Simple Description Research Articles

Simplified description of hard particles in tribological systems using statistical sample particles

AbstractTechnical applications often include tribological systems in which friction and wear occur. Hard particles, such as sand, are often present in the contact between the surfaces of two bodies in contact and affect both the system dynamics and the resulting surface topography of the contacting bodies. Real tribological systems can contain a very high number of particles. Hence, for performance reasons of numerical studies, the explicit representation of each particle in a simulation is often not practical. The approach presented here is based on a model simplification by grouping several particles to form statistical sample particles (SSPs). SSPs can only move as a whole, and thereby simplify the motions of the individual particles, but the contact stiffness and orientation dependence of the force are still determined by the set of individual particles that are part of the statistical sample. Using sample size 1, each individual particle is represented without simplification, while using a sample size larger than one, the total number of particles in the system reduces to a minimum of one SSP representing all particles in the system. This approach provides a very efficient way to specify the model complexity and desired level of detail for the particle representation within a model of a tribological system.

A new simulation method for nanoparticles solution flooding based on connection element method

Nanotechnology is widely used in medicine, electronics, materials, and energy fields. An important aspect of nanotechnology is its application in enhancing oil and gas recovery. However, the oil displacement mechanism using nanotechnology is complicated. Generally, numerical simulation methods and experiments are used to provide a simple description of the oil displacement mechanism, leading to the current inability to accurately characterize the actual underlying mechanism. Based on the connection element method, this paper proposes a new characterization method for the numerical simulation of nanoparticle solution flooding in oil reservoirs, In this case, the reservoir is considered the interaction relationship between connecting elements, and the flow rate, and oil saturation on a single connecting element are calculated. The oil displacement mechanism of nanoparticle solution flooding is investigated by focusing on increasing viscosity, changing formation permeability, and fluid relative permeability. The oil displacement mechanism expressed in this model is considered when the nanoparticles are dissolved in the base fluid (water). Herein, a dual-media model of nanoparticle solution flooding is established to describe the fractured reservoirs. The model was validated by comparing with water flooding when the nanofluids concentration is close to zero. The results show that the fitting rate can reach 98%. The proposed model was also used in an actual reservoir, the fitting rates between the calculated oil rate and actual production of four typical production wells reached 81.4%, 84.5%, 86%, and 82%. The water content decreased from 13% to 11%, and cumulative production increased by 17% after the addition of nanoparticles.

Recent advances in the SISSO method and their implementation in the SISSO++ code.

Accurate and explainable artificial-intelligence (AI) models are promising tools for accelerating the discovery of new materials. Recently, symbolic regression has become an increasingly popular tool for explainable AI because it yields models that are relatively simple analytical descriptions of target properties. Due to its deterministic nature, the sure-independence screening and sparsifying operator (SISSO) method is a particularly promising approach for this application. Here, we describe the new advancements of the SISSO algorithm, as implemented into SISSO++, a C++ code with Python bindings. We introduce a new representation of the mathematical expressions found by SISSO. This is a first step toward introducing "grammar" rules into the feature creation step. Importantly, by introducing a controlled nonlinear optimization to the feature creation step, we expand the range of possible descriptors found by the methodology. Finally, we introduce refinements to the solver algorithms for both regression and classification, which drastically increase the reliability and efficiency of SISSO. For all these improvements to the basic SISSO algorithm, we not only illustrate their potential impact but also fully detail how they operate both mathematically and computationally.

Analysis and modeling of morbidity and mortality from coronavirus outbreak in Brazil: A case study of public health challenge using unique statistical tools

The emerging outbreak of COVID-19 provided a valuable lesson for the global readiness with regard to the impact of the disease and management of the pandemic. The present case study reported the magnitude and public health effect based on the daily morbidity and mortality metrics from the coronavirus epidemic in Brazil as part of a series of investigations regarding the pattern and behavior of the outbreak with different geographical regions using the Pareto principle focusing on the major contributors of the worldwide pandemic. There were observable signs of multiple overlapping waves for the reported cases and deaths when using process-behavior (trending) charts. The cumulative daily census showed a significant approach to Morgan-Mercer-Flodin (MMF) model as a primary fit followed by exponential association as a secondary option with good regression. A simple and effective statistical description of the pandemic could be used as a quantitative measure for the effect of the outbreaks on the populations in a specific political region with the ability to compare between pre- and post-action events and different districts.

Eilenberg–Maclane spaces and stabilisation in homotopy type theory

In this note, we study the delooping of spaces and maps in homotopy type theory. We show that in some cases, spaces have a unique delooping, and give a simple description of the delooping in these cases. We explain why some maps, such as group homomorphisms, have a unique delooping. We discuss some applications to Eilenberg–MacLane spaces and cohomology.

Anisotropic debris cloud formation after hypervelocity impact into rolled magnesium alloy plates

Magnesium (Mg) alloys are attractive structural materials because of their high specific properties. However, their behavior under impact is complicated due to their anisotropic, hexagonal, close packed crystal structure and coupled deformation mechanisms of twinning and dislocation slip. Here we investigate the breakout and fragmentation of rolled AZ31B Mg alloy plates by the hypervelocity impact of spherical projectiles, using time-resolved and quantitative diagnostics. We find that the impact, subsequent penetration, and rupture of the rolled plate are followed in many cases by the development of a debris cloud that is not isotropic. We have quantified the degree of this asymmetry by employing multiple high-speed cameras, mounted along orthogonal directions, relative to the penetration axis of the projectile. A series of impact tests with velocities ranging from 1.2 to 3.6 km/s revealed that the formation and overall shape of the debris cloud were dependent on the projectile material and magnitude of the impact velocity. These salient features have also been captured in simulations of the impact event by incorporation of a simple anisotropic description of the material strength while retaining an isotropic model for material failure. Agreement between the experiments and model predictions suggests that the anisotropic strength response of Mg is primarily responsible for most of the observed anisotropy in the debris cloud formation, especially for impacts up to 3.0 km/s.

An analytical study of capillary rise dynamics: Critical conditions and hidden oscillations

The rise of a liquid column inside a thin capillary against the action of gravity is a prototypical example of a dynamic wetting process and plays an important role for applications but also for fundamental research in the area of multiphase fluid dynamics. Since the pioneering work by Lucas and Washburn, many research articles have been published which aim at a simplified description of the capillary rise dynamics using complexity-reduced models formulated as ordinary differential equations. Despite the fact that these models are based on profound simplifications, they may still be able to describe the essential physical mechanisms and their interplay. In this study, we focus on the phenomenon of oscillations of the liquid column. The latter has been observed experimentally for liquids with sufficiently small viscosity leading to comparably small viscous dissipation. Back in 1999, Quéré et al. formulated a condition for the appearance of rise height oscillations for an ODE model introduced by Bosanquet in 1923. This model has later been extended to include further dissipative mechanisms. In this work, we extend the mathematical analysis to a larger class of models including additional channels of dissipation. We show that Quéré’s critical condition is generalized to Ω+β<2, where Ω was introduced earlier and β is an additional non-dimensional parameter describing, e.g., contact line friction. A quantitative prediction of the oscillation dynamics is achieved from a linearization of the governing equations. We apply the theory to experimental data by Quéré et al. and, in particular, reveal the oscillatory behavior of dynamics for the nearly critically damped case of ethanol.

AI art in architecture

Recent diffusion-based AI art platforms can create impressive images from simple text descriptions. This makes them powerful tools for concept design in any discipline that requires creativity in visual design tasks. This is also true for early stages of architectural design with multiple stages of ideation, sketching and modelling. In this paper, we investigate how applicable diffusion-based models already are to these tasks. We research the applicability of the platforms Midjourney, DALLcdotE 2 and Stable Diffusion to a series of common use cases in architectural design to determine which are already solvable or might soon be. Our novel contributions are: (i) a comparison of the capabilities of public AI art platforms; (ii) a specification of the requirements for AI art platforms in supporting common use cases in civil engineering and architecture; (iii) an analysis of 85 million Midjourney queries with Natural Language Processing (NLP) methods to extract common usage patterns. From this we derived (iv) a workflow for creating images for interior designs and (v) a workflow for creating views for exterior design that combines the strengths of the individual platforms.

Review of Methods to Solve Desiccation Cracks in Clayey Soils

This paper reviews numerical methods used to simulate desiccation cracks in clayey soils. It examines five numerical approaches: Finite Element (FEM), Lattice Boltzmann (LBM), Discrete Element (DEM), Cellular Automaton (CAM), and Phase Field (PFM) Methods. The paper presents a simplified description of the methods, including their basic numerical formulations. Several factors such as the multiphase nature of soils, heterogeneity, nonlinearities, coupling, scales of analysis, and computational aspects are discussed. The review highlights the characteristics, strengths, and limitations of each method. FEM shows a good capacity to deal with the thermo-hydromechanical behavior of clays when drying that complement well with the ability of DEM to deal with particle interactions as well as LBM, PFM, and CAM to deal with complex crack patterns. The article concludes by reviewing the integration of multiple numerical methods to enhance the simulation of desiccation cracks in clayey soils and proposing what is the best option to continue improving the study of this problem.

International case study comparing PSA modeling approaches for nuclear digital I&C – OECD/NEA task DIGMAP

Nuclear power plants are increasingly being equipped with digital I&C systems. Although some probabilistic safety assessment (PSA) models for the digital I&C of nuclear power plants have been constructed, there is currently no specific internationally agreed guidance for their modeling. This paper presents an initiative by the OECD Nuclear Energy Agency called “Digital I&C PSA – Comparative application of DIGital I&C Modelling Approaches for PSA (DIGMAP)”, which aimed to advance the field towards practical and defendable modeling principles. The task, carried out in 2017–2021, used a simplified description of a plant focusing on the digital I&C systems important to safety, for which the participating organizations independently developed their own PSA models. Through comparison of the PSA models, sensitivity analyses as well as observations throughout the whole activity, both qualitative and quantitative lessons were learned. These include insights on failure behavior of digital I&C systems, experience from models with different levels of abstraction, benefits from benchmarking as well as major contributors to the core damage frequency and those with minor effect. The study also highlighted the challenges with modeling of large common cause component groups and the difficulties associated with estimation of key software and common cause failure parameters.

Dielectric constant measurement sensitivity in electrostatic force and force gradient microscopy-based modes

Understanding the nanoscale electrostatic interaction between a conductive atomic force microscopy (AFM) probe and a dielectric film is central to the operation of various nanoscale dielectric microscopies and determination of dielectric properties of the film. There is no simple analytical description of the electrostatic interaction generated in the confined probe-sample geometry for neither static nor dynamic AFM modes used in dielectric measurements. An accurate description of the involved physics is obtained only by means of a finite element analysis modeling of the system. However, the alternative to using the numerical analysis is not very popular due to being slower and requiring relatively high computation resources. In this work, we revised the contributions from different parts of the AFM probe to the probe-sample capacitance by both analytical and numerical methods. We tried to reconciliate the two approaches and observed the differences as a function of geometry and material parameters. Under various noise levels, the efficiency of an analytical model was tested against a finite element analysis that captures in detail the electrostatic interaction in AFM-based dielectric measurements. The investigation was performed in both spectroscopic force-distance curves and constant height scans with measurements for deflection and frequency of the AFM probe. The obtained measurement sensitivities are relevant in selecting the optimal scanning mode and its operational parameters for a given film thicknesses and dielectric constants but also show the critical role of the numerical analysis to the correct interpretation of the measurements.

An overview of surface forces and the DLVO theory

This lecture text focuses on surface forces and interactions in a liquid medium, with particular emphasis on the surface-surface interactions described by the DLVO theory, i.e., van der Waals attraction and electric double-layer repulsion. The text begins by describing the fundamental forces of nature, their connection to intermolecular interactions, and how the latter result in measurable forces between surfaces and macroscopical objects. A step-by-step reasoning on how DLVO forces arise is then presented, accompanied by a simplified description of the mathematical derivations of the main equations within the framework of the theory. The connection between the DLVO theory and the prediction of the stability of colloidal systems is presented. Examples on how the colloidal stability can be controlled or tuned are presented. The shortcomings of the original DLVO theory are discussed, and recent extended models dealing with these issues are briefly described. The text closes with a general overview of some of the most relevant non-DLVO interaction.

Educational Scale-Bridging Approach towards Modelling of Electric Potential, Electrochemical Reactions, and Species Transport in PEM Fuel Cell

The use of hydrogen fuel cells as a mobile source of electricity could prove key to the future decarbonisation of heavy-duty road and marine transportation. Due to the complex interplay of various physicochemical processes in fuel cells, further development of these devices will depend on concerted efforts by researchers from various fields, who often lack in-depth knowledge of different aspects of fuel cell operation. These knowledge gaps can be filled by information that is scattered in a wide range of literature, but is rarely covered in a concise and condensed manner. To address this issue, we propose an educational-scale-bridging approach towards the modelling of most relevant processes in the fuel cell that aims to adequately describe the causal relations between the processes involved in fuel cell operation. The derivation of the model equations provides an intuitive understanding of the electric and chemical potentials acting on protons at the microscopic level and relates this knowledge to the terminology commonly used in fuel cell research, such as catalyst electric overpotential and internal membrane resistance. The results of the model agreed well with the experimental data, indicating that the proposed simple mathematical description is sufficient for an intuitive understanding of fuel cell operation.

Pain Evaluation and Treatment in Children: A Practical Approach.

Pain is the most common complaint reported by children who access the emergency departments, but despite its frequency and the availability of many international guidelines, it often remains underreported and undertreated. Recently, the American Academy of Pediatrics and the American Pain Society have reiterated the importance of a multidisciplinary approach in order to eliminate pain in children. In all pediatric settings, an adequate assessment is the initial stage in a proper clinical approach to pain, especially in the emergency departments; therefore, an increasing number of age-related tools have been validated. A wide range of analgesic agents are currently available for pain management, and they should be tailored according to the patient's age, the drug's pharmacokinetics and the intensity of pain. In order to facilitate the choice of the appropriate drug, a treatment algorithm based on a ladder approach can be used. Moreover, non-pharmacological techniques should be considered to alleviate anxiety and distress in pediatric age. This review aims to offer a simple but intuitive description of the best strategies for pain relief in children, starting with the prompt recognition and quantification of pain through adequate assessment scales, and following with the identification of the most appropriate therapeutic choice among the ones available for pediatric age.

Description of the multi-dimensional environment at the territorial scale: A holistic framework using cluster analysis and open data in France

The impact of the environment on health is usually studied in a segmented manner, with a focus on a single source, pollutant, or exposure medium. To better understand spatial health inequalities, it is necessary to adopt multi-dimensional approaches to comprehensively describe the environment, especially at the territorial level. Clustering methods, which allow for the development of territorial typologies, are particularly interesting for this purpose. By simplifying complex datasets, these methods may reveal spatial patterns and geographical phenomena that would otherwise be difficult to observe. Based on the existing literature, there is a clear need for large-scale territorial typologies that comprehensively address the physical and outdoor environment.A robust and transposable framework was developed and applied to 3,041 municipalities in Northern France using open environmental data. It consists of five main steps: data collection, data selection, data preparation, cluster analysis, and cluster interpretation. This methodology allows for the development of an environmental classification of municipalities by identifying the primary environmental profiles represented in the study area. Cluster detection was performed based on 39 spatialized indicators that describe the level of environmental contamination (air, water, soil), the level of pollutant emissions, the proximity to emission sources, the land use, the agricultural practices, and the degree of naturalness in every municipality. As a result, municipalities were allocated into one of the seven following environmental profiles: (i) Dense urban centers; (ii) Peripheral urban municipalities; (iii) Intensive agricultural municipalities under urban influence; (iv) Intensive agricultural municipalities beyond urban influence; (v) More extensive and diversified agricultural municipalities; (vi) Municipalities with predominant livestock activities and significant natural areas; (vii) Municipalities with predominant natural areas: forests, wetlands, and water surfaces. The resulting typology goes far beyond a simple description of the urban–rural continuum. Five profiles of rural municipalities were identified, primarily distinguished by agricultural practices, degree of naturalness, and intensity of urban pressure.This approach enables researchers to identify the combination of environmental factors that shape a territory. It provides a more comprehensive and nuanced understanding of how environmental pressures and amenities are distributed in space and overlap with each other. By linking these typologies with health data, it could provide new insights into the etiology of complex diseases with unidentified environmental risk factors. Relying on open data, this framework is a valuable tool to assess etiological hypotheses at the territorial level.

Non-linear and multi-domain modelling of a free piston engine with linear electric machine

In the current technological era, with the rapid advances in low-carbon power generation solutions, there has been renewed interest in the Free Piston Engine (FPE) as a viable thermal propulsion technology. However, describing and capturing the intrinsic non-linear dynamics of the FPE is computationally challenging and, understandably, is generally characterised by a simplified linear description, which may inherently omit the dominant dynamics.Consequently, this study considers the non-linear and multi-directional nature of the coupled translation loads during motoring and power generation. Thus, presenting a non-linear and multi-domain description of the FPE. The proposed model was implemented in an opposed-piston free-piston engine configuration and validated during motoring and generating against experimental data captured from a prototype with identical parameters. The simulation results strongly correlate to the experimental data with similar translator displacement, in-cylinder pressure and bounce chamber pressure traces. Furthermore, the study demonstrated that the proposed modelling approach captured the dominant dynamics of the FPE and proved satisfactory accuracy and performance. In addition to validating the proposed modelling approach, this paper concludes with a simulation study that demonstrates the embedding of a novel surrogate Chemical Kinetics (CK) description of the hydrous ethanol auto-ignition process and the resultant influence on the FPE dynamics, most importantly, on gaseous emission formation.Therefore, this paper aims to extend the current knowledge in this novel and emerging technology by considering the characteristic non-linearity and multi-directional nature of its coupling with multi-physical domains such as mechanical, chemical and electrical.

Which language is more affected in bilinguals with Alzheimer's disease? Diagnostic sensitivity of the Multilingual Naming Test.

This study examined the joint consequences of bilingualism and Alzheimer's disease (AD) for picture naming ability to determine which language is more affected by AD and what scoring methods best distinguish patients from controls. Sixty-five Spanish-English bilinguals including 26 with dementia and 39 controls with equivalent age, education, and bilingual proficiency level, were tested on the Multilingual Naming Test (Gollan et al., 2012). Bilinguals with AD named fewer pictures than controls, and overall AD seemed to affect both languages about equally, but exploratory analyses suggested that this varied with item difficulty. In the dominant language difficult items exhibited a larger effect of AD than easy items (which were at ceiling for both patients and controls), whereas in the nondominant language items of all difficulty levels were about equally affected by AD. An "either-language" scoring procedure (that counted items as correct if produced only in one of the two languages) increased naming scores especially in balanced bilinguals, and to an equal extent in patients and controls. Receiver Operating Characteristic analyses revealed that dominant language and either-language naming scores classified bilinguals as patients versus controls equally well and adding nondominant language scores did not improve diagnostic sensitivity. Testing primarily or exclusively in the dominant language is best for detecting AD naming impairments in bilinguals. However, AD affects the ability to access names in both languages, possibly for different reasons, and simple descriptions of language decline as "parallel" or "asymmetrical" (i.e., AD affecting one language more than the other) may be misleading in terms of the theoretical implications for bilingual language processing. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

MATHEMATICAL DESCRIPTION OF THE PROCESSES OF FUNCTIONING OF THE ELECTRIC MOTOR-GENERATOR OF A CAR WITH A HYBRID POWER PLANT

The authors of the article describe and analyze the processes of functioning of a synchronous electric motor-generator (EDG). A review of mathematical descriptions of synchronous EDG is presented. A simplified mathematical description is proposed that makes it possible to simulate the process of functioning of the hybrid propulsion system (GSU) in typical modes of movement of wheeled vehicles (CTS). The functional dependences of the current, power and torque on the rotor speed of the synchronous EDG of the Toyota Prius car are presented.&#x0D; The goal is to develop a simplified mathematical description of a synchronous electric motor–generator of a car with a hybrid power plant.&#x0D; The method or methodology of the work is a numerical method based on the finite – difference scheme of the Park method, using a special numerical-iterative method of composing equations of motion.&#x0D; Results – a simplified mathematical description has been developed, which allows to determine the functional dependencies necessary for the analysis of the functioning of the CCC with GSU.&#x0D; The scope of the results. It is advisable to apply the results obtained when modeling the processes of functioning of a synchronous electric motor-generator of a hybrid power plant of wheeled vehicles.

Model Komunikasi Guru Dan Siswa Dalam Meningkatkan Prestasi Non-Akademik Melalui Virtual Learning

The communication model is a simple description of the communication process that occurs both individually and in groups. The use of this communication model is considered effective in the success of communication because the message delivered can be received by the target. In this case, what happened at Pacet 1 Public High School implementing virtual learning by utilizing the media as an intermediary, this communication model also has obstacles that occur when communicating between teachers and students such as broken sounds, missing pictures, and so on. This study aims to determine the teacher and student communication model in improving non-academic achievement through virtual learning. This study used the Shannon and Weaver communication model theory. The informants here are the headmaster of SMA Negeri 1 Pacet, the supervising teacher for the competition, and several students. Data is collected by observation, interviews, and documentation. Data validity was carried out using triangulation techniques. The results of this study indicate that in the Shannon and Weaver communication model, communication requires Information Resources (SDI) which then forms messages to be communicated through intermediaries such as smartphones using internet channels. but in the process of communication, the virtual is not free from interference (noise). And the authors see that the communication process used by teachers and students at SMA Negeri 1 Pacet is quite effective and efficient so that it can hone children's creativity.

Kudla–Rapoport conjecture for Krämer models

In this paper, we propose a modified Kudla–Rapoport conjecture for the Krämer model of unitary Rapoport–Zink space at a ramified prime, which is a precise identity relating intersection numbers of special cycles to derivatives of Hermitian local density polynomials. We also introduce the notion of special difference cycles, which has surprisingly simple description. Combining this with induction formulas of Hermitian local density polynomials, we prove the modified Kudla–Rapoport conjecture when $n=3$. Our conjecture, combining with known results at inert and infinite primes, implies the arithmetic Siegel–Weil formula for all non-singular coefficients when the level structure of the corresponding unitary Shimura variety is defined by a self-dual lattice.