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  • Nanoindentation analysis of oriented polypropylene: Influence of elastic properties in tension and compression

    Vgenopoulos, D.; Sweeney, John; Grant, C.A.; Thompson, Glen P.; Spencer, Paul E.; Caton-Rose, Philip D.; Coates, Philip D. (2018-08)
    Polypropylene has been oriented by solid-phase deformation processing to draw ratios up to ∼16, increasing tensile stiffness along the draw direction by factors up to 12. Nanoindentation of these materials showed that moduli obtained for indenter tip motion along the drawing direction (3) into to 1–2 plane (axial indentation) were up to 60% higher than for indenter tip motion along the 2 direction into the 1–3 plane (transverse indentation). In static tests, tensile and compressive determinations of elastic modulus gave results differing by factors up to ∼5 for strain along the draw direction. A material model incorporating both orthotropic elasticity and tension/compression asymmetry was developed for use with Finite Element simulations. Elastic constants for the oriented polypropylene were obtained by combining static testing and published ultrasonic data, and used as input for nanoindentation simulations that were quantitatively successful. The significance of the tension/compression asymmetry was demonstrated by comparing these predictions with those obtained using tensile data only, which gave predictions of indentation modulus higher by up to 70%.
  • Experimental study on the flexural behavior of ECC-concrete hybrid composite beams reinforced with FRP and steel bars

    Ge, W-J.; Ashour, Ashraf F.; Yu, J.; Gao, P.; Cao, D-F.; Cai, C.; Ji, X. (2018)
    This paper aims to investigate the flexural behavior of engineered cementitious composite (ECC)-concrete hybrid composite beams reinforced with fiber reinforced polymer (FRP) bars and steel bars. Thirty two hybrid reinforced composite beams having various ECC height replacement ratio and combinations of FRP and steel reinforcements were experimentally tested to failure in flexure. Test results showed that cracking, yield and ultimate moments as well as the stiffness of hybrid and ECC beams are improved compared with traditional concrete beams having the same reinforcement, owing to the excellent tensile properties of ECC materials. The average crack spacing and width decrease with the increase of ECC height replacement ratio. The ductility of hybrid reinforced composite beams is higher than that of traditional reinforced concrete beams while their practical reinforcement ratios are similar. Reinforced ECC beams show considerable energy dissipation capacity owing to ECC’s excellent deformation ability. Considering the constitutive models of materials, compatibility and equilibrium conditions, formulas for the prediction of cracking, yield and ultimate moments as well as deflections of hybrid reinforced ECC-concrete composite beams are developed. The proposed formulas are in good agreement with the experimental results. A comprehensive parametric analysis is, then, conducted to illustrate the effect of reinforcement, ECC and concrete properties on the moment capacity, curvature, ductility and energy dissipation of composite beams.
  • Reactive extrusion of polyamide 6 using a novel chain extender

    Tuna, Basak; Benkreira, Hadj (2018)
    Polyamide 6 (PA6) is an important engineering thermoplastic, very widely used but prone to thermal degradation during extrusion at temperature not far from its melt temperature (220 oC). Typically, and as measured in this study, PA6 extruded at temperature of 300 oC shows a 40% decrease in tensile modulus compared to non-extruded PA6. To rebuild PA6 molecular weight, the easiest and cheapest method is to use an appropriate chain extender. Many chain extenders have been used in the past but they are essentially suited to nucleophile induced degradation, targeting split PA6 chains carboxyl COOH and amine NH2 end groups. What has been lacking are effective chain extenders for thermally only induced degradation, i.e. for the practical cases where the PA6 is thoroughly dried before extrusion. For such a case, the degradation reaction mechanism dictates that the solution is to develop chain extenders that target the split PA6 chains amide CONH2 groups not the carboxyl COOH and amine NH2 end groups. As amide groups strongly react with anhydride functionalities, we test the effectiveness of a novel chain extender, Joncryl® ADR 3400, a styrene maleic anhydride copolymer with multiple, repeating anhydride functionality. Assessment of chain extension in this study is done as with previous work, using rheology, mechanical and thermal properties of PA6 extruded on its own and with the chain extender. The viscoelastic data conclusively show the efficacy of such chain extender with more than 10 fold changes in the comparative values of the extruded sample storage modulus G' and as much as an 85% increase in the tensile modulus.
  • A fluorescence-based assessment of the fate of organic matter in water treated using crude/purified Hibiscus seeds as coagulant in drinking water treatment

    Jones, A.N.; Bridgeman, John (2019-01)
    This study used fluorescence excitation-emission matrices (EEMs) analysis to investigate the characteristics of natural organic matter (NOM) in treated water using okra crude extract (OCE), sabdariffa crude extract (SCE) and kenaf crude extract (KCE) as coagulants. In addition, an assessment of the impact of purified okra protein (POP), purified sabdariffa protein (PSP) and purified kenaf protein (PKP) was undertaken. The performance evaluation of these coagulants in terms of increase or decrease in dissolved organic carbon (DOC) was compared with Peak T fluorescence intensity observed at excitation wavelength 220–230 nm, and emission wavelength 340–360 nm. Fluorescence analysis of water treated with the crude extracts identified the removal of DOC in peaks A and C region whereas the increase in DOC from the protein was predominantly found in peaks T and B region. Furthermore, it was observed that the purified proteins were noted to be capable of reducing the DOC concentration in raw water where all fluorophores were not detected. The application of OCE, SCE and KCE yielded an increase in DOC of 65, 61 and 55% respectively, corresponding to increases of 65, 29 and 54% in peak T fluorescence intensities, at 100 mg/l dose. Furthermore, DOC concentration was reduced by 25, 24 and 18% using POP, PSP and PKP respectively as coagulants with corresponding decreases in fluorescence intensity of 46%, 44 and 36% in POP, PSP and PKP, at a lower dose of 0.1 mg/l. Therefore, it is clear that Peak T fluorescence intensity could be used to characterise organic matter in treated water using natural extracts to assess final water quality.
  • Process simulation and assessment of crude oil stabilization unit

    Rahmanian, Nejat; Aqar, D.Y.; Bin Dainure, M.F.; Mujtaba, Iqbal M. (2018)
    Crude oil is an unrefined petroleum composed of wide range of hydrocarbon up to n‐C40+. However, there are also a percentage of light hydrocarbon components present in the mixture. Therefore, to avoid their flashing for safe storage and transportation, the live crude needs to be stabilized beforehand. This paper aims to find the suitable operating conditions to stabilize an incoming live crude feed to maximum true vapor pressure (TVPs) of 12 psia (82.7 kPa) at Terengganu Crude Oil Terminal, Malaysia. The simulation of the process has been conducted by using Aspen HYSYS. The obtained results illustrate that the simulation data are in good agreement with the plant data and in particular for the heavier hydrocarbons. For the lighter components, the simulation results overpredict the plant data, whereas for the heavier components, this trend is reversed. It was found that at the outlet temperature (85–90°C) of hot oil to crude heat exchanger (HX‐220X), the high‐pressure separator (V‐220 A/B) and the low‐pressure separator (V‐230 A/B) had operating pressures of (400–592 kPa) and (165–186 kPa), respectively, and the live crude was successfully stabilized to a TVP of less than 12 psia. The impact of main variables, that is, inlet feed properties, three‐phase separators operating pressure, and preheater train's performance on the product TVP, are also studied. Based on the scenarios analyzed, it can be concluded that the actual water volume (kbbl/day) has greater impact on the heat exchanger's duty; thus, incoming free water to Terengganu Crude Oil Terminal should be less than 19.5 kbbl/day (9.1 vol%) at the normal incoming crude oil flow rate of 195 (kbbl/day).
  • Modelling of an industrial naphtha isomerization reactor and development and assessment of a new isomerization process

    Ahmed, A.M.; Jarullah, A.T.; Abed, F.M.; Mujtaba, Iqbal M. (2018-09)
    Naphtha isomerization is an important issue in petroleum industries and it has to be a simple and cost effective technology for producing clean fuel with high gasoline octane number. In this work, based on real industrial data, a detailed process model is developed for an existing naphtha isomerization reactor of Baiji North Refinery (BNR) of Iraq which involves estimation of the kinetic parameters of the reactor. The optimal values of the kinetic parameters are estimated via minimizing the sum of squared errors between the predicted and the experimental data of BNR. Finally, a new isomerization process (named as AJAM process) is proposed and using the reactor model developed earlier, the reactor condition is optimized which maximizes the yield and research octane number (RON) of the reactor.
  • Performance analysis of a medium-sized industrial reverse osmosis brackish water desalination plant

    Al-Obaidi, M.A.; Alsarayreh, A.A.; Al-Hroub, A.M.; Alsadaie, S.; Mujtaba, Iqbal M. (2018-10-01)
    The implementation of Reverse Osmosis (RO) technology is noticeably increased to produce freshwater from brackish and seawater resources. In this work, performance analysis of a multistage multi pass medium-sized spiral wound brackish water RO (BWRO) desalination plant (1200 m³/day) of Arab Potash Company (APC) located in Jordan is evaluated using modelling and simulation. For this purpose, a mathematical model for the spiral wound RO process based on the principles of solution diffusion model is developed. The model is then used to simulate the operating conditions of low-salinity brackish water RO (BWRO) desalination plant. The results obtained are then compared against the real industrial data of BWRO desalination plant of APC which shows a high-level of consistency. Finally, the model is used to analysis the impact of the operating parameters such as salinity, pressure, temperature, and flow rate on the plant performance. The sensitivity analysis confirms that both feed flow rate and operating pressure as the critical parameters that positively affect the product salinity.
  • Cyber Threat Intelligence from Honeypot Data using Elasticsearch

    AL-Mohannadi, Hamad; Awan, Ifan U.; Al Hamar, J.; Cullen, Andrea J.; Disso, Jules P.; Armitage, Lorna (2018-05-18)
    Cyber attacks are increasing in every aspect of daily life. There are a number of different technologies around to tackle cyber-attacks, such as Intrusion Detection Systems (IDS), Intrusion Prevention Systems (IPS), firewalls, switches, routers etc., which are active round the clock. These systems generate alerts and prevent cyber attacks. This is not a straightforward solution however, as IDSs generate a huge volume of alerts that may or may not be accurate: potentially resulting in a large number of false positives. In most cases therefore, these alerts are too many in number to handle. In addition, it is impossible to prevent cyber-attacks simply by using tools. Instead, it requires greater intelligence in order to fully understand an adversary’s motive by analysing various types of Indicator of Compromise (IoC). Also, it is important for the IT employees to have enough knowledge to identify true positive attacks and act according to the incident response process. In this paper, we have proposed a new threat intelligence technique which is evaluated by analysing honeypot log data to identify behaviour of attackers to find attack patterns. To achieve this goal, we have deployed a honeypot on an AWS cloud to collect cyber incident log data. The log data is analysed by using elasticsearch technology namely an ELK (Elasticsearch, Logstash and Kibana) stack.
  • Secrets of a smile? Your gender and perhaps your biometric identity

    Ugail, Hassan (2018-06)
    With its numerous applications, automatic facial emotion recognition has recently become a very active area of research. Yet there has been little detailed study of the dynamic components of facial expressions. This article reviews research that shows gender is encoded in the dynamics of a smile, and how it may be possible to use the dynamic components of facial expressions as a form of biometric.
  • Assessment of mixing quality in full-scale, biogas-mixed anaerobic digestion using CFD

    Dapelo, Davide; Bridgeman, John (2018-10)
    An Euler-Lagrange CFD model is applied to a full-scale, biogas-mixed anaerobic digester to improve mixing efficiency and improve overall performance. Two quantitative mixing criteria previously adopted in anaerobic digestion (viz., uniformity index and dead volume) are critically assessed for the first time. A novel qualitative method is introduced to clarify the output of the quantitative methods. The first-ever quantitative assessment of mixing quality in full-scale, biogas-mixed anaerobic digestion is then proposed, and a strategy to improve mixing, involving the combined use of concentric nozzle manifolds at the base of the digester, is evaluated.
  • Gait termination on a declined surface in trans-femoral amputees: Impact of using microprocessor-controlled limb system

    Abdulhasan, Z.M.; Scally, Andy J.; Buckley, John G. (2018-08)
    Background: Walking down ramps is a demanding task for transfemoral-amputees and terminating gait on ramps is even more challenging because of the requirement to maintain a stable limb so that it can do the necessary negative mechanical work on the centre-of-mass in order to arrest (dissipate) forward/downward velocity. We determined how the use of a microprocessor-controlled limb system (simultaneous control over hydraulic resistances at ankle and knee) affected the negative mechanical work done by each limb when transfemoral-amputees terminated gait during ramp descent. Methods: Eight transfemoral-amputees completed planned gait terminations (stopping on prosthesis) on a 5-degree ramp from slow and customary walking speeds, with the limb's microprocessor active or inactive. When active the limb operated in its ‘ramp-descent’ mode and when inactive the knee and ankle devices functioned at constant default levels. Negative limb work, determined as the integral of the negative mechanical (external) limb power during the braking phase, was compared across speeds and microprocessor conditions. Findings: Negative work done by each limb increased with speed (p < 0.001), and on the prosthetic limb it was greater when the microprocessor was active compared to inactive (p = 0.004). There was no change in work done across microprocessor conditions on the intact limb (p = 0.35). Interpretation: Greater involvement of the prosthetic limb when the limb system was active indicates its ramp-descent mode effectively altered the hydraulic resistances at the ankle and knee. Findings highlight participants became more assured using their prosthetic limb to arrest centre-of-mass velocity.
  • A shape memory polymer concrete crack closure system activated by electrical current

    Teall, O.; Pilegis, M.; Davies, R.; Sweeney, John; Jefferson, T.; Lark, R.; Gardner, D. (2018-05-31)
    The presence of cracks has a negative impact on the durability of concrete by providing paths for corrosive materials to the embedded steel reinforcement. Cracks in concrete can be closed using shape memory polymers (SMP) which produce a compressive stress across the crack faces. This stress has been previously found to enhance the load recovery associated with autogenous selfhealing. This paper details the experiments undertaken to incorporate SMP tendons containing polyethylene terephthalate (PET) filaments into reinforced and unreinforced 500 × 100 × 100 mm structural concrete beam samples. These tendons are activated via an electrical supply using a nickelchrome resistance wire heating system. The set-up, methodology and results of restrained shrinkage stress and crack closure experiments are explained. Crack closure of up to 85% in unreinforced beams and 26%–39% in reinforced beams is measured using crack-mouth opening displacement, microscope and digital image correlation equipment. Conclusions are made as to the effectiveness of the system and its potential for application within industry.
  • Modelling and optimisation of a multistage Reverse Osmosis processes with permeate reprocessing and recycling for the removal of N-nitrosodimethylamine from wastewater using Species Conserving Genetic Algorithms

    Al-Obaidi, M.A.; Li, Jian-Ping; Alsadaie, S.M.; Kara-Zaitri, Chak; Mujtaba, Iqbal M. (2018-10-15)
    The need for desalinated seawater and reclaimed wastewater is increasing rapidly with the rising demands for drinkable water required for the world with continuously growing population. Reverse Osmosis (RO) processes are now among the most promising technologies used to remove chemicals from industrial effluents. N-nitrosamine compounds and especially N-nitrosodimethylamine (NDMA) are human carcinogens and can be found in industrial effluents of many industries. Particularly, NDMA is one of the by-products of disinfection process of secondary-treated wastewater effluent with chloramines, chlorines, and ozone (inhibitors). However, multi-stage RO processes with permeate reprocessing and recycling has not yet been considered for the removal of N-nitrosodimethylamine from wastewater. This research therefore, begins by investigating a number of multi-stage RO processes with permeate-reprocessing to remove N-nitrosodimethylamine (NDMA) from wastewater and finds the best configuration in terms of rejection, recovery and energy consumption via optimisation. For the first time we have applied Species Conserving Genetic Algorithm (SCGA) in optimising RO process conditions for wastewater treatment. Finally, permeate recycling is added to the best configuration and its performance is evaluated as a function of the amount of permeate being recycled via simulation. For this purpose, a mathematical model is developed based on the solution diffusion model, which is used for both optimisation and simulation. A number of model parameters have been estimated using experimental data of Fujioka et al. (Journal of Membrane Science 454 (2014) 212–219), so that the model can be used for simulation and optimisation with high accuracy and confidence.
  • Performance evaluation of multi-stage and multi-pass reverse osmosis networks for the removal of N-nitrosodimethylamine-D6 (NDMA) from wastewater using model-based techniques

    Al-Obaidi, M.A.; Kara-Zaitri, Chakib; Mujtaba, Iqbal M. (2018)
    The removal of pollutants such as N-nitrosamine present in drinking and reuse water resources is of significant interest for health and safety professionals. Reverse osmosis (RO) is one of the most promising and efficient methodologies for removing such harmful organic compounds from wastewater. Having said this, the literature confirms that the multi-stage RO process with retentate reprocessing design has not yet achieved an effective removal of N-nitrosodimethylamine-D6 (NDMA) from wastewater. This research emphasizes on this particular challenge and aims to explore several conceptual designs of multi-stage RO processes for NDMA rejection considering model-based techniques and compute the total recovery rate and energy consumption for different configurations of retentate reprocessing techniques. In this research, the permeate reprocessing design methodology is proposed to increase the process efficiency. An extensive simulation analysis is carried out using high NDMA concentration to evaluate the performance of each configuration under similar operational conditions, thus providing a deep insight on the performance of the multi-stage RO permeate reprocessing predictive design. Furthermore, an optimisation analysis is carried out on the final design to optimise the process with a high NDMA rejection performance and the practical recovery rate by manipulating the operating conditions of the plant within specified constraints bounds. The results show a superior removal of NDMA from wastewater.
  • Revamping of an acid gas absorption unit: An industrial case study

    Kheirinik, M.; Rahmanian, Nejat; Farsi, M.; Garmsiri, M. (2018-07)
    This work evaluates the efficiency of the aqueous mixture of Methyl Diethanolamine (MDEA) and Diethanolamine (DEA) at various mass concentrations to remove CO2 and H2S from natural gas in an industrial sweetening unit in Fajr Jam Gas Refining Company located in the south of Iran and gives recommendations for modifying the process. The sweetening unit includes absorber and desorption towers, flash drum, lean and rich amine exchanger, kettle type reboiler and a reflux drum. The considered process is simulated by Promax simulator (version 3.2) taking into account operational constraints and sustainability of the environment. The validity of simulation has been evaluated by comparison between simulation results and the plant data. The main objective of this work is the modification of natural gas sweetening unit to achieve lower energy consumption. Thus, the effect of amine circulating rate and MDEA to DEA ratio on steam consumption in the regeneration tower, CO2 and H2S concentration in the treated gas, and the acid gas loadings have been investigated. Therefore, substitution of DEA solvent in the unit with the aqueous mixture of DEA and MDEA is proposed. In the examined cases, the mass concentration of MDEA and DEA lies between 15 and 45 wt% and 0–30 wt%, respectively, with the reference cases having MDEA 0 wt% and DEA 31.6 wt%. The results show that in the proposed cases of alternative mixtures including cases 1 (MDEA15 wt% and DEA 30 wt%), 2 (MDEA 20 wt% and DEA 25 wt%), and 3 (MDEA 25 wt% and DEA 20 wt%) the amount of reduction in amine circulation rate are between 11.1%v/v and 19.4%v/v compared to the original amine circulation rate. Likewise, steam consumption decreases between 24.4 %wt/wt and 27 %wt/wt. Influence of anti-foam injection for the different cases were also studied and it was found that anti-foam with the concentration of 5000 ppmv is more suitable for the optimum operation and is a more cost effective.
  • Numerical modelling of natural flood management and its associated microbial risks in the United Kingdom

    Pu, Jaan H. (2018-05)
    This paper reviews and discusses the recent studies of natural flood management (NFM) and its associated microbial risks in the UK and suggests set of numerical modelling approaches for their respective investigation. This study details the importance of precise numerical representation of the NFM to flood inundations and microbial risks caused by NFM measures. Possible future numerical advancements of the numerical modelling for the NFM and microbial activities are also discussed here.
  • Maximization of propylene in an industrial FCC unit

    John, Yakubu M.; Patel, Rajnikant; Mujtaba, Iqbal M. (2018-06)
    The FCC riser cracks gas oil into useful fuels such as gasoline, diesel and some lighter products such as ethylene and propylene, which are major building blocks for the polyethylene and polypropylene production. The production objective of the riser is usually the maximization of gasoline and diesel, but it can also be to maximize propylene. The optimization and parameter estimation of a six-lumped catalytic cracking reaction of gas oil in FCC is carried out to maximize the yield of propylene using an optimisation framework developed in gPROMS software 5.0 by optimizing mass flow rates and temperatures of catalyst and gas oil. The optimal values of 290.8 kg/s mass flow rate of catalyst and 53.4 kg/s mass flow rate of gas oil were obtained as propylene yield is maximized to give 8.95 wt%. When compared with the base case simulation value of 4.59 wt% propylene yield, the maximized propylene yield is increased by 95%.
  • Simulation and sensitivity analysis of spiral wound reverse osmosis process for the removal of dimethylphenol from wastewater using 2-D dynamic model

    Al-Obaidi, M.A.; Kara-Zaitri, Chakib; Mujtaba, Iqbal M. (2018-08)
    Reverse Osmosis (RO) processes are readily used for removing pollutants, such as dimethylphenol from wastewater. A number of operating parameters must be controlled within the process constraints to achieve an efficient removal of such pollutants. Understanding the process dynamics is absolutely essential and is a pre-step for designing any effective controllers for any process. In this work, a detailed distributed two-dimensional dynamic (x and y dimensions and time) model for a spiral-wound RO process is developed extending the 2-D steady state model of the authors published earlier. The model is used to capture the dynamics of the RO process for the removal of dimethylphenol from wastewater. The performance of the 2-D model is compared with that obtained using 1-D dynamic model before the model is being used to investigate the performance of the RO process for a range of operating conditions.
  • A new methodology to optimize Turnaround Maintenance (TAM) scheduling for gas plants

    Elwerfalli, A.A.; Khan, M. Kurshid; Munive-Hernandez, J. Eduardo (2018-01)
    Time, cost and risk are the main elements that effect the operating margin of the oil and gas companies due to Turnaround Maintenance (TAM). Turnaround Maintenance (TAM) is a methodology for the total shutdown of plant facilities during a pre-defined period to execute inspection actions, replacement and repairs according to Scope of Work (SoW). This paper presents a new methodology for improving TAM scheduling of oil and gas plants. The methodology includes four stages: removing Non-critical Equipment (NE) from reactive maintenance to proactive maintenance, risk-based inspection of Critical Static Equipment (CSE), risk-based failure of Critical Rotating Equipment (CRE), and application of failure distributions. The results from improving TAM scheduling is associated with decreasing duration and increasing interval between TAM leading to improved availability, reliability, operation and maintenance costs and safety risks. The paper presents findings from the TAM model application. The methodology is fairly generic in its approach and can also be adapted for implementation in other oil and gas industries that operate under similar harsh conditions.
  • From e-government to cloud-government: challenges of Jordanian citizens’ acceptance for public services

    Alkhwaldi, A.F.A.; Kamala, Mumtaz A.; Qahwaji, Rami S.R. (2018-05)
    On the inception of the third millennium, there is much evidence that cloud technologies have become the strategic trend for many governments, not only for developed countries (e.g. the UK, Japan and the USA), but also developing countries (e.g. Malaysia and countries in the Middle East region). These countries have launched cloud computing movements for enhanced standardization of IT resources, cost reduction and more efficient public services. Cloud-based e-government services are considered to be one of the high priorities for government agencies in Jordan. Although experiencing phenomenal evolution, government cloud-services are still suffering from the adoption challenges of e-government initiatives (e.g. technological, human, social and financial aspects) which need to be considered carefully by governments contemplating their implementation. While e-government adoption from the citizens’ perspective has been extensively investigated using different theoretical models, these models have not paid adequate attention to security issues. This paper presents a pilot study to investigate citizens’ perceptions of the extent to which these challenges inhibit the acceptance and use of cloud computing in the Jordanian public sector and examine the effect of these challenges on the security perceptions of citizens. Based on the analysis of data collected from online surveys, some important challenges were identified. The results can help to guide successful acceptance of cloud-based e-government services in Jordan.

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