Recent Submissions

  • Validation of electrokinetic stabilisation of M5 Junction 7

    Alder, David; Lamont-Black, J; Hamza, Omar; Jackson, C; Jones, C; University of Derby; Electrokinetic; Jacobs; Newcastle University (ICE, 2019-01-07)
    Electrokinetic method has been increasingly applied to repair infrastructure earthwork involving landslip. The work presented in this paper attempts to improve the current understanding of this innovative technique by verifying the effectiveness of Electrokinetic treatment using in-situ and laboratory testing in addition to monitoring data obtained from the first full scale project implementing this technique, which has been carried out recently for a defected embankment slope on M5- Junction 7 in the UK. The paper outlines the design and implementation aspects of the project and discusses the findings of the post construction verification.
  • Educational advantage and employability of UK university graduates

    Pigden, Louise; Moore, Garford; University of Derby (Emerald, 2019-02-20)
    In the UK, the majority of university students specialise and study just one subject at bachelor degree level, commonly known in the UK as a single honours degree. However, nearly all British universities will permit students if they wish to study two or even three subjects, so-called joint or combined honours degrees, internationally known as a double major. The purpose of this paper is to explore whether educational advantage, measured by the “Participation of Local Areas” (POLAR) classification, correlated with rates of graduate destinations for joint and single honours graduates. This study focused particularly on Russell Group and Post-92 Universities. The authors analysed the complete data set provided from the Higher Education Statistics Agency Destination of Leavers from the Higher Education survey, and combined this with data from the POLAR4 quintiles, which aggregate geographical regions across the UK based on the proportion of its young people that participate in higher education. The data were analysed to establish whether there was a difference in the highly skilled graduate employability of the joint honours students, focusing particularly on Russell Group and Post-92 Universities, in order to build on previous published work. Single honours and joint honours graduates from higher participation POLAR4 quintiles were more likely to be in a highly skilled destination. However at both the Russell Group and the Post-92 universities, respectively, there was no trend towards a smaller highly skilled destinations gap between the honours types for the higher quintiles. For the highest POLAR4 quintile, the proportion of joint honours graduates was substantially higher at the Russell Group than at Post-92 universities. Furthermore, in any quintile, there were proportionately more joint honours graduates from the Russell Group, compared with single honours graduates, and increasingly so the higher the quintile. This study focused on joint honours degrees in the UK where the two or three principal subjects fall into different Joint Academic Coding System (JACS) subject areas, i.e. the two or three subjects are necessarily diverse rather than academically cognate. This excluded the class of joint honours degrees where the principal subjects lie within the same JACS subject area, i.e. they may be closer academically, although still taught by different academic teams. However, the overall proportion of joint honours graduates identified using the classification was in line with the UCAS (2017) data on national rates of combined studies acceptances. All Russell Group graduates, irrespective of their POLAR4 quintile, were far more likely to be in a highly skilled destination than single or joint honours graduates of Post-92 universities. Even the lowest quintile graduates of the Russell Group had greater rates of highly skilled destination than the highest quintile from Post-92 universities, for both single and joint honours graduates. This demonstrated the positive impact that graduating from the Russell Group confers on both single and joint honours graduates. This study could not explain the much smaller gap in the highly skilled destinations between single honours and joint honours graduates found in the Russell Group, compared with the Post-92. Why do a higher proportion of joint honours graduates hail form the upper POLAR4 quintiles, the Russell Group joint honours graduates were more disproportionately from the upper POLAR4 quintiles and the joint honours upper POLAR4 quintiles represented such a larger proportion of the Russell Group overall undergraduate population? Other student characteristics such as tariff on entry, subjects studied, gender, age and ethnicity might all contribute to this finding. This study demonstrated that, averaged across all universities in the UK, there was a trend for both single honours and joint honours graduates from higher participation POLAR4 quintiles to be more likely to be in a highly skilled destination, i.e. the more educationally advantaged, were more likely to be in a highly skilled destination, as a proportion of the total from each honours type. This accorded with HESA (2018b) data, but expanded those findings to include direct consideration of joint honours graduates.
  • A shape grammar approach to climatically adaptable facade systems with real time performance evaluation.

    TUNG NGUYEN, BORIS CERANIC, CHRISTOPHER CALLAGHAN; University of Derby (WIT Press, 2019-01-01)
    New computational techniques have been introduced to assist the design of adaptable building facades and to help quantify relationships between the building envelope and the environment. Designers increasingly use generative design approach for form-generation of building envelopes, and the organisation of components over a predefined form. In this research an original shape grammar approach for façade systems generation is proposed, with a rule-based method for the creation and exploration of complex shape composites based upon a set of simple initial shapes and predefined rules of composition. This is in order to explore a form finding of set of different building façade configurations before merging generated data into a simulated process of real-time daylighting and heat gains performance evaluation. The developed models adapt via responding to the data-regulation protocols responsible for sensing and processing building performance data in real time. The research reports on the prototype system development and testing, allowing continuous evaluation of multiple solutions and presenting opportunity for further improvement via multi-objective optimisation, which would be very difficult to do, if not impossible, with conventional design methods
  • Innovative approach to sustainable material sourcing and its impact on building performance

    Rajpurohit J.S., Ceranic B., Latham D.; University of Derby (WIT Press, 2019-01-29)
    In this paper, a novel use of building materials and their impact on the building performance and its climatic adaptability is explored, based on a complex case study of a unique low energy sustainable building project. In particular, an innovative use of sycamore and its suitability as a structural and constructional timber has been investigated and reported, given that the current codes of practice deem that is not appropriate for structural applications due to its durability. A research method of in-situ longitudinal study has been adopted, concentrating on the monitoring and assessment of its structural performance and conditions in which it might deteriorate. On the component level, the research reports on the methods and standards of sycamore grading and classification, service classes, resistance to decay, impact of the moisture movement and results of its laboratory and in situ testing. On the system level, the climatic adaptability of the building as a whole has been analysed via dynamic performance simulation and compared to the in-situ measurements. This was important in order to develop a holistic building performance monitoring strategy, but in particular, to understand the impact of building microclimate on the sycamore frame and hempcrete components of the external load-bearing wall. So far research has concluded that sycamore can be used as structural and constructional material in building design, but due attention has to be paid to construction detailing and provision of a breathable, low humidity environment with an effective resistance to decay and insect attack. This includes measures that ensure a low equilibrium moisture content conditions, effective ventilation provision and appropriate service class uses. It is important to state however, given the single site locality of sycamore sourcing, that results can only be interpreted in the context of the given case study, i.e. they cannot be extrapolated to broader geographical extents.
  • Framework for a chemical substance reporting system.

    Takhar, Sukhraj Singh; Liyanage, Kapila; University of Derby (2018-10-25)
    In this paper a chemical substance reporting system is presented to enable industry to assess the impacts of increasing chemical regulations. Chemical regulations impose the need to monitor, control and restrict the use of hazardous substances. As chemical substances become more regulated, industry requires mechanisms to identify potential business continuity risks, posed by increased regulation. A chemical reporting system is one such mechanism that identifies chemical substances used on their (i) own, (ii) in mixtures, (iii) in materials, (iv) in internally defined articles (products) and (v) from articles (products) procured from the supply chain. The chemical reporting system will contrast product related information against chemical regulation substance lists, identifying the applicable reporting obligations and potential supply chain risks.
  • Identification of the mechanical properties of tires for wheelchair simulation.

    Doria, Alberto; Taraborrelli,Luca; Jomaa, Tarek; Peijs, Tom; Potter, Mario; Advani, Sunjoo; Crichlow,Larry; University of Padova; International Development of Technology B.V.; Toronto Rehabilitation Institute (Bentham Open, 2016-12-30)
    The development of high performance wheelchairs and wheelchair simulators requires dynamic models taking into account the properties of tires. In this paper the properties of two wheelchair tires are measured by means of a rotating disc testing machine and are compared with the properties of bicycle tires, which have similar dimensions and structure. Tests are carried out considering variations in speed, inflation pressure and load. The possibility of fitting experimental results with the Magic Formula, the Dugoff formula and a linear model is discussed. A dynamic model of a wheelchair is developed, which includes a linear tire model derived from experimental results. Steady turning and slalom manoeuvres are simulated. Numerical results show the effect of tire properties on the handling characteristics of the wheelchair.
  • A novel one variable first-order shear deformation theory for biaxial buckling of a size-dependent plate based on the Eringen's nonlocal differential law.

    Malikan, Mohammad; Nguyen, Van Bac; Islamic Azad University; University of Derby; Islamic Azad University Mashhad Branch Mashhad Iran (the Islamic Republic of); University of Derby Derbyshire United Kingdom of Great Britain and Northern Ireland (Emerald Group Publishing Limited, 2018-10-04)
    Purpose – This paper aims to present a new one-variable first-order shear deformation theory (OVFSDT) using nonlocal elasticity concepts for buckling of graphene sheets. Design/methodology/approach – The FSDT had errors in its assumptions owing to the assumption of constant shear stress distribution along the thickness of the plate, even though by using the shear correction factor (SCF), it has been slightly corrected, the errors have been remained owing to the fact that the exact value of SCF has not already been accurately identified. By using two-variable first-order shear deformation theories, these errors decreased further by removing the SCF. To consider nanoscale effects on the plate, Eringen’s nonlocal elasticity theory was adopted. The critical buckling loads were computed by Navier’s approach. The obtained numerical resultswere then compared with previous studies’ results using molecular dynamics simulations and other plate theories for validation which also showed the accuracy and simplicity of the proposed theory. Findings – In comparing the biaxial buckling results of the proposed theory with the two-variable shear deformation theories and exact results, it revealed that the two-variable plate theories were not appropriate for the investigation of a symmetrical analyses. Originality/value – A formulation for FSDT was innovated by reconsidering its errors to improve the FSDT for investigation of mechanical behavior of nanoplates.
  • Numerical simulations of wake characteristics of a horizontal axis tidal stream turbine using actuator line model.

    Baba-Ahmadi, Mohammad H.; Dong, Ping; University of Dundee; University of Liverpool (Elsevier, 2017-06-10)
    The wake of a laboratory scale tidal stream turbine in a shallow water channel with a turbulent inflow is simulated using the hybrid LES/ALM technique, which combines large eddy simulation with the actuator line method. The turbulent inlet conditions are generated using the mapping method to avoid a precursor running and large space for saving data. The numerical results demonstrated the usefulness of the mapping technique as well as some shortcomings that still remain to be addressed. Good agreement between numerical predictions and experimental data is achieved for both the mean and turbulent characteristics of the flow behind the turbine. The examination of changes in turbulence intensity and turbulent kinetic energy in the streamwise direction confirms the existence of a peak and transition to a highly turbulent flow about three diameters downstream of the turbine, which means that the distinct characteristics of the streamwise changes of turbulence intensity or turbulent kinetic energy may serve as an effective indicator for the flow regime transition and wake behaviour.
  • Validation of the actuator line method for simulating flow through a horizontal axis tidal stream turbine by comparison with measurements

    Baba-Ahmadi, Mohammad H.; Dong, Ping; University of Dundee; University of Liverpool (Elsevier, 2017-05-20)
    The purpose of the present work is to evaluate the capability of the Actuator Line Method (ALM) to simulate flow through a horizontal axis tidal stream turbine. A numerical model combining the ALM with large eddy simulation technique is developed and applied to compute the flow past a laboratory-scale tidal stream turbine. The flow field is analysed in terms of streamwise mean velocity, turbulence intensity, turbulent kinetic energy and the decay rate of the maximum turbulent kinetic energy behind the turbine. It is found that the ALM performs well in predicting the mean flow and turbulence characteristics behind the turbine. The flow field predicted show a clear transition from an organised vorticity region near the turbine to a highly turbulent flow downstream. The location of this transition and the controlling parameters are discussed but further investigation, both numerical and experimental is required in order to clarify its effects on the flow structure and the performance of downstream turbines in tidal turbine arrays.
  • The effect of the inflation pressure of tyres on motorcycle weave stability: experiments and simulation.

    Cossalter, Vittore; Favaron, Valerio; Giolo, Enrico; Jomaa, Tarek; University of Padova (Taylor & Francis, 2016-08-03)
    Increasing the stability of a motorcycle requires an understanding of the optimal conditions of the tyre. The inflation pressure is one of the main parameters that directly affects the tyre properties, which in turn influences motorcycle stability and safety. This paper focuses on the effect of the inflation pressure of the tested tyres on motorcycle weave stability. Experimental data are collected from tests carried out in straight running at constant speed. The data analysis is based on stochastic subspace identification methods. Simulations are performed using an advanced motorcycle multi-body code with parameters measured from the tested vehicle. Finally, the comparison between simulations and experimental tests is discussed. The research results show an agreement between experimental tests and simulations where weave stability increases with inflation pressure for the specified range of tyre pressure.
  • ISO 9001 and supply chain integration principles based sustainable development: a Delphi study.

    Bastas, Ali; Liyanage, Kapila; University of Derby (MDPI, 2018-12-03)
    Driven by the increasing stakeholder and societal pressures, organizations and supply chains face the multi-dimensional challenges of not only integrating economic, environmental and social agendas into their management systems but also driving continual sustainability performance improvement. Aiming to support organizations in this sustainable development challenge, this paper explores the strategic management principles of ISO 9001 and supply chain integration from the lens of triple bottom line sustainability. Derived from theoretical synergies, a conceptual framework for integration, measurement, and improvement of triple bottom line sustainability is constructed and a business diagnostic tool introduced to facilitate the implementation of the framework. The developed conceptual framework and diagnostic tool are verified through an expert panel-based Delphi study and positive relationships formulated between the management principles of ISO 9001, supply chain integration and sustainability management. The facilitating and catalyzing role of quality management and supply chain management principles for integration and improvement of organizational sustainability is outlined.
  • On secondary instability of a transitional separation bubble.

    Yang, Zhiyin; Abdalla, Ibrahim E.; University of Derby; Jubail University College (Elsevier, 2018-12-01)
    It is well established in the natural transition of an attached boundary layer that the transition process starts with a two–dimensional primary instability (Tollmien–Schlichting wave, denoted as TS wave), followed by usually a three-dimensional secondary instability (fundamental mode or subharmonic mode) leading to the breakdown to turbulence. However, the transition process of a separation bubble (laminar flow or laminar boundary layer at separation and transition occurs downstream of the separation, leading to turbulence at reattachment) is less well understood, especially on the nature of secondary instability. The focus of this paper is on trying to advance our understanding of secondary instability of a transitional separation bubble on a flat plate with a blunt leading edge (separation is induced geometrically at the leading edge) under a very low free-stream turbulence level (< 0.1%). Large-Eddy Simulation (LES) is employed in the current study with a dynamic sub-grid-scale model. The numerical flow visualisation together with the spectral analysis has indicated that a three dimensional secondary instability, the elliptical instability, which occurs for fundamental frequency is the main mechanism at work whereas the subharmonic mode in the form of vortex-pairing is hardly active. There is no evidence for the existence of hyperbolic instability in the braid region either.
  • A plate model for compressive strength prediction of delaminated composites

    Choudhry, Rizwan Saeed; Rhead, Andrew T.; Nielsen, Mark W.D.; Butler, Richard; University of Derby; University of Bath (Elsevier, 2018-11-24)
    Damage tolerance is of critical importance to laminated composite structures. In this paper, we present a new semi-analytical method for predicting the strain at which delamination propagation will initiate following sublaminate buckling. The method uses a numerical strip model to determine the thin-film buckling strain of an anisotropic sub-laminate created by delamination, before evaluating the strain energy release rate for delamination propagation. The formulation assumes that all energy is available for propagation in a peeling mode (Mode I); avoiding an approximate mixed-mode criterion. Results are compared with twelve experimentally obtained propagations strains, covering a variety of laminates each containing a circular PTFE delamination. Comparison shows agreement to within 12% for balanced sublaminate tests in which delamination propagation occurred before intra-ply cracking. The method can be used to significantly improve the damage tolerance of laminates, opening up new opportunities for structural efficiency using elastic tailoring, non-standard ply angles and material optimisation.
  • Influence of upstream turbulence on the wake characteristics of a tidal stream turbine.

    Ahmadi, Mohammad H.B.; University of Derby (Elsevier, 2018-08-20)
    The influence of the upstream turbulence intensity on the flow characteristics downstream of a laboratory-scale horizontal axis tidal stream turbine is investigated in this study. Three test cases with the same mean velocity and different turbulence intensities are simulated numerically using the hybrid large eddy simulation/actuator line modelling technique. The mean velocity components, mean turbulent fluctuations, velocity deficit and wake extension are compared along the streamwise direction to examine the upstream turbulence effects. The inflow conditions are generated by the mapping method using the mean velocity and turbulent profiles experimentally obtained for a turbulent open channel flow. Comparing results for the mean velocity and turbulent fluctuations shows that the upstream turbulence level strongly affects the flow characteristics downstream of the turbine by influencing the tip vortices breakdown process and in turn wake recovery. The comparison also reveals that the ambient turbulence level strongly influences the velocity deficit but it does not significantly affect the streamwise velocity and the radial location of tip vortices in the flow.
  • Sustainable infrastructure delivery in Nigeria: implementation of the analytic network process for contractor selection.

    Arowosafe, Oluwunmi; Oduyemi, Olufolahan; Ceranic, Boris; Dean, Angela; University of Derby; Southeast Missouri State University (EDP Sciences, 2018-10-31)
    This paper presents research findings that involve the use of Analytic Network Process (ANP) to select contractors for Build-Operate-Transfer (BOT) infrastructure in Nigeria. To deliver sustainable infrastructure, a responsive methodology is required during selection process to combine judgement and data to effectively predict outcomes.
  • Secondary instability of separated shear layers.

    Yang, Zhiyin; University of Derby (Elsevier, 2018-11-13)
    The process through which a laminar flow undergoes transition to turbulence is of great fundamental and practical interest. Such a process is hugely complex as there are many diverse routes for a laminar flow to become turbulent flow. The transition process is usually initiated by flow instabilities - a primary instability stage followed by a secondary instability stage. This forms a rational framework for the early stage of a transition process and it is crucially important to understand the physics of instabilities leading to turbulence. This article reviews the results of studies on secondary instability of separated shear layers in separation bubbles and summaries the current status of our understanding in this area.
  • A review of critical framework assessment matrices for data analysis on overheating in buildings impact.

    Adlington, M.; Ceranic, Boris; University of Derby (World Academy of Science, Engineering and Technology, 2017-11)
    In an effort to reduce carbon emissions, changes in UK regulations, such as Part L Conservation of heat and power, dictates improved thermal insulation and enhanced air tightness. These changes were a direct response to the UK Government being fully committed to achieving its carbon targets under the Climate Change Act 2008. The goal is to reduce emissions by at least 80% by 2050. Factors such as climate change are likely to exacerbate the problem of overheating, as this phenomenon expects to increase the frequency of extreme heat events exemplified by stagnant air masses and successive high minimum overnight temperatures. However, climate change is not the only concern relevant to overheating, as research signifies, location, design, and occupation; construction type and layout can also play a part. Because of this growing problem, research shows the possibility of health effects on occupants of buildings could be an issue. Increases in temperature can perhaps have a direct impact on the human body’s ability to retain thermoregulation and therefore the effects of heat-related illnesses such as heat stroke, heat exhaustion, heat syncope and even death can be imminent. This review paper presents a comprehensive evaluation of the current literature on the causes and health effects of overheating in buildings and has examined the differing applied assessment approaches used to measure the concept. Firstly, an overview of the topic was presented followed by an examination of overheating research work from the last decade. These papers form the body of the article and are grouped into a framework matrix summarizing the source material identifying the differing methods of analysis of overheating. Cross case evaluation has identified systematic relationships between different variables within the matrix. Key areas focused on include, building types and country, occupants behavior, health effects, simulation tools, computational methods.
  • Sustainable infrastructure delivery in Nigeria: implementation of the analytic network process for contractor selection.

    Arowosafe, Oluwunmi; Oduyemi, Olufolahan; Ceranic, Boris; Dean, Angela; University of Derby; Southeast Missouri State University (EDP Open Website, 2018-10-31)
    Purpose: This paper presents research findings that involve the use of analytic network process (ANP) to select contractors for build–operate–transfer (BOT) infrastructure in Nigeria. To deliver sustainable infrastructure (SI), a responsive methodology is required for contractors' selection process, which combines judgement and data for an effective outcomes prediction. Design/methodology/approach: Theoretically grounded on a system theory, sustainable infrastructure delivery (SID) model has been developed in this study. At the deductive phase of the model is the integration of the ANP (a multicriteria decision-making technique) for data synthesis. To obtain decision criteria, 55 sustainability indicators for contractor selection were identified from the literature review. The criteria were first developed to a web-based questionnaire where respondents were requested to rank the importance of the criteria towards selecting contractors that deliver SI, using Likert scale of 1–5 (where “5” is very important and “1” is not important). The results were analysed using factor analysis. Data were further reduced to 16 variables after multicollinearity issues in the data set had been resolved. To weigh the relative importance of the 16 criteria among contractors, ANP methodology was adopted for the second-round questionnaire. The seven-man decision panel that completed the pairwise comparison survey was selected through a purposeful sampling technique. The final survey results were synthesised by Super Decisions (computer package that implements ANP) trial version to rank contractors' options and predict outcomes. Findings/results: Sensitivity analysis of the research findings reveals that the 16 criteria have differential comparative advantages, which requires critical judgement during contractor's pre-evaluation process. Although the overall priorities rank multinational construction corporations (MCC) higher than local construction companies (LCC), MCC are not absolute to deliver SI. LCC are sensitive to some key criteria that are critical to the actualisation SI agenda. Originality/value: This study fills the gap in the knowledge of SID in Nigeria. The study theoretically suggests a framework to harmonise sustainability indicators in contractor selection. The findings further provide feedbacks that can be incorporated to Government's Ministries, Department and Agencies (MDAs) procurement policy to promote SID.
  • Forming low-cost, high quality carbon tows for automotive application.

    Sharif, Tahir; Potluri, P; Choudhry, R S; Dodworth, A; University of Derby; The University of Manchester; Bright Lite Structures (BLS), UK (IOP Publishing, 2018-09-21)
    Carbon fiber reinforced composites are widely used in many industries due to their high performance. Its application in the aerospace industry has increased significantly, however, in mass produced automobile sector it is still limited. The current production of carbon fiber tow is slow and capital intensive. Thus, carbon manufactures produce higher tow counts to increase production rate to reduce its cost. In order to offset the higher cost of carbon fiber composite, an innovative and unique approach has been developed. The higher tow count carbon spools are split into smaller tow counts. Due to the delicate nature of carbon fiber, it is important to control the filamentation during that process. Different splitting process line strategies have been developed in this research work for understanding the process limitations and challenges involved. The process was made feasible for production by developing a fully automated process line with a laser feedback system. The system splits a 12K spool into two 6K tows. The quality of the 6K split tows has been determined statistically by recording real time data from the laser during the splitting process. It was demonstrated that the proposed process effectively controls filamentation and produces consistent tow quality.
  • Predicting the effect of voids on mechanical properties of woven composites.

    Choudhry, R. S.; Sharif, Tahir; Khan, Kamran A.; Khan, Sohaib Z.; Hassan, Abid; Khan, Muhammad A.; University of Derby; Khalifa University of Science Technology and Research (KUSTAR), UAE; Islamic University of Madinah; Pakistan Petroleum Limited; Cranfield University (IOP Publishing, 2018-09-21)
    An accurate yet easy to use methodology for determining the effective mechanical properties of woven fabric reinforced composites is presented. The approach involves generating a representative unit cell geometry based on randomly selected 2D orthogonal slices from a 3D X-ray micro-tomographic scan. Thereafter, the finite element mesh is generated from this geometry. Analytical and statistical micromechanics equations are then used to calculate effective input material properties for the yarn and resin regions within the FE mesh. These analytical expressions account for the effect of resin volume fraction within the yarn (due to infiltration during curing) as well as the presence of voids within the composite. The unit cell model is then used to evaluate the effective properties of the composite.

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