Now showing items 1-20 of 2281

    • Tranquillity trails – design, implementation and benefits for healthy leisure

      Watts, Gregory R.; Bauer, J. (Taylor and Francis, 2021)
      Tranquillity trails (TTs) are designed to provide a quiet and peaceful walk through mainly leafy lanes and roads and connect green open spaces where visitors can stop for thought and relaxation. There are numerous health benefits from being in close proximity to nature and TTs can facilitate this contact in mainly urban areas. This study involved the design of a trail in Tramore, a coastal town in south east Ireland. The trail links an old coastguard station, now converted to a cultural centre and coffee shop, with a Japanese garden. The trail includes a coastal path with fine views across a bay, wooded areas as well as leafy residential streets. The design of the trail was facilitated by the use of a previous developed tranquillity rating prediction tool (TRAPT) that involved the estimation of the level of man-made noise and the percentage of natural features in view. Participants who had completed the whole of the trail were encouraged to complete a questionnaire to gauge any benefits. As expected, it was reported that there were increased levels of relaxation and reduced stress. It was concluded that the approach can be used elsewhere to improve the well-being of residents and visitors.
    • Bond behaviors between nano-engineered concrete and steel bars

      Wang, X.; Dong, S.; Ashour, Ashraf F.; Ding, S.; Han, B. (Elsevier, 2021-09)
      This paper investigated the bond characteristics between eight types of nanofillers modified reactive powder concrete (RPC) and plain steel bars, aiming to explore the modifying mechanisms and establish a bond-slip relationship model for nanofillers modified RPC and steel bar interface. The experimental results indicated that the incorporation of nanofillers can increase the bond strength and reduce the slip between RPC and plain steel bars. It was shown that a 2.15 MPa/20.5% of absolute/relative increase in cracking bond strength, a 1.25 MPa/10.3% of absolute/relative increase in ultimate bond strength, a 2.35 MPa/22.4% of absolute/relative increase in residual bond strength, a 0.592 mm/56.5% of absolute/relative reduction in ultimate bond slip, and a 1.779 mm/52.1% of absolute/relative reduction in residual bond slip were the best achieved due to the addition of various nanofillers. The enhancement of nanofillers on RPC-steel bar interface has been mainly attributed to RPC microstructure improvement, optimization of intrinsic compositions, and elimination of defects in the interface, especially the underside near steel bar, due to the nano-core effect of nanofillers enriched in the interface. In addition, the bond-slip relationship of nanofillers modified RPC-steel bar interface can be accurately described by the proposed model considering an initial branch.
    • Energy-harvesting concrete for smart and sustainable infrastructures

      Wang, X.; Dong, S.; Ashour, Ashraf F.; Han, B. (A Springer Nature Publication, 2021)
      Concrete with smart and functional properties (e.g., self-sensing, self-healing, and energy-harvesting) represents a transformative direction in the field of construction materials. Energy-harvesting concrete has the capability to store or convert the ambient energy (e.g., light, thermal, and mechanical energy) for feasible uses, alleviating global energy and pollution problems as well as reducing carbon footprint. The employment of energy-harvesting concrete can endow infrastructures (e.g., buildings, railways, and highways) with energy self-sufficiency, effectively promoting sustainable infrastructure development. This paper provides a systematic overview on the principles, fabrication, properties, and applications of energy-harvesting concrete (including light-emitting, thermal-storing, thermoelectric, pyroelectric, and piezoelectric concretes). The paper concludes with an outline of some future challenges and opportunities in the application of energy-harvesting concrete in sustainable infrastructures.
    • Flow analysis of melted urea in a perforated rotating bucket

      Muhammad, A.; Rahmanian, Nejat; Pendyala, R. (2013-10)
      A comprehensive study of the internal flow field for the prilling application in a perforated rotating bucket has been carried out. Computational Fluid Dynamics (CFD) is used to investigate the flow field of urea melt inside the perforated rotating bucket. The bucket is mounted at the top of the prilling tower. In prilling process, urea melt is sprayed by the perforated rotating bucket to produce the urea droplets, which falls down due to gravity. These drops fall down through a cooling medium and solidify into prills. The velocity field in the bucket is very important to study, as it has great effect on the heat and mass transfer performance in prilling process. ANSYS 14.0 CFD package is used to simulate and Design Modeler and Catia V5 are used for geometrical model of the perforated prilling bucket. Velocity distribution on different planes are obtained and discussed.
    • Heat exchanger network optimization by differential evolution method

      Thuy, N.T.P.; Pendyala, R.; Rahmanian, Nejat; Marneni, N. (2014)
      The synthesis of heat exchanger network (HEN) is a comprehensive approach to optimize energy utilization in process industry. Recent developments in HEN synthesis (HENS) present several heuristic methods, such as Simulated Annealing (SA), Genetic Algorithm (GA), and Differential Evolution (DE). In this work, DE method for synthesis and optimization of HEN has been presented. Using DE combined with the concept of super-targeting, the ΔTmin optimization is determined. Then DE algorithm is employed to optimize the global cost function including the constraints, such as heat balance, the temperatures of process streams. A case study has been optimized using DE, generated structure of HEN and compared with networks obtained by other methods such as pinch technology or mathematical programming. Through the result, the proposed method has been illustrated that DE is able to apply in HEN optimization, with 16.7% increase in capital cost and 56.4%, 18.9% decrease in energy, global costs respectively.
    • An experimental investigation into the permeability and selectivity of PTFE membrane: a mixture of methane and carbon dioxide

      Gilassi, S.; Rahmanian, Nejat (Taylor & Francis, 2016)
      Research and technology innovations in the 1970s led to the significant commercial practice of gas separation by membranes that exists today. These advances involved developing membrane structures that could produce high fluxes and modules for packing a large amount of membrane area per unit volume (Murphy et al., 2009). At present, the share of using a polymeric membrane in the capture of CO2 is increasing and gradually the membrane technology is considered as the promising method in separation units, although the number of commercial membranes is not high. CO2 capture from natural gas is one of the controversial topics that many researchers and engineers try to find the best method satisfying both high efficiency and low capital cost. In common, chemical physical absorption towers are applied to remove CO2 from natural gas in order to prevent pipeline corrosion, even though the other component such as H2S gives rise to operating problems. The obscure angle of a conventional unit is related to the high energy consumption while the absorbent needs to be purified by the regeneration units which implement the temperature as a unique manipulating parameter for separating amine groups. The great advantages of using the membrane in gas industry are the low capital cost, easy installation and maintenance so that for this simple reason, new membranes come to the market for different types of processes. Capture of CO2 from natural gas accounts for one of the major difficulties so that the engineers try to employ membrane modules as to alter the process efficiency. However, there are only a limited number of membranes that can be used in real industry and the research still continues over this interesting topic (Burggraaf and Cot, 1996).
    • Investigation of Effect of Aluminium Oxide Nanoparticles on the Thermal Properties of Water-Based Fluids in a Double Tube Heat Exchanger

      Porgar, S.; Rahmanian, Nejat (2021-06-24)
      The thermal behavior of aluminium oxide-water nanofluid in a double pipe carbon steel heat exchanger was investigated in the present study. The overall heat transfer coefficient, Nusselt, and heat transfer coefficient of nanofluid were compared with the base fluid. The volume fraction of the nanoparticles was 1%. By adding nanoparticles to the fluid, the thermal properties of the base fluid improved significantly. The hot and cold fluid flow was considered counter-current, and the nanofluid was pumped into the inner tube and once into the outer tube, and the flow rate of each fluid was 0.05 kg/s. The convective heat transfer and the overall heat transfer coefficient enhanced 94% and 253% for the hot fluid flow in the outer tube and 308 % and 144% for the hot fluid flow in the inner tube, respectively. The pressure drop calculations also showed that the pressure drop would not change significantly when using nanofluid.
    • A New No Equilibrium Fractional Order Chaotic System, Dynamical Investigation, Synchronization and Its Digital Implementation

      Rahman, Z.-A.S.A.; Jasim, B.H.; Al-Yasir, Yasir; Abd-Alhameed, Raed A.; Alhasnawi, B.N. (MDPI, 2021-07-06)
      In this paper, a new fractional order chaotic system without equilibrium is proposed, analyti-cally and numerically investigated, and numerically and experimentally tested. The analytical and numerical investigation were used to describe the system dynamical behaviors including, the system equilibria, the chaotic attractors, the bifurcation diagrams and the Lyapunov expo-nents. Based on the obtained dynamical behaviors, the system can excite hidden chaotic attrac-tors since it has no equilibrium. Then, a synchronization mechanism based on the adaptive con-trol theory has been developed between two identical new systems (master and slave). The adaptive control laws are derived based on synchronization error dynamics of the state varia-bles for the master and slave. Consequently, the update laws of the slave parameters are ob-tained, where the slave parameters are assumed to be uncertain and estimate corresponding to the master parameters by the synchronization process. Furthermore, Arduino Due boards were used to implement the proposed system in order to demonstrate its practicality in real-world applications. The simulation experimental results are obtained by MATLAB and the Arduino Due boards respectively, where a good consistent between the simulation results and the ex-perimental results. indicating that the new fractional order chaotic system is capable of being employed in real-world applications.
    • 8-Port Semi-Circular Arc MIMO Antenna with an Inverted L-Strip Loaded Connected Ground for UWB Applications

      Addepalli, T.; Desai, A.; Elfergani, Issa T.; Anveshkumar, N.; Kulkarni, J.; Zebiri, C.; Rodriguez, J.; Abd-Alhameed, Raed A. (MDPI, 2021-06)
      Multiple-input multiple-output (MIMO) antennas with four and eight elements having connected grounds are designed for ultra-wideband applications. Careful optimization of the lines connecting the grounds leads to reduced mutual coupling amongst the radiating patches. The proposed antenna has a modified substrate geometry and comprises a circular arc-shaped conductive element on the top with the modified ground plane geometry. Polarization diversity and isolation are achieved by replicating the elements orthogonally forming a plus shape antenna structure. The modified ground plane consists of an inverted L strip and semi ellipse slot over the partial ground that helps the antenna in achieving effective wide bandwidth spanning from (117.91%) 2.84–11 GHz. Both 4/8-port antenna achieves a size of 0.61 λ × 0.61 λ mm2 (lowest frequency) where 4-port antenna is printed on FR4 substrate. The 4-port UWB MIMO antenna attains wide impedance bandwidth, Omni-directional pattern, isolation >15 dB, ECC 4.5 dB making the MIMO antenna suitable for portable UWB applications. Four element antenna structure is further extended to 8-element configuration with the connected ground where the decent value of IBW, isolation, and ECC is achieved.
    • Integration of Hidden Markov Modelling and Bayesian Network for Fault Detection and Prediction of Complex Engineered Systems

      Soleimani, Morteza; Campean, I. Felician; Neagu, Daniel (2021-05)
      This paper presents a methodology for fault detection, fault prediction and fault isolation based on the integration of hidden Markov modelling (HMM) and Bayesian networks (BN). This addresses the nonlinear and non-Gaussian data characteristics to support fault detection and prediction, within an explainable hybrid framework that captures causality in the complex engineered system. The proposed methodology is based on the analysis of the pattern of similarity in the log-likelihood (LL) sequences against the training data for the mixture of Gaussians HMM (MoG-HMM). The BN model identifies the root cause of detected/predicted faults, using the information propagated from the HMM model as empirical evidence. The feasibility and effectiveness of the presented approach are discussed in conjunction with the application to a real-world case study of an automotive exhaust gas Aftertreatment system. The paper details the implementation of the methodology to this case study, with data available from real-world usage of the system. The results show that the proposed methodology identifies the fault faster and attributes the fault to the correct root cause. While the proposed methodology is illustrated with an automotive case study, its applicability is much wider to the fault detection and prediction problem of any similar complex engineered system.
    • Solution processed PVB/mica flake coatings for the encapsulation of organic solar cells

      Channa, I.A.; Chandio, A.D.; Rizwan, M.; Shah, A.A.; Bhatti, J.; Shah, A.K.; Hussain, F.; Shar, Muhammad A.; AlHazaa, A. (2021-05-12)
      Organic photovoltaics (OPVs) die due to their interactions with environmental gases, i.e., moisture and oxygen, the latter being the most dangerous, especially under illumination, due to the fact that most of the active layers used in OPVs are extremely sensitive to oxygen. In this work we demonstrate solution-based effective barrier coatings based on composite of poly(vinyl butyral) (PVB)and mica flakes for the protection of poly (3-hexylthiophene) (P3HT)-based organic solar cells (OSCs)against photobleaching under illumination conditions. In the first step we developed a protective layer with cost effective and environmentally friendly methods and optimized its properties in terms of transparency, barrier improvement factor, and bendability. The developed protective layer maintained a high transparency in the visible region and improved oxygen and moisture barrier quality by the factor of ~7. The resultant protective layers showed ultra-flexibility, as no significant degradation in protective characteristics were observed after 10 K bending cycles. In the second step, a PVB/mica composite layer was applied on top of the P3HT film and subjected to photo-degradation. The P3HT films coated with PVB/mica composite showed improved stability under constant light irradiation and exhibited a loss of <20% of the initial optical density over the period of 150 h. Finally, optimized barrier layers were used as encapsulation for organic solar cell (OSC) devices. The lifetime results confirmed that the stability of the OSCs was extended from few hours to over 240 h in a sun test (65◦C, ambient RH%) which corresponds to an enhanced lifetime by a factor of 9 compared to devices encapsulated with pristine PVB.
    • Design of a self-learning multi-agent framework for the adaptation of modular production systems

      Scrimieri, Daniele; Afazov, S.M.; Ratchev, S.M. (2021)
      This paper presents the design of a multi-agent framework that aids engineers in the adaptation of modular production systems. The framework includes general implementations of agents and other software components for self-learning and adaptation, sensor data analysis, system modelling and simulation, as well as human-computer interaction. During an adaptation process, operators make changes to the production system, in order to increase capacity or manufacture a product variant. These changes are automatically captured and evaluated by the framework, building an experience base of adjustments that is then used to infer adaptation knowledge. The architecture of the framework consists of agents divided in two layers: the agents in the lower layer are associated with individual production modules, whereas the agents in the higher layer are associated with the entire production line. Modelling, learning, and adaptations can be performed at both levels, using a semantic model to specify the structure and capabilities of the production system. An evaluation of a prototype implementation has been conducted on an industrial assembly system. The results indicate that the use of the framework in a typical adaptation process provides a significant reduction in time and resources required.
    • Optimum power transfer in RF front end systems using adaptive impedance matching technique

      Alibakhshikenari, M.; Virdee, B.S.; Azpilicueta, L.; See, C.H.; Abd-Alhameed, Raed A.; Althuwayb, A.A.; Falcone, F.; Huyen, I.; Denidni, T.A.; Limiti, E. (Nature Publishing Group, 2021-06)
      Matching the antenna’s impedance to the RF-front-end of a wireless communications system is challenging as the impedance varies with its surround environment. Autonomously matching the antenna to the RF-front-end is therefore essential to optimize power transfer and thereby maintain the antenna’s radiation efficiency. This paper presents a theoretical technique for automatically tuning an LC impedance matching network that compensates antenna mismatch presented to the RF-front-end. The proposed technique converges to a matching point without the need of complex mathematical modelling of the system comprising of non-linear control elements. Digital circuitry is used to implement the required matching circuit. Reliable convergence is achieved within the tuning range of the LC-network using control-loops that can independently control the LC impedance. An algorithm based on the proposed technique was used to verify its effectiveness with various antenna loads. Mismatch error of the technique is less than 0.2%. The technique enables speedy convergence (< 5 µs) and is highly accurate for autonomous adaptive antenna matching networks.
    • Analysis of the combinatory effect of uniaxial electrical and magnetic anisotropy on the input impedance and mutual coupling of a printed dipole antenna

      Bouknia, M.L.; Zebiri, C.; Sayad, D.; Elfergani, Issa T.; Alibakhshikenari, M.; Rodriguez, J.; Abd-Alhameed, Raed A.; Falcone, F.; Limiti, E. (IEEE, 2021-06)
      The main objective of this work is to investigate the combinatory effects of both uniaxial magnetic and electrical anisotropies on the input impedance, resonant length and the mutual coupling between two dipoles printed on an anisotropic grounded substrate. Three different configurations: broadside, collinear and echelon are considered for the coupling investigation. The study is based on the numerical solution of the integral equation using the method of moments through the mathematical derivation of the appropriate Green’s functions in the spectral domain. In order to validate the computing method and evaluated Matlab® calculation code, numerical results are compared with available literature treating particular cases of uniaxial electrical anisotropy; good agreements are observed. New results of dipole structures printed on uniaxial magnetic anisotropic substrates are presented and discussed, with the investigation of the combined electrical and magnetic anisotropies effect on the input impedance and mutual coupling for different geometrical configurations. The combined uniaxial (electric and magnetic) anisotropies provide additional degrees of freedom for the input impedance control and coupling reduction.
    • Two-dimensional turbulent burst examination and angle ratio utilization to detect scouring/sedimentation around mid-channel bar

      Khan, M.A.; Sharma, N.; Pu, Jaan H.; Aamir, M.; Pandey, M. (Springers, 2021-07)
      River morphological dynamics are complex phenomena in natural and environmental flows. In particular, the sediment transport around braid mid-channel bars has not gained enough understanding from previous research. The effect of submergence ratio on the turbulence behavior in the proximity of the bar has been investigated in this study. The spatial distribution of turbulent flow in the proximity of bar has been studied by plotting the depth-averaged two-dimensional contours of turbulent kinetic energy. The high value of TKE has been observed in regions just downstream from the bar. It is due to the vortex shedding occurring in that region. The interaction of sweep and ejection events have been analyzed using the parameter Dominance Function obtained from the ratio of occurrence probability of ejection events to the occurrence probability of sweep events. This outcome indicates that the depth averaged parameter Dominance Function has successfully predicted the high scouring region which makes it an ideal parameter for analyzing the scour phenomena in real-world water management projects. The high scouring zone lies in the close proximity of the bar. This shows that the scouring effect from the bar is limited to its close region. The magnitude of scouring occurring at the upstream region of the bar also increases with the increment of submergence ratio. The relationship of quadrant event inclination angles with the sediment transport occurring in the proximity of bar has been also studied, where an Angle Ratio parameter has been utilized for linking the bed elevation change with the inclination angle. The results indicate that the AR parameter has been successfully tested in this study to show its competence to represent the turbulent burst-induced bed sedimentation and scouring.
    • Multi-Resonant Class-F Power Amplifier Design for 5G Cellular Networks

      Sajedin, M.; Elfergani, Issa T.; Rodriguez, J.; Violas, M.; Asharaa, Abdalfettah S.; Abd-Alhameed, Raed A.; Fernandez-Barciela, M.; Abdulkhaleq, A.M.
      This work integrates a harmonic tuning mechanism in synergy with the GaN HEMT transistor for 5G mobile transceiver applications. Following a theoretical study on the operational behavior of the Class-F power amplifier (PA), a complete amplifier design procedure is described that includes the proposed Harmonic Control Circuits for the second and third harmonics and optimum loading conditions for phase shifting of the drain current and voltage waveforms. The performance improvement provided by the Class-F configuration is validated by comparing the experimental and simulated results. The designed 10W Class-F PA prototype provides a measured peak drain efficiency of 64.7% at 1dB compression point of the PA at 3.6GHz frequency.
    • Distribution Network Reconfiguration Considering Security-Constraint and Multi-DG Configurations

      Anthony, Ikenna O.; Mokryani, Geev; Zubo, Rana H.A.; Ezechukwu, O.A. (IEEE, 2020-09)
      This paper proposes a novel method for distribution network reconfiguration considering security-constraints and multi-configuration of renewable distributed generators (DG). The objective of the proposed method is to minimize the total operational cost using security constrained optimal power flow (SCOPF). The impact of multi-configuration of renewable DGs in a meshed network is investigated. In this work, lines were added to the radial distribution network to analyse the network power flow in different network configurations. The added lines were connected to the closest generator bus which offered least operating cost. A 16-bus UK generic distribution system (UKGDS) was used to model the efficiency of the proposed method. The obtained results in multi-DG configuration ensure the security of the network in N-1 contingency criteria.
    • A Proposed IoT Architecture for Effective Energy Management in Smart Microgrids

      Numair, M.; Mansour, D-EA; Mokryani, Geev (IEEE, 2020-11)
      The current electricity grid suffers from numerous challenges due to the lack of an effective energy management strategy that is able to match the generated power to the load demand. This problem becomes more pronounced with microgrids, where the variability of the load is obvious and the generation is mostly coming from renewables, as it depends on the usage of distributed energy sources. Building a smart microgrid would be much more economically feasible than converting the large electricity grid into a smart grid, as it would require huge investments in replacing legacy equipment with smart equipment. In this paper, application of Internet of Things (IoT) technology in different parts of the microgrid is carried out to achieve an effective IoT architecture in addition to proposing the Internet-of-Asset (IoA) concept that will be able to convert any legacy asset into a smart IoT-ready one. This will allow the effective connection of all assets to a cloud-based IoT. The role of which is to perform computations and big data analysis on the collected data from across the smart microgrid to send effective energy management and control commands to different controllers. Then the IoT cloud will send control actions to solve microgrid's technical issues such as solving energy mismatch problem by setting prediction models, increasing power quality by the effective commitment of DERs and eliminating load shedding by turning off only unnecessary loads so consumers won't suffer from power outages. The benefits of using IoT on various parts within the microgrid are also addressed.
    • Active distribution network operation: A market-based approach

      Zubo, Rana H.A.; Mokryani, Geev (2020-03)
      This article proposes a novel technique for operation of distribution networks with considering active network management (ANM) schemes and demand response (DR) within a joint active and reactive distribution market environment. The objective of the proposed model is to maximize social welfare using market-based joint active and reactive optimal power flow. First, the intermittent behavior of renewable sources (solar irradiance, wind speed) and load demands is modeled through scenario-tree technique. Then, a network frame is recast using mixed-integer linear programming, which is solvable using efficient off-the-shelf branch-and cut solvers. Additionaly, this article explores the impact of wind and solar power penetration on the active and reactive distribution locational prices within the distribution market environment with integration of ANM schemes and DR. A realistic case study (16-bus UK generic medium voltage distribution system) is used to demonstrate the effectiveness of the proposed method.
    • Triple-layer Tissue Prediction for Cutaneous Skin Burn Injury: Analytical Solution and Parametric Analysis

      Oguntala, George A.; Indramohan, V.; Jeffery, S.; Abd-Alhameed, Raed A. (2021-07)
      This paper demonstrates a non-Fourier prediction methodology of triple-layer human skin tissue for determining skin burn injury with non-ideal properties of tissue, metabolism and blood perfusion. The dual-phase lag (DPL) bioheat model is employed and solved using joint integral transform (JIT) through Laplace and Fourier transforms methods. Parametric studies on the effects of skin tissue properties, initial temperature, blood perfusion rate and heat transfer parameters for the thermal response and exposure time of the layers of the skin tissue are carried out. The study demonstrates that the initial tissue temperature, the thermal conductivity of the epidermis and dermis, relaxation time, thermalisation time and convective heat transfer coefficient are critical parameters to examine skin burn injury threshold. The study also shows that thermal conductivity and the blood perfusion rate exhibits negligible effects on the burn injury threshold. The objective of the present study is to support the accurate quantification and assessment of skin burn injury for reliable experimentation, design and optimisation of thermal therapy delivery.