Recent Submissions

  • State-of-the-art review of 3DPV technology: structures and models

    Cui, Yuanlong; Zhu, Jie; Stamatis, Zoras; Chen, Xiangjie; Bi, Haixia; Qiao, Yaning; Soleimani, Zohreh; University of Derby; University of Nottingham; China University of Mining and Technology (Elsevier, 2019-10-05)
    Increasing energy conversion efficiency from sunlight to power is one of the key solutions for the world’s energy shortage and greenhouse gas reduction, but the conventional flat photovoltaic module without sun tracking mechanism has the low sunlight energy collection ability. This paper presents the state-of-the-art three-dimensional photovoltaic (3DPV) technology with high photovoltaic energy conversion efficiency, which is able to absorb off-peak sunlight and reflected light more effectively, thereby it can generate more power. At first, this paper is to catalogue and critique different 3DPV structures and models, as well as assess their characteristics. Afterwards, the main influence factors on the 3DPV structures and models including shape, height and spacing of the solar cells, latitude of the installation, optimal device design and shadow cast, are reviewed. Finally, the challenges and future technological developments of 3DPV structures and models are highlighted. This study demonstrated that the 3DPV technology can increase the captured sunlight approximately 15–30% in comparison with the conventional flat PV technology.
  • Antibacterial properties of silver nanoparticles grown in situ and anchored to titanium dioxide nanotubes on titanium implant against Staphylococcus aureus

    Gunputh, Urvashi F.; Le, Huirong; Lawton, Kiruthika; Besinis, Alexandros; Tredwin, Christopher; Handy, Richard D.; University of Derby; Plymouth University (Taylor & Francis, 2019-09-30)
    Medical grade titanium alloy, Ti-6Al-4V, with TiO2 nanotubes (TiO2-NTs) grown on the surface and then decorated with silver nanoparticles (Ag NPs) is proposed to enhance the antimicrobial properties of the bone/dental implants. However, the decoration with Ag NPs is not consistent and there are concerns about the direct contact of Ag NPs with human tissue. The aim of this study was to achieve a more even coverage of Ag NPs on TiO2-NTs and determine their biocidal properties against Staphylococcus aureus, with and without a top coat of nano hydroxyapatite (nHA). The decoration with Ag NPs was optimised by adjusting the incubation time of the TiO2-NTs in a silver ammonia solution, and using biocompatible δ-gluconolactone as a reducing agent. The optimum incubation in silver ammonia was 7 min, and resulted in evenly distributed Ag NPs with an average diameter of 47.5 ± 1.7 nm attached to the surface of the nanotubes. The addition of nHA did not compromise the antimicrobial properties of the materials; high-resolution electron microscopy showed S. aureus did not grow on the composite with nHA and with >80% biocidal activity measured by the LIVE/DEAD assay, also limited lactate production. Dialysis experiment confirmed the stability of the coatings, and showed a slow release of dissolved silver (3.27 ± 0.15 μg/L over 24 h) through the top coat of nHA.
  • Understanding the implications of chemical regulations, circular economy and corporate social responsibility for product stewardship

    Takhar, Sukhraj; Liyanage, Kapila; University of Derby (IOS Press, 2019-09-10)
    Chemical regulations exist to limit and control the amount of hazardous chemical substances being used by industry to mitigate potential risks. Increasing awareness of diminishing natural resources, increasing pollution, and reducing the amounts of harmful waste, has led towards pressure on industry to change from the traditional linear economic model (closed-loop manufacturing), towards the adoption of the Circular Economy (CE) activities. Corporate Social Responsibility (CSR) extends the relationship between industry and society, defining strategy and communications. The speed at which chemical regulations, CE and CSR adoption takes place will depend on: (1) the speed at which natural resources become more depleted; (2) increasing awareness of the effects of chemical substances by regulators and consumers; (3) increasing numbers of chemical substances being regulated as hazardous, and; (4) increasing consumer and societal pressures for change. Product Stewardship (PS) can be viewed as: (1) involving a wide range of functional areas (design, manufacture, purchasing, sales, support); (2) identifying health and safety, and environmental impacts of product(s); (3) ensuring adequate measures are in place to understand, control or limit impact(s) against a product throughout its lifecycle. The aim of this paper is to focus on using a literature review. The conclusions from this paper will attempt to outline a framework for PS to align with CE and CSR.
  • Synthesis and characterization of tungsten and barium co-doped La2Mo2O9 by sol-gel process for solid oxide fuel cells

    Shao, Lingbo; Ji, Dongdong; Yang, Jie; Xie, Jinsong; Yin, Qiyi; Le, Huirong; Hefei University; University of Derby (Elsevier, 2019-09-30)
    Herein, we demonstrate the synthesis of W and Ba co-doped La2Mo2O9 (LBMWO) nanocrystalline powder by a sol-gel process. In all the compositions have general formulae La1.9Ba0.1Mo2–xWxO8.95 (x = 0–0.40). The crystal structure, microstructure and conductivity of LBMWO were characterized by X-ray diffraction, scanning electron microscopy and electrical impedance spectroscopy. In addition, the thermal and decomposition properties of the LBMWO gel were analyzed by differential scanning calorimetry - thermogravimetric. The results reveal that all LBMWO powders calcined at 700 °C have a cubic structure; the average crystallite size is about 48 nm. The unit cell parameter of LBMWO powders increases with increase in W content. The as-synthesized nanocrystalline LBMWO samples exhibit excellent sinterability and a relatively lower sintering temperature of 900 °C. A high relative density of ∼96% is achieved after sintering at 900 °C which is in good agreement with the results of the SEM. Moreover, W and Ba co-doping suppresses the phase transition and effectively stabilizes the β-phase at low temperature. At the same time, La1.9Ba0.1Mo1.85W0.15O8.95 exhibits high ionic conductivity, 3.07 × 10−2 S/cm at 800 °C. It is therefore concluded that co-doping can improve the properties of La2Mo2O9 electrolytes.
  • Effects of the graphene nanoplatelets reinforced interphase on mechanical properties of carbon fibre reinforced polymer – A multiscale modelling study

    Le, Huirong; Lu, Yiling; Pawlik, Marzena; University of Derby (Elsevier, 2019-07-05)
    Mechanical properties of carbon fibre reinforced polymer (CFRP) are greatly affected by an interphase between fibre and matrix. Coating fibre with nanofillers has been suggested to improve the interphase properties. In this paper, a multiscale modelling framework was developed to investigate how graphene nanoplatelets (GnPs) influence the mechanical properties of CFRP laminate by reinforcing the interphase. At the nanoscale, the Mori-Tanaka homogenisation method was used to determine effective properties of the GnPs reinforced interphase. GnPs reinforced interphase properties at different GnPs orientations, and volume fractions were examined. At the microscale, a 3-D representative volume element (RVE) model based on obtained interphase properties was used to predict the elastic constants of CFRP unidirectional lamina. This RVE model consisted of three phases: carbon fibre, epoxy resin and the GnPs reinforced interphase. The incorporation of GnPs in the interphase increased both longitudinal and transverse lamina moduli. Finally, simulations of the three-point bending test were performed on the macroscale CFRP laminate. The macroscale modelling based on predicted lamina properties was found to reproduce experimentally measured flexural modulus well. It was found that the GnPs coating on fibre has a positive influence on the mechanical properties of CFRP, and the enhancement varied with orientation and local volume fraction of GnPs. In the presence of GnPs coating, 0° and 90° flexural moduli of CFRP laminate increased by 6.1% and 28.3% respectively.
  • Facile template-free synthesis of hierarchically porous NiO hollow architectures with high-efficiency adsorptive removal of Congo red

    Hu, Hanmei; Deng, Chonghai; Sun, Mei; Zhang, Kehua; Wang, Man; Xu, Jiayi; Le, Huirong; Hefei University; University of Derby (Springer, 2019-06-05)
    Hierarchically porous NiO hollow architectures (HPHAs) were synthesized via a one-pot facile chemical bath deposition method and followed by a calcination process. The crystal structure, component and morphology of the products were characterized by various techniques. The results revealed that hierarchical architectures with hollow interior are composed of mesoporous NiO nanoflakes with thickness of about 8 nm. Interestingly, the as-synthesized NiO HPHAs have the unusual three-ordered porous features including a microscale hollow interior and two mesoscale pores which are attributed to the holes on the surface of nanoflakes with an average diameter of about 3.9 nm and the cavities on the wall of microsphere in the range of 20–40 nm in diameter formed by interconnecting nanoflakes. These comprehensive hierarchically porous structures are beneficial for the adsorption performance towards Congo red in water. The absorptive capacity over NiO HPHAs achieved about 1.8 and 4.0 times as high as that of the precursor β-Ni(OH)2 hollow microspheres (HSs) and the commercial activity carbon (AC) under the same conditions. The studies of adsorption kinetics illustrated that the adsorption behavior perfectly obeyed the pseudo-second-order model and the adsorption isotherm fits the Langmuir adsorption assumption well. The maximum adsorption capacities were calculated to be 490.2 mg g−1 according to the Langmuir equation, which is excellent result compared to NiO absorbents. The high-efficiency adsorption capacities for NiO HPHAs are attributed to the large specific surface area, the synergistic effect of micro-mesoporous structure and the electrostatic interaction of NiO with CR molecules. Additionally, NiO HPHAs can be easily renewed and has good chemical stability, indicating a great promising absorbent in the application for the removal of diazo organics in wastewater.
  • Multilayered composite coatings of titanium dioxide nanotubes decorated with zinc oxide and hydroxyapatite nanoparticles: controlled release of Zn and antimicrobial properties against <em>Staphylococcus aureus</em></p>

    Gunputh, Urvashi; Le, Huirong; Besinis, Alexandros; Tredwin, Christopher; Handy, Richard; University of Derby; Plymouth University (Dove Medical Press Ltd., 2019-05-16)
    This study aimed to decorate the surface of TiO2 nanotubes (TiO2 NTs) grown on medical grade Ti-6Al-4V alloy with an antimicrobial layer of nano zinc oxide particles (nZnO) and then determine if the antimicrobial properties were maintained with a final layer of nano-hydroxyapatite (HA) on the composite. The additions of nZnO were attempted at three different annealing temperatures: 350, 450 and 550 °C. Of these temperatures, 350°C provided the most uniform and nanoporous coating and was selected for antimicrobial testing. The LIVE/DEAD assay showed that ZnCl2 and nZnO alone were >90% biocidal to the attached bacteria, and nZnO as a coating on the nanotubes resulted in around 70% biocidal activity. The lactate production assay agreed with the LIVE/DEAD assay. The concentrations of lactate produced by the attached bacteria on the surface of nZnO-coated TiO2 NTs and ZnO/HA-coated TiO2 NTs were 0.13±0.03 mM and 0.37±0.1 mM, respectively, which was significantly lower than that produced by the bacteria on TiO2 NTs alone, 1.09±0.30 mM (Kruskal–Wallis, P<0.05, n=6). These biochemical measurements were correlated with electron micrographs of cell morphology and cell coverage on the coatings. nZnO on TiO2 NTs was a stable and antimicrobial coating, and most of the biocidal properties remained in the presence of nano-HA on the coating.
  • Experimental data of bio self-healing concrete incubated in saturated natural soil

    Souid, Adam; Esaker, Mohamed; Elliott, David; Hamza, Omar; University of Derby (Elsevier, 2019-08-22)
    he provision of suitable incubation environments is vital for successful implementation of bio self-healing concrete (bio-concrete). We investigated the effect of soil incubation to examine if the self-healing process can be activated in comparison with the conventional incubation environment (water). The data was collected from laboratory-scale experiments conducted on mortar specimens. The mortar was impregnated with Bacillus subtilis and this bacteria was encapsulated in calcium alginate for protection from the production process. The mortar specimens were mechanically cracked and then incubated within fine-grained fully saturated natural soil for about 4 weeks. The cracks were inspected before and after incubation by light microscopy to evaluate the healing ratio. The mineral precipitations on crack surfaces were examined by Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray Spectrometry (EDX). The data reflects the efficiency of bio-concrete for certain structures such as tunnels and deep foundation, where concrete elements are exposed to ground conditions.
  • Geohazard assessment of landslides in south Brazil: Case study

    Hamza, Omar; De Vargas, Tiago; Boff, Fernando Eduardo; Hussain, Yawar; Sian Davies-Vollum, K.; University of Derby; Centro Universitário da Serra Gaúcha (FSG); University of Brasilia (Springer Science and Business Media LLC, 2019-09-10)
    Slope instability phenomena such as mudslides represent a major geohazard in Brazil, which has caused devastation in many states and affected the lives of people, particularly in self-built settlements on steep slopes. This paper presents and discusses slope stability issues encountered in Caxias do Sul in the State of Rio Grande do Sul, which exemplifies the existing situation of landslide risk assessment in southern Brazil. Local geology and ground conditions of the area in relation to slope instability were reviewed and gaps in information required for mitigating risk were identified, such as inadequate geotechnical information and lack of full inspection and continuous monitoring of active landslides. Although risk assessment has been developed for the city and regarded as a fundamental management tool in the mitigation of landslide hazards, the study showed that the risk assessment works are outdated and not effectively considered for the development of the city. With significant unplanned urban expansion (where houses have been self-built on very steep terrains without geotechnical assessment of the ground and slope conditions), new geohazard mapping is essentially required. Several key recommendations were provided for mitigating the destructive effect of landslides and improving their management in mountainous urban settings.
  • Effective mean free path and viscosity of confined gases

    Xie, Jianfei; University of Derby; University of Edinburgh; University of Strathclyde; University of Warwick (AIP Publishing, 2019-07-16)
    The molecular mean free path (MFP) of gases in confined geometries is numerically evaluated by means of the direct simulation Monte Carlo method and molecular dynamics simulations. Our results show that if calculations take into account not only intermolecular interactions between gas molecules but also collisions between gas molecules and wall atoms, then a space-dependent MFP is obtained. The latter, in turn, permits one to define an effective viscosity of confined gases that also varies spatially. Both the gas MFP and viscosity variation in surface-confined systems have been questioned in the past. In this work, we demonstrate that this effective viscosity derived from our MFP calculations is consistent with those deduced from the linear-response relationship between the shear stress and strain rate using independent nonequilibrium Couette-style simulations as well as the equilibrium Green-Kubo predictions.
  • Variation of molecular mean free path in confined geometries

    Xie, Jianfei; University of Edinburgh (AIP Publishing, 2019-08-05)
    This paper aims to settle disputes in the literature about the spatial variation of the molecular mean free path (MFP) in confined geometries. The MFP of a gas is determined by using both molecular dynamics (MD) and the direct simulation Monte Carlo (DSMC) technique. In spatially-homogeneous cases, the numerical results exactly recover the kinetic theory predictions of a constant MFP. However, in microchannels, the MFP is found to vary near to the bounding walls and reduce at the surfaces to half of its bulk value as long as collisions between gas molecules and wall atoms are taken into account in the calculation of the MFP.
  • Thematic analysis of the learning experience of joint honours students: their perception of teaching quality, value for money and employability

    Pigden, Louise; Jegede, Franc; University of Derby (Taylor and Francis, 2019-09-04)
    The focus of the research was students’ perceptions of whether joint honours degrees represented a sound student learning experience and led to good academic and employability outcomes. In this minority mode of study for the United Kingdom, students study two academic subjects, rather than the more usual single subject. The qualitative methodology followed was a thematic analysis of self-administered questionnaire data, collected from joint honours students at four English universities in the United Kingdom. The principal results were that the students experienced difficulties in fitting into the two communities of learning for their respective subjects; in being adequately supported; in disparities in teaching, learning and assessment between their two subjects, and in a high workload. The major conclusion was that although the students perceived their learning experiences to have value by virtue of having studied two subjects, a number of issues stymied their achieving the best learning experience possible.
  • Design of heat sinks for wearable thermoelectric generators to power personal heating garments: A numerical study

    Soleimani, Zohreh; Zoras, Stamatis; Cui, Yuanlong; Ceranic, Boris; Shahzad, Sally; University of Derby; University of Sheffield (Institute of Physics, 2019-06-01)
    To mitigate climate change attributed to the built environments, there have been tremendous efforts to improve air conditioning systems in the buildings. The possibility of harvesting body heat as a renewable energy source to power a wearable personal heating system is investigated. The aim of this study is to integrate a wearable personal heating system with a thermoelectric generator (TEG) that harvests the body heat which is used to convert it into electricity. Moreover, the interaction between the TEG configuration and power output is studied. The power generation of TEG system is obtained by COMSOL Multiphysics software. The simulation results concluded that all the four proposed heat sink configurations can improve the power output of the wearable TEG at 1.4 m/s and 3m/s compared to that of the reference model. Furthermore, the perforated and trapezium shapes of heat sinks have a significantly better performance in comparison to conventional heat sinks.
  • Mechanical properties and tribological behaviour of electroless Ni–P–Cu coatings on corrosion-resistant alloys under ultrahigh contact stress with sprayed nanoparticles.

    Leech, Andrew; Le, Huirong; Meng, Maozhou; University of Derby; Plymouth University (Elsevier, 2019-06-20)
    Threaded components manufactured from corrosion resistant alloys (CRA's) are vulnerable to galling. This paper develops a test matrix to systematically investigate the mechanical properties and tribological performance of electroless nickel phosphorous coatings on CRA's when subjected to high contact stress. Samples manufactured from 28Cr stainless steel were shot-peened for various periods prior to being electo/electroless coated. The coefficient of friction (CoF) of different coating systems was evaluated via sliding cross-pin method. Various wet and dry lubricants were utilised to examine tribological performance, furthermore the adhesion strength of the coatings was investigated by a bond and pull-off method. The study has shown a significant reduction in CoF for electroless nickel phosphorous coatings with prior shot-peening treatment and sprayed nanoparticles.
  • Setting a framework for organisational sustainable development

    Liyanage, Kapila; Bastas, Ali; University of Derby (Elsevier, 2019-07-02)
    Increasing worldwide demand for products and services is applying a significant pressure on firms and supply chains operationally and financially, along with negative implications on our planet and the public. New perspectives and approaches are required to be adopted by all members of the society, including the businesses for sustainable development. However, enabling such integration from an organisational management perspective is not straightforward, due to complexities and conflicts associated with balanced integration of economic, environmental and social agendas. Aimed towards addressing this important industrial and societal research requirement, a tailored framework is presented, constructed upon the deeply rooted management principles of quality management (QM)and supply chain management (SCM) to facilitate integration of triple bottom line sustainability into business management. The framework outlines the practical steps for implementation of such an approach, including the quantitative, current state maturity assessment as one of the key application steps. This approach is taken forward to an application step, at an organisation in Cyprus, undertaken through the action research study method that enabled demonstrating both its application, and its positive effects on the sustainable development of the participating organisation. Several contributions are made, including the formulation of a practical approach to organisational integration of triple bottom line sustainability through QM and SCM. Particularly, a new management perspective was introduced with implications to many organisational managers that adopt ISO 9001 and supply chain integration principles, setting a framework for extending these principles beyond their original QM and SCM agendas towards organisational sustainable development.
  • The impacts of sustainability, extended producer responsibility and the circular economy on product pricing models

    Takhar, Sukhraj; Liyanage, Kapila; Department of Mechanical Engineering & the Built Environment (Gupta Publications, 2019-07)
    This paper examines product pricing in relation to Sustainability, Extended Producer Responsibility and the Circular Economy. Traditional linear economic systems focus on the use of mass production techniques to achieve the most competitively priced products on the marketplace. This in turn requires a large volume of resources to be consumed. The linear economic system is based on a closed loop system, where resources are used in product manufacture, and then used consumed by end user(s), to finally becoming waste products. Increasing consumption of natural resources, led to the evolution of (1) sustainability measures aimed at ensuring producers utilized more sustainable resources; (2) extended producer responsibility (EPR) schemes which placed burdens on producers to bear an economic cost for recovery and recycling activities for products they manufactured, and; (3) the circular economy, which sees producers encouraged to design products which use resources which are capable of being used by the r-imperatives. The results show implementing sustainability, EPR and the circular economy measures do impact costs and product prices.
  • Typological analysis of slidequakes emitted from landslides: experiments on expander body pile and Sobradinho landslide (Brasilia, Brazil)

    Hussain, Y; Hussain, S; Martino, S; Cárdenas-Soto, M; Hamza, O; Rodriguez-Rebolledo, J; Uagoda, R; Martinez-Carvajal, H; University of Brasilia; University of Rome; et al. (Services Paulinelli, 2019-06-19)
    Reactivation of a landslide is usually accompanied by microseismic signals emitted from the deforming soil mass. The reproduction of similar signals in a physical model test conducted under control conditions can allow researchers to explore and test such complicated signals to improve the prediction of full-scale failure. The present study investigates the similarity between the slidequakes (microseismicity) naturally emitted from an existing colluvial landslide (Sobradinho, Brazil) in response to rainfalls and the emissions generated by a pullout test of an expander body (EB) pile in tropical soil under controlled conditions. The microseismic signals emitted from both experimental sites (i.e. the landslide and the EB pile test) were recorded and compared. Data were acquired by mini-arrays of four short-period seismometers. For the signal nomenclature, a typological scheme was adopted, in which sonograms/spectral contents of the signals were used. As a result, short duration microseismic signals were observed during the pullout test. In contrast, at the Sobradinho landslide, the testing detected signals of different characteristics whose source mechanisms have remained ambiguous, mainly because of the short duration of the data campaigns. However, at the landslide, propagating events were observed that might be attributed to the energies generated by the river bedload during the heavy rains. The present study offers some insight into the pre-collapse dynamic behavior of unstable slopes in clayey formations.
  • Monitoring of Sobradinho landslide (Brasilia, Brazil) and a prototype vertical slope by time-lapse interferometry

    Hussain, Y; Cárdenas-Soto, M; Augoda, R; Martino, S; Rodriguez-Rebolledo, J; Hamza, O; Martínez-Carvajal, H; University of Brasilia; National Autonomous University of Mexico; University of Rome; et al. (Sociedade Brasileira de Geologia (Brazil), 2019-06-03)
    The application of geophysical monitoring technologies may offer an opportunity to understand the dynamic of slopes in response to factors triggering their instability. In this study, Ambient Noise Interferometry was used as a monitoring approach on a man-made reduced-scale vertical slope and on a natural-scale landslide in Sobradinho (Brazil), under the influence of mechanical stress and rainfall, respectively. For both experiments, we adopted similar data acquisition system and processing workflow. After preprocessing of ambient seismic noise, the time-lapse changes were determined in terms of relative velocity changes using the moving window cross spectral technique. For the vertical slope, terrestrial laser scanning was also performed to detect crack or fissure generation. The prototype experiment results showed a decreasing trend of relative velocity changes and reached a minimum value of -0.6% at the end of the experiment. No change was detected on the digital elevation model that was computed from terrestrial laser scanning images, due to the absence of centimeter scale superficial fissures. At natural scale (Sobradinho landslide), no significant variation in relative velocity changes was detected for the rainy and non-rainy days, mainly because of the inadequate change in the degree of saturation, which was found within a relatively short period of data acquisition.
  • Electrokinetic treatment of desiccated expansive clay

    Hamza, Omar; Ikin, Jamie; University of Derby (ICE Publishing, 2019-04-23)
    Structures built on shallow foundations in expansive clay, where vegetation and weather condition can significantly reduce the moisture content, must overcome the risk associated with excessive desiccation condition such as shrinkage and settlement. For many existing structures, removal of trees may not necessarily be an effective solution as it might cause swelling and heave on the long-term. This study explores a system that could be operated during prolong drought periods to rehydrate and neutralise the negative pore pressures of expansive clay avoiding the development of excessive desiccation. Electrokinetic (EK) is a proven method that has increasingly been adopted for dewatering and consolidation of fine-grained soils. Our hypothesis is to reverse the EK process by extracting water from saturated stratum below groundwater level and force it into the “early-stage” desiccated area, accelerating the rehydration and reducing suction. The theory was examined by a laboratory model using moderately expansive clay. After draining the soil for 23 days reaching moderate desiccation state, water was allowed into the lower part of the soil while applying the EK treatment using nine electrodes, placed in a radial pattern and inserted 110mm into the soil with approximately 30% of their lengths below the water level. As a result of the electro-osmotic process, the average moisture content increased in the model by more than two-fold within 8 hours. The suction measurement (taken in the middle of the desiccated area) showed an initial slow response followed by fast and consistent reduction rate, where suction dropped by 93% within 5 hours and ultimately down to 1kPa at the end of the treatment. The paper offers some insight into the factors controlling the proposed system and provides a good basis for future research to manage the risks associated with desiccation of expansive soils.
  • Dynamic modeling of non-cylindrical curved viscoelastic single-walled carbon nanotubes based on the second gradient theory

    Malikan, Mohammad; Nguyen, Van Bac; Islamic Azad University; University of Derby (IOP Publishing, 2019-04-17)
    This paper is devoted to the theoretical study of the dynamic response of non-cylindrical curved viscoelastic single-walled carbon nanotubes (SWCNTs). The curved nanotubes are largely used in many engineering applications, but it is challenging in understanding mechanically the dynamic response of these curved SWCNTs when considering the influences of the material viscosity. The viscoelastic damping effect on the dynamic response is considered here by using the Kelvin-Voigt viscoelastic model. A modified shear deformation beam theory is here employed to formulate the governing partial differential equations. When the SWCNTs are considered in a small scale model, quantum impacts are important for a correct evaluation of the mechanical response of the nanosystem. This is here investigated by embedding the well-known nonlocal strain gradient approach into the governing equations. The extracted equations are solved by utilizing the Galerkin analytical approach in which the governing partial differential equations are reduced to ordinary differential equations and numerical findings are achieved for various boundary conditions. In order to evaluate the efficiency of the proposed theory, the outcomes in terms of natural frequencies of the vibrating nanotubes are verified with respect to the available literature. It follows a vast systematic study, where several parameters are varied to investigate the influences of geometrical properties involving different polygons of the SWCNTs on the dynamic response.

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