Layer Model Research Articles

A revised ocean mixed layer model for better simulating the diurnal variation in ocean skin temperature

Abstract. Sea surface temperature (SST) is a crucial parameter in climate, weather, and ocean sciences due to its decisive role in ocean–atmosphere interactions. Identifying errors in the prognostic scheme used by the current European Centre for Medium-range Weather Forecasts (ECMWF) model for predicting the diurnal variation in ocean skin temperature led to a revisit and revision of the ocean mixed layer (OML) model. Validation of the revised model was conducted by comparing simulated temperatures at the sub-skin level and 1 m depth with observations from shipborne infrared measurements and buoys. These comparisons revealed a strong correlation, with an absolute mean deviation of less than 0.1 K and a standard deviation under 0.5 K, which are found to be comparable to errors in satellite observations of SST. Given that these results are derived from the same model simulations, the error statistics for the simulated skin temperature and its diurnal variation should have the same degree of accuracy. Furthermore, the simulation results closely align with anticipated solar radiation distributions, whereas ERA5 ocean skin temperature shows a significant lack of alignment with solar radiation. Consequently, the revised OML model shows promising potential for improving the simulation of diurnal SST variations in weather and climate models.

Bi-level optimization of novel distribution network with VPP and flexible load cluster

To satisfy the power requirements of modern industrial parks, while also enhancing energy efficiency and system economy, a bi-level optimization model is proposed for a novel distribution network, which incorporates a virtual power plant (VPP) and flexible load cluster. The proposed optimization model for the distribution network layer considers factors such as minimum voltage offset and operating cost. It accounts for uncertainties associated with new energy sources, control of the soft open point (SOP), as well as dispatching of the static var compensator (SVC). A normalized normal constraint (NNC) method is used to obtain Pareto front. The power flow model is converted into a normalized cone programming model utilizing second-order cone relaxation technique. The VPP optimization layer aims to achieve the lowest operational cost and comprehensively considers the complementarity of multiple types of distributed energy resources. The bi-level iterative solution is obtained using the analytical target cascading (ATC) method. Finally, the enhanced IEEE 33-node system example demonstrates that the proposed bi-level optimization model effectively reduces the system’s operating cost, optimizes the power flow distribution, and minimizes network losses.

Injection-induced seismic moment in layered rock formations

Appropriate estimation of seismic moment release during fluid injection is critical to mitigate the risk of induced seismic hazards and to guide safe operation in the geo-energy industry. However, the present single-layer models overlook the contributions of fault slip in different rock layers to the seismic moment release. Here we report an analytical model incorporating a multiple-layer function to predict the injection-induced seismic moment in layered rock formations. This model is established based on fault slip triggered by aseismic motion, particularly considering the locations of aseismic slip front and fluid diffusion front on a seismogenic fault in relative to the layer interface. We compare the maximum seismic moment obtained from our model to those estimated from three single-layer models and those measured from eleven field cases. The results highlight possible underestimation of the maximum seismic moment using the single-layer models in the layered rock formations. We also emphasize that a proper selection of layer model is significant to reasonably assess the seismic moment release. Lastly, we apply both the single-layer and double-layer models to predict the maximum seismic moment of the 5 February 2019 Mw 4.0 earthquake in the Weiyuan Shale Gas Field in Sichuan, China. The engineering application further confirms the necessity of using the double-layer model in the layered rock formations. Additionally, the assessment of amplification factors for fault segments provides a better understanding of induced seismic hazards in different rock layers and possibly guides the safety threshold of injection rate during fluid injection.

Biomimetic tubular materials: from native tissues to a unifying view of new vascular, tracheal, gastrointestinal, oesophageal, and urinary grafts.

Repairing tubular tissues-the trachea, the esophagus, urinary and gastrointestinal tracts, and the circulatory system-from trauma or severe pathologies that require resection, calls for new, more effective graft materials. Currently, the relatively narrow family of materials available for these applications relies on synthetic polymers that fail to reproduce the biological and physical cues found in native tissues. Mimicking the structure and the composition of native tubular tissues to elaborate functional grafts is expected to outperform the materials currently in use, but remains one of the most challenging goals in the field of biomaterials. Despite their apparent diversity, tubular tissues share extensive compositional and structural features. Here, we assess the current state of the art through a dual layer model, reducing each tissue to an inner epithelial layer and an outer muscular layer. Based on this model, we examine the current strategies developed to mimic each layer and we underline how each fabrication method stands in providing a biomimetic material for future clinical translation. The analysis provided here, addressed to materials chemists, biomaterials engineers and clinical staff alike, sets new guidelines to foster the elaboration of new biomimetic materials for effective tubular tissue repair.

High-Resolution 3D Geological Modeling of Three-Phase Zone Coexisting Hydrate, Gas, and Brine

Three-dimensional geological modeling is essential for simulating natural gas hydrate (NGH) productivity and formulating development strategies. Current approaches primarily concentrate on the single-phase modeling of either hydrate or free gas layers. However, an increasing number of instances suggest that the three-phase coexistence zone, which includes hydrate, gas, and water, is common and has become a focal point of international research, as this type of reservoir may present the most viable opportunities for exploitation. At present, there exists a significant gap in the research regarding modeling techniques for such reservoirs. This study undertakes a comprehensive modeling investigation of the three-phase zone reservoir situated in the sand layer of the Qiongdongnan Basin. By employing deterministic complex geological modeling techniques and integrating existing seismic and logging data, we have developed a three-phase coexistence zone model that precisely characterizes the interactions between geological structures and utilizes them as auxiliary constraints. This approach effectively mitigates the potential impact of complex geological conditions on model accuracy. Through a comprehensive analysis of 105 seismic profiles, we enhanced the model’s accuracy, resulting in the creation of a three-phase coexistence zone model comprising 350,000 grids. A comparison between the modeling results and well data indicates a relatively small error margin, offering valuable insights for future development efforts. Furthermore, this method serves as a reference for modeling hydrates in marine environments characterized by three-phase coexistence on a global scale.

Can the atmospheric boundary layer-based potential evaporation model increase the accuracy of generalized complementary functions?

ABSTRACT Complementary functions could reliably and effectively estimate actual evaporation and receive wide attention in recent years. However, estimating potential evaporation (Epo) greatly influences the accuracy of complementary functions. In this study, we compare the atmospheric boundary layer model (ABL2021) with the Priestly–Taylor model (P-T) and the maximum evaporation model (YR2019) for estimating Epo. Eighty-six flux sites are utilized to fit parameters for three generalized complementary functions, including the sigmoid function (H2018), the polynomial function (B2015), and the exponential function (G2021) with various potential evaporation models. The results suggest that ABL2021 shows the best agreement with the observations at large lake sites. The uncertainties for estimation of actual evaporation induced by different potential evaporation models are larger than different complementary functions. ABL2021 significantly reduces the differences in performance between different complementary functions. It suggests that ABL2021 improves the accuracy of the generalized complementary functions in most cases and can provide a calibration-free method for Epo estimation. G2021 performs better and shows more flexibility than the other generalized complementary functions. Therefore, G2021 combined with ABL2021 shows a potential to develop a robust method for estimating actual evaporation based on the complementary principle.

HAIS-IDS:A Hybrid Artificial Immune System Model for Intrusion Detection in IoT

The application of the Internet of Things(IoT) is increasing exponentially, the dynamic data flow and distributive operation over low resource devices possesses huge threat to sensitive human data. This paper introduces an artificial immune system (AIS) based approach to intrusion detection in IoT network ecosystems, the proposed approach implements dual-layered AIS; which is robust to zero-day attacks and designed to adapt new types of attack classes in the form of antibodies.In this paper, a Hybrid method has been presented which uses Hybrid of Clonal Selection using Variation auto-encoders as Innate Immune Layer and Apaptive Dentritic Model for identifying intrusions over IoT Specific Datasets.Moreover we present extensive empirical analysis over six IoT network benchmark datasets for semi-supervised multi-class classification task and obtain superior performance compared to five state-of-the-art baselines. Finally, VC-ADIS achieves 99.83% accuracy over MQTT-set dataset.

Two highly-ordered global structures observed in packed beds of balls inside vibrated cylinder: Experiment and modelling of layers

During the vibration of plastic balls put into a cylinder three basic global orderings of the packed beds of balls were observed. Computed microtomography measurements enabled to determine coordinates of all balls. Internal layers and their structure in crystallized beds were studied and a model was developed to predict the radii of the layers. Structural analysis, based on the Coordination Polyhedron method, was used to identify all regular local structural units present in the bed: face-centred cubic (fcc), hexagonal close-packed (hcp), icosahedral (ico) and decahedral (dec). Two already-observed global structures, namely: random loose packing (RLP) and hexagonal layer (HL) with horizontal rows of balls, were investigated in detail. The third one, called columnar structure here, was found during the experiment and has the HL structure with vertical rows of balls. Its internal structure is highly ordered, composed of regularly-spaced columns of atoms with characteristic linear chains of non-crystalline dec units.

MATHEMATICAL MODELING OF THE PROCESS OF SEPARATION OF MIXTURES BY LIQUID EXTRACTION

While designing liquid-phase extraction processes, one of the main conditions is to determine the kinetic characteristics of the exchange processes necessary to determine the flows and masses of the components. Existing mass transfer models describe mass transfer processes on a semi-empirical and empirical basis with a limited range of applications, simplifying the real picture in most cases. In this regard, the development of models that more widely describe the processes of liquid-phase extraction and allow their application is considered one of the important tasks. Based on the generalization of the Chilton-Colborne hydrodynamic analogy in gradient flows and further development of the Landau-Levich boundary layer model, a mathematical model has been developed to determine the mass transfer coefficients in the extraction process in continuous and dispersed phases using minimal experimental data obtained at the stage of hydrodynamic studies

Effect of Dielectric Properties of Cochlea on Electrode Insertion Guidance Based on Impedance Variation

The cochlear neuromodulator provides substantial auditory perception to those with impaired hearing. The accurate insertion of electrodes into the cochlea is an important factor, as misplaced may lead to further damage. The impedance measurement may be used as a marker of the electrode insertion guidance. It is feasible to investigate the impact of the dielectric properties of the cochlea tissue layers on the electrode insertion guidance using sophisticated bio-computational methods that are impractical or impossible to perform in cochlear implant (CI) patients. Although previous modeling approaches of the cochlea argued that the capacitive impact of the tissue layer can be neglected using the quasi-static (QS) approximation method, it is widely accepted that tissue acts as a frequency filter. Thus, the QS method may not always be appropriate due to short-duration pulses. This study aimed to investigate the impact of the frequency-dependent dielectric properties of the cochlea tissue layers on the impedance variation by following a systematic approach. The volume conductor model of the cochlea layers was developed, the dielectric properties of each tissue layer were attained, and the cochlea neuromodulator settings were applied to obtain the results based on both QS and transient solution (TS) methods. The results based on the QS and TS methods were compared to define to what extent these parameters affect the outcome. It was suggested that the capacitive impact of the cochlea layers should be considered after a certain frequency level.

Study of non-stationary cutting processes in power skiving

The paper presents the results of the modelling and study of the cutting process in the cut-in phase during the machining of external gears by the power skiving. The studies were carried out on the basis of the previously developed graphical model of the cut layers and the model of the cutting force as a function of the chip cross-sectional area, the shear strength limit of the workpiece material, and the intensity of plastic deformation during cutting. The regularities of the cutting force in the cut-in phase of gear machining are shown for successive tool revolutions in four passes with a gradual increase in the depth of cut. It is shown that the peak values of the cutting force at the contact between the front face of the cutter and the face plane are two times higher than under the conditions of steady stationary cutting in a preformed gap. At the same time, the amplitude of the cutting force and its average value over the cut-in passes are 1.7–3.7 times and 1.2–1.5 times higher, respectively, than the corresponding values of these parameters for steady state cutting. It is these peak jumps in the cutting force that limit the maximum depth of the cut, number of passes, and axial feed. Based on the data obtained, recommendations were developed to modify the traditional gear cutting scheme in power skiving. It is proposed to use short tool strokes with a low cutting depth along the length of the cut-in path and, after forming a gap in this area, to cut at a full depth to the full height of the gear rim. The possibility of a significant reduction of gear machining time using the proposed scheme of technological operation is demonstrated.

Simplification of solvation shell with water clusters in the simulation of electrochemical nitrogen reduction reaction.

Electrochemical methods for nitrogen reduction have received extensive attention due to the mild reaction conditions. In order to gain an insight into the mechanism of the electrochemical nitrogen reduction process, theoretical simulations are necessary. However, current simulation studies contain many imprecise approximations that may hinder the real recognition of the reaction process. Although solvation methods have recently been developed to provide efficient descriptions, their further applications are hindered by controversy over modeling of solvents and the enormous computational effort required. In this work, we simplify the solvation conditions by using water clusters and compare them with an accurate water layer model. The results demonstrate that the simplified water clusters can effectively capture protons, simulate the surface electric environment, and enable the calculation of the activation energy of the reaction. This method offers an affordable approach for simulating the surface potentials and solvents and provides a new reference for the theoretical study of the electrochemical nitrogen reduction reaction.

Modeling Borehole Resistivity Logs with Exponentially Graded Multilayered Soil Inversion for Electrical Engineering Applications

In this paper, we present the application of a special soil resistivity model, the Exponentially Graded Multilayered Soil model, to the interpretation of Borehole Resistivity Logging surveys. The model, which was recently introduced by the authors, offers an alternative to the interpretation provided by constant resistivity layer models. The model is applied to synthetic soil surveys as well as to a real survey that is not satisfactorily interpreted using conventional models. This model aids in the design and calculation of grounding systems in electrical engineering, providing an alternative to calculations performed by traditional layered models.

Lithospheric magnetic structure of cratonic regions in Central-Eastern China inferred from aeromagnetic anomalies: Insights into magnetization in the uppermost mantle

Most of the subcontinental lithospheric mantle (SCLM) beneath Proterozoic cratons consists of refertilized Archaean SCLM. Variations in SCLM composition and its physical properties significantly affect the stabilization and preservation of the ancient continents. In this paper, aeromagnetic data are analyzed to reveal the magnetic structure of the lithospheric mantle beneath two major Precambrian blocks in central-eastern China, i.e., the Upper Yangtze Block (UYB) and Ordos Block (OB). After being reduced to the pole, the Fourier power spectrum of the aeromagnetic anomalies is calculated to determine the depth to magnetic sources. Considering the lower spatial resolution of the power spectral analysis in dealing with the long-wavelength aeromagnetic anomalies, we applied the scale-normalized continuous wavelet transform (CWT) on the magnetic data to trace the magnetic sources, with special focus on deeper ones. Synthetical model of a magnetic layer and application to the profile data validate the effectiveness of this scale normalization scheme in improving the wavenumber/spatial resolution in the CWT scalogram.In order to present a detailed magnetic structure, we carried out 2.5D forward modeling work on the magnetic data of a 2280 km-long nearly N-S profile across the UYB and OB. Due to the inherent ambiguity in the modeling results, the CWT-based spectral analysis is successfully adopted to provide source depth constraints for the initial model. The constrained forward modeling results indicate strong inhomogeneities among main tectonic blocks of studied area, like humans have different fingerprints. The magnetization of OB is larger than that of UYB since its Archean to Paleoproterozoic metamorphic basement are widely exposed at the surface, while the Precambrian basement of UYB is mostly overlain by unmetamorphosed Sinian cover and weakly metamorphosed Neoproterozoic strata. The most interesting aspect is that deep-seated magnetic sources might reside in the uppermost mantle of UYB and OB, suggesting vertical layering in the SCLM in cold cratonic regions.

Computational fluid dynamics for naval hydrodynamics

This article describes key issues which have to be addressed to apply Computational Fluid Dynamics to Naval Hydrodynamics. The specific aspects of Naval Hydrodynamics are discussed and illustrated by recent simulations and comparisons with available experiments. Free-surface flows with or without waves and even violent phenomena such as ventilation or cavitation can be modelled with mixture-fluid surface capturing. Turbulence modelling of thick boundary layers and vortical flows requires anisotropic RANS models or hybrid RANS/LES in case of strongly separated flows. Moreover, fluid–structure interaction in the form of rigid or flexible body motion and multi-body systems is crucial to represent ship manoeuvring and propulsion. Finally, the paper underlines the central role played by anisotropic adaptive grid refinement in the accurate simulation of marine flows.

Characterization of optical depth for laser produced plasma extreme ultraviolet source

This study investigates the emission mechanism of laser-produced plasma extreme ultraviolet source (LPP-EUV). In the experiment, the EUV radiation is generated by a 1064 nm laser interacting with slab Sn target. The EUV emission is characterized by EUV energy monitors and an EUV spectrometer. The dependency of CE on laser intensity and plasma relative optical depth is explored by a plasma emission-absorption layer model. The dependency is confirmed by an optical interferometry measurement of plasma electron density for the first time. Our work provides a method for characterizing and optimizing the optical depth of laser driven EUV source.

Boundary Layer Modelling of Flow Acceleration and Energy Transfer Effects in Smart Pavement Design

The integration of remote technology into the construction industry has advanced the emergence of smart, self-learning infrastructure across all levels of land transportation design and development. However, energy harvesting capabilities for smart road ventilation purposes have not yet been fully researched as the world gravitates towards energy sustainability. This study thus presents a mathematical investigation of the self-draining design potentials of road pavements, leveraging on energy absorption and conversion to accelerate conductive and convective ventilation of these pavements during wet conditions, as a means of ensuring the skid resistance and safety of such pavements are not compromised. Applying numerical methods with the aid of commercial software code MATLAB®, the classical physics of fluid-surface interaction was used to model accelerated drainage of microflood off paved surfaces through methodical modification of the thickness of the boundary layer associated with the flow regime over the flat road surface. Results indicate significant influences of energy exchange, thermal, and viscous diffusivity on flow acceleration. Alterations in parameters such as the slip factor, thermally induced Brownian motion or phoretic characteristics of the fluid particles at the boundary induce accelerated flow at the surface of the pavement. The findings contribute to the advancement of smart infrastructure by offering practical insights into the potential benefits of integrating energy-harvesting technologies into road pavement systems. By optimizing flow acceleration mechanisms, smart pavements can play a crucial role in improving road safety and sustainability in urban environments.

Effect of Fe3+ doping on the electronic structure and surface hydration properties of quartz

In this study, the effects of Fe3+ doping on the crystal structure and surface properties of quartz were analyzed using density functional theory (DFT) calculations and molecular dynamics (MD) simulations. The crystal structure, surface model, and adsorption model of the water molecule layer for Fe3+-doped α-quartz were established. The DFT calculations reveal that Fe3+ doping affects the α-quartz lattice parameters and surface active sites. The adsorption energy near the sites occupied by Fe3+ is −66.20 kJ/mol, which is considerably lower than that of the undoped system (−42.35 kJ/mol). This makes it easier for water molecules to be adsorbed on the Fe3+-doped α-quartz (001) surface. The frontier orbital energy, electron density difference, charge density, and Mulliken bond population analyses indicate that the presence of Fe3+ improves the ability of the (001) surface of α-quartz to attract and bind water molecules. This improvement is mainly due to the formation of hydrogen bonds between the surface hydroxyl groups and water molecules on the surface of Fe3+-doped quartz and the equilibrium of the electrostatic interaction between the cation and water molecules. MD simulations show that a hydration layer with a thickness of approximately 8 Å is formed on the surface of Fe3+-doped α-quartz. Compared with the undoped system, the hydration film on the surface of the doped system is thicker, indicating that the incorporation of Fe3+ impurities in the lattice enhances the surface hydration characteristics of quartz. These results offer theoretical guidance for achieving efficient separation and thorough purification of quartz.

A novel elastoplastic impact contact model for thin orthotropic layer

A complex stress state is often an obstacle in obtaining analytical solutions to elastoplastic contact problems of orthotropic structural materials. In this study, an analytical model is presented for investigating the impact contact between a rigid body and a thin orthotropic layer situated on a rigid foundation. By assuming that the local indentation during impact contact is due to the elastoplastic deformation, a theoretical study is carried out to predict the contact response of the orthotropic layer, which obeys an elastic-perfectly plastic stress-strain law. A relationship between contact force and indentation is derived, and the coefficient governing the rebound response is determined. The presented results show generally good agreement with the experimental and numerical results available in the literature. The impact contact model can also be utilized in the impact response analysis of coated structures. Parametric analysis results indicate that the elastic model tends to overestimate the impact resistance of thin layers. The elastoplastic contact law can accurately account for the decrease in contact force due to plastic indentation and permanent deformation. Moreover, the yield strength significantly influences the impact contact time and the permanent indentation deformation of the thin-layer structure.

Flip-chip package solder-underfill reliability using finite element analysis

A semiconductor package is responsible to safeguard the die from the external environment that can affect its performance and reliability. A flip-chip package ensures that the assembly, which is capable of high input-output function, maintains its operation and safeguards the interconnection paths particularly the solder ball deformation and fatigue. In this study, a finite element analysis model of the solder-underfill layers of a flip-chip package was developed and validated by statistical comparison of the warpage and stress from experimental data and theoretical calculations of composite deformation and stress. Quarter modeling reduces the computational load while maintaining sufficient detail that allows for efficient use of computational resources. It is then complemented by the design of experiment which systematically varied the parameters to explore the design space and optimize the configuration. Moreover, the method was able to account for nonlinear effects, especially on the impact of solder content on die stress. This provides a more precise control over the thermo-mechanical behavior of the package which would lead to more informed decisions in designing packages. The results have shown desirability of 0.8491 with an optimal layer thickness setting of 0.06 mm and solder content of 18.1% in consideration of the nonlinear factor effect of solder content on the die stress.