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This paper presents the development of cheap and selective Paper-based Analytical Devices (PADs) for selective Pd(II) determination from very acidic aqueous solutions. The PADs were obtained by impregnating two cm-side squares of filter paper with an azoic ligand, (2-(tetrazolylazo)-1,8 dihydroxy naphthalene-3,6,-disulphonic acid), termed TazoC. The so-obtained orange TazoC-PADs interact quickly with Pd(II) in aqueous solutions by forming a complex purple-blue-colored already at pH lower than 2. The dye complexes no other metal ions at such an acidic media, making TazoC-PADs highly selective to Pd(II) detection. Besides, at higher pH values, other cations, for example, Cu(II) and Ni(II), can interact with TazoC through the formation of stable and pink-magenta-colored complexes; however, it is possible to quantify Pd(II) in the presence of other cations using a multivariate approach. To this end, UV-vis spectra of the TazoC-PADs after equilibration with the metal ions solutions were registered in the 300–800 nm wavelength range. By applying Partial Least Square regression (PLS), the whole UV-vis spectra of the TazoC-PADs were related to the Pd(II) concentrations both when present alone in solution and also in the presence of Cu(II) and Ni(II). Tailored PLS models obtained with matrix-matched standard solutions correctly predicted Pd(II) concentrations in unknown samples and tap water spiked with the metal cation, making the method promising for quick and economical sensing of Pd(II). [ABSTRACT FROM AUTHOR]

• Derivatives of Dirac delta function were introduced to describe the action of joint parts in dynamic analysis. • Analytical solutions were provided to study dynamic responses of joints in infinite beams under time-lag loads. • Connection between joints and standard beams induces great differences in dynamic responses. This paper investigates the analytical method for the infinite beam with joint parts resting on a foundation under time-lag loads. The ground is simulated as a viscoelastic foundation. The existence of joint parts in beams is explained by introducing virtual forces expressed through the Dirac delta function. Integral transformation simplifies the dynamic governing equations for standard beam sections and joint parts into an algebraic equation. The convolution theorem converts the solutions into the time domain. The analytical solutions for dynamic analysis of standard beam sections and joint parts are obtained conveniently in the frequency domain. The proposed analytical method is verified by comparing it with the traditional methods and also validated by numerical examples with time-lag loads. Parametric discussions study the effects on the dynamic response of joint parts and standard beam sections, such as the amplitude and frequency of time-lag loads and coefficient of bending stiffness reduction of joint parts. The parametric analyses emphasize the dramatic effect of critical parameters on the discontinuous deformation of beams. The damage caused by critical values of some factors is emphasized. The severe effects of discontinuous deformation induced by dynamic loads in the safety of beam structures are revealed in this paper. The differences in dynamic responses between the beam and joint part must be monitored to ensure the safety of whole beam structures. [ABSTRACT FROM AUTHOR]

Asymmetric 3D wave propagation in transversely isotropic thermoelastic solids is presented by using of potential functions and integral transforms. Governing equations of thermoelastodynamic boundary-value problem (TBVP) are including three equations of motion and an energy equation which make a set of four coupled partial differential equations (PDE) in terms of displacements and temperature. By using of the displacement- and temperature-potential function relationships, four coupled equations of TBVP are reduced to two uncoupled PDEs governing the potential functions which are of sixth and second orders. To solve these uncoupled PDEs, complex Fourier expansions and Hankel integral transforms are used in this paper to suppress the angular and radial variables respectively in cylindrical coordinate system. Consequently, sixth and second order ordinary differential equations (ODE) in terms of depth are received. By solving ODEs, satisfying the radiation and boundary conditions and applying the Hankel inverse transforms, the displacement and temperature functions have been determined in the real space. To validate the analytical and numerical results, some comparisons have been made with the results presented in the literature where excellent agreements have been observed. Important points have been mentioned about speed of SH, SV, P and Rayleigh waves in transversely isotropic and isotropic thermoelastic solids. [ABSTRACT FROM AUTHOR]

In recent decades, the outcrossing rate method has gained popularity for structural time-dependent reliability assessments (TRA). Despite numerous efforts, developing a general analytical outcrossing rate method for a nonstationary non-Gaussian performance function to estimate the failure probability within the forecast time interval remains a significant challenge. This paper introduces an analytical outcrossing rate method for non-Gaussian cases, named the three-moments-based outcrossing rate (TMO) method. The outcrossing rate is formulated based on the third-moment outcrossing rate with no assumption of the correlation between the performance function and its derivative process, allowing for a comprehensive understanding of the performance characteristics of a structure. Following the development of the proposed outcrossing rate, a TRA methodology is established to evaluate the failure probability of the nonstationary non-Gaussian performance function. Notably, the TMO method only requires statistical moments of the nonstationary non-Gaussian performance function, which are easy to calculate, facilitating efficient implementation. Three numerical examples are presented to demonstrate the applicability, efficiency, and accuracy of the proposed TMO method. It can be concluded that the proposed TMO method provides an accurate and useful approach for TRA in engineering applications. [ABSTRACT FROM AUTHOR]

Characteristics of a rainfall event (e.g., rainfall duration D and intensity I) have a significant influence on the probabilistic stability analysis of the rainfall-induced landslides. However, most previous probabilistic stability analyses of rainfall-induced landslides have been performed under a given rainfall pattern without considering the uncertainty of the rainfall characteristics. The Monte Carlo simulation method, which takes a lot of computing resources and time, has been widely used in previous studies. In this paper, a fully analytical method is proposed to estimate the slope failure probability induced by a random rainfall event (PF1) and the annual slope failure probability (PFA), which considers both rainfall uncertainty and the variability of saturated hydraulic conductivity Ks. Triple integration is used by the analytical method to avoid repeated sampling and calculation. Compared with the Monte Carlo simulation method, the analytical method greatly improves the calculating efficiency. The outcomes based on the analytical method are consistent with those obtained by the Monte Carlo simulation method, which verifies the accuracy of the analytical method. When the mean of the saturated hydraulic conductivity (μKs) is large, PF1 decreases with the increase in the coefficient of variation (COV) of Ks. When μKs is small, PF1 and PFA increase with the increase in COV of Ks (COVKs). [ABSTRACT FROM AUTHOR]

Logs record the software and hardware running information. By viewing system logs, you can find system faults and causes to ensure system stability and normal running. The purpose of log parsing is to parse semi-structured original logs into readable log templates. The existing parsing methods often only focus on parsing the original logs, but ignore the later template processing. As a result, the accuracy of the results cannot be further improved. Since then, this paper proposed a new log parsing method FMLogs. This method designed regular expressions and adjusted threshold parameters to obtain the best performance. Meanwhile, it used character-level frequency statistics and MinHash methods to merge log templates with the same length and different log templates. FMLogs conducted extensive experiments on seven real datasets, achieving an average analytic accuracy of 0.924 and an F1-score of 0.983. The experimental results show that FMLogs is an effective log parsing method with high accuracy, high efficiency, and stable performance. [ABSTRACT FROM AUTHOR]

AbstractThis paper investigates the propagation of guided waves in a high-speed rotating concrete shell reinforced with graphene oxide powders (GOP) using higher-order shear deformation theory (HSDT). The study addresses the complexities introduced by initial hoop tension and provides a comprehensive analytical solution procedure. Concrete shells are widely used in various engineering applications due to their robustness and durability; however, their mechanical performance can be significantly enhanced by the incorporation of GOP, which improves the material properties, such as tensile strength and modulus of elasticity. The analysis begins with the formulation of the governing equations based on HSDT, which accurately captures the effects of transverse shear deformation and rotary inertia, crucial for high-speed rotating structures. The presence of initial hoop tension, resulting from the centrifugal forces in the rotating shell, is integrated into the model to reflect real-world conditions. The modified equations are then solved analytically to obtain the dispersion relations for the guided wave modes. The results reveal that the inclusion of GOP significantly alters the wave propagation characteristics, enhancing the shell’s ability to transmit high-frequency waves with minimal attenuation. The initial hoop tension is found to shift the frequencies of the guided wave modes, indicating a coupling effect between the mechanical loading and wave propagation. This study provides valuable insights into the dynamic behavior of reinforced concrete shells in high-speed rotational environments, offering a potential pathway for the design of advanced structural components in aerospace, automotive, and civil engineering applications. [ABSTRACT FROM AUTHOR]

Fractional flow reserve (FFR) determined invasively has been globally accepted as the gold standard for determining the functional significance of coronary artery stenoses. However, despite its great importance, the invasive method has certain disadvantages, including the risk of vascular injuries, the need for vasodilation, and significant medical costs. That is why great attention was paid to the development of non-invasive methods that would enable reliable diagnosis without exposing patients to the risk of unwanted consequences. This paper aimed to create and verify an alternative, less resource- and time-demanding, non-invasive solution. The determination of FFR is based on the application of the fundamental laws of fluid dynamics. All energy losses in the coronary artery with stenosis were identified and analyzed in detail. A three-dimensional model of a coronary artery was generated using the corresponding angiographic images. Finally, the pressure due to stenosis was calculated and the FFR was determined. The results obtained using the proposed analytical method were compared with available experimental data for 40 patients who experienced the invasive coronary angiography. The coefficient of determination, mean difference and standard deviation values are determined to be 0.726, -0.017 and 0.056, respectively. These values were slightly higher for FFR values above 0.80. The FFR calculated by the proposed analytical method has a relatively good correlation with clinical data, which leads to the conclusion that it can provide a reliable assessment of the functional significance of coronary stenosis. [ABSTRACT FROM AUTHOR]

The liquefied natural gas (LNG) fuel tank in a large container ship is loaded with liquid LNG at an ultra-low temperature (-163°C), there is a significant temperature difference in the cargo hold area where the entire fuel tank is located, which will have an important impact on the steel grade design and structural safety of the cargo tank in container ship. This paper develops two heat transfer models using Computational Fluid Dynamics method (CFD method) and an analytical method to analyze the temperature distribution in a large container ship equipped with Type-B LNG fuel tank. These models incorporate the arrangement and heat transfer characteristics of LNG fuel tanks. The temperature field analysis is conducted under typical the environmental conditions specified in the Code for the Construction and Equipment of Ships Transporting Liquefied Gas in Bulk (IGC Code) and the United States Coast Guard Code (USCG Code), based on the CFD method and the analytical method, and the results of temperature field distribution are compared. Additionally, a parametric analysis of the hull temperature field is further carried out, the results show that the thermal conductivity of the insulation layer in LNG storage tanks and the types of the loaded liquid cargo have a limited impact on the final temperature field distribution in hull structure. However, the selection of steel grade in the local structure of the cargo hold, especially in the inner hull part, may lead to significant changes. [ABSTRACT FROM AUTHOR]

Chromium occurs naturally in different oxidation states. Amongst them, hexavalent chromium is classified as both genotoxic and carcinogenic while trivalent chromium can be considered as an essential element. Therefore, speciation analysis is essential when conducting dietary exposure assessment. Several critical reviews have been published on chromium speciation analysis in foodstuffs in the last decade. However, a method that can account for species interconversion during the extraction procedure has not been reported in the reviews. In recent years, an online method using species-specific isotope dilution mass spectrometry has been developed for the simultaneous determination of trivalent and hexavalent chromium in foodstuffs. Apart from that, new methods based on offline analytical techniques, to analyse trivalent and hexavalent chromium separately, are still under development. Therefore, one of the objectives of this paper is to review these recently published analytical methods and assess whether they are fit for chromium speciation analysis in foodstuffs. Additionally, an objective is also to assess whether their limits of detection are sufficiently low for dietary exposure assessment with respect to the neoplastic effects of hexavalent chromium. Moreover, possible future research gaps are identified based on the current knowledge and existing literature. [ABSTRACT FROM AUTHOR]

In this paper, we address various optical soliton solutions and demonstrate the different dynamics of solitary waves to a (3+1)-dimensional nonlinear Schrödinger equation (NLSE) with parabolic law (NLSE) using a newly created powerful and effective method named as the extended generalized Riccati equation mapping method. This technique presents an organized manner to reveal the essential dynamics. There is great significance of the nonlinear Schrödinger equations and their several formulations in numerous fields of science, particularly in nonlinear optics, optical fibers, quantum electronics, and plasma physics. Through the use of numerical simulations and mathematical analysis, we explore the characteristics and behavior of these solitary wave solutions in a variety of scientific contexts. These results demonstrate the essential complexity of the governing equation and yield novel derived solutions. These solutions contribute to a better understanding of nonlinear wave phenomena by highlighting the fundamental dynamics establishing solitary waves in the NLSE. To enhance our wider knowledge, we provide effective graphic representations of the nonlinear wave structures in the derived solutions utilizing a variety of graphs, including 3D, 2D, and density plots. Moreover, a specific transformation has been applied to transform the system into a planar dynamical system, and several phase portraits have been presented to examine its behavior. Furthermore, upon introducing a perturbed term, chaotic behavior has been observed across different parameter values through both two-dimensional and three-dimensional graphics. [ABSTRACT FROM AUTHOR]

Seismic displacements are critical analysis components for evaluating the slope stability during earthquakes and essentially regulated by the yield acceleration of slopes. The conventional Newmark’s method applies the constant yield acceleration to estimate the seismic displacement of slopes, albeit disregarding the time-dependent nature of yield acceleration. This paper presents an efficient analytical method for determining the seismic displacement of Bedding Slopes stabilized with anchor Cables and Piles (BSCP) by considering the dynamic yield acceleration. The dynamic process of yield acceleration was achieved by updating the instantaneous elongation of anchor cables and rotation of piles at each time increment. This was then incorporated within the Newmark’s method to solve the seismic displacement of the BSCP. The results show that the proposed method can reliably predict the general trend of seismic displacement of the BSCP under earthquake loadings, and correlates well with the dynamic finite difference method. Notably, the yield acceleration increases dynamically during the excitation of seismic ground motion and is closely related to the type of earthquake waves. Ignoring the dynamic yield acceleration leads to an overestimation of the post-seismic displacement of the BSCP. Moreover, the proposed method allows for the multi-layer landslide with minor alternations in the formulation of each component of work rates. This study facilitates a better displacement-based seismic design of the BSCP. [ABSTRACT FROM AUTHOR]

The time-dependent system of partial differential equations of the second order describing the electric wave propagation in electrically and magnetically anisotropic homogeneous media is considered in the paper. A method for the computation of the polynomial solutions of the initial value problem for the considered system is proposed. Symbolic computations are used and these symbolic computations are implemented in Maple. It is proved also that these polynomial solutions are approximate solutions of the considered initial value problem with smooth initial data and the inhomogeneous term. The computational experiments confirm the robustness of the suggested method for the computation of electric fields in general electrically and magnetically anisotropic media. [ABSTRACT FROM AUTHOR]

Centrifugal force is one of the factors that cannot be ignored in high-speed shaft systems. The multiple corrugated diaphragm (MCD) Coupling is suitable for high-power and high-speed situations; hence, it is crucial to investigate the stress and deformation of the wave disc under centrifugal load. This paper first uses the rotating shell thin film model to derive the circumferential stress and deformation displacement of the MCD under centrifugal load. Then, the finite element method is used to verify the results obtained from the analytical solution. The results show the feasibility of using the rotating shell thin film model for centrifugal load analysis of the MCD, providing a new approach for the theoretical analysis of the MCD. [ABSTRACT FROM AUTHOR]

This research focuses on the fractional complex order plant (FCOP). The significant contribution is the role of complex plant models in system stability and robustness and associated physical phenomena. A general transfer function is studied in the paper. Other plant models may be built with this structure since the FCOP is a general mathematical form covering integer order plant (IOP) and fractional order plant (FOP). Using the equations produced with the proposed technique and the recommended integer order proportional derivative (IOPD controller, physical changes in integer, fractional and complex coefficients, and orders are observed within this paper. Analysis of the plant controlled with an IOPD controller is done by applying an integrator to reveal the differences. The effects of the parameters are discussed together with the visuals, supported by simulations. The aim is to tune the controller parameters to achieve the phase and specifications as the researcher desired. It is observed that the integrator greatly takes part in reducing the steady‐state error. The IOP with the integrator showed the lowest steady‐state error, and also, the settling and overshoot time were enhanced. Increase in the phase margin also caused an increase in the phase crossover frequency. It is also observed that the fractional order affected the phase crossover frequency comparing with the IOP, and the complex order modification also had an effect comparing to the fractional order version. The complex order of the system is considered with its conjugate components in the imaginary part thus, the results are found separately for each case. [ABSTRACT FROM AUTHOR]

With the continuous expansion of the scale of power generated by grid-connected renewable energy, the form and operation characteristics of power grids have undergone significant changes, and the power electronic characteristics of power systems are prominent, resulting in the frequent occurrence of wide-band oscillation problems when renewable energy power generation equipment is connected to a power grid. Oscillation has the characteristics of nonlinearity and has an oscillation frequency ranging from a few hertz to several thousand hertz or more, which seriously threatens the stable operation of power grids. This paper summarizes the wide-band oscillation events that occur worldwide under the background of renewable energy access to power grids, classifies the wide-band oscillation events according to the distribution of oscillation frequency bands, and sorts out the characteristics of various oscillations. From the perspectives of the source side and network side, the existing oscillation suppression measures are classified and prospected. [ABSTRACT FROM AUTHOR]

This paper investigates the instability and buckling characteristics of a porous microplate under the influence of electrostatic fields, taking into account the implications of the intermolecular Casimir forces. Employing the modified couple stress theory, this research formulates equations that encapsulate the interplay between electrostatic and Casimir forces within porous plates. The analysis integrates distributed support loads, employing both Galerkin mode summation and finite element methods to solve static deformation equations and determine pull-in instability voltages and buckling loads. A novel approach is introduced, and equilibrium relationships are derived with respect to displacement to determine both the buckling load and instability voltage. This study effectively compares classical and non-classical theories, scrutinizing the effects of dimensionless length scale parameters and porosity ratios on maximum displacement, pull-in instability voltages, and buckling loads. The results demonstrate that the analytical method converges swiftly and aligns with the findings of the finite element method. The method for deriving equilibrium relationships proves to be accurate in predicting both instability voltage and buckling load. Additionally, the instability voltage exhibits an almost linear relationship with variations in the percentage of porosity, and similarly, the buckling load undergoes linear changes with alterations in porosity percentage. Hence, formulas for the linear relationships are calculated for both of these associations. [ABSTRACT FROM AUTHOR]

An investigation is performed in this paper to analyze the nonlinear thermo-electro-mechanical response of long sandwich cylindrical shells with functionally graded porous (FGP) core and thin piezoelectric actuator layers. The FGP core of the sandwich shell is assumed to be temperature- and microstructure-dependent. It is assumed that the sandwich shell is subjected to uniform lateral pressure loading in a thermo-electrical environment. The equilibrium equations of the shell with infinite length are established with the aid of the virtual displacement principle and von Kármán kinematic assumptions. The governing equations are obtained in terms of displacement components based on the first-order shear deformation model of shallow cylindrical shells and the modified couple stress theory. These nonlinear differential equations are analytically solved for a sandwich shell having both the simply-supported and clamped–clamped edge conditions by employing a two-step perturbation technique. Analytical closed-form solutions are determined as a relationship including the load parameter and the mid-span deflection. The comparison examples are made with the existing results in the literature for a simple functionally graded shell, where good agreement is obtained. It is shown that the nonlinear response of the sandwich shell is highly dependent upon the temperature variation, power law index, porosity coefficient, couple stress parameter, piezoelectric layers, and geometrical parameters of the shell. [ABSTRACT FROM AUTHOR]

This paper presents an analytical solution of the differential equations describing the pulsatory liposome dynamics. We consider a unilamellar liposome filled with an aqueous solution of osmotic solute inserted in a hypotonic aqueous medium. Due to the osmosis process the liposome has a cyclic evolution. The lipid vesicle swells to a critical size, at which point a transbilayer pore suddenly appears. Part of the internal solution leaks through this pore. The liposome relaxes and returns to the initial size. The swelling starts again and the liposome goes through a periodical process. The swelling of the liposome is described by a differential equation. The appearance of the pore changes the evolution of the liposome. The internal solution comes out through the pore and the liposome starts its deflation (relaxation). The evolution of the pore has two phases: first, the radius of the pore increases to its maximum value, then the radius decreases until it disappears, and the liposome reaches its initial size. During each cycle, the liposome will release a quantity (a pulse) of the solution from its interior. All the processes which contribute to the liposome relaxing and its coming back to the initial size are described by three differential equations. This system of differential equations can be integrated using numerical methods. The functions - which model our biological engine in three stages, are as follows: R(t) - the liposome radius, r(t) - the pore radius, C(t) - solute concentration, Q(t) - the osmotic solute amount inside the liposome. The graphs representing these functions contain important linear portions, which suggested a solution using analytical methods. Based on some analytical methods, we solve these equations, and their explicit solutions are validated by comparing with numerical results of previous studies. [ABSTRACT FROM AUTHOR]

The basic objectives of stability-indicating analytical methods are to provide information about the test settings and to establish the stability for all pharmaceuticals. In the present scenario, it is crucial for all drug components to reach their goals. In the present review, the regulatory components of stability-indicating approaches have been evaluated. The validated stability-indicating methods are necessary in accordance with ICH guidelines Q1A (R2), Q3B (R2), and Q6A, as well as FDA 21 CFR section 211. In order to prove the specificity, force degradation studies should be performed prior to the stability tests. Force degradation of the pharmaceuticals, drug substances, drug products, and excipients is carried out in a variety of conditions to determine the stability of the analytical technique. In this paper, the strategies for developing a stability-indicating method, computational methodologies, regulatory issues, and benefits are discussed. [ABSTRACT FROM AUTHOR]

This paper describes an analytical method for investigating the tunnel–pile interaction for new tunnels crossing the pile foundation of the Shenzhen Bay Bridge, with a case study using a cavity expansion-based model. The three-dimensional analytical model developed in this study evaluates the ground deformation and pile response induced by the construction of tunnels for the two Metro #13 lines and the Wanghai Road tunnel, and assesses the effectiveness of mitigation measures such as ground stabilisation and isolation walls. The study reveals significant vertical displacement and surface settlement caused by the Wanghai Road tunnel, and horizontal deformation and bending moments in specific pile foundations. The results show that reinforcement measures can effectively control formation deformation disturbance, and metro jet system isolation walls can limit horizontal and vertical displacements caused by excavation. To ensure the safe operation of the Shenzhen Bay Bridge, the study highlights the importance of comprehensively evaluating the safety of shield crossing schemes. The proposed analytical method could also serve as a pre-design tool and reference for optimising tunnel construction, providing valuable guidance for future reinforcement schemes. In general, this study provides significant insights into the tunnel–pile interaction, which will be useful for bridge and tunnel engineering design and construction. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) are the emerging class of carbonized materials with an ultra-small size (< 10 nm) and remarkable optical properties. In this paper, blue emissive CDs were synthesized from Plumeria obtusa (PO) flower named "PO-CDs" via a conventional hydrothermal approach. The as-prepared PO-CDs showed emission at 419 nm when excited at 335 nm with a high quantum yield (18%). This approach is effortless, inexpensive, and very reliable with the view of the green and facile method. The intensity of as-prepared PO-CDs was quenched by metribuzin pesticide via a static quenching mechanism. The reduction in PO-CDs intensity offers a wider linear range of calibration from 0.5 to 100 μM, with the detection limit of 22.57 nM. Lastly, the interaction and quenching mechanism between PO-CDs and metribuzin confirmed by various analytical techniques. The PO-CDs-based fluorescent probe was effectively applied to detect metribuzin in the cherry tomato samples. [ABSTRACT FROM AUTHOR]

Airborne transient electromagnetic (ATEM) technology is a technique often used in mineral exploration and geological mapping. Due to inductive polarization (IP) phenomena, the ATEM response curve often shows a negative response or declines rapidly to the attenuation curve. Traditional resistivity inversion techniques do not explain the IP response of a signal well, so the negative response is usually removed during data processing, resulting in a reduced correctness and authenticity of the findings. In this paper, in the parameter inversion based on the Cole–Cole model, the Jacobian matrix chain analysis method is used to calculate, and the current waveform calculation is also considered in the inversion. The results show that compared with the perturbation method, the analysis technique can greatly reduce the calculation time and improve the inversion efficiency. In the single-point one-dimensional inversion and lateral constraint quasi-two-dimensional inversion, the Cole–Cole four-parameter forward response has strong inversion accuracy, which can successfully invert the actual exploration content and the Cole–Cole four-parameter response. Some measured sounding data in the Qingchengzi survey area of Liaoning Province, China have a negative response to IP, and the resistivity scheme cannot be used alone for inversion, but the real underground resistivity structure can be obtained through the method studied in this paper, and good exploration results can be obtained. [ABSTRACT FROM AUTHOR]

AbstractThe main difficulties when analyzing pharmaceutically active compounds (PhACs) in solid environmental samples is the complexity of the samples and the low concentration levels of such pollutants. Most efforts are focused in achieving good analytical performance parameters such as high recoveries or low detection limits without considering if the methods are environmentally friendly. In this work, the main tools proposed for assessing the greenness of analytical methodologies (Analytical Eco-scale, Green Analytical Procedure Index (GAPI), and Analytical GREEnness metric (AGREE)) have been applied to nine analytical procedures that include recent important analytical tendencies. The three metrics identified the paper spray ionization method as the greenest procedure since it used untreated samples for direct mass spectrometry analysis. Using Analytical Eco-scale, most of the evaluated procedures were rated as “acceptable green”. However, the use of internal standards resulted key in the environmental impact of the method which provided contradictory results versus other metrics. GAPI found greenness similarities between most of selected methods, hindering a greenness classification. AGREE allowed the weighting of each evaluation criterion providing a greenness ranking. The application of each metric detecting their weaknesses and strengths was discussed. The incorporation of validation analytical features in greenness metrics was a gap revealed. [ABSTRACT FROM AUTHOR]

This paper presents a new analytical procedure to model the umbra generated during an eclipse considering an oblate ellipsoid of rotation as occulting body and a conical shadow. The method is based on purely geometrical considerations and results in the analytical definition of the entry and exit points from the conical shadow starting from the knowledge of the Sun position vector, the occulting body position vector and the orbital elements of the spacecraft orbiting the occulting body. The conical shadow also permits analytical definition of the entry and exit points of the penumbra region, which cannot be defined by using the classic cylindrical approach. Some numerical applications are proposed to test the effectiveness of the analytical formulations and to check the error in the prediction of the time spent in the shadow by the satellite. Finally, a discussion between the new conical shadow model and the classic cylindrical eclipse is carried out to see the improvements introduced by the refined geometry and the effects on space missions focusing on the cumulative error when multiple revolutions are considered. • A new analytical method to compute umbra entry/exit points in an eclipse is derived. • The Earth's surface is modelled as an oblate ellipsoid of rotation. • The model permits the definition of the penumbra region and its entry and exit points. • The method is a higher-order refined model without loss of computational time. • Umbra/penumbra regions are modelled as the Cartesian equation of a conical surface. [ABSTRACT FROM AUTHOR]

The rotation and orientation of Mars is commonly described using two different sets of angles, namely (1) the Euler angles with respect to the Mars orbit plane and (2) the right ascension, declination, and prime meridian location angles with respect to the Earth equator at J2000 (as adopted by the IAU). We propose a formulation for both these sets of angles, which consists of the sum of a second degree polynomial and of periodic and Poisson series. Such a formulation is shown here to enable accurate (and physically sound) transformation from one set of angles to the other. The transformation formulas are provided and discussed in this paper. In particular, we point that the quadratic and Poisson terms are key ingredients to reach a transformation precision of 0.1 mas, even 30 years away from the reference epoch of the rotation model (e.g., J2000). Such a precision is required to accurately determine the smaller and smaller geophysical signals observed in the high-accuracy data acquired from the surface of Mars. In addition, we present good practices to build an accurate Martian rotation model over a long time span ( ± 30 years around J2000) or over a shorter one (e.g., lifetime of a space mission). We recommend to consider the J2000 mean orbit of Mars as the reference plane for Euler angles. An accurate rotation model should make use of up-to-date models for the rigid (this study) and liquid (Le Maistre et al., Nature 619, 733–737 (2023)) nutations, relativistic corrections in rotation (Baland et al., Astron. Astrophys. 670, A29 (2023)), and polar motion induced by the external torque (this study). Our transformation model and recommendations can be used to define the future IAU solution for the rotation and orientation of Mars using right ascension, declination, and prime meridian location. In particular, thanks to its quadratic terms, our transformation model does not introduce arbitrary and non-physical terms of very long period and large amplitudes, thus providing unbiased values of the rates and epoch values of the angles. [ABSTRACT FROM AUTHOR]

This paper investigates the influence of the loss distribution and magnetic saturation on the efficiency performance, which includes the location of maximum efficiency point, the size of high‐efficiency region and the value of maximum efficiency, for an interior permanent magnet synchronous motor (IPMSM). The loss expressions considering magnetic saturation are first proposed and then the efficiency‐losses function model of the IPMSM is constructed. The efficiency performance of the motor is analyzed quantitatively. The general principle is summarized including adjusting the location of maximum efficiency point, expanding the size of high‐efficiency zone and improving the maximum value of efficiency from the perspective of loss distribution and magnetic saturation. Two IPMSMs with different magnetic circuit characteristics are designed to verify the correctness of the analytical method by finite‐element analysis (FEA). Finally, prototypes are manufactured for the experiment and measurement results are given for validations. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The scientific characterization of the properties of mesoporous materials is a key link for their development and application. In this paper, the development history, application scope, and characteristics of mesoporous adsorption and commonly used classical analytical models are briefly introduced by tabular comparison. To systematically understand the classical mesoporous analysis methods in physical adsorption, they were classified into four categories: modeled, model-free, completely model-free, and reverse methods. Then, these methods and three frequently-used analytical software for mesoporous adsorption were compared and analyzed. This has reference value for technicians of adsorption instrument management as well as for teaching and research of mesoporous materials. [ABSTRACT FROM AUTHOR]

Previous studies on the collapse performance of steel frames mainly focused on a single column loss. Even though the multi-column loss has been increasingly studied recently, it is generally based on the numerical analysis and relevant analytical study is rare. Moreover, the behavior of the frame after the multi-column loss should be more sensitive to its boundary condition due to a greater affected zone, compared with the single-column loss. However, this boundary condition effect has not been given enough attention in existing studies. To fill in these research gaps, this paper investigates the collapse resistance of the steel frame in two-interior-column-removal scenarios. To quantify the boundary condition effects, four column-removal scenarios, namely, two general-interior columns (GG), one general-interior column and one edge-interior column (GE), two edge-interior columns (EE), and one edge-interior column and one corner-interior column (EC) are studied. It is found that in the scenarios of GG and GE, the resistance-displacement relationship of the frame shows a tri-linear characteristic. In the scenarios of EE and EC, however, a bi-linear characteristic is exhibited. Compared with the GG scenario, the ultimate bearing capacities of the frame in the GE, EE and EC scenarios decrease by about 12%–20%, 33%–43% and 39%–52%, respectively. [ABSTRACT FROM AUTHOR]

The paper aims to obtain the expression of the velocity of lubricating fluid in the hydrodynamic journal bearings by analytical method. In the classical short-bearing theory, the fluid flow was studied by ignoring the effect of centrifugal force of the lubricating fluid film. However, the self-oscillation of the shaft of high-power motors does not follow the rules in classical hydrodynamic lubrication theory. To explain this phenomenon, a modified form of Reynolds equation, in which the influence of centrifugal force of the lubricant is not ignored, is established. The study aims to establish the modified Reynolds equation by including the effect of centrifugal forces for the case of the short bearing type. Integration of the Navier-Stokes equations, yield the expressions for the components of velocity of the lubricating fluid in the gap. The oil's pressure in the hydrodynamic journal bearing is obtained by solving the modified Reynolds equation. The numerical results are considered in the case of the stable equilibrium position of the motion of the shaft, i.e. the symmetry axis of the shaft does not move. The plots of the velocity components in the tangential axial direction are displayed too. The theoretical results of a parabolic velocity distribution similar to that of a Newtonian fluid, derived from a Bingham plastic flow model. The flow in the gap, which are obtained by analytical method, are completely consistent with its boundary conditions and its physical properties. Further, with these results, the paper as a lemma to solve the dynamics problem in floating ring bearing with the influence of the centrifugal force of the lubricant. [ABSTRACT FROM AUTHOR]

In this paper, the design and analysis of a 30 kW, 30,000 r/min high-speed permanent magnet motor (HSPMM) for compressor application are provided. In order to provide a reasonable electromagnetic design scheme, the electromagnetic performances of the HSPMM under different structures are analyzed and compared by the finite element method (FEM). The thermal performances and cooling system of the HSPMM are, respectively, analyzed and designed by computational fluid dynamics (CFD). Finally, the HSPMM's rotor strength is studied by both FEM and analytical methods, and the influencing factors of which are also researched in this paper. [ABSTRACT FROM AUTHOR]

Some interest has been recently directed towards analytic mathematical models for reproducing the current–voltage (I–V) characteristics of solar cells, mainly due to their convenient property of expressing current as an explicit function of voltage (which is not true for the traditional one-diode model). However, as is the case with the one-diode model itself, existing analytic models do not yield a good fit in the case of S-shaped I–V characteristics. In this brief paper, an analytic explicit model based on a three-piece quadratic curve is proposed that surpasses such difficulty and enables accurate representation of S-shaped curves. To evaluate the proposed model, validation was carried out against three empirical solar cell I–V characteristics. In all cases, simulation results show that the proposed approach is more accurate than other closed-form models in the literature. • Fully analytic mathematical model for S-shaped I–V characteristics. • Piecewise quadratic nature ensures high mathematical tractability. • Parameter extraction via closed-form equations. • Over 60% reduction in RMSE compared to previous model. • The maximum power point is fitted with zero error. [ABSTRACT FROM AUTHOR]

This paper proposes an analytical method based on large-deformation theory to predict the mechanical responses of the existing pipeline. The hypothesis that the soil and structure can be contacted or separated is proposed. The method primarily obtains the pipeline's horizontal displacement and axial force and predicts the soil gap formation potentially beneath the pipeline. Moreover, the deformation and axial force of the pipeline obtained by our method agree well with the in situ data and measured data from the centrifuge test. Compared with the other methods, the settlements and internal forces have the same characteristics except for the axial force. The results based on the small deformation theory are larger because of ignoring the axial displacement and axial force. The axial force can offset parts of the vertical load acting on the pipeline. When using the large-deformation theory without considering the horizontal displacement, the phenomenon of pipelines being only in tension is not in conformity with reality. In our proposed method, the axial force is compressive at the centerline and tensile at the hogging zone, which is consistent with the centrifuge test. It indicates that our method has extensive applications. Besides, the effects of the proportionality coefficient of vertical displacement to horizontal displacement h, coefficient of subgrade reaction k, equivalent bending stiffness EI, and maximum settlement of the underlying soil Smax2 are studied. The settlements and axial forces of the existing pipeline increase with the increase of k, Smax2 and decrease of h, EI. In contrast, the axial force increases with the increased EI. [ABSTRACT FROM AUTHOR]

This paper proposes a novel torque ripple model of V-Shape interior permanent magnet (IPM) synchronous machine based on the general field modulation theory (GAFMT). Firstly, the magnetic field modulation behavior of a 12-stator-slot/8-rotor-pole (12/8) IPM machine is discussed, where the expressions of permanent-magnet-excited (PM-excited) and armature fields are derived. Secondly, the total torque ripple is divided into three components, namely, the PM-excited cogging torque, the armature cogging torque, and the modulation torque ripple. Additionally, the relationship between the field harmonics and the torque ripple is discussed based on the GAFMT. Then, a finite element analysis (FEA)-assisted dual fast Fourier transformation (FFT) method is proposed to obtain the accurate value of the field amplitude for torque ripple calculation. The field analysis results based on the GAFMT and the proposed torque ripple are then validated by comparing their results with those obtained from the FEA simulations, and a good agreement is observed, demonstrating the effectiveness of the field analysis and the proposed torque ripple model. Finally, experiments on a prototype 12/8 IPM machine demonstrate the validity of the torque ripple model, providing an effective method for torque ripple suppression of IPM machines. [ABSTRACT FROM AUTHOR]

As permanent magnet claw pole machine (PMCPM) is designed with a complex 3D magnetic structure, the 3D finite element method (FEM) is commonly used for its accurate performance analysis. However, using 3D FEM will consume a long time in the initial design stage. Its analysis time can be saved greatly by using the analytical method (AM) or equivalent magnetic circuit method (MCM), however, the obtained performance is not accurate and some performance even cannot be obtained if only one of these methods is used. To overcome the above constraints, this paper proposes a calculation method that combined analytical and equivalent magnetic circuit method (AMCM) to calculate the main electromagnetic performance of PMCPM quickly. Its calculated results are verified by corresponding results obtained by using the 3D FEM. It can be seen that the proposed AMCM is effective for calculating the main electromagnetic performance and designing of PMCPM. [ABSTRACT FROM AUTHOR]

Multiple cracks interaction is an important topic in fracture mechanics. The related solutions are helpful to understand the failure process and the toughening mechanism of brittle materials. Previous works on the topic were most for homogenous material. In this paper, we extend the analysis and examine the problem of interaction of two coaxial penny-shaped cracks near an arbitrarily graded interface in functionally graded materials (FGMs). The cracks are modelled as circular edge dislocation loops. An efficient dislocation solution for FGMs and Fredholm integral equation technique are used to solve the crack problem. Both exact solution using a system of integral equations and approximate solution by virtue of Kachanov's method are presented. Unlike most existing analytical treatments to the crack problems in FGMs with the assumption of special gradation, i.e., graded shear modulus according to special functions and constant Poisson's ratio, the present method is more flexible since it can consider arbitrarily graded shear modulus and Poisson's ratio. The validity of the present solutions is checked by comparing to existing results in literatures for two stacked penny-shaped cracks in homogenous material and a penny-shaped crack near a graded interface with exponentially graded shear modulus. Finally, a practical example of double cracks interaction in a real epoxy-glass FGM with measured data of material properties is considered. The error due to the assumption of special gradation is also discussed. [ABSTRACT FROM AUTHOR]

In this paper, new soliton solutions with Atangana–Baleanu (AB) fractional for ion sound and Langmuir waves (ISALWs) are presented. An extended sub-equation method (ESEM) is used in symbolic software to deal with this governing model to obtain various soliton solutions in terms of trigonometric functions, hyperbolic functions, and other functional forms. Brand-new and general solitary wave solutions were obtained for the governing model. The behavior of the soliton solutions was also examined with the three-dimensional (3D) graphics. The dynamical behavior of the obtained solutions shows that they are various varieties of soliton shapes, including bell-shaped, single-soliton-shaped, and mixed-type solitons. This approach is thought to be a promising one for handling a variety of AB fractional evolution systems to validate the effectiveness of the ESEM. [ABSTRACT FROM AUTHOR]

The contactless electromagnetic de-tumbling method does not have physical contact with the uncooperative space targets and can avoid generating new space debris. Due to pollution-free and high safety performance advantages, this method has a tremendous prospect in the application of de-tumbling the uncooperative space targets. In this paper, an improved arc-linear electromagnetic device and its corresponding de-tumbling method are presented based on the principle of electromagnetic eddy current, which is mainly used for the uncooperative space targets. The analytical model of the electromagnetic device is obtained by introducing the Carter and Russel-Norsworthy coefficients and validated by the finite element method (FEM). Then, the effect on the de-tumbling torque with different electromagnetic parameters is further analyzed. Finally, the three-dimensional dynamic simulation of the uncooperative space target is carried out. The results show that the uncooperative space target can be de-tumbled in a short time by the proposed contactless electromagnetic de-tumbling device. [ABSTRACT FROM AUTHOR]

A z-section purlin steel sheet is considered in this paper to understand its structural behavioragainst the wind uplift loading. Generally toUDL is considered for a practical & effectivedesign as main aspect of loading. A verylimited research is done on combined bendingand lateral torsional buckling, so it is importantto investigate the impact of combine loading onthe zsection which is partially restrained andapplied with uplift loading. In this to describelateral torsional behavior and bending, ananalytical model is developed for the z-sectionwhich is partially restrained. Thin walledclassical bending theory is used to derive thebending stress formula for the z-section. Thepresent developed analytical model thencompare with the Eurocode EN1993-1-3 modeland with FEA results. [ABSTRACT FROM AUTHOR]

The mechanism of toppling deformation and failure is important in the stability analysis of anti-dip layered rock slopes, especially in a complex hydrogeological environment. In this paper, the flexural failure model is proposed for describing the mechanical behavior of toppling rock slope using the cantilever beam theory. A method for safety evaluation, considering the action of hydrodynamic force from groundwater, is developed. This model is then applied to conduct a case study of a toppling rock slope at a hydropower station on the Lancang River. The results show that the variation of reservoir water level increases both the tensile stresses and the deflections of rock slabs, which is manifested macroscopically by flexural displacements and failure. Based on the failure surfaces, the slope can be divided into three parts: toppling zone, creep zone, and shear zone. The failure mode of toppling rock slope is a combination of shear and toppling. Under the combined action of earthquake and rapid water drawdown, the toppling rock slope is at risk of shear instability at the leading edge; hence monitoring should be strengthened and prevention measures should be taken. [ABSTRACT FROM AUTHOR]

Polyoxyethylene tallow amine (POE-tallowamine) is widely used as pesticide adjuvant in commercial glyphosate formulations in the world. It has been reported that POE-tallowamine was more toxic than the active ingredient (glyphosate), raising concerns around the world. In this paper, the chemical structure, toxicities, the distribution in the environment and analytical methods of POEtallowamine were reviewed to provide scientific evidence for the further research, the normative application and the management of POE-tallowamine in our country. [ABSTRACT FROM AUTHOR]

Nonlinear Blasius equation of boundary layer plays a crucial role in different physics and engineering fields. For nearly a century, researchers have been trying to find a convergent and closed analytical solution of the Blasius equation. In this paper, an analytical self‐consistent method (ASCM) is presented to solve this equation. Then, the method was implemented in other forms of Blasius equation, that is, Sakiadis flow and shrinking sheet problem. The analytical solutions obtained show the success of ASCM and agree closely with the corresponding numerical results. The reliability and efficiency of the proposed method are demonstrated on the numerical experiments. [ABSTRACT FROM AUTHOR]

Nonlocal strain gradient theory is widely used when dealing with micro- and nano-structures. In such framework, small-scale effects cannot be ignored. In this paper a model of radial vibration of an isotropic elastic nanosphere is theoretically investigated. The frequency equation is obtained from a nonlocal elastic constitutive law, based on a mix between local and nonlocal strain. This model is composed of both the classical gradient model and the Eringen's nonlocal elasticity model. To check the validity and accuracy of this theoretical approach, a comparison is made with the literature in certain specific cases, which shows a good agreement. Numerical examples are finally conducted to show the impact of small-scale effects in the radial vibration, which need to be included in the nonlocal strain gradient theory of nanospheres. It reveals that the vibration behavior greatly depends on the nanosphere size and nonlocal and strain gradient parameters. Particularly, when the nanospheres radius is smaller than a critical radius, the small-scale effects play a key role. Thus, the obtained frequency equation for radial vibration is very useful to interpret the experimental measurements of vibrational characteristics of nanospheres. [ABSTRACT FROM AUTHOR]

In this paper, we use the modified exp − ψ θ -function method to observe some of the solitary wave solutions for the microtubules (MTs). By treating the issues as nonlinear model partial differential equations describing microtubules, we were able to solve the problem. We then found specific solutions to the nonlinear evolution equation (NLEE) covering various parameters that are particularly significant in biophysics and nanobiosciences. In addition to the soliton-like pulse solutions, we also find the rational, trigonometric, hyperbolic, and exponential function characteristic solutions for this equation. The validity of the method we developed and the fact that it provides more solutions are demonstrated by comparison to other methods. We next use the software Mathematica 10 to generate 2D, 3D, and contour plots of the precise findings we observed using the suggested technique and the proper parameter values. [ABSTRACT FROM AUTHOR]

The mechanical performance of three-dimensional woven composites is usually modeled by an ideal model with straight tow paths and constant cross-sectional areas. This ideal model predicts inaccurate properties due to oversimplification of tow shapes. In this paper, we present a more accurate method to predict properties of the 3D woven composite considering waviness and contraction of tows due to interference between them. The tow waviness is defined by elliptic and trigonometric functions. The shrinkage of the tow cross-sectional area is modeled using a cubic polynomial. The elastic moduli are predicted using the modeled tows and the weighted average model. The predicted properties are compared with test results to verify the accuracy. In addition, the usefulness of the present method is verified by comparing the calculated moduli using the ideal model. We conclude that the present method is useful for the design of structures to which 3D woven composites are applied. [ABSTRACT FROM AUTHOR]

For calculating the vertical earth pressure on the crown of a load shedding culvert (LSC) underneath the embankment fill, an analytical method is proposed in this paper. It can determine the corresponding position on the slip surface when the shear stress of the embankment fill on the slip surface just reaches the limit value. The method proposed in this paper considers the fact that the linearly elastic–perfectly plastic model is closer to the shear stress–strain model of embankment fill on the slip surface. According to the stress state of the embankment fill on the slip surface, the lateral earth pressure coefficient expression is derived from the geometric relationship of the Mohr's circle, in which the internal friction angle is considered as the independent variable. The stress states of the differential elements of embankment fill over LSC crown are analysed through equilibrium considerations. Thus, the analytical method for calculating the vertical earth pressure on the crown of LSC is obtained. The calculation examples are presented and compared with numerical results of FLAC 2D, which demonstrates that the difference between the proposed analytical and the numerical results is less than 10%. The results show that as the internal friction angle of embankment fill, the height of load shedding block (LSB) and the ratio of elastic modulus of the embankment fill to elastic modulus of the compressible material layer (Ef /Es) increase, the vertical earth pressure on the crown of the LSC decreases. The phenomenon is because the shear stress of the embankment fill on the slip surface over the LSC crown mostly reaches the limit value, such that the most of loads of the central fill mass overburdening the LSH surface are transferred to the adjacent fill masses. [ABSTRACT FROM AUTHOR]

Acoustic noise modeling, analysis, and reduction are critical in the design of switched reluctance machines for noise-sensitive applications. Although the analytical method can provide a fast simulation of the acoustic noise, it is generally less accurate compared to the numerical method. In order to improve the simulation accuracy, a novel analytical method is presented in this paper. The proposed method considers the excitation of the high-axial-order vibration modes to simulate the vibration behavior and the acoustic noise in the three-dimensional (3D) domain. Methods of obtaining the input data for the 3D analytical simulations are presented. The acoustic noise results obtained from the numerical simulations and experiments from an 8/6 switched reluctance motor drive are used to validate the analytical method presented in this paper. [ABSTRACT FROM AUTHOR]

The basic objectives of stability-indicating analytical methods are to provide information about the test settings and to establish the stability for all pharmaceuticals. In the present scenario, it is crucial for all drug components to reach their goals. In the present review, the regulatory components of stability-indicating approaches have been evaluated. The validated stability-indicating methods are necessary in accordance with ICH guidelines Q1A (R2), Q3B (R2), and Q6A, as well as FDA 21 CFR section 211. In order to prove the specificity, force degradation studies should be performed prior to the stability tests. Force degradation of the pharmaceuticals, drug substances, drug products, and excipients is carried out in a variety of conditions to determine the stability of the analytical technique. In this paper, the strategies for developing a stability-indicating method, computational methodologies, regulatory issues, and benefits are discussed. [ABSTRACT FROM AUTHOR]

In dealing with rockfall risk mitigation, a proper assessment of the phenomenon is the key to correctly and precisely managing its possible consequences. In doing so, numerical simulations are an unavoidable step of the assessment process. The proper description of the slope and the falling rock is paramount. Thus, it is highly relevant to accurately assess block size and shape. Block size directly defines the kinetic energy involved in the phenomenon, whilst shape directly influences its trajectory. Tools to properly assess both block size and shape are available, either in analytical form or relying upon Discrete Fracture Network (DFN) models. However, at present, no concrete demonstration of the equivalence of these two methods is provided in the literature. Moreover, block size and shape are always treated separately, while it is likely that a relationship of some sort exists between the two as they derive from the same features of the rock mass (i.e., the 3D geometry of its discontinuities). This paper presents a comprehensive study concerning (1) the comparison between DFN and analytical approaches and (2) the existence and quantification of a shape–size correlation. A modeling campaign consisting of 20 different geometrical structures is performed with both methods, with the aim of obtaining In Situ Block Size Distributions and Shape Distributions. Although the DFN and the analytical approach have different advantages and disadvantages, they have proved to be comparable in terms of results. Both methods identify the existence of a correlation between shape and size of the blocks: the shape distribution changes with reference to block size. This result points out the importance of implementing shape distribution in rockfall numerical simulations. Finally, a suitable case study from the literature has been selected to test the applicability and usefulness of the new findings for the design of rockfall barriers. [ABSTRACT FROM AUTHOR]