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Over the last 10 years, a dispersion of applications of additive manufacturing (AM) into various fields has emerged. One area in which AM has created a surge of research interest and innovation in recent years relates to the fabrication of smart materials, which is fueled by the ever-broadening scope of deployment of functional devices. As researchers embrace this new paradigm, the spread merits a careful appraisal of the trends to understand the dynamics of evolution of this technology in different sub-fields. In light of the aforesaid, this paper chronicles the recent progress and presents a snapshot of reported resources and processing considerations enabling the accelerated adoption of fused deposition modelling (FDM) for polymeric smart structures. Sections of the review capture reported processing conditions and properties of components fabricated with FDM using either piezoelectric poly(vinylidene fluoride) polymer along with its composites or shape memory polymers/composites. The review highlights applications that range from simple planar structures, lattice/auxetic structures, energetic composites, adaptive/shape-morphing metamaterials, to thermo-/optical-/hydro-sensitive components. It is surmised that while the adoption of FDM in this area has been rapid, more concerted efforts are needed concerning the synthesis of smart polymer feedstocks, process simulation for defect minimization, tuning of the FDM process, and standardization of tests for characterizations of fabricated samples.
K.B. Mustapha; Khaled Mohamed Metwalli. A Review of Fused Deposition Modelling for 3D Printing of Smart Polymeric Materials and Composites. European Polymer Journal 2021, 156, 110591 .
AMA StyleK.B. Mustapha, Khaled Mohamed Metwalli. A Review of Fused Deposition Modelling for 3D Printing of Smart Polymeric Materials and Composites. European Polymer Journal. 2021; 156 ():110591.
Chicago/Turabian StyleK.B. Mustapha; Khaled Mohamed Metwalli. 2021. "A Review of Fused Deposition Modelling for 3D Printing of Smart Polymeric Materials and Composites." European Polymer Journal 156, no. : 110591.
Medium-density fibreboard (MDF) belongs to a class of engineered wood products facilitating efficient use of wood wastes. For this class of materials, the development of predictive models is crucial for the simulation of their responses under mechanical loads. In this study, samples of sandwich structures based on MDF as the skins and a mushroom-based foam as the core are fabricated and tested under edgewise compression tests. Results from the tests support the idea that increasing the thickness of the skins strengthens the response of the sandwich structure against buckling failure, but also revealed that thicker skins are susceptible to complex failure modes. Towards data-driven constitutive modelling of the nonlinear elastic-plastic response of this bio-based structure, predictive models premised on feedforward backpropagation neural network (FFNN), cascade-forward backpropagation neural network (CFNN), and generalized regression neural network (GRNN) were developed. Performance of the models was assessed via error criteria that include the coefficient of determination (R2), root mean squared error (RMSE) and mean absolute error (MAE). Results from the models indicate that CFNN with 15 hidden neurons under the Levenberg-Marquardt backpropagation training algorithm outperformed FFNN and GRNN models, with R2=1.0, RMSE=0.0030 and MAE=0.0019.
Yong Jie Wong; K.B. Mustapha; Yoshihisa Shimizu; Akinori Kamiya; Senthil Kumar Arumugasamy. Development of surrogate predictive models for the nonlinear elasto-plastic response of medium density fibreboard-based sandwich structures. International Journal of Lightweight Materials and Manufacture 2021, 4, 302 -314.
AMA StyleYong Jie Wong, K.B. Mustapha, Yoshihisa Shimizu, Akinori Kamiya, Senthil Kumar Arumugasamy. Development of surrogate predictive models for the nonlinear elasto-plastic response of medium density fibreboard-based sandwich structures. International Journal of Lightweight Materials and Manufacture. 2021; 4 (3):302-314.
Chicago/Turabian StyleYong Jie Wong; K.B. Mustapha; Yoshihisa Shimizu; Akinori Kamiya; Senthil Kumar Arumugasamy. 2021. "Development of surrogate predictive models for the nonlinear elasto-plastic response of medium density fibreboard-based sandwich structures." International Journal of Lightweight Materials and Manufacture 4, no. 3: 302-314.
Taofeeq Ibn-Mohammed; Khameel B. Mustapha. Life Cycle Analysis of Solar Photovoltaic Technologies. Photovoltaic Sustainability and Management 2021, 1 -28.
AMA StyleTaofeeq Ibn-Mohammed, Khameel B. Mustapha. Life Cycle Analysis of Solar Photovoltaic Technologies. Photovoltaic Sustainability and Management. 2021; ():1-28.
Chicago/Turabian StyleTaofeeq Ibn-Mohammed; Khameel B. Mustapha. 2021. "Life Cycle Analysis of Solar Photovoltaic Technologies." Photovoltaic Sustainability and Management , no. : 1-28.
The World Health Organization declared COVID-19 a global pandemic on the 11th of March 2020, but the world is still reeling from its aftermath. Originating from China, cases quickly spread across the globe, prompting the implementation of stringent measures by world governments in efforts to isolate cases and limit the transmission rate of the virus. These measures have however shattered the core sustaining pillars of the modern world economies as global trade and cooperation succumbed to nationalist focus and competition for scarce supplies. Against this backdrop, this paper presents a critical review of the catalogue of negative and positive impacts of the pandemic and proffers perspectives on how it can be leveraged to steer towards a better, more resilient low-carbon economy. The paper diagnosed the danger of relying on pandemic-driven benefits to achieving sustainable development goals and emphasizes a need for a decisive, fundamental structural change to the dynamics of how we live. It argues for a rethink of the present global economic growth model, shaped by a linear economy system and sustained by profiteering and energy-gulping manufacturing processes, in favour of a more sustainable model recalibrated on circular economy (CE) framework. Building on evidence in support of CE as a vehicle for balancing the complex equation of accomplishing profit with minimal environmental harms, the paper outlines concrete sector-specific recommendations on CE-related solutions as a catalyst for the global economic growth and development in a resilient post-COVID-19 world.
T. Ibn-Mohammed; K.B. Mustapha; J. Godsell; Z. Adamu; K.A. Babatunde; D.D. Akintade; A. Acquaye; H. Fujii; M.M. Ndiaye; F.A. Yamoah; S.C.L. Koh. A critical analysis of the impacts of COVID-19 on the global economy and ecosystems and opportunities for circular economy strategies. Resources, Conservation and Recycling 2020, 164, 105169 -105169.
AMA StyleT. Ibn-Mohammed, K.B. Mustapha, J. Godsell, Z. Adamu, K.A. Babatunde, D.D. Akintade, A. Acquaye, H. Fujii, M.M. Ndiaye, F.A. Yamoah, S.C.L. Koh. A critical analysis of the impacts of COVID-19 on the global economy and ecosystems and opportunities for circular economy strategies. Resources, Conservation and Recycling. 2020; 164 ():105169-105169.
Chicago/Turabian StyleT. Ibn-Mohammed; K.B. Mustapha; J. Godsell; Z. Adamu; K.A. Babatunde; D.D. Akintade; A. Acquaye; H. Fujii; M.M. Ndiaye; F.A. Yamoah; S.C.L. Koh. 2020. "A critical analysis of the impacts of COVID-19 on the global economy and ecosystems and opportunities for circular economy strategies." Resources, Conservation and Recycling 164, no. : 105169-105169.
In the light of its versatility, the additive manufacturing technology is shaping up to be a boon for the fabrication of advanced structures. As demands soar for the accelerated adoption of this emerging technology, understanding the mechanics of parts derived from the process is crucial to reaping its full potential. In this study, six different unit cells are used to build up different architected structures with artificially introduced missing unit cells. The six structures are screened using the finite element analysis after which focus is restricted to two, which are then produced via the fused filament fabrication method. Assessments of the compressive resistance of the architected structures are conducted. Results indicate a considerable gradual deterioration of the buckling and compressive resistance with an increasing number of missing cells. At higher compressive loads, rupture of unit cells, cracks, minor wrinkling and tearing of the architected structures were observed.
Khameel B. Mustapha; Mohammad Saad; Yousif A. Abakr. Flatwise Compression and Buckling Characterizations of Adhesive-Free Additively Manufactured Defected Architected Structures. Recent Advances in Computational Mechanics and Simulations 2020, 279 -289.
AMA StyleKhameel B. Mustapha, Mohammad Saad, Yousif A. Abakr. Flatwise Compression and Buckling Characterizations of Adhesive-Free Additively Manufactured Defected Architected Structures. Recent Advances in Computational Mechanics and Simulations. 2020; ():279-289.
Chicago/Turabian StyleKhameel B. Mustapha; Mohammad Saad; Yousif A. Abakr. 2020. "Flatwise Compression and Buckling Characterizations of Adhesive-Free Additively Manufactured Defected Architected Structures." Recent Advances in Computational Mechanics and Simulations , no. : 279-289.
A model is proposed for investigating the size-dependent frequency response of arbitrarily oriented microscale frames used in the build-up of lattice structures with micro unit cells. The model employs the Rayleigh–Love, the Timoshenko and the modified couple stress theories to overcome the weaknesses of the conventional theories. Descriptions of the model and finite element implementation are presented. Predictions from the reduced forms of the model agree with published results. The frequency analyses of different microscale frames reveal the influence of material lengthscale, dead weight, lateral inertia and orientation angles. For small aspect ratios, neglecting the lateral inertia effect incurs a substantial error in predicting the frequencies of higher modes, but only marginally affects the lower modes. The resonant frequencies exhibit a sharp drop in the presence of dead weight, but it increases in the presence of material lengthscale.
Khameel B Mustapha. Free vibration of microscale frameworks using modified couple stress and a combination of Rayleigh–Love and Timoshenko theories. Journal of Vibration and Control 2020, 26, 1285 -1310.
AMA StyleKhameel B Mustapha. Free vibration of microscale frameworks using modified couple stress and a combination of Rayleigh–Love and Timoshenko theories. Journal of Vibration and Control. 2020; 26 (13-14):1285-1310.
Chicago/Turabian StyleKhameel B Mustapha. 2020. "Free vibration of microscale frameworks using modified couple stress and a combination of Rayleigh–Love and Timoshenko theories." Journal of Vibration and Control 26, no. 13-14: 1285-1310.
The rising cost of energy and concerns about the environmental impact of manufacturing processes have necessitated the need for more efficient and sustainable manufacturing. The ceramic industry is an energy intensive industrial sector and consequently the potential to improve energy efficiency is huge, particularly through the introduction of modern sintering technologies. Although several energy efficient sintering processes have been developed, there is no comprehensive techno-economic analysis which compares and contrasts these techniques. This paper presents a critical review and analysis of a number of sintering techniques and compares them with the recently developed cold sintering process (CSP), including mode of operation, sintering mechanism, typical heating rates, duration of sintering, energy consumption profile and energy saving potential, limitations, key challenges for further development and current research efforts. By using a figure of merit, pounds per tonne of CO2 saved (£/tCO2-eq), which links initial capital investment with energy savings, within a framework derived from ranking principles such as marginal abatement cost curves and Pareto optimisation, we have demonstrated that under the scenarios considered for 3 separate functional oxides ZnO, PZT and BaTiO3, CSP is the most economically attractive sintering option, indicating lower capital costs and best return on investment as well as considerable energy and emission savings. Although the current work establishes the viability of CSP as a competitive and sustainable alternative to other sintering techniques, the transition from laboratory to industry of CSP will require hugely different facilities and instrumentation as well as relevant property/performance validation to realise its full potential.
T. Ibn-Mohammed; C.A. Randall; Khameel Mustapha; Jing Guo; J. Walker; S. Berbano; S.C.L. Koh; D. Wang; D.C. Sinclair; I.M. Reaney. Decarbonising ceramic manufacturing: A techno-economic analysis of energy efficient sintering technologies in the functional materials sector. Journal of the European Ceramic Society 2019, 39, 5213 -5235.
AMA StyleT. Ibn-Mohammed, C.A. Randall, Khameel Mustapha, Jing Guo, J. Walker, S. Berbano, S.C.L. Koh, D. Wang, D.C. Sinclair, I.M. Reaney. Decarbonising ceramic manufacturing: A techno-economic analysis of energy efficient sintering technologies in the functional materials sector. Journal of the European Ceramic Society. 2019; 39 (16):5213-5235.
Chicago/Turabian StyleT. Ibn-Mohammed; C.A. Randall; Khameel Mustapha; Jing Guo; J. Walker; S. Berbano; S.C.L. Koh; D. Wang; D.C. Sinclair; I.M. Reaney. 2019. "Decarbonising ceramic manufacturing: A techno-economic analysis of energy efficient sintering technologies in the functional materials sector." Journal of the European Ceramic Society 39, no. 16: 5213-5235.
In this study, sandwich structures with commercial-grade aluminium alloy skins and bio-inspired core (mycofoam) were fabricated and tested to obtain the axial compression response in terms of in-plane deformation measures and stress. The ensuing spectrum of response data from experimental tests were then fed into three different data driven models that include simple linear regression (SLR), artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS). The performance of the models is compared in estimating the compressive response of sandwich panels with the mycofoam. To assess the performance of models, coefficient of determination (R2), root mean squared error (RMSE) and mean absolute error (MAE) are used. Eleven different training algorithms are tested in ANN and Bayesian Regularization backpropagation with 9 hidden neurons is found to be the optimum ANN structure. In ANFIS model, triangular-shaped membership function (MF) with 20 rules gives the highest performance among 8 different MFs. All three models are found to be capable in estimating the compressive response. ANFIS model has the highest performance, followed by ANN model then SLR model with R2, RMSE and MAE being 0.9999, 0.0818, 0.0415 for the training dataset; 0.9999, 0.1626, 0.0491 for the testing dataset and 0.9999, 0.0943, 0.0437 for the validation dataset, respectively.
Yong Jie Wong; Senthil Kumar Arumugasamy; K.B. Mustapha. Development of a computational predictive model for the nonlinear in-plane compressive response of sandwich panels with bio-foam. Composite Structures 2019, 212, 423 -433.
AMA StyleYong Jie Wong, Senthil Kumar Arumugasamy, K.B. Mustapha. Development of a computational predictive model for the nonlinear in-plane compressive response of sandwich panels with bio-foam. Composite Structures. 2019; 212 ():423-433.
Chicago/Turabian StyleYong Jie Wong; Senthil Kumar Arumugasamy; K.B. Mustapha. 2019. "Development of a computational predictive model for the nonlinear in-plane compressive response of sandwich panels with bio-foam." Composite Structures 212, no. : 423-433.
This book addresses the static and dynamic analysis of linear elastic size-dependent structures based on the modified couple stress theory. It focuses on establishing the governing equations of the size-dependent structures, deriving the associated finite element models, and implementing those models using the R programming language. The implemented functions are employed to develop a special R package (equivalent to a MATLAB toolbox) called microfiniteR for this book. In each chapter, the governing equations are formulated using the variational method, and the behaviour of the structures is examined on the basis of their load-deformation characteristics (in the case of static analyses) and by evaluating their eigenvalues (in the case of dynamics and buckling problems). The first chapter introduces readers to the R programming language, beginning with the resources needed to make use of the language and ending with a list of recommended texts. The remaining chapters cover the requisite linear elastic theory and highlight the implemented R functions. Each chapter concludes with a brief summary and relevant references.
Khameel B. Mustapha. R for Finite Element Analyses of Size-dependent Microscale Structures. Tunable Low-Power Low-Noise Amplifier for Healthcare Applications 2019, 1 .
AMA StyleKhameel B. Mustapha. R for Finite Element Analyses of Size-dependent Microscale Structures. Tunable Low-Power Low-Noise Amplifier for Healthcare Applications. 2019; ():1.
Chicago/Turabian StyleKhameel B. Mustapha. 2019. "R for Finite Element Analyses of Size-dependent Microscale Structures." Tunable Low-Power Low-Noise Amplifier for Healthcare Applications , no. : 1.
This article presents a short overview of wood-based sandwich structures. Focusing on structures with wood-based skins and wood-based core materials, the article addressed the methods of manufacturing and highlighted the mechanical properties along with the applications of this greenest group of sustainable sandwich materials. A list of links to international standards normally employed in testing the mechanical properties and further details about these structures are provided at the end of the article.
Khameel B. Mustapha. Manufacturing, Applications and Mechanical Properties of Lightweight Wood-Based Sandwich Panels. Encyclopedia of Renewable and Sustainable Materials 2018, 411 -416.
AMA StyleKhameel B. Mustapha. Manufacturing, Applications and Mechanical Properties of Lightweight Wood-Based Sandwich Panels. Encyclopedia of Renewable and Sustainable Materials. 2018; ():411-416.
Chicago/Turabian StyleKhameel B. Mustapha. 2018. "Manufacturing, Applications and Mechanical Properties of Lightweight Wood-Based Sandwich Panels." Encyclopedia of Renewable and Sustainable Materials , no. : 411-416.
Khameel Bayo Mustapha. Finite Element Computations in Mechanics with R. Finite Element Computations in Mechanics with R 2018, 1 .
AMA StyleKhameel Bayo Mustapha. Finite Element Computations in Mechanics with R. Finite Element Computations in Mechanics with R. 2018; ():1.
Chicago/Turabian StyleKhameel Bayo Mustapha. 2018. "Finite Element Computations in Mechanics with R." Finite Element Computations in Mechanics with R , no. : 1.
Open access articleSolar cells are considered as one of the prominent sources of renewable energy suitable for large-scale adoption in a carbon-constrained world and can contribute to reduced reliance on energy imports, whilst improving the security of energy supply. A new arrival in the family of solar cells technologies is the organic-inorganic halide perovskite. The major thrust for endorsing these new solar cells pertains to their potential as an economically\ud and environmentally viable option to traditional silicon-based technology. To verify this assertion, this paper presents a critical review of some existing photovoltaic (PV) technologies in comparison with perovskite structured solar cells (PSCs), including material and performance parameters, production processes and manufacturing complexity, economics, key technological challenges for further developments and current research efforts. At present, there is limited environmental assessment of PSCs and consequently, a\ud methodologically robust and environmentally expansive lifecycle supply chain assessment of two types of PSC modules A and B is also undertaken within the context of other PV technologies, to assess their potential for environmentally friendly innovation in the energy sector. Module A is based on MAPbX3 perovskite structure while module B is based on CsFAPbX3 with improved stability, reproducibility and high performance efficiency.\ud The main outcomes, presented along with sensitivity analysis, show that PSCs offer more environmentally friendly and sustainable option, with the least energy payback period, as compared to other PV technologies.\ud The review and analysis presented provide valuable insight and guidance in identifying pathways and windows of opportunity for future PV designs towards cleaner and sustainable energy production
T. Ibn-Mohammed; S.C.L. Koh; Ian Reaney; Adolf Acquaye; G. Schileo; Khameel Mustapha; Richard Greenough. Perovskite solar cells: An integrated hybrid lifecycle assessment and review in comparison with other photovoltaic technologies. Renewable and Sustainable Energy Reviews 2017, 80, 1321 -1344.
AMA StyleT. Ibn-Mohammed, S.C.L. Koh, Ian Reaney, Adolf Acquaye, G. Schileo, Khameel Mustapha, Richard Greenough. Perovskite solar cells: An integrated hybrid lifecycle assessment and review in comparison with other photovoltaic technologies. Renewable and Sustainable Energy Reviews. 2017; 80 ():1321-1344.
Chicago/Turabian StyleT. Ibn-Mohammed; S.C.L. Koh; Ian Reaney; Adolf Acquaye; G. Schileo; Khameel Mustapha; Richard Greenough. 2017. "Perovskite solar cells: An integrated hybrid lifecycle assessment and review in comparison with other photovoltaic technologies." Renewable and Sustainable Energy Reviews 80, no. : 1321-1344.
Some high-speed rotating micro-machines and micro-vibration devices rely on the use of whirling micro-shafts subject to the effect of gravity and magnetic fields. At present, the consequences of the interaction between the elastic deformation of such shafts and the magnetic/gravitational field effects remain unresolved. Focusing on micro-scale whirling shafts with very high torsional rigidity, this study presents a theoretical treatment grounded in the theory of micro-continuum elasticity to examine the ramification of this interaction. The differential transformation method (DTM) is used to obtain extensive numerical results for qualitative assessments of the magnetic-gravitational effects interaction on standing, hanging and horizontally positioned spinning micro-scale shafts. The influence of bearing-support flexibility on the response of the whirling micro-shaft is also considered with rotational and translational springs. The gravitational sag reduces the stability of whirling standing micro-shafts and increases that of the hanging micro-shafts. Further, for all the micro-shafts configurations investigated, the magnetic field is observed to stiffen the response of the shaft and favorably shifts the critical points of vibration of the whirling shafts forward.
K. B. Mustapha; Z. W. Zhong; S. B. A. Kashem. Vibration Behavior of Gravity-Loaded Whirling Micro-Scale Shafts Influenced by an Axial Magnetic Field. International Journal of Structural Stability and Dynamics 2017, 17, 1750110 .
AMA StyleK. B. Mustapha, Z. W. Zhong, S. B. A. Kashem. Vibration Behavior of Gravity-Loaded Whirling Micro-Scale Shafts Influenced by an Axial Magnetic Field. International Journal of Structural Stability and Dynamics. 2017; 17 (9):1750110.
Chicago/Turabian StyleK. B. Mustapha; Z. W. Zhong; S. B. A. Kashem. 2017. "Vibration Behavior of Gravity-Loaded Whirling Micro-Scale Shafts Influenced by an Axial Magnetic Field." International Journal of Structural Stability and Dynamics 17, no. 9: 1750110.
Developments in micro-systems’ operations rely on identifying and controlling the dynamic responses of micrometre-scale elements. Pre-twisted micro-elements feature prominently in these systems, yet very little is known about the interacting effect of motley factors on their behaviours. Presented here is a model of pre-twisted micro-beams that accounts for the coupling of scale-dependent, rotary inertia and spinning effects in vibratory and wave propagation analyses. In tackling the problem, the system’s physical domain is transformed into the mathematical realm via a scale-dependent micro-continuum theory, while its time evolution is captured by Hamiltonian mechanics. Analytic expressions are obtained for the long-wavelength limit and dispersion relations. The spectrum relations of the waves are established from an octic characteristics equation (which, being in violation of the Abel–Ruffini theorem is treated numerically). Splitting of the waves within the system is observed, and the frequencies of the split shift for altered values of the pre-twist angle and rotary inertia effect. Thinner, highly pre-twisted micro-scale beams experience a widening (narrowing) of the difference between the two phase speeds (group velocities) of the waves. Further, pre-twisting lowers the natural frequencies associated with odd-numbered modes of vibration of the element, while the small-scale effect strongly affects the higher vibration modes.
K. B. Mustapha. Dynamic behaviours of spinning pre-twisted Rayleigh micro-beams. European Journal of Computational Mechanics 2017, 26, 473 -507.
AMA StyleK. B. Mustapha. Dynamic behaviours of spinning pre-twisted Rayleigh micro-beams. European Journal of Computational Mechanics. 2017; 26 (5-6):473-507.
Chicago/Turabian StyleK. B. Mustapha. 2017. "Dynamic behaviours of spinning pre-twisted Rayleigh micro-beams." European Journal of Computational Mechanics 26, no. 5-6: 473-507.
Considered as a less hazardous piezoelectric material, potassium sodium niobate (KNN) has been in the fore of the search for replacement of lead (Pb) zirconate titanate for piezoelectrics applications. Here, we challenge the environmental credentials of KNN due to the presence of ~60 wt% Nb2O5, a substance much less toxic to humans than Pb oxide, but whose mining and extraction cause significant environmental damage.
T. Ibn-Mohammed; S. C. L. Koh; I. M. Reaney; D. C. Sinclair; Khameel Mustapha; Adolf Acquaye; D. Wang. Are lead-free piezoelectrics more environmentally friendly? MRS Communications 2017, 7, 1 -7.
AMA StyleT. Ibn-Mohammed, S. C. L. Koh, I. M. Reaney, D. C. Sinclair, Khameel Mustapha, Adolf Acquaye, D. Wang. Are lead-free piezoelectrics more environmentally friendly? MRS Communications. 2017; 7 (1):1-7.
Chicago/Turabian StyleT. Ibn-Mohammed; S. C. L. Koh; I. M. Reaney; D. C. Sinclair; Khameel Mustapha; Adolf Acquaye; D. Wang. 2017. "Are lead-free piezoelectrics more environmentally friendly?" MRS Communications 7, no. 1: 1-7.
Approximate numerical solutions are obtained for the vibration response of a functionally graded (FG) micro-scale beam entrapped within an axially-directed magnetic field using the differential transformation method (DTM). Idealized as a one-dimensional (1D) continuum with a noticeable microstructural effect and a thickness-directed material gradient, the microbeam’s behavior is studied under a range of nonclassical boundary conditions. The immanent microstructural effect of the micro-scale beam is accounted for through the modified couple stress theory (MCST), while the microscopic inhomogeneity is smoothened with the classical rule of mixture. The study demonstrates the robustness and flexibility of the DTM in providing benchmark results pertaining to the free vibration behavior of the FG microbeams under the following boundary conditions: (a) Clamped-tip mass; (b) clamped-elastic support (transverse spring); (c) pinned-elastic support (transverse spring); (d) clamped-tip mass-elastic support (transverse spring); (e) clamped-elastically supported (rotational and transverse springs); and (f) fully elastically restrained (transverse and rotational springs on both boundaries). The analyses revealed the possibility of using functional gradation to adjust the shrinking of the resonant frequency to zero (rigid-body motion) as the mass ratio tends to infinity. The magnetic field is noted to have a negligibly minimal influence when the gradient index is lower, but a notably dominant effect when it is higher.
K. B. Mustapha; Muhammad A. Hawwa. Eigenanalyses of Functionally Graded Micro-Scale Beams Entrapped in an Axially-Directed Magnetic Field with Elastic Restraints. International Journal of Structural Stability and Dynamics 2016, 16, 1 .
AMA StyleK. B. Mustapha, Muhammad A. Hawwa. Eigenanalyses of Functionally Graded Micro-Scale Beams Entrapped in an Axially-Directed Magnetic Field with Elastic Restraints. International Journal of Structural Stability and Dynamics. 2016; 16 (6):1.
Chicago/Turabian StyleK. B. Mustapha; Muhammad A. Hawwa. 2016. "Eigenanalyses of Functionally Graded Micro-Scale Beams Entrapped in an Axially-Directed Magnetic Field with Elastic Restraints." International Journal of Structural Stability and Dynamics 16, no. 6: 1.
The main aim of this work is to analyze the various heat transport mechanisms and their roles in efficiency enhancement of a thin-film solar cell due to embedded metallic nanoparticles at the rear of the cell, from both electrical and thermal aspects. The nanoparticles present deep inside the cell reflect incident radiation which then increases the optical path length for enhanced electricity generation. The increase in the optical path length also tends to induce additional but undesirable thermal heating which reduces the performance of the cells. The relationship between the improved conversion efficiency and the thermal effect is the crucial factor of maximizing the performance of thin-film solar cells and has yet to be explored. An accurate theoretical/numerical modeling is warranted in this case. Here, we present an analysis of combined light propagation and preliminary phonon transport in the cell to study solar-energy deposition and the associated thermal gradient.
Jia Jiun Lai; Victor N.S. Bong; Basil T. Wong; Khameel B. Mustapha. Modeling of Light Propagation and Phonon Conduction inside Metallic Nanoparticles Enhanced Thin-Film Solar Cells. Journal of Nano Research 2016, 38, 26 -35.
AMA StyleJia Jiun Lai, Victor N.S. Bong, Basil T. Wong, Khameel B. Mustapha. Modeling of Light Propagation and Phonon Conduction inside Metallic Nanoparticles Enhanced Thin-Film Solar Cells. Journal of Nano Research. 2016; 38 ():26-35.
Chicago/Turabian StyleJia Jiun Lai; Victor N.S. Bong; Basil T. Wong; Khameel B. Mustapha. 2016. "Modeling of Light Propagation and Phonon Conduction inside Metallic Nanoparticles Enhanced Thin-Film Solar Cells." Journal of Nano Research 38, no. : 26-35.
This study is concerned with the mathematical modeling of microtubules for torsional vibration analysis. Microtubules (MTs) are prone to mechanical torsion, and hence conductance oscillation, when they act as molecular pathways for cargo transport. The period of this torsional oscillation has an intimate, but yet-to-be-understood relationship with the MTs’ stiffness and end conditions. In the spirit of the foregoing concern, this study embarks on the characterization of the shift in the torsional resonance of an isolated MT in the presence of an end attachment in the form of either outer kinetochores (treated as a torsional spring) or a linker molecule (treated as a concentrated mass). The MT is itself idealized as a strain gradient micro-shaft, with its governing equation augmented by enriched boundary conditions due to the attachments. The solution of the model is then sought through the differential transformation method (DTM). Validation of the reduced form of the model is evaluated with benchmark results in the literature. Under a rapidly increasing magnitude of an attached rotary mass, the analyses indicate the existence of a drift of the frequency towards zero, a scenario that could induce a transition to rigid-body motion. Conversely, in the presence of spring-like elastic anchors, the analyses reveal a softening effect that increases the torsional resonant frequencies of the MT. Sensitivity assessments through Pareto analyses predict an interaction effect between the size-effect and the magnitude of an attached mass.
Khameel B. Mustapha; Basil T. Wong. Torsional frequency analyses of microtubules with end attachments. ZAMM - Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik 2015, 96, 824 -842.
AMA StyleKhameel B. Mustapha, Basil T. Wong. Torsional frequency analyses of microtubules with end attachments. ZAMM - Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik. 2015; 96 (7):824-842.
Chicago/Turabian StyleKhameel B. Mustapha; Basil T. Wong. 2015. "Torsional frequency analyses of microtubules with end attachments." ZAMM - Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik 96, no. 7: 824-842.
Khameel Mustapha; Dong Ruan. Size-dependent axial dynamics of magnetically-sensitive strain gradient microbars with end attachments. International Journal of Mechanical Sciences 2015, 94-95, 96 -110.
AMA StyleKhameel Mustapha, Dong Ruan. Size-dependent axial dynamics of magnetically-sensitive strain gradient microbars with end attachments. International Journal of Mechanical Sciences. 2015; 94-95 ():96-110.
Chicago/Turabian StyleKhameel Mustapha; Dong Ruan. 2015. "Size-dependent axial dynamics of magnetically-sensitive strain gradient microbars with end attachments." International Journal of Mechanical Sciences 94-95, no. : 96-110.
Piezoelectric beams are principal components of energy harvesters that rely on piezoelectric transduction mechanism. Some recent applications of piezoelectric energy harvesters include magnetic field energy scavenging from power lines, and in the detection of magnetic field. The coupling of piezoelectricity and magnetic field holds great potentials for applications in contact free self-powered micro-electromechanical systems (MEMs). In this study, a preliminary assessment is presented, of the influence of an axially-directed magnetic field on the propagation of a packet of transverse elastic waves within a piezoelectric micro-scale beam. Presented results include a qualitative assessment of the effect of voltage variations, the magnetic field and the size-effect parameter on the dispersion relation of the wave. The two limiting branches of the phase and group speeds, inferred through the Descartes' rule of sign, are also illustrated. The study demonstrates the dramatic increase in the propagating speed of the piezoelectric micro-scale beam as its material length scale approaches the geometric length. It also reveals the dampening of the beam's acoustic signature as a result of the axially-directed magnetic field effect.
Kb Mustapha; Basil T. Wong; Mustapha K.; Wong B.T.. Insights into the influence of magnetic fields on the propagation of elastic wave packets within a piezoelectric micro-scale beams. 2015 Joint IEEE International Symposium on the Applications of Ferroelectric (ISAF), International Symposium on Integrated Functionalities (ISIF), and Piezoelectric Force Microscopy Workshop (PFM) 2015, 120 -123.
AMA StyleKb Mustapha, Basil T. Wong, Mustapha K., Wong B.T.. Insights into the influence of magnetic fields on the propagation of elastic wave packets within a piezoelectric micro-scale beams. 2015 Joint IEEE International Symposium on the Applications of Ferroelectric (ISAF), International Symposium on Integrated Functionalities (ISIF), and Piezoelectric Force Microscopy Workshop (PFM). 2015; ():120-123.
Chicago/Turabian StyleKb Mustapha; Basil T. Wong; Mustapha K.; Wong B.T.. 2015. "Insights into the influence of magnetic fields on the propagation of elastic wave packets within a piezoelectric micro-scale beams." 2015 Joint IEEE International Symposium on the Applications of Ferroelectric (ISAF), International Symposium on Integrated Functionalities (ISIF), and Piezoelectric Force Microscopy Workshop (PFM) , no. : 120-123.