We derive two iterative methods with memory for approximating a simple root of any nonlinear equation. For this purpose, we take two optimal methods without memory of order four and eight and convert them into the methods with memory without increasing any further function evaluation. These methods involve a self-accelerator (parameter) that depends upon the iteration index to increase the order of

In this paper, the matters of dissipativity and synchronization for non-autonomous Hopfield neural networks with discontinuous activations are investigated. Firstly, under the framework of extending Filippov differential inclusion theory, several effective new criteria are derived. The global dissipativity of Filippov solution to neural networks is proved by using generalized Halanay inequality and

In this communication, we show that a family of partial differential equations such as the linear and nonlinear wave equations propagating in an inhomogeneous medium may be derived if the action functional is replaced by a new functional characterized by two occurrences of integrals where the integrands are non-standard singular Lagrangians. Several features are illustrated accordingly.

Fractional calculus has been shown to improve the dynamics of differential system models and provide a better understanding of their dynamics. This paper considers the time–fractional version of the Degn–Harrison reaction–diffusion model. Sufficient conditions are established for the local and global asymptotic stability of the model by means of invariant rectangles, the fundamental stability theory

This paper studies the (3 + 1)-dimensional generalized Kadomtsev–Petviashvili–Boussinesq (KPB) equation via the Hirota’s bilinear form and symbolic computation. Mixed type lump solutions are presented, which include rational function, trigonometric function and hyperbolic function. The propagation and the dynamical behaviors of these mixed type of lump solutions are shown by some three-dimensional

In this paper, we present a new algorithm for the detection of distorted and overlapping circlelike objects in noisy grayscale images. Its main step is an edge detection using rotated difference kernel estimators. To the resulting estimated edge points, circles are fitted in an iterative manner using a circular clustering algorithm. A new measure of similarity can assess the performance of algorithms

Engineer and roboticist Zach Ousnamer is helping to prepare NASA’s Perseverance rover for its launch to the red planet.

One-quarter of the global lowland population could depend on water from higher elevations by mid-century.

The pandemic is prompting some early-career researchers to rethink their hopes for a university post.

COVID-19 is exposing the fragility of the goals adopted by the United Nations — two-thirds are now unlikely to be met.

The coexistence of superconducting and correlated insulating states in magic-angle twisted bilayer graphene1,2,3,4,5,6,7,8,9,10,11 prompts fascinating questions about their relationship. Independent control of the microscopic mechanisms that govern these phases could help uncover their individual roles and shed light on their intricate interplay. Here we report on direct tuning of electronic interactions

A novel hybrid system primarily consisting of a photovoltaic module (PVM) and a direct contact membrane distillation (DCMD) is proposed, where the relatively long wavelength sunlight transmitted through the PVM is converted into heat and then supplied to the DCMD for water purification. The models of both PVM and DCMD are mathematically formulated and validated, and the performance of the hybrid system

To solve the increasingly serious global energy problem, an innovative cascade absorption heat transformer system using industrial low-level waste heat is presented in this paper. Based on an accurate model and simulations, the cascade system is studied in terms of an energy, exergy, and economy analysis. To achieve a trade-off between the thermodynamic and economic performance, a multi-objective optimization

In this paper, a modified version of the bat algorithm (BA), called enhanced Lévy flight bat algorithm (ELBA), is proposed for accurate and efficient parameter extraction of different photovoltaic (PV) models from experimental data. Typically, it is formulated as a multimodal nonlinear optimization problem in which the objective function is to minimize the root mean square error verified between the

Presented in this paper is harvested nonlinear energy from a vibration energy harvester device; the device has been designed, manufactured, and tested successfully – the device performance is verified theoretically to some extent. The design concept is on the basis of merging the nonlinearities of the building block (i.e. a beam) and those induced by the motion limiters, which for some design parameters

In this article, a meshfree method for the numerical solution of conversation law equations is considered. Some problems which have shock such as advection problems are not properly solved by radial basis function collocation meshfree method. Therefore, we use the integrated radial basis function (IRBF) method for some of these problems. In the current study, the governing models have been discretized

Tachometric and thermal anemometers are two types of instruments mainly used in typical standard measurements in meteorology, ventilation, air conditioning, technical and industrial measurements. Both types of these instruments have many beneficial metrological properties, which causes their widespread use in many measurement issues. However, the sensors of mechanical anemometers have large dimensions

Laser trackers (LTs) are widely used for large-scale dimensional metrology. Periodic LT performance evaluation is a key aspect in ensuring measurement reliability. The existing documentary standards for LT performance evaluation require scale bars and special artifacts that are often unavailable for many LT users. A network-based method is considered in this paper as a simple and effective approach

Poor selection of footwear, underestimation of foot health, sedentary life, and lack of accessible foot screening can have significant long-term adverse effects on the health of lower limbs. Unobtrusive, pervasive methods for automated foot screening have the potential to allow for timely detection of foot abnormalities. In the present study, we describe a proof-of-concept where data collected through

Current strategies for quality-related process monitoring mainly focus on a single quality indicator. For multiple related indicators, traditional algorithms extract the same quality-related features from variable spaces while neglecting the specific features of each indicator. Considering the correlation among these quality indicators, essential information can be captured in common features without

Increasing performance requirements of advanced products demands new, versatile fabrication techniques. Additive technology represents one of the most prospective fields of future production. B4C-based composites were fabricated on titanium substrate by selective laser melting (SLM) using titanium (Ti-6Al-4V) and boron carbide (B4C) powder mixture at different weight ratio (Ti:B4C = 1:0, 9:1, 8:2,

Conical end-mills are widely used in CNC machining and the flank has a great influence on the performance of the end-mill. However, the complex structures of conical flank make it difficult to grind. The traditional method for conical flank grinding is to control the grinding wheel with a 3-axis archimedes helix motion, which cannot guarantee the accuracy of the desired flank parameters, i.e., relief

A new forming process for magnesium alloy sheet, namely, electromagnetic impacting medium forming (EIMF), is proposed. Medium is compressed by strong magnetic force which is produced from varied magnetic field between coil and driver sheet. Magnesium alloy sheet can be deformed by a strong force from medium. In EIMF, once impacting or more times impacting is easily implemented, that is difficulty in

This paper established three micro-cutting simulation models for SiCp/Al composites with a volume fraction of 45%. The three models of SiCp/Al composites, established by ABAQUS software, are equivalent homogeneous model, multiphase mixture model, and multiphase mixture cohesive model. And the three models were compared and analyzed. The results showed that the equivalent homogeneous model was suitable

In this work, the result of reachable set bounding and extended dissipative control synthesis of the Markovian jump time-delayed system is studied subject to stochastic actuator failures and partially known transition probabilities. Specifically, a novel actuator fault model is designed, in which the actuator fault matrix satisfies a certain probabilistic condition. Under the construction of an appropriate

In this paper, we study the properties and structure of the maximal-adjacency-spectrum unicyclic graphs with given maximum degree. We obtain some necessary conditions on the maximal-adjacency-spectrum unicyclic graphs in the set of unicyclic graphs with vertices and maximum degree and describe the structure of the maximal-adjacency-spectrum unicyclic graphs in the set. Besides, we also give a new upper

Extreme learning machine (ELM) has been put forward for single hidden layer feedforward networks. Because of its powerful modeling ability and it needs less human intervention, the ELM algorithm has been used widely in both regression and classification experiments. However, in order to achieve required accuracy, it needs many more hidden nodes than is typically needed by the conventional neural networks

Based on the practical application of an enterprise, we address the multistage job shop scheduling problem with several parallel machines in the first stage (production), a few parallel machines in the second stage (processing and assembly), and one machine in the following stages (including joint debugging, testing, inspection, and packaging). First, we establish the optimization objective model for

The influence of soil heterogeneity is studied on the bending of circular thin plates using two modified Vlasov foundation models. The model parameters are determined reasonably using an iterative technique. According to the principle of minimum potential energy and considering transversely isotropic soils and Gibson soils, the governing differential equations and boundary conditions for circular thin

To address the problem of multiattribute group decision-making with interval grey numbers, decision matrices are adjusted using kernels of interval grey numbers to reduce the psychological effects of decision-makers. The comprehensive weights of attributes are obtained by aggregating the subjective weights with objective weights, which are calculated based on the accuracy and difference of attributes

The claim process in an insurance risk model with uncertainty is traditionally described by an uncertain renewal reward process. However, the claim process actually includes two processes, which are called the report process and the payment process, respectively. An alternative way is to describe the claim process by an uncertain alternating renewal reward process. Therefore, this paper proposes an

Seismic hazard prediction is essential for earthquake preparation in urban areas. Prediction methods based on refined the finite element method (FEM) models and time-history analysis require higher calculation, which is hard to apply universally. In this paper, by applying two simplified models and time-history analysis, the authors were able to develop a refined seismic hazard prediction system for

This article presents the results of experiments concerning a computational fluid dynamics (CFD)/numerical analysis of the flow of air in the grinding zone during the sharpening of the face surface of hob cutters while using the MQL method. The carrying out of a simulation allows one to determine the influence of various settings of the angle of the spray nozzle on the amount of air directly reaching

During the development of the wind turbine system, blades are considered as the most critical components. The blades’ dynamic characteristics must be investigated during the design process to improve their mechanical performance. This work presents an experimental updating of a segmented wind turbine blade numerical model. For this purpose, the blade segments were manufactured using the fused deposition

With the development of automation technologies, data can be collected in a high frequency, easily causing autocorrelation phenomena. Control charts of residuals have been used as a good way to monitor autocorrelated processes. The residuals have been often computed based on autoregressive (AR) models whose building needs much experience. Data have been assumed to be first‐order autocorrelated, and

In this report, we show that hyperspectral high-resolution photoluminescence mapping is a powerful tool for the selection and optimization of the laser ablation processes used for the patterning interconnections of subcells on Cu(Inx,Ga1–x)Se2 (CIGS) modules. In this way, we show that in-depth monitoring of material degradation in the vicinity of the ablation region and the identification of the underlying

Poly-generation system is gaining more attentions recently due to its advantages of the effective promotion on energy utilization efficiency and deceleration of environmental pollution, as well as the security and reliable improvement on power supply. In this study, a novel trigeneration system composed of a gas turbine cycle (GTC), a regenerative supercritical carbon dioxide (sCO2) Brayton cycle,

We present a method for PPP adjustment based on Recursive Least Square Estimation (RLSE). This method estimates the stochastic model of GPS, GLONASS, Galileo and BeiDou observations by using RLS-Variance Components Estimation (RLS-VCE). The accuracy and the convergence time of horizontal, altitudinal and three-dimensional components is compared by using both nominal and RLS-VCE method so that the estimated

The fact that the calculation model and optimization method are critical to the optimization efficiency of ride comfort. To improve the reliability of this process for heavy vehicles, this article proposes a systematic modelling method that is based on the coupled nonlinear dynamics of suspension components and a hierarchical optimization method that considers passenger comfort, cargo safety, and parts

The interest in Ultra-High Concentrator Photovoltaic (UHCPV) devices has motivated the use of solar cells under ultra-high irradiance levels (+1000 suns). Temperature effects and variations in the spectrum of the incoming light on the solar cells need to be analysed to understand their performance under real operating conditions. In this work an experimental setup, based on an indoor multi-flash solar

In this paper, the effects of detection speed on eddy current testing (ECT) signals are studied, and the quantitative evaluation method of rail surface cracks at different speeds is proposed. According to the finite element simulation analysis, the excitation frequency and coil parameters are optimized. A high-speed ECT system is established for rail crack detection experiments in a lift-off range

Abstract This paper presented an efficient electronic nose (e-nose) system, named “NOS.E”, for odour analysis and assessment. In addition to the reliable hardware and software designs, an airflow intake system is implemented to ensure the precise odour analysis procedure in the NOS.E system. Besides, a particular control logic was introduced to improve the test efficiency of the NOS.E by reducing operation

The use of the magnetic flux density change as a diagnostic parameter in screw tightening torque of bolts is discussed in this study. The proposed methodology uses the inverse magnetostrictive effect, considering that the magnetic flux density changes according to the internal stress of the bolt. In the experiments, we measured the strain and magnetic flux density of the magnetostrictive material FeCo

The simulation of the artillery interior and intermediate ballistics problem is performed to investigate the influence of a gas dynamics device, muzzle brake, on the muzzle hazard phenomena, such as flash and blast waves. The correlation of the chemical reactions with the characteristics of the muzzle flow field is analyzed by the simulation for a further understanding of the secondary combustion phenomenon

This paper presents the design optimization of composite submersible cylindrical pressure hull subjected to 3 MPa hydrostatic pressure. The design optimization study is conducted for cross-ply layups [0s/90t/0u], [0s/90t/0u]s, [0s/90t]s and [90s/0t]s considering three uni-directional composites, i.e. Carbon/Epoxy, Glass/Epoxy, and Boron/Epoxy. The optimization study is performed by coupling a Multi-Objective

Compared with the conventionally gaseous or liquid working media, the specific internal energy of supercritical carbon dioxide (SCD) is higher at the same temperature and pressure, and the critical temperature of carbon dioxide is close to room temperature, making SCD a potential new working medium for pneumatic launch. To analyze the feasibility of this conception, an analytical model of a pneumatic

The prediction of the fragment velocity distribution of a cylindrical cased charge with end caps is one of the key issues to assess the damage efficiency of the warhead. However, limited work has been conducted to predict the fragment velocity distributions along the axis of cylindrical cased charges with end caps. This paper presents a study of the velocity distribution of fragments caused by the

Many modern structural systems usually consist of multiple failure modes. One failure mode may affect other failure modes due to the same working environment and random input variables, meaning that these failure modes are not independent. The assumption of independence among failure modes simplifies the calculation of reliability of structural systems, but it adds approximation error. Different from

Magnesium (Mg) alloy sheets have attracted considerable attention as one of the most promising lightweight structural materials for weight reduction–oriented industries owing to their excellent properties compared with conventional materials. However, basal-textured Mg alloy sheets exhibit extremely inferior formability at room temperature due to their hexagonal close-packed structure and the limited

In Fig. 8, the characteristic lines were disorderly arranged.

Residual stress on the surface and subsurface has a great influence on the distortion and fatigue life. Rapid and accurate prediction of residual stress is important for the optimization of the machining process in intelligent manufacturing. A novel analytical model is proposed based on the equivalent stress method in this paper. The nonlinear flow characteristics of the work-piece material in the

Grade AH36 ship steel plate, frequently used in offshore applications, was joined underwater by shielded metal arc welding (SMAW) using two different types of electrodes (E6013 and E7014). The ship steel plate was also joined under atmospheric conditions in order to compare both joints in terms of mechanical and metallurgical properties. The E6013 rutile electrode was isolated by wrapping before use

In order to reduce misalignment, enhance tight tolerance, and improve machining efficiency, a novel double cone integrated tool was developed and experimentally investigated during one-shot drilling of aluminum and aluminum alloy stacks in this paper. This special tool geometry can finish drilling, reaming, and countersinking processes at the same time. Its machining properties were comparatively evaluated

Understanding the influences of drilling parameters on machinability characteristics of NFRCs is of value to both academia and manufacturing industries. The present work investigates drilling-induced delamination and hole quality of fully biodegradable flax/poly(lactic acid) composites in response to cutting speed, feed rate, drill diameter, and drill material. Among various types of drilling-induced

The structure and properties of cold-rolled strips with a thickness of 3 mm from an experimental aluminum alloy 1580 with a lower scandium content of 0.03% (wt.) relative to the grade of the aluminum alloy and a 5083 similar alloy without scandium were studied. Ingots obtained at the laboratory installation of semicontinuous casting of the foundry department of the Siberian Federal University (Siberian