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Malaria is an infectious and communicable disease, caused by one or more species of Plasmodium parasites. There are five species of parasites responsible for malaria in humans, of which two, Plasmodium Falciparum and Plasmodium Vivax, are the most dangerous. In Djibouti, the two species of Plasmodium are present in different proportions in the infected population: 77% of P. Falciparum and 33% of P. Vivax. In this study we present a new mathematical model describing the temporal dynamics of Plasmodium Falciparum and Plasmodium Vivax co-infection. We focus briefly on the well posedness of this model and on the calculation of the basic reproductive numbers for the infections with each Plasmodium species that help us understand the long-term dynamics of this model (i.e., existence and stability of various eqiuilibria). Then we use computational approaches to: (a) identify model parameters using real data on malaria infections in Djibouti; (b) illustrate the influence of different estimated parameters on the basic reproduction numbers; (c) perform global sensitivity and uncertainty analysis for the impact of various model parameters on the transient dynamics of infectious mosquitoes and infected humans, for infections with each of the Plasmodium species. The originality of this research stems from employing the FAST method and the LHS method to identify the key factors influencing the progression of the disease within the population of Djibouti. In addition, sensitivity analysis identified the most influential parameter for Falciparium and Vivax reproduction rates. Finally, the uncertainty analysis enabled us to understand the variability of certain parameters on the infected compartments. [ABSTRACT FROM AUTHOR]

In this paper, we develop a fast linearized virtual element method (VEM) for the approximation of the nonlinear time-fractional diffusion equations on polygonal meshes. The L1-scheme with graded meshes is used to deal with the non-smooth system, the Newton linearized method is adopted to handle the nonlinear term and VEM is employed to discrete the spatial variable. Then the error splitting approach is used to prove the unconditional optimal error estimate of the fully discrete linearized L1-VEM scheme. In order to reduce the storage and computational cost caused by the nonlocality of the Caputo fractional operator, a fast memory-saving L1-VEM is developed. It is proved that the difference between the solution of the L1-VEM and the fast L1-VEM can be made arbitrarily small and is independently of the sizes of the time and/or space grids. Finally, numerical results are implemented to verify the theoretical results. [ABSTRACT FROM AUTHOR]

In this paper, a coupled model is built to research the space-fractional magnetohydrodynamic (MHD) flow and heat transfer problem. The fractional coupled model is solved numerically by combining the matrix function vector products method in the temporal direction with the spectral method in the spatial direction. A fast method based on the numerical scheme is established to reduce the computational time. With the help of the Bayesian method, the space-fractional orders of the coupled model are estimated, and the problem of multi-parameter estimation in the coupled model is solved. Finally, a numerical example is carried out to verify the stability of the numerical methods and the effectiveness of the parameter estimation method. Results show that the numerical method is stable, which converges with an accuracy of O (τ 2 + N − r) . The fast method is efficient in reducing the computational time, and the parameter estimation method can effectively estimate parameters in the space-fractional coupled model. The numerical solutions are discussed to describe the effects of several important parameters on the velocity and the temperature. Results indicate that the Lorentz force produced by the MHD flow blocks the movement of the fluid and prolongs the time for the fluid to reach a stable state. But the Hall parameter m weakens this hindrance. The Joule heating effects play a negative role in heat transfer. [ABSTRACT FROM AUTHOR]

From the perspective of magnetohydrodynamics (MHD), the heat transfer properties of Maxwell fluids under MHD conditions with modified dynamic viscosity present complex challenges in numerical simulations. In this paper, we develop a time-fractional coupled model to characterize the heat transfer and MHD flow of Maxwell fluid with consideration of the Hall effect and Joule heating effect and incorporating a modified dynamic viscosity. The fractional coupled model is numerically solved based on the L 1 -algorithm and the spectral collocation method. We introduce a novel approach that integrates advanced algorithms with a fully discrete scheme, focusing particularly on the computational cost. Leveraging this approach, we aim to significantly enhance computational efficiency while ensuring accurate representation of the underlying physics. Through comprehensive numerical experiments, we explain the thermodynamic behavior in the MHD flow process and extensively examine the impact of various critical parameters on both MHD flow and heat transfer. We establish an analytical framework for the MHD flow and heat transfer processes, further investigate the influence of magnetic fields on heat transfer processes, and elucidate the mechanical behavior of fractional Maxwell fluids. [ABSTRACT FROM AUTHOR]

Malaria is an infectious and communicable disease, caused by one or more species of Plasmodium parasites. There are five species of parasites responsible for malaria in humans, of which two, Plasmodium Falciparum and Plasmodium Vivax, are the most dangerous. In Djibouti, the two species of Plasmodium are present in different proportions in the infected population: 77% of P. Falciparum and 33% of P. Vivax. In this study we present a new mathematical model describing the temporal dynamics of Plasmodium Falciparum and Plasmodium Vivax co-infection. We focus briefly on the well posedness of this model and on the calculation of the basic reproductive numbers for the infections with each Plasmodium species that help us understand the long-term dynamics of this model (i.e., existence and stability of various eqiuilibria). Then we use computational approaches to: (a) identify model parameters using real data on malaria infections in Djibouti; (b) illustrate the influence of different estimated parameters on the basic reproduction numbers; (c) perform global sensitivity and uncertainty analysis for the impact of various model parameters on the transient dynamics of infectious mosquitoes and infected humans, for infections with each of the Plasmodium species. The originality of this research stems from employing the FAST method and the LHS method to identify the key factors influencing the progression of the disease within the population of Djibouti. In addition, sensitivity analysis identified the most influential parameter for Falciparium and Vivax reproduction rates. Finally, the uncertainty analysis enabled us to understand the variability of certain parameters on the infected compartments.

In this paper, a fast method to generate a constant-modulus (CM) waveform for a multiple-input, multiple-output, (MIMO) radar is proposed. To simplify the optimization process, the design of the transmit waveform is decoupled from the design of transmit beamformers (TBs) and subpulses. To further improve the computational efficiency, the TBs' optimization is conducted in parallel, and a linear programming model is proposed to match the desired beampattern. Additionally, we incorporate the perturbation vectors into the TBs' optimization so that the TBs can be adjusted to satisfy the CM constraint. To quickly generate the CM subpulses with the desired range-compression (RC) performance, the classical linear frequency modulation (LFM) signal and non-LFM (NLFM) are adopted as subpulses. Meanwhile, to guarantee the RC performance of the final angular waveform, the selection of LFM signal parameters is analyzed to achieve a low cross-correlation between subpulses. Numerical simulations verify the transmit beampattern performance, RC performance, and computational efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

As living standards rise, more and more people are paying attention to their own health, especially issues such as cerebral thrombosis, cerebral infarction, and other cerebral blood flow problems. An accurate simulation of blood flow within cerebral vessels has emerged as a crucial area of research. In this study, we focus on microcirculatory blood flow in ischemic brain tissue and employ a 0D‐1D geometric multi‐scale coupled model to characterize this process. Given the intricate nature of human cerebral vessels, we apply a numerical method combining the finite element method and the third‐order Runge–Kutta method to resolve the coupled model. To enhance computational efficiency, we introduce a fast method based on the reduced‐order extrapolation algorithm. Our numerical example underscores the stability of the method and convergence accuracy to Oh3+τ3, while significantly improving the accuracy and efficiency of blood flow simulation, making the mechanism analysis more accurate. Additionally, we present examples detailing variations and distribution of intracranial pressure and blood flow in ischemic brain tissue throughout a cardiac cycle. Both reduced vascular compliance and vascular stenosis can have adverse effects on intracranial cerebral pressure and blood flow, leading to insufficient local oxygen supply and negative effects on brain function. Meanwhile, there will also be corresponding changes in volume flow and pulsatile blood pressure. [ABSTRACT FROM AUTHOR]

Mercury is a naturally occurring metal found in various inorganic and organic forms within the environment. Due to its high toxicity, there is global concern regarding human exposure to this element. The combination of high-performance liquid chromatography and inductively coupled plasma mass spectrometry (HPLC-ICP-MS) is commonly used to analyze the different forms of mercury in a sample due to its high sensitivity and ability to selectively detect mercury. However, the traditional HPLC-ICP-MS methods are often criticized for their lengthy analysis times. In this study, we have refined the conventional approach by transitioning to ultra-high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (UHPLC-ICP-MS). This modification has resulted in significant reductions in runtime as well as reagent and argon usage, thereby offering a more rapid, environmentally friendly, and cost-effective method. We successfully adapted an HPLC-ICP-MS method to UHPLC-ICP-MS, achieving the analysis of Hg2+ and MeHg+ within 1 min with a mobile phase consumption of only 0.5 mL and a sample volume of 5.0 µL; this is a major advance compared to HPLC analysis with run times generally between 5 and 10 min. The method's performance was assessed by analyzing muscle and liver tissue samples (serving as reference material) from fish, demonstrating the versatility of the method in relation to different complex matrices. [ABSTRACT FROM AUTHOR]

In the topology optimization design and strength check of a vehicle-mounted howitzer cab, it is necessary to obtain plenty of impact load laws under different firing conditions. How to obtain the impact load on the cab quickly is one of the challenges in the design of a vehicle-mounted howitzer. In this paper, the deep learning (DL) method is introduced to solve the impact load on the cab. A fast prediction method for cab impact load based on a ConvLSTM multidimensional feature neural network is proposed. The calculation of the impact load on the cab under different operating conditions is achieved, and the solving speed is close to the real-time level. The numerical examples show that the accuracy of the DL model is comparable to that of traditional computational fluid dynamics (CFD) simulation, but the solving time is on the millisecond level. The computational efficiency has been greatly improved, with the potential for offline training and online computing. When there is a slight change in the morphology of the cab, the proposed model remains applicable. The results can quickly provide load conditions for cab strength checking and topology optimization, help to shorten the development period of a vehicle-mounted howitzer, and lay the foundation for the construction of a digital twin model of a vehicle-mounted howitzer system. [ABSTRACT FROM AUTHOR]

In this paper, we first establish a new fractional magnetohydrodynamic (MHD) coupled flow and heat transfer model for a generalized second-grade fluid. This coupled model consists of a fractional momentum equation and a heat conduction equation with a generalized form of Fourier law. The second-order fractional backward difference formula is applied to the temporal discretization and the Legendre spectral method is used for the spatial discretization. The fully discrete scheme is proved to be stable and convergent with an accuracy of O(τ2 + N−r), where τ is the time step-size and N is the polynomial degree. To reduce the memory requirements and computational cost, a fast method is developed, which is based on a globally uniform approximation of the trapezoidal rule for integrals on the real line. The strict convergence of the numerical scheme with this fast method is proved. We present the results of several numerical experiments to verify the effectiveness of the proposed method. Finally, we simulate the unsteady fractional MHD flow and heat transfer of the generalized second-grade fluid through a porous medium. The effects of the relevant parameters on the velocity and temperature are presented and analyzed in detail. [ABSTRACT FROM AUTHOR]

From the perspective of magnetohydrodynamics (MHD), the heat transfer properties of Maxwell fluids under MHD conditions with modified dynamic viscosity present complex challenges in numerical simulations. In this paper, we develop a time-fractional coupled model to characterize the heat transfer and MHD flow of Maxwell fluid with consideration of the Hall effect and Joule heating effect and incorporating a modified dynamic viscosity. The fractional coupled model is numerically solved based on the L1-algorithm and the spectral collocation method. We introduce a novel approach that integrates advanced algorithms with a fully discrete scheme, focusing particularly on the computational cost. Leveraging this approach, we aim to significantly enhance computational efficiency while ensuring accurate representation of the underlying physics. Through comprehensive numerical experiments, we explain the thermodynamic behavior in the MHD flow process and extensively examine the impact of various critical parameters on both MHD flow and heat transfer. We establish an analytical framework for the MHD flow and heat transfer processes, further investigate the influence of magnetic fields on heat transfer processes, and elucidate the mechanical behavior of fractional Maxwell fluids.

In this paper, a coupled model is built to research the space-fractional magnetohydrodynamic (MHD) flow and heat transfer problem. The fractional coupled model is solved numerically by combining the matrix function vector products method in the temporal direction with the spectral method in the spatial direction. A fast method based on the numerical scheme is established to reduce the computational time. With the help of the Bayesian method, the space-fractional orders of the coupled model are estimated, and the problem of multi-parameter estimation in the coupled model is solved. Finally, a numerical example is carried out to verify the stability of the numerical methods and the effectiveness of the parameter estimation method. Results show that the numerical method is stable, which converges with an accuracy of O(τ2+N−r). The fast method is efficient in reducing the computational time, and the parameter estimation method can effectively estimate parameters in the space-fractional coupled model. The numerical solutions are discussed to describe the effects of several important parameters on the velocity and the temperature. Results indicate that the Lorentz force produced by the MHD flow blocks the movement of the fluid and prolongs the time for the fluid to reach a stable state. But the Hall parameter m weakens this hindrance. The Joule heating effects play a negative role in heat transfer.

In this paper, a fast method to generate a constant-modulus (CM) waveform for a multiple-input, multiple-output, (MIMO) radar is proposed. To simplify the optimization process, the design of the transmit waveform is decoupled from the design of transmit beamformers (TBs) and subpulses. To further improve the computational efficiency, the TBs’ optimization is conducted in parallel, and a linear programming model is proposed to match the desired beampattern. Additionally, we incorporate the perturbation vectors into the TBs’ optimization so that the TBs can be adjusted to satisfy the CM constraint. To quickly generate the CM subpulses with the desired range-compression (RC) performance, the classical linear frequency modulation (LFM) signal and non-LFM (NLFM) are adopted as subpulses. Meanwhile, to guarantee the RC performance of the final angular waveform, the selection of LFM signal parameters is analyzed to achieve a low cross-correlation between subpulses. Numerical simulations verify the transmit beampattern performance, RC performance, and computational efficiency of the proposed method.

In this paper, we study the magnetohydrodynamic (MHD) flow and heat transfer of the fractional Jeffrey fluid in a straight channel, of which the cross section is a two-dimensional irregular convex domain. We consider a spatial fractional operator to modify the classical Fourier's law of thermal conduction, and obtain the time-space fractional coupled model. The fractional coupled model is solved numerically by the L 2 − 1 σ method in the temporal direction and the unstructured mesh finite element method in the spatial direction. Besides, we prove the stability and convergence of the numerical scheme. In order to reduce the computational time, a fast method is proposed. Finally, a numerical example is given to verify the theoretical analysis and the efficiency of the fast method. Furthermore, an example is considered to discuss the effects of the fractional parameters on the MHD flow and heat transfer of the fractional Jeffrey fluid. [ABSTRACT FROM AUTHOR]

Mercury is a naturally occurring metal found in various inorganic and organic forms within the environment. Due to its high toxicity, there is global concern regarding human exposure to this element. The combination of high-performance liquid chromatography and inductively coupled plasma mass spectrometry (HPLC-ICP-MS) is commonly used to analyze the different forms of mercury in a sample due to its high sensitivity and ability to selectively detect mercury. However, the traditional HPLC-ICP-MS methods are often criticized for their lengthy analysis times. In this study, we have refined the conventional approach by transitioning to ultra-high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (UHPLC-ICP-MS). This modification has resulted in significant reductions in runtime as well as reagent and argon usage, thereby offering a more rapid, environmentally friendly, and cost-effective method. We successfully adapted an HPLC-ICP-MS method to UHPLC-ICP-MS, achieving the analysis of Hg2+ and MeHg+ within 1 min with a mobile phase consumption of only 0.5 mL and a sample volume of 5.0 µL; this is a major advance compared to HPLC analysis with run times generally between 5 and 10 min. The method’s performance was assessed by analyzing muscle and liver tissue samples (serving as reference material) from fish, demonstrating the versatility of the method in relation to different complex matrices.

Piecewise linear interpolation has been widely applied to discretize the Caputo fractional derivative operator that yields the widely used L1 method. In this paper, a corrected L1 method is proposed for discretizing the Caputo fractional derivative operator, which achieves the similar level of accuracy as that of the L1 method. The corrected L1 method is applied to solve the fractional initial value and time-fractional subdiffusion problems, the convergence of the corresponding numerical schemes is rigorous proved. In order to reduce the storage and computational cost caused by the nonlocality of the Caputo fractional operator, a fast memory-saving corrected L1 method is developed. It is proved that the difference between the solution of the corrected L1 method and the fast corrected L1 method can be made arbitrarily small and is independently the sizes of the time and/or space grids.Numerical results support the theoretical analysis. [ABSTRACT FROM AUTHOR]

The fractional derivative with nonsingular kernel has been widely used to many physical fields which was shown to offer a new insight into the mathematical modeling of natural phenomena. In this paper, we first study the well‐posedness and regularity of the multidimensional variable‐order time‐fractional reaction–diffusion equation with Caputo–Fabrizio fractional derivative and then present and analyze a Galerkin finite element approximation to the proposed model based on the proved smoothing properties of the solutions. To improve the computational efficiency of the variable‐order Caputo–Fabrizio derivative, we approximate the kernel of the fractional derivative by the K‐term truncation of its Taylor expansion at a fixed fractional order to develop a fast evaluation scheme which significantly reduces the memory requirement from O(N) to O(K) and the computational complexity from O(N2) to O(K2N) where N refers to the number of time steps. We accordingly develop a fast Galerkin finite element method to the proposed model. Numerical experiments are carried out to substantiate the theoretical findings and to show the performance of the fast method. [ABSTRACT FROM AUTHOR]

Molecular imprinting is an efficient strategy to make the detection of compounds more specific and more selective. This targeted analytical strategy using molecularly imprinted polymer (MIP) synthesis needs to obtain the optimized conditions. A selective molecularly imprinted polymer was prepared for caffeic acid (CA) detection after varying the following synthesis parameters: functional monomer type (N-phenylacrylamide, N-PAA or methacrylic acid, MAA), solvent type (acetonitrile/methanol or acetonitrile/toluene), and the polymerization method (UV or thermal initiation). The optimal polymer was obtained using MAA as a functional monomer, acetonitrile/methanol as solvent, and UV polymerization. Morphological characterizations were done for the optimal CA-MIP using mid-infrared spectroscopy, scanning electron microscopy, and nitrogen adsorption. The optimal polymer showed good specificity and selectivity in the presence of interferents (antioxidants having a chemical structure close to CA) in a hydroalcoholic solution. The electrochemical detection of CA was performed by cyclic voltammetry (CV) after the interaction between CA and the optimal MIP in a wine sample. The linear range of the developed method was between 0 and 1.11 mM, the limit of detection (LOD) was 0.13 mM, and the limit of quantification (LOQ) was 0.32 mM. HPLC-UV was used to validate the newly developed method. Recovery values were between 104% and 111%. [ABSTRACT FROM AUTHOR]

In carrying out internal supervision duties, SPI UIN Sunan Kalijaga Yogyakarta innovates by carrying out digital document-based supervision using the Google Drive service. SPI auditors often felt problems in using Google Drive, namely having to check the completeness of financial accountability documents manually one by one by opening a file on Google Drive. One of the goals of developing this application is to facilitate SPI auditors in checking the completeness of financial accountability report documents. The problems can be solved by creating an audit application. The audit application has been developed using the FAST method. Central admin, SPI admin, operator, superior operator, auditor, team leader, technical controller, and Head of SPI are user access rights in this application. The developed application has met the minimum requirements of SPI UIN Sunan Kalijaga Yogyakarta. Other universities can adopt this application.

In this article, we consider the two‐dimensional nonlinear time–space fractional Schrödinger equation with space described by the fractional Laplacian. A second‐order fractional backward difference formula in the temporal direction while Fourier spectral method in the spatial direction is proposed to solve the model numerically. In the numerical implementation, a fast method is applied based on a globally uniform approximation of the trapezoidal rule for the integral on the real line to decrease the memory requirement and computational cost. By using the generalized discrete Gronwall inequality developed by Dixon and McKee and the temporal–spatial error splitting argument, the convergence of the fast time‐stepping numerical method is also proved in a simple manner without imposing the Courant‐Friedrichs‐Lewy (CFL) condition. Finally, some numerical results are provided to support the theoretical analysis. [ABSTRACT FROM AUTHOR]

This paper proposes a 2-dimensional low computational cost mirror Kirchhoff approximation (MKA) and the design of simulation parameters to accurately predict the shadowing gain for an arbitrarily shaped conductor cylinder. The disadvantages of the conventional MKA, such as lacking designs for the simulation parameters and a limited applicable range, have motivated the establishment of an extended MKA. The authors propose the design of the simulation parameters for MKA. The applicable range of MKA is extended to an arbitrarily shaped cylinder by multiple planes. This work finds that only the space domain of the zeroth plane and the angular spectrum domain of the last plane need separate windowing functions for accuracy and the calculation time. The details of those windowing functions are introduced, and their necessities are explained. The authors validate the proposed method for an elliptical conductor cylinder with the size of the human body at millimeter waves (17 GHz – 66.5 GHz). Simulations are conducted by changing the object’s location, direction, and frequencies. The results show that the proposed method presents a good accuracy, which has a low root-mean-square error of less than 0.5 dB by comparing it with a full-wave approach based on the method of moment. Furthermore, the calculation time is improved by 1.4 – 67.2 times by comparing it with the uniform theory of diffraction using special functions.

Molecular imprinting is an efficient strategy to make the detection of compounds more specific and more selective. This targeted analytical strategy using molecularly imprinted polymer (MIP) synthesis needs to obtain the optimized conditions. A selective molecularly imprinted polymer was prepared for caffeic acid (CA) detection after varying the following synthesis parameters: functional monomer type (N-phenylacrylamide, N-PAA or methacrylic acid, MAA), solvent type (acetonitrile/methanol or acetonitrile/toluene), and the polymerization method (UV or thermal initiation). The optimal polymer was obtained using MAA as a functional monomer, acetonitrile/methanol as solvent, and UV polymerization. Morphological characterizations were done for the optimal CA-MIP using mid-infrared spectroscopy, scanning electron microscopy, and nitrogen adsorption. The optimal polymer showed good specificity and selectivity in the presence of interferents (antioxidants having a chemical structure close to CA) in a hydroalcoholic solution. The electrochemical detection of CA was performed by cyclic voltammetry (CV) after the interaction between CA and the optimal MIP in a wine sample. The linear range of the developed method was between 0 and 1.11 mM, the limit of detection (LOD) was 0.13 mM, and the limit of quantification (LOQ) was 0.32 mM. HPLC-UV was used to validate the newly developed method. Recovery values were between 104% and 111%.

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In this work, we find that the matrix representing the curl–curl operator in a partial differential equation solver of Maxwell’s equations can be analytically decomposed into a gradient divergence operator and a Laplacian, both of which can be constructed from the mesh information without any need for computation. The curl–curl operator can hence be replaced by the Laplacian to find the divergence-free component of the field solution. The Laplacian is positive definite and well-conditioned. As a result, the convergence of an iterative solution of Maxwell’s equations can be guaranteed, and also significantly accelerated. Based on the finding, we represent the divergence-free component of the unknown field solution by deducting its curl-free component. The curl-free component resides in the nullspace of the curl–curl operator, which is also analytically known from the mesh information no matter it is a regular grid or an unstructured mesh. After the divergence-free component is rapidly solved from a Laplacian counterpart of the original system matrix, the curl-free component can also be solved from a Laplacian matrix, and hence having fast and guaranteed convergence. The total computational cost of the proposed method is simply a small number of sparse matrix-vector multiplications. The proposed method has been successfully applied to solve ill-conditioned on-chip, packaging, and antenna radiation problems at both low and high frequencies, involving both inhomogeneous dielectrics and lossy conductors. Numerical experiments have demonstrated its fast and guaranteed convergence, as well as trivial computational cost independent of problem size. [ABSTRACT FROM AUTHOR]

The series connection of a standard three-level active neutral-point-clamped (ANPC) inverter and two cascaded H-bridge (CHB) modules comprising the flying capacitors (FCs) instead of the isolated dc voltage sources forms a seven-level hybrid topology that is referred to as improved ANPC (I-ANPC) converter. This article proposes an active voltage balancing technique for control of this hybrid multilevel inverter. The suggested method is based on a set of effortless logic equations that aim to stabilize the FC voltages within the CHB modules at their requisite reference values as well as to control the output voltage of the overall hybrid converter based on the phase-shifted-carrier pulsewidth modulation strategy. The experimental results obtained from a single-phase I-ANPC inverter's prototype are presented to validate the proposed control technique and its simple logic equations. [ABSTRACT FROM AUTHOR]

Value analysis and engineering, on one hand, and risk analysis, on the other, are two very significant approaches whose application is widely accepted in various scientific fields. This paper will highlight the possibilities of combining the two methodologies for a more comprehensive approach to solving business problems. Considering the concepts and principles on which these approaches are based, it is possible to integrate them during project implementation. The broad possibilities of combining the methods of these two fields will be illustrated by the combination of the FAST and FMEA methods, where it is shown how, with a slight increase in time, the benefits of both of these methods can be achieved, with an example from an automotive industry, in particular, the example of a car door handle.

Reinforced concrete (RC) with masonry infill is one of the most common structural typologies in Nepal, especially in the Kathmandu Valley. Masonry infills are typically made of solid clay bricks produced locally in Nepal. This study aims to calibrate the spectral-based analytical method, namely, FAST, for Nepalese RC-infilled buildings. The FAST method has been initially conceived for Southern European RC buildings with hollow clay brick infills. The calibration is achieved by reviewing code prescriptions and construction practices for RC masonry infills in Nepal and updating the FAST method. The variables of FAST method are calibrated using different information sources and a Bayesian updating procedure to consider the global and local material properties for solid clay bricks. The FAST-NEPAL method obtained is then verified, considering a single school design, for which a detailed state-of-the-art vulnerability assessment is available. Being particularly suitable for large-scale assessment, the method is further validated using data from Ward-35 of Kathmandu Metropolitan City (in the vicinity of Tribhuvan International Airport) obtained from photographic documentation included in a geo-referenced database of buildings collected after the 2015 Nepal earthquake and prepared for census purposes. The comparisons show that the FAST-NEPAL method can be conservative relative to the other data sources for vulnerability and is more accurate at capturing low-level damage. This makes the approach suitable for large-scale preliminary assessment of vulnerability for prioritisation purposes.

The ill-conditioned numerical system arising from an electromagnetic analysis is often due to the discretized curl–curl operator which has both zero eigenvalues and large ones inversely proportional to the square of the smallest feature size. In this work, we analytically decompose the discretized curl–curl operator into a gradient divergence operator and a Laplacian without numerical computation. We further split the field solution into a gradient field (curl-free component) and a divergence-free one to take advantage of the decomposition. The gradient divergence operator vanishes when acting on the divergence-free component of the field solution. As a result, we can replace the highly ill-conditioned curl–curl operator with a Laplacian for computing the divergence-free component regardless of inhomogeneity and source settings. Since the Laplacian is positive definite and well-conditioned, the new system matrix can converge quickly in a small number of iterations. The method is applied to accelerate time-domain solutions of Maxwell’s equations in ill-conditioned problems such as integrated circuits (ICs). Numerical results have validated its accuracy and efficiency. [ABSTRACT FROM AUTHOR]

We prove the wellposedness of a distributed-order space-fractional diffusion equation with variably distribution and its support, which could adequately model the challenging phenomena such as the anomalous diffusion in multiscale heterogeneous porous media, and smoothing properties of its solutions. We develop and analyze a collocation scheme for the proposed model based on the proved smoothing properties of the solutions. Furthermore, we approximately expand the stiffness matrix by a sum of Toeplitz matrices multiplied by diagonal matrices, which can be employed to develop the fast solver for the approximated system. We prove that it suffices to apply O(log N) terms of expansion to retain the accuracy of the numerical discretization of degree N, which reduces the storage of the stiffness matrix from O(N2) to O(N log N), and the computational cost of matrix-vector multiplication from O(N2) to O(N log2N). Numerical results are presented to verify the effectiveness and the efficiency of the fast method. [ABSTRACT FROM AUTHOR]

In this work, we establish a model to describe the unsteady magnetohydrodynamic (MHD) flow of fractional Oldroyd-B fluid between parallel plates on heat transfer, by introducing the fractional derivative into the constitutive equation. The flow is driven bymagnetic, electroosmotic and pressure gradient forcings. In the numerical implementation, the spectral collocation method combined with fast algorithm based on sum-of-exponentials (SOE) approximation is performed to solve the model. Effects of several parameters on the velocity profiles, temperature field and Nusselt number are investigated graphically. [ABSTRACT FROM AUTHOR]

Putative health effects of dietary trans fatty acids (TFAs) receive a growing attention; while very little is known about the metabolism of these special food components. In vitro studies carried out in cultured cells provide an efficient and standardizable approach to follow the metabolic fate of TFAs, but it requires suitable techniques for the quantitative measurement of FAs in cell samples. Here, the development and validation of a simple and reliable method for the quantification of a group of relevant FAs by gas chromatography and flame ionization detection is presented. Sample preparation used a fast one-step and chloroform-free process for simultaneous extraction and esterification, and chromatographic separation was achieved in 25 min using a Zebron ZB-88 capillary column. A linear calibration (of R2 >0.99) was obtained in the concentration range of 1-200 µg/mL for each FA. Recovery rate was 82 % for samples of non-esterified FAs and >95 % for complex lipids, such as ceramides, diglycerides and triglycerides. The LOD and LOQ were below 0.5 µg/mL, and a robust method precision was achieved (RSD % was below 6 % for each lipid classes). The present method was also tested on a cultured cell line with or without FA treatment at close to physiological concentration, and the observed changes in the metabolite concentration levels revealed characteristic differences between the metabolism of cis and trans unsaturated FAs. [ABSTRACT FROM AUTHOR]

In this paper, a weighted and shifted Grünwald-Letnikov difference (WSGD) Legendre spectral method is proposed to solve the two-dimensional nonlinear time fractional mobile/immobile advection-dispersion equation. We introduce the correction method to deal with the singularity in time, and the stability and convergence analysis are proven. In the numerical implementation, a fast method is applied based on a globally uniform approximation of the trapezoidal rule for the integral on the real line to decrease the memory requirement and computational cost. The memory requirement and computational cost are O(Q) and O(QK), respectively, where K is the number of the final time step and Q is the number of quadrature points used in the trapezoidal rule. Some numerical experiments are given to confirm our theoretical analysis and the effectiveness of the presented methods. [ABSTRACT FROM AUTHOR]

Due to the unique chemical and physical properties of graphene, as a promising material for energy conversion and storage applications, functional groups introduction on graphene surface or edges is a useful strategy for modification of its properties. For the first time, we suggest a simple, eco-friendly, and scalable for synthesising of N-rGO as a cathode material for oxygen reduction reaction (ORR) in fuel cells. An electrochemical method has been employed to investigate the mechanism of N-doping. The N-rGO electrocatalyst prepares by a one-pot electrochemical way using the raw materials of graphite rod and urea solution with DC power supply. The N-rGO had a high N content (6.8 at. %) in comparison to literature. The mechanism of N-doped reduced graphene oxide been carefully studied. [ABSTRACT FROM AUTHOR]

In this paper, a second-order numerical scheme for the time-fractional phase field models is proposed. In this scheme, the fractional backward difference formula is used to approximate the time-fractional derivative and the extended scalar auxiliary variable method is used to deal with the nonlinear terms. The energy dissipation property for the numerical scheme is proved. Our discussion includes the time-fractional Allen–Cahn equation, the time-fractional Cahn–Hilliard equation, and the time-fractional molecular beam epitaxy model. In the numerical implementation, a fast method based on a globally uniform approximation of the trapezoidal rule for the integral on the real line is adopted to decrease the memory requirement and computational cost. Finally, some numerical examples are given to confirm the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

A three-dimensional scalar stationary scattering problem is considered. It is formulated in the form of a weakly singular Fredholm boundary integral equation of the first kind with a single unknown function. The equation is approximated by a system of linear algebraic equations, which is then solved numerically by an iterative method. The mosaic-skeleton method is used at the stage of the approximate solution of this system in order to reduce the computational complexity of the approach. [ABSTRACT FROM AUTHOR]

Prevalence and incidence of the marine toxins (paralytic, amnesic, and lipophilic toxins) including the so-called emerging toxins (these are, gymnodimines, pinnatoxins, or spirolides among others) have increased in recent years all over the world. Climate change, which is affecting the distribution of their producing phytoplankton species, is probably one of the main causes. Early detection of the toxins present in a particular area, and linking the toxins to their causative phytoplankton species are key tools to minimize the risk they pose for human consumers. The development of both types of studies requires fast and highly sensitive analytical methods. In the present work, we have developed a highly sensitive liquid chromatography-mass spectrometry methodology (LC-MS/MS), using a column with fused-core particle technology, for the determination of fourteen lipophilic toxins in a single run of 3.6 min. The performance of the method was evaluated for specificity, linearity, precision (repeatability and reproducibility) and accuracy by analysing spiked and naturally contaminated samples. The in-house validation was successful, and the limit of detection (LOD) and quantification (LOQ) for all the toxins were far below their regulatory action limits. The method is suitable to be considered in monitoring systems of bivalves for food control.

Dynamic security assessment (DSA) is widely used in dispatching operation systems, and the small signal stability is one of the DSA's most time-consuming calculation methods. In this article, a fast method is proposed aiming to predict the small signal stability metrics of designated oscillation mode, for example frequency or damping ratio. The method is much faster than the simulation and suitable for the online application. First, the t-distributed stochastic neighbour embedding (t-SNE) algorithm is performed which can create a mapping from the power system components to 2D coordinate depending on the electrical distance of each other; then, it will be transformed into a grid structure by meshing operation, on which the convolutional neural network (CNN) model can be run properly. Finally, with a large amount of simulation samples, the CNN model can be well trained using static quantities as its input and small signal stability metrics as its prediction target. While a new operation mode needs to be evaluated, the result will be obtained by CNN directly. The validity of proposed method is verified using online data of State Grid Corp of China. It is proved that the method meets the requirements for speed and accuracy of online analysis system.

Metallic aerogels as a novel class of three-dimensional inorganic polymers have attracted a lot of attentions in academic researches. In this manuscript, an efficient way for the production of Pd aerogel is presented. The proposed way includes advantages such as one-pot synthesis, being fast, simple and surfactant free. The Pd aerogel is successfully synthesized by the reduction of H 2 PdCl 4 with sodium borohydride followed by supercritical drying with liquid carbon dioxide. The extraordinary 3D network with the large porosity of Pd aerogel is confirmed by using TEM, FESEM, XRD, EDS, FT-IR and nitrogen isotherm techniques. The extraordinary 3D polymer is used as a support-less anode catalyst for the oxidation of formic acid. Based on the obtained results, the mass activity of 3D nanonetwork was estimated to be 1791.4 mAmg−1 Pd , which was 2.67 times higher compared to Pd/C (668.5 mAmg−1 Pd) nanocatalyst. Moreover, the Pd/C indicated a positive shift in onset potential, lower ECSA, greater E a , greater R CT as well as weaker stability in comparison to the resultant aerogel. The exceptional catalytic behavior of 3D nanonetwork toward oxidation of formic acid was seriously affected by unique properties such as large porosity, high surface area as well as self-supporting characteristic of 3D nanonetwork. • Fast and one-pot synthesis strategy for the creation of Pd aerogel assembled by nanochaines. • Pd aerogel shows high electrocatalytic activity and durability toward formic acid oxidation. • The porous 3D network of Pd aerogel is formed during the self-assembly process. [ABSTRACT FROM AUTHOR]

In this paper, a fast second‐order accurate difference scheme is proposed for solving the space–time fractional equation. The temporal Caputo derivative is approximated by ℱL2‐1σ formula which employs the sum‐of‐exponential approximation to the kernel function appeared in Caputo derivative. The second‐order linear spline approximation is applied to the spatial Riemann–Liouville derivative. At each time step, a fast algorithm, the preconditioned conjugate gradient normal residual method with a circulant preconditioner (PCGNR), is used to solve the resulting system that reduces the storage and computational cost significantly. The unique solvability and unconditional convergence of the difference scheme are shown by the discrete energy method. Numerical examples are given to verify numerical accuracy and efficiency of the difference schemes. [ABSTRACT FROM AUTHOR]

Highlights • A time-saving model was proposed for predicting plume's infrared thermal radiations. • An assessment of computational error and efficiency was made. • Flow properties of plumes in the full domain were examined. • Radiation characteristics were obtained numerically. • A relationship between the cutoff temperature and plume's length was shown. Abstract In this paper, a fast estimating method of thermal infrared radiation signatures for low-altitude exhaust plumes was proposed. In engineering application, it is essential to predict the thermal radiation effect of the plume as soon as possible. A simple numerical model was established considering thermal, species formation, entrainment and radiating effects. In this methodology, the mixing region was treated as a hot, under-expanded, reacting and isotonic flow. The reacting flows were simulated by solving the governing equations with finite rate kinetics and conservation matching relations. A single-line-group (SLG) model with Curtis-Godson approximation was utilized to evaluate radiative properties of radiating species. A line-of-sight (LOS) method was used to compute the spectral radiation intensity. This computational model was verified against the Atlas-II's reference data within the wavelengths of 2–6 μm. The simulation analyzed combustion flows and infrared thermal effects of a typical exhaust plume along flight trajectory points. Results show that the current model can dramatically improve the computational efficiency by 100–1000 times by comparing with the commonly used method. According to this model, the plume's range and an appropriable cutoff temperature for thermal radiation calculations are easy to obtain. Infrared radiation phenomena accord with the experimental observations. As a main outcome, this simple model can provide a time-saving and range-unlimited method for the infrared radiation signature prediction of a low-altitude plume in engineering application. [ABSTRACT FROM AUTHOR]

Dynamic security assessment (DSA) is widely used in dispatching operation systems, and the small signal stability is one of the DSA's most time-consuming calculation methods. In this article, a fast method is proposed aiming to predict the small signal stability metrics of designated oscillation mode, for example frequency or damping ratio. The method is much faster than the simulation and suitable for the online application. First, the t-distributed stochastic neighbour embedding (t-SNE) algorithm is performed which can create a mapping from the power system components to 2D coordinate depending on the electrical distance of each other; then, it will be transformed into a grid structure by meshing operation, on which the convolutional neural network (CNN) model can be run properly. Finally, with a large amount of simulation samples, the CNN model can be well trained using static quantities as its input and small signal stability metrics as its prediction target. While a new operation mode needs to be evaluated, the result will be obtained by CNN directly. The validity of proposed method is verified using online data of State Grid Corp of China. It is proved that the method meets the requirements for speed and accuracy of online analysis system. [ABSTRACT FROM AUTHOR]

Abstract PID controllers are the most common type of controllers used in industry. However, to find the best PID performance is a challenging task. Assessment of the best PID performance leads to the minimization of the deviation from set point as indicated by closed loop transfer function. This is a non-convex optimization problem and there is no direct solution for finding this benchmark. Solving this problem iteratively as proposed in literature requires long calculation times. Furthermore, iterative methods are not guaranteed to find the minimum value. Using as many as possible infinite impulse response coefficients, or increasing the number of finite impulse coefficients gradually, causes undesirably large calculation times. We propose a fast method to evaluate the minimum variance by a fixed number of finite impulse response coefficients. This finite impulse model is double the size of the stable system impulse response (it contains the transient response and the same duration of steady state). Thus it avoids undesired iteration, and consequently, the PID minimum variance is quickly evaluated. Time is a critical factor as the purpose to assess this index is for use in online monitoring. The proposed method is tested on benchmark simulation examples from literature. Highlights • Assessment of PID achievable performance for linear, stationary SISO processes. • Guidelines developed for choosing the appropriate size of the finite impulse response for the system. • Fast non-iterative method to estimate the PID benchmark. [ABSTRACT FROM AUTHOR]

In fast Fourier transform (FFT)-based iterative methods for electromagnetic analysis of planar structures, the convolution between Green’s function (GF) and the basis functions is carried out by a product in the spectral domain. In layered media, the GF is known analytically but exhibits singularities in the spectral domain, giving rise to numerical inaccuracy when processed by a direct FFT. We propose a direct spectral approach where the convolution is carried out with due account for the presence of a singular kernel. Using Contour-FFT, the integration contour is deformed and the spatial convolution is expressed as a rapidly converging series of FFTs. We also introduce a novel inverse Contour-FFT operator required for the process. As other FFT-based methods, the short-range interactions are corrected using a precomputed sparse operator, to which we propose an implementation compatible with the Contour-FFT. We control the accuracy of the method with a simple scheme that adapts the method’s parameters to the problem at hand. Several practical numerical examples demonstrate the efficiency and accuracy of the method for the analysis of large nonregular printed structures. [ABSTRACT FROM AUTHOR]

Damage data on low-to-mid-rise Reinforced Concrete (RC) buildings, collected during the UK Earthquake Engineering Field Investigation Team post-earthquake reconnaissance mission on the August 24 Central Italy earthquake, are employed to derive empirical fragility relationships. Given the small dataset, the new data distributions are used for the Bayesian update of fragility functions derived for the L’Aquila earthquake (same seismic region and similar construction typologies). Other properties such as number of storeys, age of construction and shape in plan of the buildings are also analyzed. This information is employed to assess the ability of the FAST method to predict damage states in non-regular infilled RC buildings for the municipalities of Amatrice, Accumoli, Arquata del Tronto and Norcia, all severely affected by the 2016 Central Italy sequence. FAST is a spectral-based method to derive capacity curves and peak ground acceleration damage state thresholds for buildings. It is a dedicated methodology for regular RC frame buildings with masonry infills, first calibrated on damage data from the 2009 L’Aquila earthquake and applied to the 2011 Lorca (Spain), the 2012 Emilia (Italy) events for damage back-analyses. The new data from the August 2016 Central Italy earthquake provide a test-bed for FAST further employments in case of less homogenous building samples. The application of FAST presented here accounts for different shake-maps produced by both the United States Geological Survey and the Italian National Institute of Geophysics and Volcanology which are significantly different and representative of different refinements of the demand scenario. For the area of Amatrice, where the two shake-maps provide similar estimates and the buildings considered match reasonably well the typology for which FAST is calibrated, the comparison between damage level observed and as provided by FAST is very satisfactory. For other structural typologies like RC industrial structures and dwellings with non-hollow-clay-bricks as infills, FAST needs further calibration. [ABSTRACT FROM AUTHOR]

The purpose of the present work is to establish an ultra-minimal invasive percutaneous puncture inoculation method for a VX2 orthotopic lung cancer rabbit model with fewer technical difficulties, lower mortality of rabbits, a higher success rate and a shorter operation time, to evaluate the growth, metastasis and apoptosis of tumor by CT scans, necropsy, histological examination, flow cytometry and immunohistochemistry. The average inoculation time was 10-15 min per rabbit. The tumorbearing rate was 100%. More than 90% of the tumor-bearing rabbits showed local solitary tumor with 2-10 mm diameters after two weeks post-inoculation, and the rate of chest seeding was only 8.3% (2/24). The tumors diameters increased to 4-16 mm, and irregularly short thorns were observed 3 weeks after inoculation. Five weeks post-inoculation, the liquefaction necrosis and a cavity developed, and the size of tumor grew further. Before natural death, the CT images showed that the tumors spread to the chest. The flow cytometry and immunohistochemistry indicated that there was less apoptosis in VX2 orthotopic lung cancer rabbit model compared to chemotherapy drug treatment group. Minimal invasive percutaneous puncture inoculation is an easy, fast and accurate method to establish the VX2 orthotopic lung cancer rabbit model, an ideal in situ tumor model similar to human malignant tumor growth. [ABSTRACT FROM AUTHOR]

The electrochemical reduction of cobalt (II) formate on graphene/glassy carbon electrode (G/GCE) surface in HCl (5 wt%) is used to prepare Pd-Co electrocatalyst. The Pd-Co nanostructures decorated on the graphene nanosheets were prepared in two steps: (1) electrochemical reduction of cobalt (II) formate and (2) the galvanic replacement reaction between Co and Pd 2+ . This approach has a number of advantages including being environmentally friendly, simple, low-price, and very fast. The morphology and bulk compositions of the samples were investigated via Field Emission Scanning Electron Microscopy (FESEM), X-ray diffraction (XRD) patterns, Energy Dispersive X-ray Spectroscopy (EDS). Electrochemical techniques, including Cyclic Voltammetry (CV), Chronoamperometry (CA) and Electrochemical Impedance Spectroscopy (EIS) measurements were used to analyze the electrochemical activity of the samples. The peak current density for oxidation of formic acid on Pd-Co/G electrocatalyst was very high (151.32 mA cm −2 ). The Pd-Co/G increased the current density 7.1 times more than Pd/C. Besides, the onset oxidation potential and peak potential for Pd-Co/G electrocatalyst illustrated a negative shift in comparison to Pd/C. Chronoamperometry experiment showed that the stability of the Pd-Co/G catalyst was remarkably promoted. The Pd-Co/G electrocatalyst represents extraordinary electrocatalytic activity and durability toward formic acid oxidation. [ABSTRACT FROM AUTHOR]