Narrow Results

The effect of the damaged car evacuation on the traffic flow behavior is investigated, in the one-dimensional deterministic Nagel–Schreckenberg model, using parallel dynamics. A realistic model applied to the cars involved in collisions is considered. Indeed, in this model we suppose that the damaged cars must be removed from the ring with a probability P_exit. This investigation enables us to understand how the combination of the two probabilities, namely P_col and P_exit, acts on density and current. It is found that the current and density at the steady state, depend strongly on the initial density of cars in the ring. However, for the intermediate initial density ρ_i, the current J decreases when increasing either P_exit and/or P_col. While, for high initial density, J increases passes through a maximum and decreases for large values of P_exit. Furthermore, the current can decrease or increase with the collision probability depending on the initial density.

The Nagel–Schreckenberg (NS) cellular automata (CA) model for describing the vehicular traffic flow in a street with open boundaries is studied. To control the traffic flow, a traffic signalization light operating for a fixed-time scheme is placed in the middle of the street. Extensive Monte Carlo simulations are carried out to calculate various model characteristics. Essentially, we investigate the formation of the cars queue behind traffic light dependence on the duration of green light T_g, injecting and extracting probabilities α and β, respectively. Two phases of average training queues were found. Besides, the dependence of car accident probability per site and per time step on T_g, α and β is computed.

A topological defect in the form of the Abrikosov–Nielsen–Olesen vortex is considered as a gauge-flux-carrying tube that is impenetrable for quantum matter. Charged scalar matter field is quantized in the vortex background with the perfectly reflecting (Dirichlet) boundary condition imposed at the side surface of the vortex. We show that a current circulating around the vortex and a magnetic field directed along the vortex are induced in the vacuum, if the Compton wavelength of the matter field exceeds considerably the transverse size of the vortex. The vacuum current and magnetic field are periodic in the value of the gauge flux of the vortex, providing a quantum-field-theoretical manifestation of the Aharonov–Bohm effect. The total flux of the induced vacuum magnetic field attains notable finite values even for the Compton wavelength of the matter field exceeding the transverse size of the vortex by just three orders of magnitude.

The life time and quality of thermal spray coatings are strongly influenced by the technological parameters of the coating process and characteristics of the coated surface. In this paper, 16Mn steel substrates of different surface roughness are coated by Cr₃C₂-NiCr using a plasma spray technique. The adhesion of the coating to the substrate has been studied in relation to the roughness of the substrate and the plasma current of the spraying process. The results showed that the adhesion of the Cr₃C₂-NiCr coating to 16Mn steel substrate is strongly influenced by the roughness and the current intensity. The range of substrate surface roughness and current intensity at which the Cr₃C₂-NiCr exhibited high adhesion to the steel substrate are discussed in this paper.

We discuss the directed motion of overdamped Brownian particles based on a two-dimensional ratchet model with a non-conservative impulsive force field. We consider the combined effects on the stationary current due to local spatial asymmetry in the longitudinal direction as well as the constrained harmonic force in the transverse direction. We notice that the current reversal is induced by the change of colored noise strength and the dynamics in the transverse direction influences the directed motion in the longitudinal direction significantly. The non-conservative impulsive force that represents the chemical energy consumed in the conformation changing process is a crucial factor to the directed motion of the Brownian motors.

The optical performance of RGB LEDs used in displays is highly sensitive to the drive current and ambient temperature. The emitting intensity and dominant wavelength of RGB LEDs are investigated with the various currents and temperatures, and then the relevant mathematic models are proposed and summarized. Hence, the emitting intensity and dominant wavelength of RGB LEDs under any operating condition can be known from these models.

In the 21st century, understanding the mechanism of high-temperature superconductivity has emerged as a pinnacle achievement in condensed matter physics, capturing the lifelong interest of numerous physicists. This paper endeavors to offer a theoretical elucidation for this mechanism, advancing the broader field of physics. Recognizing that high-temperature superconductivity is an aspect of condensed matter physics — underpinned by Maxwell’s classical electromagnetic theory — we turn to theoretical mechanics and field theory, which are foundational perspectives in the contemporary scientific era. By framing Maxwell’s classical electromagnetic theory within the context of theoretical mechanics and field theory, this paper not only sheds light on the mechanism of high-temperature superconductivity but also recasts Maxwell’s theory within a purer theoretical mechanics and field theory domain. This represents a paradigmatic shift and cognitive transformation in physics. Furthermore, leveraging this theoretical mechanics and field theory interpretation of electromagnetic phenomena, we discern that electromagnetic phenomena can be more aptly explained without resorting to the concepts of charges and electric fields, leading to a reinterpretation of Coulomb’s law. We propose that protons and electrons might exist as entities devoid of charge-specific attributes and negate the possibility of a strongly correlated particle system within them.

The electrical conductivity and volt–ampere characteristics (VAC) of the p-CuTlS₂ single crystal with specific resistance $\rho =40\mathrm{\Omega }\cdot \mathrm{\text{cm}}$ and irradiated by $\gamma$-quantum were studied in the range of 100–300K temperature and 10–10⁴V/cm. It was determined that the cause of the conduction disorder observed in the CuTlS₂ single crystal at low electric fields and high radiation doses is the formation of defect clusters dominated by cation vacancies. A sharp increase in current at high electric fields and temperatures occurs as a result of thermo-field ionization of the acceptor level with activation energy $\mathrm{\Delta }{E}_a=0.08$eV and the ionization voltage decreases with increasing radiation dose. Based on the determination of the parameters ($\lambda ,r_m,n_0,\epsilon$) that determine the mechanism of current flow, the dependence of the shape of the potential hole on the radiation dose was determined.

Since we cannot solve the equation, we know nothing about the properties of the fracmemristor circuit. In this paper, HP memristor is used in fracmemristor circuit for the first time. After a series of mathematical processing, the HP fracmemristor can be equivalent to two parts which are represented as F and VM, respectively. The F part is the fractance. The VM part is related to the current, and it can best reflect the fracmemristor property of the circuit. Therefore, we hope that we can understand the fracmemristor circuit by the simulation research of the HP fracmemristor circuit. Firstly, the amplitude frequency characteristic and phase frequency characteristic of HP fracmemristor are obtained by using Matlab. And compared with the fractance, they have different characteristics. After that, the 1/2 order fracmemristor property is studied. By approximating processing the 1/2 Laplasse operator and then using Laplasse transform and inverse Laplasse transform, we can get the total resistance change with time, the changes of total resistance with the current figure, the voltage of part F changes with the current, the voltage of part VM with the current changes, as well as the total voltage with current changes. From these diagrams, the U-I diagram of the VM section intersects at two points. The currents at these two points are symmetrical about the origin, and the voltages at the two points are slightly different. Moreover, the magnitude of the current and voltage is stable at the point of intersection, and does not change with the magnitude of the input current. For HP fracmemristor circuits, its properties depend on the size of the current. When the current is very small, the HP fracmemristor exhibits the characteristics of fractance, and the influence of the VM part can be ignored. With the increase of current, the effect of fractance F is reduced, and the effect of VM is increased. When the current increases to a certain size, the output of the circuit is the same as that of the VM part, and the effect of the fractance F part can be ignored.

Nowadays, the power quality (PQ)-related issues have become more prominent in power electronic devices. For compensating PQ disturbances various types of power devices are used. The unified power quality conditioner (UPQC) is one of the power electronic devices that is used for compensating the PQ. To reduce the PQ disturbances, the performance of series and shunt active power filters (APFs) must be improved. In this paper, an enhanced controller is proposed for improving the performance of series and shunt APFs and compensating the PQ. The enhanced technique used is the combination of artificial neural network (ANN) and gravitational search algorithm (GSA) which is used for generating the control signals of the APF and reducing the PQ problem. The shunt APF is used for reducing the harmonic disturbances. The DC-link voltage is regulated by utilizing the proposed enhanced controller technique. Subsequently, the THD value of the proposed system is measured. The proposed method is implemented in MATLAB/Simulink platform and its performance is evaluated. The performance of the proposed method is evaluated and compared with the base controller and ANN controller.

In this paper, the Levy flight-based chicken swarm optimization (LFCSO) is proposed to follow the highest power of grid-joined photovoltaic (PV) framework. To analyze the grid-associated PV framework, the characteristics of current, power, voltage, and irradiance are determined. Because of the low yield voltage of the source PV, a big advance up converter with big productivity is required when the source PV is associated with the matrix power. A tale great advance up converter dependent on the exchanged capacitor and inductor is illustrated in this paper. The LFCSO algorithm with the adaptive neuro-fuzzy inference system is used to generate the control pulses of the transformer-coupled inductor DC–DC converter-less switched capacitor. While using the switched capacitor-coupled inductor, the voltage addition is expanded in the DC–DC converter and the power of PV is maximized. Here, the normal CSO algorithm is updated with the help of Levy flight functions to generate optimal results. To get the accurate optimal results, the output of the proposed LFCSO algorithm is given as the input of the ANFIS technique. After that, the optimal results are generated and they provide the pulses for the system. The working guideline is analyzed and the voltage addition is derived with the utilization of the proposed technique. From that point forward, it predicts the exact maximum power of the converter according to its inputs. Under the variety of solar irradiance and partial shading conditions (PSCs), the PV system is tested and its characteristics are analyzed in different time instants. The proposed LFCSO with ANFIS method is actualized in Simulink/MATLABstage, and the tracking executing is examined with a traditional method such as genetic algorithm (GA), perturb and observe (P&O) technique–neuro-fuzzy controller (NFC) and fuzzy logic controller (FLC) technique.

This paper describes a model of the net sediment transport rate under linear and arbitrary nonlinear oscillatory flows in the sheetflow regime. The model is based on a two-phase flow description. The turbulent diffusivity was formulated to take into account phase-lag effects for different wave conditions and sediment properties. An introduction of a modifier to the turbulent diffusivity produced asymmetry in the concentration profiles, which qualitatively agrees with temporal and spatial distributions of the concentration profiles measured during laboratory visualization experiments. The model can predict transport rates in the sheetflow regime for combined waves and co-directional currents and for waves alone. The model is validated for a wide range of sediment median particle diameters, wave periods, and maximum flow velocities. Comparisons with experimental data on transport rates under linear and nonlinear waves, including velocity and acceleration asymmetric oscillations, were made and showed good agreement. Other comparisons encompassing combined waves and currents were conducted, also with good agreement.

Most of the existing sediment transport models are not synchronously driven by both the wave field and the flow field. This paper describes a 3D sediment transport model with waves and currents directly coupled within the model to continuously account for different-scale activities especially those that have significant contribution to local sediment transport processes such as formation of sediment plumes and turbidity maxima. A practical issue in modeling coastal sediment transport, besides the concern of model accuracy, is the efficiency of the model. In the present model, the wave action equation, instead of the computational demanding elliptic mild-slope equation, is used to calculate the wave parameters. The wave action equations take into account wave refraction and diffraction as well as the tidal hydrodynamic modification. The calculation of the wave and current forcing is coupled during the time marching process so that the effects due to short-term activities can be considered. The model has been verified against laboratory measurements and has also been applied to simulate actual sediment transport situations in the Pearl River Estuary (PRE), China. It has been quantitatively shown that the suspended sediment concentration in the PRE increases significantly when waves are present. Sediment deposition occurs at the upstream region of the PRE while erosion takes place mostly at the down-estuary region due to exposure to wave actions.

A new set of differential equations with the free surface elevation and the depth-integrated volume flux being the dependent variables is derived for description of monochromatic waves on steady currents over gradually varying bottoms. The derivation is based on the vertical integration of the continuity equation and the equation of motion for general free-surface flows. A similarity law on the dynamic pressure and the horizontal velocity, modified from a relevant relation for small amplitude waves on uniform currents, has been introduced. A finite-difference scheme with second-order accuracy is proposed for solutions of the equations. The computational algorithm is proved to be conditionally stable and easy to implement. Key points on specification of boundary and initial conditions are discussed in details. Computations are carried out to investigate the nonlinear effects on wave shoaling over a uniform slope with following or opposing current in presence. A case test of the proposed model is also performed and satisfactory agreement obtained between the computational results and reported laboratory data.

This paper presents a new third-order trajectory solution in Lagrangian form for the water particles in a wave-current interaction flow based on an Euler–Lagrange transformation. The explicit parametric solution highlights the trajectory of a water particle and the wave kinematics above the mean water level and within a vertical water column, which were calculated previously by an approximation method using Eulerian approach. Mass transport associated with a particle displacement can now be obtained directly in Lagrangian form. The angular frequency and Lagrangian mean level of the particle motion in Lagrangian form differ from those of the Eulerian. The variations in the wave profile and the water particle orbits resulting from the interaction with a steady uniform current of different magnitudes are also investigated. Comparison on the wave profiles given by the Eulerian and Lagrangian solution to a third-order reveals that the latter is more accurate than the former in describing the shape of the wave profile. Moreover, the influence of a following current is found to increase the relative horizontal distance traveled by a water particle, while the converse is true in the case of an opposing current.

In high school and undergraduate physics, magnetic forces are often introduced as not being capable of doing work. In this paper, we explore the truth of this statement, analyzing the work done in various physical scenarios, including the bending of a wire in an external magnetic field, as well as the interaction between magnetic dipoles. In particular, the formation of surface charges and thorough analysis of the Hall force are elaborated. This paper addresses certain misconceptions regarding magnetic forces and work, and is expected to be of interest to students and educators alike.

The controlling method for high-voltage pulse form or pulse parameter is extremely important in high speed switching technique. Function generation can repeatedly make various forms and widths of pulse waves such as low-voltage sine wave, square wave, and sawtooth wave. Waveform control is not easy when voltage exceeds a certain amount of kVs. Pulse forming network (PFN) or pulse forming line (PFL) has been used so far along with trigger gap, rail gap, semiconductor switch, ignitron, cyratron, and autocompression switch, which are used as switching device. For PFN, multistep LC circuit is introduced to widen the pulse width, and for PFL, a method to lengthen the charging line is adopted. These methods are difficult to control because a large number of devices are used, and the devices are getting bigger in terms of size. In order to compensate this weakness, the researchers of this study made self-stimulating pulse forms with various pulse widths by actively engrafting the low-voltage two-step or four-step circuits with the AVR one-chip microprocessor technology, which is widely used for two-step or four-step electric network recently with low price.

The stratification of upper layer of coastal water can be regarded as an unused energy source in summer. In addition, the coastal water has capability to store the urban heat owing to the heat capacity difference to the atmosphere. This study assesses the usage and capacity of coastal water for heat storage. A set of numerical simulations of the urban heat release into coastal zone is performed for Osaka bay of Japan. The estimated urban heat along Osaka Bay is 1 kGJ/h within the distance from 500 m to 5000 m from the coastal line. The urban heat released within 2000 m from the coastal line had little influence on sea surface temperature of Osaka Bay.