Concept Of Layer Research Articles

Nonlocal Nernst-Planck-Poisson System for Modeling Electrochemical Corrosion in Biodegradable Magnesium Implants

AbstractThis paper provides a comprehensive derivation and application of the nonlocal Nernst-Planck-Poisson (NNPP) system for accurate modeling of electrochemical corrosion with a focus on the biodegradation of magnesium-based implant materials under physiological conditions. The NNPP system extends and generalizes the peridynamic bi-material corrosion model by considering the transport of multiple ionic species due to electromigration. As in the peridynamic corrosion model, the NNPP system naturally accounts for moving boundaries due to the electrochemical dissolution of solid metallic materials in a liquid electrolyte as part of the dissolution process. In addition, we use the concept of a diffusive corrosion layer, which serves as an interface for constitutive corrosion modeling and provides an accurate representation of the kinetics with respect to the corrosion system under consideration. Through the NNPP model, we propose a corrosion modeling approach that incorporates diffusion, electromigration and reaction conditions in a single nonlocal framework. The validity of the NNPP-based corrosion model is illustrated by numerical simulations, including a one-dimensional example of pencil electrode corrosion and a three-dimensional simulation of a Mg-10Gd alloy bone implant screw decomposing in simulated body fluid. The numerical simulations correctly reproduce the corrosion patterns in agreement with macroscopic experimental corrosion data. Using numerical models of corrosion based on the NNPP system, a nonlocal approach to corrosion analysis is proposed, which reduces the gap between experimental observations and computational predictions, particularly in the development of biodegradable implant materials.

Social Justice in Reservation - An Analysis

Reservation is one of the mechanisms of protective discrimination for eradicating the present institutionalized effects of past discriminations, through positive governmental steps awarding preferential treatment in favour of certain weaker sections of the society. Reservation is applied only in graded societies, where certain groups enjoyed more powers and privileges, while the other sections have been wholly or partially neglected. It involves encouragement sharing in favour of certain weaker sections of the society. It involves encouragement sharing of opportunities in the executive, legislative bodies, in educational institutions and in public services. Demand by the unprivileged classes to enjoy the same opportunities of the privileged class resulted in social conflict in the earlier stages. In course of time, the unprivileged section came to enjoy social, political and economic and other privileges on par with others. As per the Constitution of India, it is a temporary phenomenon used for some special achievement. In course of time, the unprivileged section came to enjoy social, political and economic and other privileges. Thus, everybody in the beneficiary categories Viz., Other Backward Classes in all India level, Backward Classes and Most Backward Classes in Tamil Nadu, Scheduled Castes and Scheduled Tribes did not enjoy the same status in the society. Due to the reservation policy, there are tremendous transformations in the social structure. It is evident that, there are noteworthy rich people among the backward and depressed castes. Similarly there are poor people in the forward castes as well. Not only that as per the Constitution of India, it is a temporary phenomenon used for some special achievement. In this research paper, an attempt has been made to examine and compare the concepts of exclusive reservation and creamy layer and to study the changing trends in the reservation policy towards social justice.

Physics-informed Neural Network for Force-free Magnetic Field Extrapolation

In this paper, we propose a physics-informed neural network extrapolation method that leverages machine learning techniques to reconstruct coronal magnetic fields. We enhance the classical neural network structure by introducing the concept of a quasi-output layer to address the challenge of preserving physical constraints during the neural network extrapolation process. Furthermore, we employ second-order optimization methods for training the neural network, which are more efficient compared to the first-order optimization methods commonly used in classical machine learning. Our approach is evaluated on the widely recognized semi-analytical model proposed by Low and Lou. The results demonstrate that the deep learning method achieves high accuracy in reconstructing the semi-analytical model across multiple evaluation metrics. In addition, we validate the effectiveness of our method on the observed magnetogram of active region.

Method—Multi-Cell Testing with Active Driven Gas Layer Concept: Advantages and Limitations

This study validates a novel method for simultaneous durability testing of multiple symmetrical cells with Ni/ceria fuel electrodes. The investigation demonstrates that gas diffusion losses in the multi-cell test setup utilizing the active driven gas layer concept have a smaller impact on cell performance compared to the single-cell setup. This method proves effective for testing multiple identical cells, offering a time and cost-efficient approach. However, testing symmetrical cells with different fuel electrodes reveals an unexpected pseudo-inductive loop in the impedance spectra, observable only in the multi-cell setup. Analysis of impedance spectra and relaxation times indicates that differences in electrode polarization resistance result in varying gas compositions at the two electrodes of a cell, disrupting symmetry and superimposing an additional Nernst voltage term. To understand this, an electrical equivalent circuit model with the Nernst voltage term was developed to reproduce the observed behavior. Comparison of experimental and simulation results substantiates the model and elucidates the mechanisms. The findings indicate that testing multiple cells with the active driven gas layer concept is applicable only for identical cells and not for those with different electrodes.

Fatigue delamination damage analysis in composite materials through a rule of mixtures approach

The present study investigates delamination damage initiation and propagation within a homogenization theory of mixtures, using the concept of virtual layers and virtual interfaces. It eliminates spatial discretization of layers, introducing a resultant damage variable to capture structure’s bulk response under both monotonic and cyclic loads. Fatigue-induced deterioration is classified into sub-critical, critical, and over-critical stages based on interfacial stresses. Calibration is conducted employing the widely-available Wöhler curves for each loading mode independently. An advance-in-time strategy is included in the model to enhance the simulation speed. The reliability of the approach is assessed for crack initiation and propagation separately through standard test coupons, showing good correlation with experimental data in mode I, mode II, and mixed-mode loading conditions. Depending on the calibration procedure adopted, the model is applicable to a wide range of stress ratios. In addition, it could be integrated into any standard finite element framework using the desired number of elements through the thickness regardless of the physical amount of layers. This allows easy modification of stacking sequences or the number of layers within the constitutive law without mesh structure changes, facilitating simulation of large-scale composite laminates with minimal accuracy loss and reduced computational costs.

On the enhancement of acceptable blockage of open jet wind tunnel by employing modifications based on concepts of boundary layer and jet flow for testing of aero-rotors

The conventional closed and open jet tunnels suffer from various adverse blockage effects that alter the flow conditions generating erroneous results when larger than allowable blockage models are tested. The maximum acceptable blockage is limited to 25 % for an open jet tunnel. The physics behind the inferior blockage capacity and their redressal is investigated. Hitherto, numerical models are developed to rectify the blockage troubles that introduce an additional complex case-based mathematical modeling to reckoning the results. In the current paper novel approach to redesigning the tunnel to solve blockage troubles is investigated that facilitates evading of mathematical techniques and securing accurate results straightforwardly. A hypothetical design incorporating the remedies is proposed, capable of conditioning the flow in a manner that debilitates the adverse effects of solid blockage, wake blockage, jet expansion, etc. The hypothesis is theoretically expounded by the boundary layer and jet flow phenomenon. The modified blower-type open jet wind tunnel constitutes a centrifugal blower, long inlet duct, plenum chamber around the test section, and collector. The modified wind tunnel is tested through experiments executed on four different-sized Savonius rotors creating 10 %, 30 %, 50 %, and 60 % blockage. The static pressure along the contours of the blades of rotors is obtained. The experimental results are juxtaposed with CFD results carried out at free-wind boundary conditions and standard classic experimental results performed in conventional wind tunnel at 11 % blockage. A blockage enhancement of 25 % is achieved by the approach of modification in the design of a conventional open jet wind tunnel.

Lighting Design for Lanna Buddhist Architecture: A Case Study of Suan Dok Temple, Chiang Mai, Thailand

In Chiang Mai, Thailand, there has been an increasing demand for lighting design strategies that enhance tangible and intangible values of cultural heritage destinations. This research explores the role of lighting design in enhancing the cultural experiences and promoting the cultural tourism of Lanna Buddhist architecture. Suan Dok Temple was selected as a case study due to its historical, social, and cultural significance. This research uses qualitative approaches such as field surveys, photographic documentation, and interviews with temple authorities, cultural heritage experts and tourism professionals for the formulation of initial users’ requirements and lighting design criteria and concept. Data analysis suggested that cultural heritage and conservation, cultural tourism management, and operation and maintenance are important factors in heritage lighting design for cultural tourism. Realistic rendering images of lighting design scenes for the temple’s chedis and vihara are generated based on the concept of luminance layers representing the Buddhist cosmology idea. In addition, lighting operation and installation details are developed and presented to stakeholders for discussion on contextual and operational appropriateness. Finally, the study discusses critical lighting design factors for the development of lighting design solutions for heritage sites, particularly Lanna Buddhist temples, contributing to sustainable cultural tourism.

Effective heat transfer associated with CO2 and CH4 adsorption on HKUST-1 metal-organic framework deposited in situ on heat exchanger

The aim of this study was to analyze the heat transfer properties a copper heat exchanger with the in situ synthesized HKUST-1 metal-organic framework (MOF). For this purpose, a dedicated reactor was constructed to enable the direct measurements of heat of adsorption of CO2 and CH4, that accompanies the dynamic course of these processes. In parallel, CO2 and CH4 adsorption isotherms were determined at various temperatures and the heat of adsorption was calculated by an indirect method. Temperature changes on the heat exchanger as a result of cyclic adsorption/desorption processes of CO2 and CH4 on the HKUST-1 layer were registered, and the results of adsorption heat by direct and indirect methods were compared. Comparing the results of indirect and direct measurements of temperature changes accompanying CO2 adsorption, a difference of 19 % was obtained. In the case of CH4 adsorption, the results obtained by the two methods differed by 22 %. Based on the experimental results, it was proven that HKUST-1 synthesized in situ on a copper heat exchanger has improved heat transfer properties. The proposed concept of MOF layer on heat exchanger allows for efficient thermal stimulation of sorption processes and simultaneous MOF regeneration while minimizing the thermal energy supplied to the system.

An enhanced quasi-3D HSDT for free vibration analysis of porous FG-CNT beams on a new concept of orthotropic VE-foundations

The original primary objective of this study is to conduct a comprehensive investigation into the free vibration behavior of beams with porosity, reinforced by carbon nanotubes (CNTs). These beams are supported by an arbitrary orthotropic variable elastic foundation (AOVEF). The focus lies on understanding how the presence of porosity and CNT reinforcement, coupled with the complex support provided by the AOVEF, influences the vibration characteristics of the beams. In addition, we intend to examine the impact of a number of micromechanical models on the vibration properties of these beams. Four carbon nanotube variables are introduced to symbolize several CNT variations. CNTs’ mechanical properties are examined through a variety of micromechanical models. Shear deformation effects are considered into account in the framework of higher-order shear deformation (HSDT) beam theory. The equations of motion are constructed using Hamilton’s concept and the equation system for the FG-CNT beam with supported ends is solved via the Navier methodology. A new approach in elastic foundation modeling is the Arbitrarily Orthotropic Variable Elastic (AOP-VE) foundation. It builds on the Winkler layer concept but introduces the idea of a variable response along the length of the beam foundation. Unlike the Winkler-Pasternak model, AOP-VE allows for control over the directional properties of the Pasternak foundation. The study looks into multiple aspects, involving various distribution kinds of CNTs, the impact of Winkler and Pasternak factors, mode values, side-to-length ratio, porosity, and angle variation. The results indicate that these parameters have a major effect on the inherent vibration features of FG-CNT beams. The study results in various novel findings that improve the understanding of the subject topic and set a standard for future studies.

Characterizing the Janus colloidal particles in AC electric field and a step towards label-free cargo manipulation

In recent years, researchers have been exploring Janus particles, a unique type of colloidal system, which has gained enormous attention across diverse fields, from soft matter physics to biology. These particles, possessing an asymmetric surface, can be manipulated in the fluid using external energy sources. This versatility makes them suitable for mimicking biological systems and applications like cargo transportation, drug delivery, biosensing, and environmental cleanup. The study focuses on the response of metal-dielectric (Ti-PMMA) Janus spheres in the AC field, created through the Physical Vapor Deposition (PVD) technique. When subjected to a uniform AC electric field, these particles exhibit different dynamic behaviors at various frequency ranges. The particles show diverse responses from induced-charge electrophoresis (ICEP: 500 Hz-80 kHz) to reversed motion (r: ICEP:100 kHz-1 MHz) and linear chain formation (1 MHz). Additionally, they randomly cluster near the lower characteristic frequency (800 Hz) of the ICEP, whereas they exhibit the 3D motion at frequencies (100 Hz) below this lower characteristic value. The mechanisms behind these dynamic phenomena could be explained by considering the concept of electric double layer (EDL), self-dielectrophoresis (sDEP), dipolar interactions, hydrodynamic interactions, and electrothermal effects. These active Janus Colloids are further leveraged to manipulate 1 µm diameter PMMA passive microparticles and E. coli bacteria at 1 kHz, showcasing their potential applications in cargo delivery under various microfluidic research areas. The manipulation of payloads could be explained based on dielectrophoretic trapping due to locally generated field gradients around the surface of the Janus sphere. Therefore, the present work offers an unprecedented opportunity to study such out-of-equilibrium complex active matter systems and create novel functional materials. Moreover, it could also be extended as a fuel-free microrobotics system for various biomedical applications such as sensing and on-demand drug or cargo delivery inside the microfluidics chamber.

Towards fully electrically controlled domain-wall logic

Utilizing magnetic tunnel junctions (MTJs) for write/read and fast spin-orbit-torque (SOT)-driven domain-wall (DW) motion for propagation, enables non-volatile logic and majority operations, representing a breakthrough in the implementation of nanoscale DW logic devices. Recently, current-driven DW logic gates have been demonstrated via magnetic imaging, where the Dzyaloshinskii-Moriya interaction (DMI) induces chiral coupling between perpendicular magnetic anisotropy (PMA) regions via an in-plane (IP) oriented region. However, full electrical operation of nanoscale DW logic requires electrical write/read operations and a method to pattern PMA and IP regions compatible with the fabrication of PMA MTJs. Here, we study the use of a Hybrid Free Layer (HFL) concept to combine an MTJ stack with DW motion materials, and He+ ion irradiation to convert the stack from PMA to IP. First, we investigate the free layer thickness dependence of 100-nm diameter HFL-MTJ devices and find an optimal CoFeB thickness, from 7 to 10 Å, providing high tunneling magnetoresistance (TMR) readout and efficient spin-transfer torque (STT) writing. We then show that high DMI materials, like Pt/Co, can be integrated into an MTJ stack via interlayer exchange coupling with the CoFeB free layer. In this design, DMI values suitable for SOT-driven DW motion are measured by asymmetric bubble expansion. Finally, we demonstrate that He+ irradiation reliably converts the coupled free layers from PMA to IP. These findings offer a path toward the integration of fully electrically controlled DW logic circuits.

Entropy analysis of MHD hybrid nanoparticles with OHAM considering viscous dissipation and thermal radiation

This research explores the 3-D flow characteristics, entropy generation and heat transmission behavior of nanofluids consisting of copper and titanium in water as they flow across a bidirectional apparent, while considering the influence of magneto-hydrodynamics. The thermophysical properties of nanofluids are taken advantage of utilizing the Tiwari and Das demonstrate. The concept of the boundary layer has facilitated the comprehension of the physical ideas derived from it. By applying requisite transformations, the connected intricate sets of partial differential equation have been converted into ordinary differential equation. The modified model is calculated employing the widely recognized technique known as OHAM by using Mathematica program BVPh2.0 Software. For different dimensionless parameters computational and graphical investigations have been performed. It is notice that as fluid parameters change, they exhibit distinct responses in comparison to the temperature, velocity profiles and entropy generation. The results show that velocity profile rise with greater estimates of the magnetic parameter and the rate of entropy formation. Furthermore, thermal profiles become less significant as Eckert and Prandtl numbers increase.

Hidden work, frustration and multiple layers of occupational health in emergency situations: a longitudinal study during the COVID-19 pandemic.

This study examines the effects of the COVID-19 pandemic over time. Specifically, we derive from the organizational model of frustration to propose and test a model of pandemic-induced hidden work affecting employees' emotional responses of frustration along with behavioral responses and outcomes with respect to occupational health. We thereby develop a concept of multiple layers of occupational health that spans across stress, satisfaction with work-life balance (SWLB), burnout, subjective well-being, and physical health. Based on a longitudinal web-based survey of 198 working professionals conducted at seven points in time (1,143 data points, with 118 fully completed responses across all time points) for a wide range of industries in 2020, the study tests the proposed relationships using random coefficient modeling. The results show that COVID-19-situation-induced hidden work invokes emotional responses of frustration, which in turn influence outcomes referring to multiple layers of occupational health-positively affecting stress and burnout, and negatively influencing SWLB, subjective well-being, and physical health. Implications for research and practice are discussed.

Enhancing performance and scalability of HTL-free organic solar cells with keggin polyoxometalates-type additive

Interfacial layers play a crucial role in enhancing the performances and stabilities of organic solar cells (OSCs). Despite achieving high efficiencies from OSCs, the challenges associated with large-area manufacturing and the need for nanoscale uniformity during coating have hindered the large-scale production of these devices. To address these issues, we propose the concept of hole transport layer (HTL)-free OSCs to simplify the fabrication processes and improve the efficiency of production. In this study, we explore the potential of phosphotungstic acid (PTA), a Keggin polyoxometalate, both as a promising HTL and as an additive in HTL-free OSCs to enhance device performances and scalabilities in cell-to-module OSCs. Remarkably, incorporating PTA as an annealing-free HTL and as an additive in the photoactive layer (PM6:Y6:PC71BM) significantly increases power conversion efficiency (PCE) up to 17.28 % and 16.33 %, respectively, with respect to that of the reference device with PEDOT:PSS (15.88 %). We successfully fabricate a large-area OSC module, exhibiting an impressive PCE of 15.18 % and an active area of 54 cm2, achieving approximately 85 % of the effectiveness of small-area OSCs. The improved performance is attributed to the enhanced transmittance, excellent carrier-dynamic capacity, suppressed carrier recombination, and reduced trap-states in the ternary bulk-heterojunction OSCs. This study demonstrates the promising versatility of PTA for application in OSCs, offering potential enhancements in device performance and scalability for future applications.

Significance of Melting Heat Transfer, Inclined Magnetic Field, and Thermal Radiation on the Dynamics of Williamson Nanofluid Above a Stretching Sheet

This study investigates the melting heat transfer in MHD flow that occurs when the flow is past a stretched sheet. With the use of the boundary layer concept, a set of non-linear ODEs is derived from a system of PDEs of motion and energy. After transforming the non-linear ODEs and their boundary conditions into dimensionless form with the use of appropriate similarity conversions, the equations are then numerically solved by employing the MATLAB inbuilt solver bvp4c method in conjunction with the shooting methodology. Through the use of a variety of charts and tables, the authors analyze and describe in depth the effects that relevant factors have on a variety of flow fields. As melting factor (Me) increases, it is discovered that the effect of Me on fluid temperature and velocity distributions decreases. Williamson parameter and inclined magnetic profile are shown to have decreasing impact on velocity and momentum parameter. After that, the findings are compared with the earlier published findings in limited situations of the issue, and it is discovered that they are in exceptional specify with those findings.

(Invited) Enabling High Quality Dielectric Passivation on Monolayer WS2 Using a Sacrificial Graphene Oxide Template

Two-dimensional transition metal dichalcogenides (2D TMDC’s) hold a wide variety of applications, among which microelectronic devices. 2D TMDC’s are promising alternatives for today’s silicon-based technology but suffer from various integration challenges. Among others, direct dielectric growth on the 2D surface occurs poorly due to their self-passivated surfaces resulting in island-like growth initiated at defect sites. This work focuses on enabling uniform high-k dielectric nucleation and growth on 2D TMDC’s via a sacrificial, graphene oxide-based buffer layer. Essentially, the role of the sacrificial graphene buffer layer is twofold: 1) serve as a passivation layer, protecting the underlying 2D TMDC (i.e., WS2) during processing and 2) act as a nucleation layer, enabling uniform atomic layer deposition (ALD) high-k dielectric (i.e,. HfO2) growth. A graphene layer is transferred on monolayer WS2, after which polymeric transfer residues are cleaned via a combination of wet treatments and a dry hydrogen downstream plasma exposure. The cleaned graphene is functionalized via a dry UV/O3 oxidative treatment, which enriches its basal plane with carbon-oxygen single bond functionalities by sacrificing its π-network. This way, the graphene carbon lattice itself remains intact and retains its passivation properties. Moreover, a substrate dependency is observed where graphene transferred on WS2 requires longer UV/O3 exposure to ensure functionalization compared to a SiO2 substrate and can be explained by UV-light induced, ultrafast charge transfer between the graphene and WS2 monolayer. The carbon-oxygen groups formed on graphene’s basal plane act as nucleation sites during a subsequent HfO2 ALD process. A constant roughness is noted for the HfO2 film grown on the graphene oxide capped WS2, indicating uniform material deposition even in the early stages of the ALD process. This is in sharp contrast when HfO2 is directly grown on the WS2 monolayer, whose roughness stabilizes only after many ALD cycles (up to 256), demonstrating the poor, island-like growth mechanism. In addition, a similar hafnium areal density is measured for the graphene oxide capped WS2 compared bare SiO2, which was selected to represent a well-functionalized surface and thus confirming the efficiency of the graphene oxide-based nucleation layer. For devices incorporating the graphene oxide buffer layer concept, a crucial question is to what extent the graphene oxide layer gives rise to leakage currents by providing a conductive path between source and drain. Electrical evaluation of a GFET by means of I-V measurements reveal a significant shift in Dirac point towards positive gate voltage for transferred graphene, which is typically associated with p-type doping originating from the polymeric transfer residues still present on the surface. The Dirac point shifts towards 0-point voltage after final hydrogen downstream plasma cleaning, confirming the effectiveness of the established cleaning protocol. Moreover, Graphene’s conductivity is suppressed after UV/O3 to the nA range, as caused by the formation of carbon-oxygen functionalities and associated sacrifice of its π-network. The residual current may be further suppressed by extending the UV/O3 treatment, but nevertheless demonstrates that the graphene oxide buffer layer will not give rise to significant leakage currents.

Enhanced Charge Separation in Nanoporous BiVO4 by External Electron Transport Layer Boosts Solar Water Splitting.

The optimization of charge transport with electron-hole separation directed toward specific redox reactions is a crucial mission for artificial photosynthesis. Bismuth vanadate (BiVO4 , BVO) is a popular photoanode material for solar water splitting, but it faces tricky challenges in poor charge separation due to its modest charge transport properties. Here, a concept of the external electron transport layer (ETL) is first proposed and demonstrated its effectiveness in suppressing the charge recombination both in bulk and at surface. Specifically, a conformal carbon capsulation applied on BVO enables a remarkable increase in the charge separation efficiency, thanks to its critical roles in passivating surface charge-trapping sites and building external conductance channels. Through decorated with an oxygen evolution catalyst to accelerate surface charge transfer, the carbon-encased BVO (BVO@C) photoanode manifests durable water splitting over 120h with a high current density of 5.9mAcm-2 at 1.23V versus the reversible hydrogen electrode (RHE) under 1sun irradiation (100mWcm-2 , AM 1.5G), which is an activity-stability trade-off record for single BVO light absorber. This work opens up a new avenue to steer charge separation via external ETL for solar fuel conversion.

Theoretical analysis of Reiner-Philippoff fluid flow in two layers due to metachronal propulsion: Subject to surrounding temperature

Mucociliary clearance plays a crucial role within the respiratory system as an initial protective mechanism against infections. Hence, it is imperative to validate any assumptions made regarding the mucociliary clearance and its impact on its functionality. This study examines flow of two-dimensional Reiner-Philippoff fluid within a ciliated channel, resulting in the separation of the fluid into two immiscible layers due to variations in viscosity. The governing equations are shortened through utilization of the long wavelength and Reynolds number (low) approximation. The impacts of emerging parameters are examined through the utilization of graphical representations. It has been observed that when there are variations in fluid properties, such as density, thermal conductivity, and viscosity between two neighboring zones, concept of a peripheral layer should be employed in order to achieve more accurate and realistic outcomes. The figures indicate that an increase in viscosities, thermal conductivities, and fluid characteristics leads to an elevation in temperature field in both layers. Moreover, the potential future scope of this study holds the promise of making substantial contributions to the comprehension of intricate fluid dynamics and fostering the advancement of novel technologies that can be practically applied across various domains. Additional research into the thermal characteristics of the system may contribute to a deeper comprehension of the complex interplay between temperature fluctuations and the dynamics of Reiner-Philippoff fluids. This has the potential to facilitate the advancement of thermal control mechanisms or the investigation of temperature-responsive materials for the purpose of manipulating fluid flow properties.

Fast reactive interdiffusion between solid brass and liquid aluminium

The formation mechanisms of intermetallic layers and the development of the interface between solid brass and molten Al alloy were experimentally investigated using semi-infinite solid-liquid diffusion couples. Isothermal annealing of commercial CuZn37 – AA7075 diffusion couples was conducted for the selected temperatures of 650 °C, 660 °C, 680 °C and 700 °C, for three annealing times of 10 s, 20 s and 40 s, followed by quenching. Regardless of the temperature, the interface consisted of three intermetallic layers that are reaction products as defined in the Al–Cu–Zn phase diagram. In order to explain the growth behaviour and bring insights into the interface formation mechanisms, the thermodynamics of the Al–Cu–Zn was investigated by CALPHAD (calculation of phase diagrams). Based on these ex-situ results, three distinct phenomena were observed. First, intermetallic layers dissolve simultaneously into the molten Al alloy when the annealing time exceeds 40 s. Second, parts of the intermetallic layer that are in contact with the molten Al, detach from the interface region in the direction of molten Al alloy leading to a decrease in the layer thickness and deviation from planar-like geometry. Third, the formation of the three intermetallic layers is exclusively the result of solid-liquid interactions followed by quenching. Previous studies have shown a scattered interface character between solid brass and molten aluminium which results from interactions in the solid-solid state due to low cooling rates. As a result, the concept of primary intermetallic layers was introduced to describe the interface formation upon the contact of solid brass with molten aluminium alloy.

Improving efficiency and cost of ordering algorithms in pathfinding using shell layers

Optimal path planning is a fundamental problem in artificial intelligence (AI) and has wide applications in areas such as robotics, transportation, and logistics. In this paper, we propose a novel approach for ordering algorithms in pathfinding problems using the concept of shell layers. Our approach aims to improve the computational efficiency and distance cost of ordering algorithms. To evaluate the effectiveness of our approach, we compare it with five state-of-the-art techniques commonly used in the field of ordering algorithms on eight different scenarios with varying configurations. Our results show that our proposed approach outperformed the state-of-the-art techniques in terms of time-computational complexity and distance cost in most of the scenarios, demonstrating its potential as a new state-of-the-art technique for ordering algorithms. Specifically, our approach outperformed the nearest neighbor, A*, branch and bound, Christofides, and genetics ordering algorithms. However, we also identified two specific situations where our approach was outperformed by two state-of-the-art algorithms due to the specific distribution of the goal nodes. These findings highlight the importance of evaluating and comparing ordering algorithms in various scenarios. Our approach has significant implications for AI research and development, as it has the potential to improve the performance of pathfinding algorithms in various applications. We also discuss the limitations of our approach and potential areas for further research, such as investigating the effectiveness of our approach in different types of graphs and exploring the potential use of machine learning techniques to optimize the shell layer construction. The code for this study is available at https://github.com/abdullah1aloush1/MuGONA.