MATLAB Code Research Articles

High Purity Orbital Angular Momentum Modes Reconfiguration Using Uniform Circular Array Antenna to Enhance Channel Capacity and Spectral Efficiency

Technology based on OAM (orbital angular momentum) has great potential for enhancing the bandwidth efficiency of telecommunication systems. Although OAM waves are orthogonal, it is possible to multiplex various modes within a single frequency channel. Significantly, the overall spectrum efficiency, as well as channel capacity, can be improved. Multiple users can share the same frequency channel by using orthogonal modes, which eliminates the requirement for extra resources like time and frequency. This research uses MATLAB code to derive a uniform circular array (UCA) antenna factor under the cylindrical coordinate system. This factor is used to illustrate the array antenna's electric field to generate OAM waves or radio waves that carry the OAM mode. OAM modes can be reconfigured for the no. of UCA elements (N) needed to generate a ripple-free radiation pattern based on the UCA antenna factor. Additionally, the significance of UCA radius and observational distance (the field plane-UCA plane gap) on the phase distribution and radiation pattern from OAM mode 1 to 5 is graphically evaluated and optimized. The MATLAB simulations compute the electric field phase distribution pattern (EFPDP) and normalized radiation pattern (NRP) at 76 GHz. The method predicts the peak, side lobes, and comparable radiation patterns of the radiation pattern, offering an effective means of optimizing OAM modes and analysing trade-offs.

Phase-field modeling and linearly energy-stable Runge–Kutta algorithm of colloidal crystals on curved surfaces

In this work, we develop an efficient and unconditionally energy-stable numerical method for solving a generalized H−1-gradient flow based Swift–Hohenberg equation for colloidal crystal on surfaces. By introducing an appropriate truncated nonlinear potential, we construct linear and temporally second-order accurate scheme based on the linear convex splitting and implicit-explicit Runge–Kutta approaches. The surface is discretized by a set of triangles. The spatial approximation is performed based on the finite volume type method. During every time step, our task simply involves solving a set of elliptic-type equations that have constant coefficients. We analytically prove the energy dissipation law and unique solvability. Numerical examples indicate that the proposed scheme not only works well on various surfaces but also has desired accuracy and energy stability. We also provide the MATLAB code for generating triangular mesh on the curved surface in the link: http://github.com/yang521/MATLAB-distmesh.

Solution of nonlinear Burger's equation arising in longitudinal dispersion phenomena

The present article showcases a novel approach for obtaining the approximate solution of the nonlinear Burgers' equation, a frequently occurring equation in the study of wave propagation and dispersion phenomena. The Double Power Series Method, a methodology not conventionally applied to this equation, introduces a unique analytical perspective. The method's versatility in handling two independent variables makes it particularly well-suited for addressing the complexities of the Burgers' equation, providing a comprehensive representation of fluid concentration for arbitrary distances and times. Through this novel approach, we study the intricate dynamics governing the relationship between convection and diffusion forces in longitudinal dispersion. This research not only enriches the theoretical foundation of nonlinear partial differential equations but also holds promise for practical applications across fluid dynamics, environmental engineering, and beyond. Both numerical and graphical solutions are meticulously computed through MATLAB coding, facilitating a robust physical interpretation of the results. This study contributes valuable insights into the behavior of fluids in dispersion scenarios, offering a practical approach to understanding and predicting such phenomena.

A Study on The Optical Properties of Long-Infrared Intraband Transitions of Quadruple Gaas/Alxga1-Xas Quantum Well Under Applied Electric Field

Semiconductor-emitting/absorbing infrared devices are in the common interest of the scientific and industrial community due to their broad application in these fields. GaAs/AlGaAs based devices are one of the most studied semiconductor heterostructures. In this study, I have aimed to design GaAs/AlGaAs quantum well (QW) semiconductor heterostructures to emit/absorb in the long infrared region and studied the optical properties. To do that, I have designed a quadruple QW, which is composed of GaAs/Al0.44Ga0.56As QW and quantum barriers (QB). I have solved the time-independent Schrödinger equation using the finite element method-based matlab code under effective mass approximation. The wave functions and corresponding energy eigenvalues are obtained for varied electric field (EF) intensities. I have shown that our design can operate up to 80 kV/cm, which is the limit for first bounded energy eigenstates. It is observed that E_32 transition provides long-infrared emission/absorption corresponding to the 0.12-0.14 eV transition energy and it is constant with increased EF intensity. In addition, it is seen that the overlap of the wave functions is increasing with EF intensity which enhances radiative transition in the structure. I have calculated the linear absorption coefficient and refractive index change. I have observed that the absorption coefficient of E_32 transition is increasing with EF intensity while E_31 is decreasing and E_21 is constant. As a last, I have shown that EF intensity has a minor effect on refractive index change.

Modelling 2-D Heat Transfer Problem for Different Material Combination

The analysis of heat transfer problems can be highly complex due to factors such as temperature, position, and time. Most heat transfers are typically two-dimensional as conduction is often negligible in the third dimension. Two-dimensional heat conduction problems can be solved analytically or numerically. In steady-state conditions, the Laplace equation can be applied to solve two-dimensional heat conduction problems analytically, in which the separation of variables method is used to solve the Laplace equation under fixed boundary conditions to determine the temperature at a specific point. The Laplace equation plays a significant role in the solution of heat transfer problems, as it demonstrates the behavior of linear and non-linear equations in the computational fluid dynamics domain. Despite their inability to provide exact results at any point, numerical methods are superior to analytical methods when handling complex geometries with various boundary conditions. This project involves the development of a computational code using MATLAB to solve two-dimensional steady-state heat conduction problems using Gauss-Seidel iterations. Comparing analytical solutions from Excel with numerical solutions from MATLAB and ANSYS, specifically the developed MATLAB code, revealed an accuracy level of 99.902% for the Laplace equation. An analysis of the produced code from MATLAB found that it could solve two-dimensional steady-state heat conduction across different combinations of materials while allowing users to specify initial and boundary conditions to produce a contour plot similar to ANSYS.

Energy harvesting from friction-induced vibrations in vehicle braking systems in the presence of rotary unbalances

A severe limitation of energy harvesting from friction-induced vibrations in vehicle brakes is that the voltage generated is significant only at low vehicle speeds. The present work suggests a strategy to overcome this limitation by the utilisation of ambient vibrations resulting from rotary unbalances of vehicle components. A realistic model for vibrations in the brake pad of a disc brake under the action of rotary unbalance is used. The brake pad vibration is modelled using a non-smooth stick–slip oscillator in the presence of Stribeck friction. A weightless shaft of rectangular cross-section rotating at constant angular speed and having an unbalanced mass concentrated at its centre is used to model rotary unbalances. It is shown that the rotary unbalance provides parametric excitation to the brake pad mass undergoing friction-induced self-excited vibration leading to synchronising patterns via Neimark–Sacker bifurcation. Such synchronisation is successful in ensuring steady voltage generation over a much wider speed bandwidth. The qualitative nature of the different solution regimes interspersed with periodic intervals are determined by Lyapunov exponents. The technique used to arrive at the Lyapunov exponents in the present discontinuous model is outlined, and MATLAB code for the same is provided in the appendix.

Study of hydrodynamics in FBG using cold model unit: Modelling by MATLAB

The variation of different process parameters like bed height in static condition, diameter of the particles and density of the particles on the hydrodynamic behavior of a fluidized bed gasifier (FBG) in the cold model unit have been studied by using a Perspex material column of inside diameter 0.30 m and 0.15 m for the free board section and dense bed section respectively. A column of 1.95 m height was selected for the proposed experimental work. Experiments were conducted and attempts had also been made for the development of the correlations of Equivalence Ratio and Euler’s number by changing the different process parameters of the process on the basis of DA (dimensionless analysis). The mentioned numbers of the calculated values by DA as well as by MATLAB coding were compared with the experimental values. The percentage deviation such as standard deviation and mean deviation values for Equivalence ratio and Euler’s number were calculated to be 1.89, −0.049 and 2.64, 10.8 respectively which were within the permissible limits and showed a very good approximation. A chi-square test (ξ2) for the said parameters (Equivalence Ratio and Euler’s number) gave 0.0002 and 18685.04 respectively which indicates a satisfactory correlation fit of the process. Hence the developed correlation from this study can be applied for industrial unit as well as for the pilot plant unit over a wide range of parameter with a suitable factor for scale-up.

Thermo-economic-environmental evaluation of an innovative solar-powered system integrated with LNG regasification process for large-scale hydrogen production and liquefaction

In order to achieve a sustainable energy future, it is of utmost importance to harness solar energy for the production of liquid hydrogen. This undertaking is justified by the significant role that liquid hydrogen plays as a clean and highly efficient fuel source, effectively addressing the pressing concerns regarding greenhouse gas emissions and reducing reliance on conventional fossil fuels. An additional advantage lies in the easy storage and transportation capabilities of liquid hydrogen, making it a viable solution for energy storage across diverse sectors. In this regard, the current research presents a novel solar-powered setup consisting of parabolic trough solar collectors (PTSCs), a sequential organic Rankine cycle (ORC), a liquefied natural gas (LNG) regasification unit, and a module dedicated to the production and subsequent liquefaction of hydrogen. A meticulously crafted MATLAB code is utilized to replicate the operations of the proposed system, facilitating a thorough examination of its energy, exergy, environmental, and economic performance. The proposed system exhibits a net output power of 1.13 MW and possesses the capacity to produce hydrogen at a rate of 34.92 kg/h, featuring a levelized cost of hydrogen (LCOH) of 3.59 $/kg. Additionally, the system encompasses a cooling capability of 192 kW. From an environmental perspective, this configuration contributes to a decrease in carbon dioxide emissions by 255.96 kg/h. After conducting a dynamic analysis with meteorological data, it was determined that the system has the potential to generate an annual hydrogen output of 536.84 tons in San Francisco.

A Contemporary Systematic Review on Meta-heuristic Optimization Algorithms with Their MATLAB and Python Code Reference

AbstractOptimization is a method which is used in every field, such as engineering, space, finance, fashion market, mass communication, travelling, and also in our daily activities. In every field, everyone always wants to minimize or maximize something called the objective function. Traditional and modern optimization techniques or Meta-Heuristic (MH) optimization techniques are used to solve the objective functions. But the traditional optimization techniques fail to solve the complex and real-world optimization problem consisting of non-linear objective functions. So many modern optimization techniques have been proposed exponentially over the last few decades to overcome these challenges. This paper discusses a brief review of the different benchmark test functions (BTFs) related to existing MH optimization algorithms (OA). It discusses the classification of MH algorithms reported in the literature regarding swarm-based, human-based, physics-based, and evolutionary-based methods. Based on the last half-century literature, MH-OAs are tabulated in terms of the proposed year, author, and inspiration agent. Furthermore, this paper presents the MATLAB and python code web-link of MH-OA. After reading this review article, readers will be able to use MH-OA to solve challenges in their field.

Pair programming with ChatGPT for sampling and estimation of copulas

Without writing a single line of code by a human, an example Monte Carlo simulation-based application for stochastic dependence modeling with copulas is developed through pair programming involving a human partner and a large language model (LLM) fine-tuned for conversations. This process encompasses interacting with ChatGPT using both natural language and mathematical formalism. Under the careful supervision of a human expert, this interaction facilitated the creation of functioning code in MATLAB, Python, and R. The code performs a variety of tasks including sampling from a given copula model, evaluating the model’s density, conducting maximum likelihood estimation, optimizing for parallel computing on CPUs and GPUs, and visualizing the computed results. In contrast to other emerging studies that assess the accuracy of LLMs like ChatGPT on tasks from a selected area, this work rather investigates ways how to achieve a successful solution of a standard statistical task in a collaboration of a human expert and artificial intelligence (AI). Particularly, through careful prompt engineering, we separate successful solutions generated by ChatGPT from unsuccessful ones, resulting in a comprehensive list of related pros and cons. It is demonstrated that if the typical pitfalls are avoided, we can substantially benefit from collaborating with an AI partner. For example, we show that if ChatGPT is not able to provide a correct solution due to a lack of or incorrect knowledge, the human-expert can feed it with the correct knowledge, e.g., in the form of mathematical theorems and formulas, and make it to apply the gained knowledge in order to provide a correct solution. Such ability presents an attractive opportunity to achieve a programmed solution even for users with rather limited knowledge of programming techniques.

Stratification and Radiation of Heat in Hybrid Gold-Graphene/Ethylene Glycol Nanofluid Flows Past a Leaning Cylinder

Hybrid gold-graphene/ethylene-glycol (EG) nanofluid past a permeable leaning cylinder is devoted in the current investigation under the effect of thermal radiation and stratification. The governing partial differential equations are reformulated into nonlinear ordinary differential equations by implementing similarity terms. A shooting approach is elected to reformulate the equations into a boundary value problem which is determined by applying a bvp4c code in MATLAB. The effects of selected parameters regarding the recent model on dimensionless velocity and temperature disseminations, reduced skin friction coefficient and reduced Nusselt number are analyzed and presented in graphs and tables. It is perceived that by rising the value of the thermal stratification and radiation parameter, the reduced Nusselt number for the preferred mono and hybrid nanofluids will be declined. The reduced Nusselt number is reported to be the highest value when considering hybrid gold (ϕ s1=0.02)-graphene (ϕ s2 = 0.04)/EG nanofluid.

Discriminative Dictionary Pair Learning With Scale-Constrained Structured Representation for Image Classification.

The dictionary pair learning (DPL) model aims to design a synthesis dictionary and an analysis dictionary to accomplish the goal of rapid sample encoding. In this article, we propose a novel structured representation learning algorithm based on the DPL for image classification. It is referred to as discriminative DPL with scale-constrained structured representation (DPL-SCSR). The proposed DPL-SCSR utilizes the binary label matrix of dictionary atoms to project the representation into the corresponding label space of the training samples. By imposing a non-negative constraint, the learned representation adaptively approximates a block-diagonal structure. This innovative transformation is also capable of controlling the scale of the block-diagonal representation by enforcing the sum of within-class coefficients of each sample to 1, which means that the dictionary atoms of each class compete to represent the samples from the same class. This implies that the requirement of similarity preservation is considered from the perspective of the constraint on the sum of coefficients. More importantly, the DPL-SCSR does not need to design a classifier in the representation space as the label matrix of the dictionary can also be used as an efficient linear classifier. Finally, the DPL-SCSR imposes the l2,p -norm on the analysis dictionary to make the process of feature extraction more interpretable. The DPL-SCSR seamlessly incorporates the scale-constrained structured representation learning, within-class similarity preservation of representation, and the linear classifier into one regularization term, which dramatically reduces the complexity of training and parameter tuning. The experimental results on several popular image classification datasets show that our DPL-SCSR can deliver superior performance compared with the state-of-the-art (SOTA) dictionary learning methods. The MATLAB code of this article is available at https://github.com/chenzhe207/DPL-SCSR.

Entropy analysis and hydrothermal behavior of magnetohydrodynamic MOS2–Fe3O4/H2O hybrid nanofluid flow driven by buoyancy in a square enclosure with diverse fin heights

Fins, referred to as extended surfaces, play a crucial role in enhancing heat transfer across various industrial sectors. They achieve this by increasing the surface area available for convective heat transfer. These widespread applications span fields such as energy production, mechanical engineering, surface studies, heat recovery processes, and chemical engineering. The broad utility of fins has prompted researchers to enhance their precision through diverse methods, including numerical, experimental, and analytical approaches. Motivated by these practical applications, this study undertakes a theoretical investigation to analyze the effects of varying fin heights on the behavior of a hybrid hydromagnetic nanofluid within a porous square enclosure. The study explores three distinct cases. In the first case, fixed-height heat fins are attached to the upper and lower walls. In the second case, the fin attached to the upper wall remains static, while those on the lower wall are extended from 0.25L to 0.5L. Conversely, the third case involves extending the height of the upper fin from 0.25L to 0.5L. The in-house MATLAB code, coupled with a finite difference method, is employed to solve the governing equations, and its reliability is confirmed through comparison with prior publications. Thorough numerical simulations are conducted, encompassing control parameters such as thermal radiation, Rayleigh number, nanoparticle volume fraction, Hartmann number, heat generation/absorption, and Darcy number. The numerical results are visually presented through streamlines, isotherms, and average Nusselt number plots, elucidating the impact of these parameters across a range of scenarios. It is noticed that case 3 exposes a 96.06% higher heat transfer rate than case 2 with higher values of volume fraction and Rayleigh number. In all three cases, the Rayleigh number and Hartmann number cause a reduction in the entropy generation. For a higher Rayleigh number, employing a hybrid nanofluid containing a volume fraction of 5% causes a 110.41% reduction in heat transfer for the case involving bottom fin height compared to case 1. Similarly, extending the top fin leads to a heat transfer reduction of 100.41%.

Biomarker Profiling for Alzheimer‐like Dementia in Aged Non‐human Primates

AbstractBackgroundAlzheimer’s disease (AD) places increasingly burdens on global healthcare. Non‐human primates (NHPs) have been used in preclinical pharmacology for AD drug discovery and they were mainly based on induction by amyloid plaque. However, previous strategies focused on clearance and prevention of amyloid plaques and neurofibrillary inclusions have mostly yielded discouraging results in clinical trials for AD. More fitting NHP models reflective of natural ageing of brain with an AD‐related clinical profile would be most desirable for translational pharmacology. To address this, the pilot study herein profiled a group of aged NHPs for biomarkers characteristic of AD‐like dementia, including cognitive behavior, diagnostic neuroimaging, EEG, and amyloid beta 42 (Aβ42) in cerebrospinal fluid (CSF).MethodTwo groups of male Macaca fascicularis (adult: 9‐11 years, n = 4; aged: 20‐25 years, n = 10) were trained to perform a delayed response task (DRT) to assess their short term memory. Meanwhile, their CSF levels of Aβ42 were determined. EEG signals at rest were captured with Neuroscan EEG System and data processed with customized Matlab code. The volume of hippocampus in eight selected animals were analyzed through a 3‐D reconstruction with MRI imaging.ResultSix (6) out of 10 aged animals showed lower DRT performance (successful rate < 80%) than the remaining 4 and those in the adult group. The overall DRT performance was positively correlated with the CSF levels of Aβ42 in all animals. Moreover, we observed the slowing of EEG activity (increased δ & θ activity and decreased β activity) in the frontal lobe and smaller average volume of hippocampus in the low DRT performers vis‐à‐vis the rest of the animals.ConclusionWe identified a group of aged NHPs with spontaneous dementia, with cognitive, electrophysiological and brain structural characteristic of mild cognitive impairment in the humans. Their CSF levels of Aβ42 inversely correlated with the memory function. Most notably, EEG and neuroimaging showed promising potential as non‐invasive approaches for the evaluation of aging‐related dementia of NHP in the longitudinal studies. The translational value of such animals could provide important insight to the disease progress and the therapeutic efficacy of AD treatment in the preclinical stages.

Modeling and Design of a Multistream Plate-Fin Heat Exchanger in the Air Separation Units by Pinch Technology

Recent years have seen considerable advancement in cryogenic technology. Air separation devices have used the cold box with heat exchanger plate-fin (PFHE) in numerous applications. Cryogenic technologies are used in many industrial processes to recover heat and reduce energy consumption. The multistream plate-fin heat exchanger (MSPFHE) is heavily utilized in the air separation plant’s (ASU) design. The plate-fin heat exchanger, one of the most important applications in the cryogenic industry, is the focus of the current investigation. The air entering this operation has been cooled by utilizing energy from streams originating from the distillation tower in the air separation unit (ASU) to reduce energy usage. The project aims to develop and create a multistream plate-fin heat exchanger (MSPFHE) that may be used in the cold box of an air separation unit practically and without limitations. The pinch technique, a method based on the usage of composite curves, was used in the creation of MSPFHE. With pinch technology, it is possible to divide a multistream exchanger into block portions that represent enthalpy intervals and identify the entry and departure sites for the streams. The correlations used in the MSPFHE thermal design model were first modeled and compared to earlier models as part of this effort. This model has been turned into MATLAB code and utilized in two case studies to yield acceptable results during the sizing step. Calculations of thermodynamic properties, heat transfer, pressure drop, choice of fin type, and final heat exchanger size were all part of the design of the MSPFHE. Finally, based on the software’s ability to reproduce the identical environmental conditions nature produces, the case study results have been validated using Aspen EDR. These findings were matched to findings from the literature and determined to be reliable and consistent.

A new MATLAB code for locating lineaments in the earth’s crust from gravity data—a case of the transition zone between Benue basin and Lake Chad basin: Cameroon

A new MATLAB code for locating lineaments in the earth’s crust from gravity data—a case of the transition zone between Benue basin and Lake Chad basin: Cameroon

SQAT: a MATLAB-based toolbox for quantitative sound quality analysis

Literature suggests that psychoacoustic metrics, which are established by models firmly based on the human auditory system, are able to better approximate perceptual attributes of sounds in a quantitative manner than conventional metrics based on the sound pressure level. Therefore, psychoacoustic metrics are commonly used as sound quality indicators in practical applications, such as product design or environmental noise assessment, in which human perception plays an important role. However, their calculation is not straightforward and the non-availability of verified, well-documented, open-source implementations in a single environment poses a challenge to reproducible research. In this contribution, we introduce the sound quality analysis toolbox (SQAT), an open-source compilation of MATLAB codes containing the implementation of the following key psychoacoustic metrics: loudness (ISO 532-1:2017), sharpness (DIN 45692:2009), roughness (Daniel & Weber's model), fluctuation strength (Osses et al. model), and tonality (Aures' model). A comprehensive description of the implemented psychoacoustic metrics is provided. Furthermore, a verification study is presented in order to demonstrate the reliability of the implementations, supporting the use of SQAT as a reliable tool for future works in the field of sound quality assessment based on psychoacoustic metrics.

Complex dynamics of induced vortex formation and thermal-fluid coupling in tri-hybrid nanofluid under localized magnetic field: a novel study

Hybrid nanofluids offer higher stability, synergistic effects, and better heat transfer compared to simple nanofluids. Their higher thermal conductivity, lower viscosity, and interaction with magnetic fields make them ideal for various applications, including materials science, transportation, medical technology, energy, and fundamental physics. The governing partial differential equations are numerically solved by employing a finite volume approach, and the effects of various parameters on the nanofluid flow and thermal characteristics are systematically examined from the simulations based on a self-developed MATLAB code. The parameters included magnetic field strength, the Reynolds number, the nanoparticle volume fraction, and the number and position of the strips in which the magnetic field is localized. It has been noted that the magnetized field induces the spinning of the tri-hybrid nanoparticles, which generates the intricate structure of vortices in the flow. The local skin friction (CfRe) and the Nusselt number (Nu) increase significantly when the magnetic field is intensified. Moreover, adding more nanoparticles in the flow enhances both Nu and CfRe, but with different effects for different nanoparticles. Silver (Ag) shows the highest increase in both Nu (52%) and CfRe (110%), indicating strong thermal-fluid coupling. Alumina (Al2O3) and Titanium Dioxide (TiO2) show lower increases in both Nu (43% and 34%) and CfRe (14% and 10%), indicating weaker coupling in the flow. Finally, compared with the localized one, the uniform magnetic field has a minor effect on the flow and temperature distributions.

Optimizing the Design of a Dry-Type Single Phase Gapped-Core Shunt Reactor to Empower National Industries

The import dependency of essential components in our country's electrical power system poses a significant challenge, emphasizing the importance of focusing on the design, development, and maintenance of power system components, particularly shunt reactors, from an economic standpoint. Domestic production of these components contributes to employment opportunities and enhances self-sufficiency. This study aims to address these challenges by optimizing the design of a dry-type single phase gapped-core shunt reactor with a rating of 100 kVAr and 10 kV. The reactor operates at a frequency of 50 Hz and experiences a maximum core flux density of 1.2 T. The study thoroughly examines the fundamental aspects related to the design of gapped-core shunt reactors. An optimal design is achieved by determining the optimal ratio of the cross-sectional area to the height of each core disk, employing a MATLAB code to minimize the reactor's initial manufacturing cost (IC) or losses. In addition, the proposed design undergoes simulation and analysis using the finite element method (FEM) in the MAXWELL software. The reactor's inductance is obtained through both Maxwell three-dimensional (3D) simulation and analytical methods, demonstrating a reasonable agreement that validates the effectiveness and reliability of the proposed approach.

An efficient MATLAB code for stress-constrained level set topology optimization method

An efficient MATLAB code for stress-constrained level set topology optimization method