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关键词： Corrosion: mass transfer   Green inhibitor   Steel alloy   Modelling   HYDROCHLORIC-ACID   CARBON-STEEL   EXTRACT  

摘要： The corrosion process of steel alloys in acidic environments is typically considered to be governed by charge transfer (activation) control. Nonetheless, in aerated solutions, mass transfer can affect the electrochemical measurements. This study examines the corrosion inhibition of N80 steel in 1 M sulfuric acid using okra leaf extract (OLE), utilizing electrochemical polarization techniques at various concentrations of the inhibitor and different temperatures. The outcomes of electrochemical data of current densities and overpotentials were fitted to a high-order polynomial equation and the Maclaurin series formula. The coefficients of the high-order polynomial equation were evaluated using a non-linear regression method, which is in turn used in the Maclaurin series formula. A series of complex equations were derived, incorporating a factor (beta) to account for the impact of mass transfer on the activation-controlled corrosion process. A complex equation set of beta-models was processed using MATLAB computer programming. In addition, a beta-model was correlated to a mass transfer correction factor (gamma) and polarization resistance (R-p). beta-values ranged from 0.005 to 0.916 (average 0.198), which indicates the presence of a mass transfer effect in addition to the activation effect (mixed control corrosion mechanism). Conversely, the polarization resistance (Rp) increased with higher inhibitor concentrations and decreased as the temperature rose.

关键词： MATLAB  

摘要： Optical parameters of materials, such as the refractive and extinction coefficients, are very important in dictating their potential utilization in different applications. Therefore, their precise determination is of paramount importance. In many cases several characterizations have to be undertaken, in conjunction with some sort of modelling, to extract these parameters and others. In this work, a software named "HebalOptics" that can extract the full optical properties from the measured transmittance spectrum of thin solid films has been developed using MATLAB programming language. The program uses Cauchy formulation of the refractive index and the extinction coefficient in the visible spectrum as well as the generalized Smellier formalism extended to include the infra-red region of the spectrum. The reverse modelling of the transmittance, to obtaining the Lorentz constants is achieved using a trust-region-reflective algorithm procedure. We demonstrated the versatility of this program by extracting the optical properties of several samples. The special feature of the presented software is its ability any type of transmittance curves, whether it has fringes or not since this is a requirement to evaluate the thickness of a thin film. The obtained optical parameters are: the refractive index (n), the extinction coefficient (k), the absorption coefficient (α), the energy gap (Eg), the film thickness (d), the mean square value of the surface irregularity and the porosity. These parameters accuracy is demonstrated by the good fitting of the measured transmittance to the model and the low value of the merit function defined as the sum of the squared differences over the whole measurement region. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.

关键词： GNSS   IFCB estimation   IFCB forecast   PPP   Inter-frequency clock bias   SATELLITES   GPS  

摘要： To address the lack of publicly available inter-frequency clock bias (IFCB) products and the impact of IFCB on real-time or near-real-time multi-frequency precision positioning, a MATLAB-based software for multi-GNSS IFCB estimation and forecast (M_IFCB) was produced for multi-frequency users. This software can estimate the IFCB of GPS, BDS-2, Galileo and BDS-3 satellites and provide three alternative forecast models for GPS satellites with large IFCB amplitude variations. To verify the availability of M_IFCB, 194 and 41 globally evenly distributed MGEX continuous tracking stations were used for IFCB estimation and GPS triple-frequency uncombined precise point positioning (PPP) performance evaluation, respectively. The results show that the precision of the static solutions of the triple-frequency uncombined PPP increased by about 20.4% in the horizontal direction and 18.5% in the vertical direction, respectively. Incorporating the predicted IFCB correction, the precision of the static solutions increased by about 19.9% in the horizontal direction and 17.6% in the vertical direction, respectively.

关键词： Atmospheric effects   Software development   Computer science   Site testing   Methods: numerical   Techniques: image processing   SAN-PEDRO-MARTIR   TURBULENCE   SPECKLE   LAYER  

摘要： To enhance operational efficiency and meet experimental demands, we have developed a graphical user interface (GUI) using MATLAB for Acquiring Single Star SCIDAR Data, leveraging the software's integrated GUI Development Environment (GUIDE) tool. This interface streamlines the preprocessing and numerical computation of the power spectrum of atmospheric speckles while providing real-time graphical representations of atmospheric parameters, including the vertical profile of the refractive index structure function C-n(2)(h). It also incorporates parameters related to adaptive optics and high angular resolution, such as seeing, enabling immediate and instantaneous visual assessment of observational conditions. Furthermore, the novelty of this GUI lies in the ease of acquiring and processing data from various atmospheric parameters. The Single Star SCIDAR (Scintillation Detection and Ranging) method relies on analyzing the scintillation of light from single stars to assess the turbulent characteristics of the atmosphere. This assessment is based on the description provided by C-n(2)(h) derived from minimizing an objective function determined using the power spectrum of atmospheric speckles from single stars. For this purpose, a minimization algorithm called active-set is used.

关键词： MATLAB  

摘要： Photovoltaic (PV) output power can be able to increase through the application of the Maximum Power Point Tracking (MPPT) method. Therefore, the MPPT method increases the energy yield and consistency of the PV system. In this research, a passive Second-Order Lever Single-Axis Solar Tracking (SOLSAST) system is used to investigate the MPPT in different solar radiation and temperatures in partial and non-partial situations. The PVs of SOLSAST systems are arranged in Parallel Connection and Series Connections and examined by the MPPT algorithms when different shading experiments are conducted. In this case, simulations are carried out using MATLAB along with hardware models for the SOLSAST system. The performance of MPPT algorithms is compared and analyzed at different levels of partial and non-partial situations of the SOLSAST system. As compared to non-conventional algorithms, the optimization algorithms performed well here. © The Institution of Engineers (India) 2024.

关键词： MATLAB  

摘要： One of the most critical challenges in optical fiber communication systems using non-orthogonal multiple access (NOMA) techniques is reducing the peak-to-average power ratio (PAPR). Optical NOMA often leads to high PAPR, causing non-linear distortion and limiting the system’s gain. The advanced Selected Mapping (SLM) algorithm is introduced in this work to reduce the PAPR of the O-NOMA. In conventional SLM, multiple phase sequences are applied to the input data, which requires numerous Inverse Fast Fourier Transform, increasing computational complexity. The proposed approach simplifies this by selecting a central reference phase sequence, reducing the number of candidate sequences and the number of IFFT operations required. This reduction in complexity does not significantly compromise the PAPR reduction capability, making the method more efficient. The SLM algorithm addresses this issue by applying the phase rotation factor to the transmitted signals, redistributing the power, and reducing the peak levels. This article highlights the benefits and challenges of implementing SLM in optical NOMA systems, including its compatibility with existing NOMA schemes. Matlab 2016 analyzes parameters such as bit error rate (BER), PAPR, and out-of-band radiation. A 66% PAPR reduction can be obtained using the suggested SLM with various phase variables. Furthermore, there is a −2650 reduction in spectrum leakage. The simulation outcomes of the work reveal the potential of SLM to reduce PAPR and enhance the BER and PSD performance of optical NOMA compared with the existing algorithms. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.

关键词： Image processing   Sigma delta modulation   MATLAB   Optimization   Wiener filter   ARITHMETIC CIRCUITS   FIR   ALGORITHM   DESIGN  

摘要： Image degradation, caused by various factors, often results in noise and blur. For image restoration, inverse filters are typically used, while Wiener filters are employed for noise reduction. Unlike text or voice processing, image processing deals with significantly larger data volumes, necessitating greater computational resources. This demand can saturate resource-limited hardware such as FPGAs and ASICs, making architectural optimization essential for designing a complete System on Chip or Network on Chip. Although several hardware optimization methods exist in the literature, each has its limitations. Sigma-Delta Modulation has emerged as a promising technique in recent years, particularly for reducing the complexity of DSP systems by shortening word lengths from multi-bit to single-bit. This reduction simplifies systems and conserves hardware resources. While SDM has been widely applied in various domains, including basic arithmetic and complex adaptive filters, its use has been largely confined to speech and text processing. In recent work, the authors proposed a novel application of SDM in image processing. This study extends that investigation by designing a single-bit SDM-based Wiener filter for image noise reduction. The proposed single-bit filter is functionally compared against traditional Wiener filters, Steepest-Descent filters, and Adaptive Mean filters. Key statistical metrics such as noise variance, signal-to-noise ratio, Mean Squared Error, and Peak SNR are simulated and analyzed for real-time performance evaluation. The results demonstrate that the proposed single-bit technique remains robust against noise in dynamic environments. An FPGA-based implementation of the single-bit system further highlights its efficiency, requiring fewer resources and consuming less operational power. The findings confirm that the proposed design outperforms conventional methods in terms of effectiveness, statistical performance, and resource-optimized implementation

关键词： NONMETALLIC INCLUSIONS   DEFORMATION   EVOLUTION   MACHINABILITY   ANISOTROPY   ADDITIVES   BEHAVIOR   SULFIDE   BISMUTH   FERRITE  

摘要： The influence of the various rare earth element gadolinium contents on inclusions, microstructure, and hardness of free-cutting Y15Mn steel was investigated. And the Matlab programming was explored to provide a more accurate method for the statistics of MnS inclusions in two-dimensional state. Scanning electron microscopy (SEM) was employed to observe the type, morphology, and distribution of inclusions in samples. Results revealed that with the increase of *** content, the transformation sequence of inclusions followed a specific order: MnS -> Al-Gd-O -> Gd-O-S -> (Gd-O-S)-(Gd-S) -> Gd-S and the proportion of MnS distributed along the grain boundary gradually decreased in the direction from the center. Notably, the type of inclusions can be affected by the feeding sequence of alloying elements during the smelting process. The Al-Gd-O inclusion was the product of the full reaction of rare earth Gd with Al2O3 crucible, which was only observed in the experiment, where rare earth Gd was preferentially added. And the holding time after adding rare earth Gd in the smelting process was positively correlated with the size of inclusions. The morphology of inclusions was changed from dendritic to short rod-like shape, eventually forming spindle-like rare earth inclusions as the increase of at the *** content was higher than 462 ppm, inclusions were evenly distributed in the sample. By comparing the two-dimensional morphology of MnS inclusions in the steel and the three-dimensional morphology after electrolysis, it was found that the method of counting MnS inclusions through the cross section of the sample was not accurate. The MnS distributed along the grain boundary was well identified by Matlab programming so that inclusion statistics were closer to the real state of the three-dimensional situation. As the *** content increased from 0 ppm to 462 ppm, the hardness of the steel increased from 44.9 to 49.9 HRA.

关键词： MATLAB  

摘要： Recently, optical simulation has attracted more attention in different thin film applications. Each layer’s thickness and refractive index are the most essential simulation parameters. This paper discusses and fits the refractive index of aluminum nitride at different geometrical and physical conditions over a wide wavelength range for optical simulations. This study simplifies the use of aluminum nitride in thin film-simulated applications and devices. Plotted curves and fitted equations with MATLAB scripts for aluminum nitride refractive indices at different conditions will be provided to minimize modeling errors. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.

关键词： Hydrogen Fuel Cell   Electric Vehicle   Battery SOC   Modeling   Postal car   MANAGEMENT-SYSTEM  

摘要： This research puts forward the modeling of a Hydrogen Fuel Cell Electric Vehicle (HFCEV) and its validation, in comparison with battery electrical vehicle (BEV) based on a postal vehicle and its subsystems. The main investigation parameters are the amount of hydrogen consumed, and the change in the state of charging of the battery. For the profile of the same speed route, an HFCEV model and a BEV model, consisting of multiple subsystems, were developed, and simulated in the MATLAB (R) Simulink environment. We make use of various sources of drive cycles to obtain our outcomes such as the New European Diving Cycle (NEDC). By running simulations for different stages, we are able to generate simulation results. The discrepancies in the graphs and the visual demonstrations guided us to variable conclusions on how different factors affect an electric vehicle's performance and efficiency. The simulation result shows that the (BEV) is 30% more effective for NEDC drive cycle comparing with (HFCEV).