentiodynamic (CP) polarization and Electrochemical Impedance Spectroscopy (EIS) were used to assess the corrosion resistance of steel fibres which has great potential to replace conventional steel reinforcement in railway tunnel construction. The analytical model based on electric circuit modelling indicates that concrete containing discrete steel fibres has an inherent corrosion resistance to stray AC interference due to the electrical double layer developed on the surface.
  • Impact of detuning and dephasing on a laser-corrected subnatural-linewidth single-photon source

    López Carreño, Juan Camilo; Zubizarreta Casalengua, E.; Laussy, Fabrice P.; Valle, Elena del (IOP Publishing, 2019-01-08)
    The elastic scattering peak of a resonantly driven two-level system has been argued to provide narrow-linewidth antibunched photons. Although independent measurements of spectral width on the one hand and antibunching, on the other hand, do seem to show that this is the case, a joint measurement reveals that only one or the other of these attributes can be realised in the direct emission. We discuss a scheme which interferes the emission with a laser to produce simultaneously single photons of subnatural linewidth. In particular, we consider the effect of dephasing and of the detuning between the driving laser and/or the detector with the emitter. We find that our scheme brings such considerable improvement as compared to the standard schemes as to make it the best single-photon source in terms of all-order multi-photon suppression by several orders of magnitudes. While the scheme is particularly fragile to dephasing, its superiority holds even for subnatural-linewidth emission down to a third of the radiative lifetime.
  • Geochemical characterization of banana, buriti palm, jute and coir fibres for use as biogeotextiles for erosion control

    Egbujuo, Charles, Izuchukwu; Fullen, M.A.; Guerra, Antonio J.T.; Opara, Alexander Iheanyi (VGTU Press, 2018-10-09)
    Geochemical analysis of selected plant fibres used as geotextiles for erosion control was conducted to evaluate their geochemical composition and to determine the elements that could potentially be nutrients for plants or cause heavy metal contamination in soils. Analysis of the samples was performed using X-ray Diffraction and X-ray Fluorescence spectrometry. Results revealed that potassium concentrations varied from 3.63% in jute-mat (India)-50.73% in banana-leaf (São Romão, Brazil), with a mean of 27.17%. Similarly, calcium concentrations varied from 0.09% in banana-leaf (São Romão) –37.0% in banana-leaf/stem (Oleo, Brazil). Iron concentrations varied from 0.15% in banana-leaf/stem samples (Oleo) –4.47% in jute-cloth (India). Since banana-leaf/stem had the highest concentration of macro-nutrients, it is therefore proposed that banana-leaf has the highest potential for adding nutrients to the soil system when biodegraded. In addition, heavy metal analysis of the samples revealed that none of the fibres have high concentrations that may contaminate the soil upon decomposition.
  • Problems of drought and its management in Yobe State, Nigeria

    Hassan Gana, Abdullahi; Fullen, M.A.; Oloke, David A. (Elsevier, 2019-01-09)
    Drought poses an enormous global threat to sustainable development and is expected to increase with global climate change. Drought and desertification are major problems in Yobe State (north-east Nigeria). This study investigates the main problems associated with drought in Yobe State. Qualitative methods were employed to investigate socio-economic impacts of drought via Focus Group Discussions (FDG). Farmers and officials from the State Ministry of the Environment were the discussants. Both groups confirmed the frequency and severity of drought in Yobe. However, farmers have practises that cause environmental degradation. Developing a viable and holistic approach to drought mitigation is crucial, to arresting and hopefully reversing environmental degradation. Understanding the causes and consequences of drought will help develop drought mitigation and management strategies. Currently, there is no proper drought mitigation and management framework in Yobe State. This paper introduces the socio-economic and environmental effects of drought and makes recommendations for mitigation and management strategies in Yobe State.
  • Targeted sound attenuation capacity of 3D printed noise cancelling waveguides

    Arjunan, Arun (Elsevier, 2019-03-08)
    The study explores the creation of 3D printed sound cancelling waveguides that can be customised for selected frequencies as a function of geometry. The potential for attenuation in these waveguides is characterised through experimentally measured acoustic-absorption (α) and Transmission Loss (TL). This was done to evaluate the potential of geometry-controlled waveguides in the development of passive sound cancelling structures. Geometrically complex waveguides to exploit the Herschel–Quincke-Arjunan (HQA) waveguide model manufactured in Nylon-12 using Selective Laser Melting (SLM) are presented. The attenuation of the waveguides was compared to the bulk Nylon-12 materials to segregate the material-based influence. The results showed that the performance of HQA waveguides can be controlled as a function of length, diameter and waveguide-tortuosity. Accordingly, under right parameters significant improvement in α (0.96, 0.80, 0.61 and 0.98) and TL (65.59%, 30.15%, 53.36% and 95.28%) can be achieved at the design frequency. The proposed methodology can be used to develop customisable waveguides exploiting the principles of acoustic wave interference for a range of application including building walls, noise barriers and absorptive panels.
  • Compressive performance of an arbitrary stiffness matched anatomical Ti64 implant manufactured using Direct Metal Laser Sintering

    Vance, Aaron; Bari, Klaudio; Arjunan, Arun (Elsevier, 2018-11-08)
    The reduction of stress shielding following Segmental Bone Defect (SBD) repair requires stiffness matching strategies. Accordingly, this work introduces a Ti6Al4V (Ti64) SBD tibial implant that mimics the segmented bone anatomy using a digital bio-model derived from X-Ray μCT Scan data. The implant features a sheathed periodic unit cell design that can perform slightly lower than the segmented bone being replaced for potential stiffness matching. Finite Element Analysis (FEA) was carried out for the selection of unit cell and to predict the implant performance. The results were then compared to compression test data from a Ti64 Grade 23 implant manufactured using Direct Metal Laser Sintering (DMLS) to assess predictability. The outcome of this research shows an anatomical stiffness matched design that maybe suitable for SBD repair of a tibial segment that can be manufactured using DMLS. The developed implant exhibits Young's Modulus (E) of 12.03, 11.94 and 14.58 GPa using Maxwell's criterion, FEA and experimental (highest) methodologies respectively. This is slightly lower than the segmented bone that exhibited 18.01 GPa (ETibia) to allow for stiffness matching following a period of osseointegration depending on ‘critical size’. Furthermore, the surface roughness of the implant was found to be favourable for osteoblasts attachment.
  • Building information modelling in the framework of knowledge management

    Suresh, Subashini; Renukappa, Suresh; Kamunda, Andrew (ICISDM2019 Conference Proceedings, 2019-04-06)
    The UK private water industry has seen a lot of growth in expenditure since privatisation. Ofwat, Defra and DWI have set targets for the water companies to be customer focused, reducing bills, be innovative as well as encourage competition. The emergence of Building Information Modelling (BIM) has offered opportunities to the water industry to achieve cost and programme efficiencies as the rest of the construction industry. This, together with emerging information technology has allowed organisations to take steps in collaborative working, making information available at the right time to the right people, which is fundamental to Knowledge Management (KM). There is limited research in the subject of BIM being used in the context of and tool for KM within the UK water industry. Hence the aim of the study is to explore and understand how the UK water industry is using BIM for KM. A qualitative case study was used for the collection and analysis of data with the results obtained through review of water company supply chain processes, documents, observations and semi structured interviews. The key finding from the study is the significant impact of organisational culture influence on the implementation of BIM & KM in which the water industry supply chain has been aligning its business goals, identifying needed knowledge, creating KM resources and sharing knowledge through BIM as one of KM resources or tools. In conclusion, research identifies that the water industry is heading in the right direction, with leadership and management at the forefront of instilling a positive KM culture, though it is still developing. Ongoing training and provision of resources for KM should continue to be invested in to yield cost, programme, quality and knowledge capture benefits. The close definitions for Information and Knowledge should be taken advantage of for development and implementing of KM strategies using BIM as one of its key tool or resource.
  • Acoustic absorption of passive destructive interference cavities

    Arjunan, Arun (Elsevier, 2018-12-20)
    Acoustic products are primarily designed for broadband acoustic absorption. However, frequency-dependent acoustic absorption featuring passive design-based solutions are necessary to combat the growing noise pollution. Accordingly, this research investigates the targeted creation of sound absorption as a function of geometry utilising the principle of Acoustic Interference (AI). A methodology to design freeform geometries that can create targeted acoustic absorption is presented. The effectiveness of this methodology is then experimentally validated while quantifying the influence of length, diameter and geometry orientation. The results establish that AI has the potential to create ‘near perfect’ sound absorption that can be customised depending on the source frequency. The design freedom revealed by this study allows the exploitation of freeform geometries as passive high-efficiency sound absorbing devices.
  • Why does the UK need a Human Taphonomy Facility?

    Williams, Anna; Rogers, Christopher James; Cassella, John (Elsevier, 2019-01-21)
    Human Taphonomy Facilities (HTFs) are outdoor laboratories where scientific research is carried out on donated human cadavers in order to understand how human decomposition progresses in a variety of conditions. There are currently eight such facilities in the USA, one in Australia and one on mainland Europe. Forensic scientists in the UK have started to ask the question ‘Does the UK need a Human Taphonomy Facility?’. A review of the literature produced by the existing HTFs, as well as published opinion and commentaries about these facilities and the feasibility of one in the UK has been undertaken. The existing arguments for and against the establishment of a Human Taphonomy Facility in the UK have been examined. Given recent media interest in the possibility of the establishment of a Human Taphonomy Facility in the UK, and the surrounding controversy, it is important to evaluate the potential benefit or harm of the creation of such a facility to Society and the scientific community.
  • New chemical engineering provision: Quality in diversity

    Tizaoui, Chedly; Campbell, Grant; Belton, Daniel; Triñanes, Pablo Garcia; Cox, Phil; Brown, David (Elsevier, 2019-03-05)
    Recent growth in chemical engineering student numbers has driven an increase in the number of UK universities offering the subject. The implications of this growth are described, along with the different challenges facing new providers in the UK compared with established departments. The approaches taken by the various new entrants are reviewed, with reference to recruitment strategies, infrastructure, the use of external facilities, and the particular flavours of chemical engineering being offered by the new providers. Information about the differentiating features of the large number of chemical engineering degree courses now available is somewhat indistinct: this should be rectified in the interests both of prospective students and of employers. Dilemmas facing new providers include the need to address the fundamentals of the subject as well as moving into more novel research-led areas; enabling students to develop the competencies to sustain them for a whole career as well as meeting immediate employer needs; and providing sufficient industry understanding when academics may lack substantial industrial experience. The central importance of practical provision and of the design project, and the approaches taken by new providers to deliver these components, are reviewed, together with the role of software tools in chemical engineering education, and measures to facilitate industry input into courses. As long as it is not used prescriptively or to inhibit innovation, the accreditation process provides constructive guidance and leverage for universities developing new chemical engineering programmes.
  • The cytotoxicity and synergistic potential of aspirin and aspirin analogues towards oesophageal and colorectal cancer

    Kilari, R.S.; Bashir, A.I.J.; Devitt, A.; Perry, C.J.; Safrany, C.J.; Nicholl, Iain D. (Bentham, 2018-11-12)
    BACKGROUND: Oesophageal cancer (OC) is a deadly cancer because of its aggressive nature with survival rates that have barely improved in decades. Epidemiologic studies have shown that low-dose daily intake of aspirin can decrease the incidence of OC. METHODS: The toxicity of aspirin and aspirin derivatives to OC and a colorectal cancer (CRC) cell line were investigated in the presence and absence of platins. RESULTS: The data in this study show the effects of a number of aspirin analogues and aspirin on OC cell lines that originally presented as squamous cell carcinoma (SSC) and adenocarcinoma (ADC). The aspirin analogues fumaryldiaspirin (PN517) and the benzoylsalicylates (PN524, PN528 and PN529), were observed to be more toxic against the OC cell lines than aspirin. Both quantitative and qualitative apoptosis experiments reveal that these compounds largely induce apoptosis, although some necrosis was evident with PN528 and PN529. Failure to recover following the treatment with these analogues emphasized that these drugs are largely cytotoxic in nature. The OE21 (SSC) and OE33 (ADC) cell lines were more sensitive to the aspirin analogues compared to the Flo-1 cell line (ADC). A non-cancerous oesophageal primary cells NOK2101, was used to determine the specificity of the aspirin analogues and cytotoxicity assays revealed that analogues PN528 and PN529 were selectively toxic to cancer cell lines, whereas PN508, PN517 and PN524 also induced cell death in NOK2101. In combination index testing synergistic interactions of the most promising compounds, including aspirin, with cisplatin, oxaliplatin and carboplatin against the OE33 cell line and the SW480 CRC cell line were investigated. Compounds PN517 and PN524, and to a lesser extent PN528, synergised with cisplatin against OE33 cells. Cisplatin and oxaliplatin synergised with aspirin and PN517 when tested against the SW480 cell line. CONCLUSION: These findings indicate the potential and limitations of aspirin and aspirin analogues as chemotherapeutic agents against OC and CRC when combined with platins.
  • Arabic text classification methods: Systematic literature review of primary studies

    Alabbas, Waleed; al-Khateeb, Haider M.; Mansour, Ali (IEEE, 2017-01-05)
    Recent research on Big Data proposed and evaluated a number of advanced techniques to gain meaningful information from the complex and large volume of data available on the World Wide Web. To achieve accurate text analysis, a process is usually initiated with a Text Classification (TC) method. Reviewing the very recent literature in this area shows that most studies are focused on English (and other scripts) while attempts on classifying Arabic texts remain relatively very limited. Hence, we intend to contribute the first Systematic Literature Review (SLR) utilizing a search protocol strictly to summarize key characteristics of the different TC techniques and methods used to classify Arabic text, this work also aims to identify and share a scientific evidence of the gap in current literature to help suggesting areas for further research. Our SLR explicitly investigates empirical evidence as a decision factor to include studies, then conclude which classifier produced more accurate results. Further, our findings identify the lack of standardized corpuses for Arabic text; authors compile their own, and most of the work is focused on Modern Arabic with very little done on Colloquial Arabic despite its wide use in Social Media Networks such as Twitter. In total, 1464 papers were surveyed from which 48 primary studies were included and analyzed.
  • Classification of colloquial Arabic tweets in real-time to detect high-risk floods

    Alabbas, Waleed; al-Khateeb, Haider M.; Mansour, Ali; Epiphaniou, Gregory; Frommholz, Ingo (IEEE, 2017-10-09)
    Twitter has eased real-time information flow for decision makers, it is also one of the key enablers for Open-source Intelligence (OSINT). Tweets mining has recently been used in the context of incident response to estimate the location and damage caused by hurricanes and earthquakes. We aim to research the detection of a specific type of high-risk natural disasters frequently occurring and causing casualties in the Arabian Peninsula, namely `floods'. Researching how we could achieve accurate classification suitable for short informal (colloquial) Arabic text (usually used on Twitter), which is highly inconsistent and received very little attention in this field. First, we provide a thorough technical demonstration consisting of the following stages: data collection (Twitter REST API), labelling, text pre-processing, data division and representation, and training models. This has been deployed using `R' in our experiment. We then evaluate classifiers' performance via four experiments conducted to measure the impact of different stemming techniques on the following classifiers SVM, J48, C5.0, NNET, NB and k-NN. The dataset used consisted of 1434 tweets in total. Our findings show that Support Vector Machine (SVM) was prominent in terms of accuracy (F1=0.933). Furthermore, applying McNemar's test shows that using SVM without stemming on Colloquial Arabic is significantly better than using stemming techniques.
  • On Textual Analysis and Machine Learning for Cyberstalking Detection

    Frommholz, Ingo; al-Khateeb, Haider M.; Potthast, Martin; Ghasem, Zinnar; Shukla, Mitul; Short, Emma (Springer, 2016-06-01)
    Cyber security has become a major concern for users and businesses alike. Cyberstalking and harassment have been identified as a growing anti-social problem. Besides detecting cyberstalking and harassment, there is the need to gather digital evidence, often by the victim. To this end, we provide an overview of and discuss relevant technological means, in particular coming from text analytics as well as machine learning, that are capable to address the above challenges. We present a framework for the detection of text-based cyberstalking and the role and challenges of some core techniques such as author identification, text classification and personalisation. We then discuss PAN, a network and evaluation initiative that focusses on digital text forensics, in particular author identification.
  • Postural instability in an immersive Virtual Reality adapts with repetition and includes directional and gender specific effects

    Frannson, Per-Anders; Patel, Mitesh; Jensen, Hanna; Lundberg, Michèle; Tjernström, Fredrik; Magnusson, Måns; Hansson, Eva Ekvall (Nature Publishing Group, 2019-02-28)
    The ability to handle sensory conflicts and use the most appropriate sensory information is vital for successful recovery of human postural control after injury. The objective was to determine if virtual reality (VR) could provide a vehicle for sensory training, and determine the temporal and spatial nature of such adaptive changes. Twenty healthy subjects participated in the study (10 females). The subjects watched a 90-second VR simulation of railroad (rollercoaster) motion in mountainous terrain during five repeated simulations, while standing on a force platform that recorded their stability. The immediate response to watching the VR movie was an increased level of postural instability. Repeatedly watching the same VR movie significantly reduced both the anteroposterior (62%, p < 0.001) and lateral (47%, p = 0.001) energy used. However, females adapted more slowly to the VR stimuli as reflected by higher use of total (p = 0.007), low frequency (p = 0.027) and high frequency (p = 0.026) energy. Healthy subjects can significantly adapt to a multidirectional, provocative, visual environment after 4–5 repeated sessions of VR. Consequently, VR technology might be an effective tool for rehabilitation involving visual desensitisation. However, some females may require more training sessions to achieve effects with VR.
  • Fecal concentrations of cortisol, testosterone, and progesterone in cotton-top tamarins hosted in different zoological parks: Relationship among physiological data, environmental conditions and behavioral patterns

    Fontani, Sara; Vaglio, Stefano; Beghelli, Valentina; Mattioli, Michela; Bacci, Silvia; Accorsi, Pier Attilio (Taylor and Francis, 2014-05-14)
    The aim of this investigation was to study the welfare of 3 captive groups of cotton-top tamarins housed in different zoological parks. Ethological observations were conducted during 1 year. In addition, fecal samples were collected and the concentrations of glucocorticoids, androgens, and progestogens were measured. Within each group, no significant differences in fecal cortisol concentrations were found between subjects. The fecal concentrations of testosterone and progesterone significantly differed depending on the sexes and ages of the tamarins. A significant association was found among hormone concentrations, exhibit dimensions, and group composition. A highly significant correlation was found between all hormones considered and the space available for each subject. Significant differences in behavioral patterns were observed among groups, including social–individual, affiliative–aggressive, and anogenital–suprapubic scent marking. Correlations between hormone measurements and behaviors were detected. In conclusion, this study confirmed the associations between some behaviors exhibited by these nonhuman primates and both cortisol and testosterone; these data also highlight the role played by progesterone in these behaviors.
  • Effective methods to detect metamorphic malware: A systematic review

    Irshad, Mustafa; Al Khateeb, Haider M.; Mansour, Ali; Ashawa, Moses; Hamisu, Muhammad (Inderscience, 2018-03-28)
    The succeeding code for metamorphic Malware is routinely rewritten to remain stealthy and undetected within infected environments. This characteristic is maintained by means of encryption and decryption methods, obfuscation through garbage code insertion, code transformation and registry modification which makes detection very challenging. The main objective of this study is to contribute an evidence-based narrative demonstrating the effectiveness of recent proposals. Sixteen primary studies were included in this analysis based on a pre-defined protocol. The majority of the reviewed detection methods used Opcode, Control Flow Graph (CFG) and API Call Graph. Key challenges facing the detection of metamorphic malware include code obfuscation, lack of dynamic capabilities to analyse code and application difficulty. Methods were further analysed on the basis of their approach, limitation, empirical evidence and key parameters such as dataset, Detection Rate (DR) and False Positive Rate (FPR).
  • Prospects and challenges of concentrated solar photovoltaics and enhanced geothermal energy technologies

    Wilberforce, Tabbi; Baroutaji, Ahmad; El-Hassan, Zaki; Thompson, James M.; Soudan, Bassel; Ghani Olabi, Abdul (Elsevier, 2018-12-19)
    Reducing the total emissions of energy generation systems is a pragmatic approach for limiting the environmental pollution and associated climate change problems. Socio economic activities in the 21st century is highly determined by the energy generation mediums, particularly the renewable resources, across the world. Therefore, a thorough investigation into the technologies used in harnessing these energy generation mediums should contribute to their further advancement. Concentrated Solar Photovoltaics (CSP) and Enhanced Geothermal Energy (EGE) are considered as emerging renewable energy technologies with high potential to be used as suitable replacements for fossil products (petroleum, coal, natural gas etc.). Despite the accelerated developments in these technologies, they are still facing many challenges in terms of cost. This review paper presents a detailed background about these renewable energy technologies and their main types such as solar tower, parabolic trough, and so on. Also, the principle challenges impeding the advancement of these energy technologies into commercialisation are discussed. Possible solutions for the main challenges are presented and the future prospects for such energy generation mediums are reported.
  • Time constraints imposed by anthropogenic environments alter social behaviour in long-tailed macaques

    Marty, Pascal R.; Beisner, Brianne; Kaburu, Stefano S. K.; Balasubramaniam, Krishna N.; Bliss‐Moreau, Eliza; Ruppert, Nadine; Sah, Shahrul Anuar Mohd; Ismail, Ahmad; Arlet, Małgorzata E.; Atwill, Edward R.; McCowan, Brenda (Elsevier, 2019-03-12)
    Humans and their associated anthropogenic factors may strongly affect the demographics, activity, and fragmentation of wild animal populations. Yet, the degree and nature of such impact on indicators of animals’ social relationships remain largely under-investigated, despite the well-documented importance of strong social ties for an individuals’ health and fitness. Here, we examined whether interactions with humans may affect core aspects of social life in a primate species, by constraining the time available for individuals to engage in social interactions. Specifically, we predicted that individuals who spent more time monitoring or interacting with humans reduce their time socializing with conspecifics (i.e., the time constraints hypothesis). Alternatively, human presence may result in increased levels of stress, leading to an increase in social behaviours which serve as a coping mechanism (i.e., the social stress hypothesis). We collected data between September 2016 and September 2017 on four groups of long-tailed macaques in Malaysia at two sites with differing levels of human impact. In support of the time constraints hypothesis, we found that at the site with moderate human impact, monkeys who monitored human activity more frequently engaged less often in grooming. In contrast, at the site with high human impact, we found evidence supporting the social stress hypothesis, as indicators of stress were positively associated with social interactions, although we could not link them to the presence of humans. Our results suggest that the nature of human impact on macaques’ social behaviour is dependent upon the intensity of human activity and interaction with the macaques. These findings therefore provide insights into how humans may influence individual fitness and group social structure in animals living in an anthropogenic environment. More broadly, our results may lead to a better understanding of animal behaviour in anthropogenic environments, implementing conservation and population management strategies, and mitigating human-wildlife conflict.
  • Neonatal imitation predicts infant rhesus macaque (Macaca mulatta) social and anxiety-related behaviours at one year

    Kaburu, Stefano S.K.; Paukner, Annika; Simpson, Elizabeth A.; Suomi, Stephen J.; Ferrari, Pier F. (Nature, 2016-10-11)
    The identification of early markers that predict the development of specific social trajectories is critical to understand the developmental and neurobiological underpinnings of healthy social development. We investigated, in infant rhesus macaques (Macaca mulatta), whether newborns’ capacity to imitate facial gestures is a valid predictive marker for the emergence of social competencies later in development, at one year of age. Here we first assessed whether infant macaques (N = 126) imitate lipsmacking gestures (a macaque affiliative expression) performed by a human experimenter in their first week of life. We then collected data on infants’ social interactions (aggression, grooming, and play) and self-scratching (a proxy indicator of anxiety) at 11–14 months when infants were transferred into a new enclosure with a large social group. Our results show that neonatal imitators exhibit more dominant behaviours, are less anxious, and, for males only, spend more time in play at one year old. These findings suggest that neonatal imitation may be an early predictor of infant sociality and may help identify infants at risk of neurodevelopmental social deficits.

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