Computer Code Research Articles

First-principles study on the stability and optoelectronic properties of the novel C6O2 nanostructure

This study presents the prediction of a novel 2D nanostructure, C6O2, characterized as a direct bandgap semiconductor with a rectangular atomic arrangement. Employing computational codes based on density functional theory (DFT), we optimized the lattice parameters, yielding (a = 6.26 Å and b = 2.43 Å). Stability analysis, including cohesive energy (with a value of −7.85 eV/atom) and phonon dispersion within the first Brillouin zone, confirms the acceptable stability of the C6O2 structure. Electronic properties in the ground state were investigated using both HSE06 and GGA approaches. Our results indicate that the predicted structure exhibits a direct bandgap with energy values of 0.108 eV (PBE), 0.11 eV (mBJ), and 0.415 eV (HSE06) at the M point. Furthermore, we explored the optical properties of this nanostructure using the HSE06 approach. Notably, the ground state exhibits moderate absorption across the visible light spectrum (around 3–5 eV) and a low reflection rate. These findings suggest that C6O2 holds promise for future experimental endeavors in designing electro-optical applications.

Volume fraction detection in multiphase systems using neutron activation analysis and artificial neural network

This study presents an application of an Artificial Neural Network (ANN) to detect fluids in an annular flow regime using Prompt-Gamma Neutron Activation Analysis (PGNAA). The ANN was trained using gamma-ray spectra resulting from neutron interactions with chemical elements found in fluids typical of multiphase flow in oil exploration. These spectra were generated through mathematical simulation using the MCNP6 Monte Carlo computer code to model nuclear particle transport. A241Am-Be polyenergetic neutron source was simulated for these calculations. Several combinations of fluid fractions were developed to create a dataset used for both training and evaluation of the ANN. The ANN demonstrated robust generalization capabilities by accurately predicting the volume fraction of the three investigated fluids (saltwater, oil, and gas), even for cases not included in the training phase. The combination of ANN and PGNAA proved effective for analyzing multiphase systems, with over 92% of all showing errors of less than 5%.

Non-smooth Bayesian optimization in tuning scientific applications

Tuning algorithmic parameters to optimize the performance of large, complicated computational codes is an important problem involving finding the optima and identifying regimes defined by non-smooth boundaries in black-box functions. Within the Bayesian optimization framework, the Gaussian process surrogate model produces smooth mean functions, but functions in the tuning problem are often non-smooth, which is exacerbated by the fact that we usually have limited sequential samples from the black-box function. Motivated by these issues encountered in tuning, we propose a novel Gaussian process model called a clustered Gaussian process (cGP), where the components are dynamically updated by clustering. In our studies, the performance of cGP can be better than stationary GPs in nearly 90% of the experiments and better than non-stationary GPs in nearly 70% of the repeated experiments while requiring less computational cost. cGP provides a novel approach for dynamic GP, computes more efficiently than recursive partitioning, and discovers non-smoothness regimes. We provide extensive experiments including high-performance computing (HPC) and industrial simulation functions to show the effectiveness of our methods.

BSP – Computer code for evaluating protection against bremsstrahlung radiation from extended beta radiation sources

For a long time, radiation safety specialists have been aware of computer codes designed to calculate human dose exposure from beta or gamma radiation. However, these products have a major drawback: they do not consider the radiation fields generated by extended beta radiation sources due to bremsstrahlung. Existing solutions are either not widely available or use outdated nuclear-physical constants and methods for calculating dosimetric characteristics. A computer code was developed specifically for calculating shielding against bremsstrahlung. It allows to estimate effective, equivalent, exposure dose rate, ambient dose equivalent, and air kerma rate from bremsstrahlung. It utilizes the ANS/ANSI 6.4.3 materials data and the last dose conversion factors from ICRP 116.

Teaching in the Era of Artificial Intelligence: Reimagining Activities and Assignments in Preservice Special Education Teacher Education Programs

Artificial intelligence (AI) text generators, such as ChatGPT and Copilot, have been used for various purposes such as creating written content, writing or debugging computer code, answering questions, providing information, and improving written communication. This robust functionality of AI text generators along with the high rate of use reported by college students highlights the need for instructors in special education teacher preparation programs to contend with the impact of AI on teaching and learning. The purpose of this article is to provide examples of how teacher educators might reimagine assignments and activities in the era of AI text generators. Specifically, the authors explore ways that AI applications might be intentionally incorporated or, conversely, intentionally restricted in the design of course assignments and activities.

Recombination fraction in pre-recombinant inbred lines (PRERIL) - revisiting a century old problem in genetics

BackgroundTraditional recombinant inbred lines (RILs) are generated from repeated self-fertilization or brother-sister mating from the F1 hybrid of two inbred parents. Compared with the F2 population, RILs cumulate more crossovers between loci and thus increase the number of recombinants, resulting in an increased resolution of genetic mapping. Since they are inbred to the isogenic stage, another consequence of the heterozygosity reduction is the increased genetic variance and thus the increased power of QTL detection. Self-fertilization is the primary form of developing RILs in plants. Brother-sister mating is another way to develop RILs but in small laboratory animals. To ensure that the RILs have at least 98% of homozygosity, we need about seven generations of self-fertilization or 20 generations of brother-sister mating. Prior to homozygosity, these lines are called pre-recombinant inbred lines (PRERIL). Phenotypic values of traits in PRERILs are often collected but not used in QTL mapping. To perform QTL mapping in PRERILs, we need the recombination fraction between two markers at generation t for t < 7 (selfing) or t < 20 (brother-sister mating) so that the genotypes of QTL flanked by the markers can be inferred.ResultsIn this study, we developed formulas to calculate the recombination fractions of PRERILs at generation t in self-fertilization, brother-sister mating, and random mating. In contrast to existing works in this topic, we used computer code to construct the transition matrix to form the Markov chain of genotype array between consecutive generations, the so-called recurrent equations.ConclusionsWe provide R functions to calculate the recombination fraction using the newly developed recurrent equations of ordered genotype array. With the recurrent equations and the R code, users can perform QTL mapping in PRERILs. Substantial time and effort can be saved compared with QTL mapping in RILs.

Wave-Current Interaction Effects on the OC4 DeepCwind Semi-Submersible Floating Offshore Wind Turbine

In order to investigate the hydrodynamic performances of semi-submersible type floating offshore wind turbines (FOWTs), particularly the effect of body-wave-current interaction, the OC4 FOWT is considered in the presence of co-existing regular wave and uniform current fields. The wind loads are not considered at this stage. The problem is treated in the framework of potential-flow theory in the frequency domain, assuming waves of small steepness, and the solution is obtained by using a perturbation expansion method for the diffraction potential with respect to the normalized current speed. Analytical and numerical formulations have been used to treat the inhomogeneous free-surface boundary condition involved in the hydrodynamic problem formulation for the derivation of the associated perturbation potential. The hydrodynamic loads were obtained after evaluating the pressure field around the multi-body configuration using three different computer codes. The results from the three computer codes compare very well with each other and with the numerical predictions of other investigators. Finally, the mean second-order drift forces are calculated by superposing their zero-current values with the corresponding current-dependent first-order corrections, with the latter being evaluated using a ‘heuristic’ approach.

The long road to ignition: An eyewitness account

This paper reviews the many twists and turns in the long journey that culminated in ignition in late 2022 using the laser heated indirect-drive approach to imploding DT filled targets at the National Ignition Facility (NIF), located at the Lawrence Livermore National Laboratory (LLNL). We describe the early origins of the Laser Program at LLNL and key developments such as the paradigm shifting birth of high energy density physics (HEDP) studies with lasers, changes in choice of laser wavelength, and the development of key diagnostics and computer codes. Fulfilling the requirements of the multi-faceted Nova Technical Contract was a necessary condition for the approval of the NIF, but more importantly, the end of the Cold War and the cessation of nuclear testing were key catalysts in that approval, along with the ready-and-waiting field of HEDP. The inherent flexibility of the field of laser driven inertial confinement fusion played a fundamental role in achieving success at the NIF. We describe how the ultimately successful ignition target design evolved from the original “point design” target, through the lessons of experiment. All key aspects of that original design changed: The capsule's materials and size were changed; the hohlraum's materials, size, laser entrance hole size, and gas fills were also all changed, as were the laser pulse shapes that go along with all those changes. The philosophy to globally optimize performance for stability (by raising the adiabat and thus lowering the implosion convergence) was also key, as was progress in target fabrication, and in increasing NIF's energy output. The persistence of the research staff and the steadfast backing of our supporters were also necessary elements in this success. We gratefully acknowledge seven decades of researcher endeavors and four decades of the dedicated efforts of many hundreds of personnel across the globe who have participated in NIF construction, operation, target fabrication, diagnostic, and theoretical advances that have culminated in ignition.

Meso-scale investigation on the permeability of frozen soils with the lattice Boltzmann method

Complex composition and intricate pore-scale structure of frozen soils poses significant challenges in reliably and efficiently obtaining their permeability. In this study, we propose a modified quartet structure generation set (QSGS) numerical tool for generating frozen soils and present the development of a computational simulation code based on the multiple-relaxation-time lattice Boltzmann method (LBM). In the modified QSGS, the arc-shaped water-ice interface is depicted, and the influence of pore-scale geometry on freezing temperature is considered. The validity of combining the proposed QSGS model and the LBM code is proved by comparing calculated results to analytical and experimental results of porous media. Our objective was to investigate the effects of soil features, including porosity, grain diameter, shape anisotropy of soil particles, and ice content on the intrinsic permeability of frozen soil. Additionally, we examined the relationship between these features and the specific surface area and tortuosity. Numerical results show that the intrinsic permeability of frozen soils increases with increasing porosity, larger granular diameter, and anisotropy, which is identical with the pressure gradient. The presence of ice led to clogging flow pathways and drastically decreased the intrinsic permeability, which is significantly less than unfrozen soil with same effective porosity. This study provides a useful tool to investigate the intricate interplay between the pore-scale structure and the intrinsic permeability of frozen soils.

Effect of solar wind disturbances on small-amplitude simultaneous Forbush events during solar cycle 23

The transient and rapid reduction in galactic cosmic ray (GCR) flux intensity, commonly referred to as Forbush decrease (FD), is widely used as a mediator variable in searching for solar-terrestrial weather linkages. Whereas literature in the field is replete with high-amplitude (FD(%) ⩾3) FD-based analyses, the empirical connections between low-amplitude (FD(%) ⩽3) events and Sun-Earth variables are seldom tested. It is recently observed that the dearth of such studies might be due to the daunting task of accurate detection/precise timing of FDs and other transient astrophysical events. Using a sensitive version of the FD detection algorithm, we selected 264, 267, and 206 low amplitude (FD(%) ⩽3) FDs from the daily GCR data of Hermanus (HRMS), Newark (NWRK) and Oulu (OULU) neutron monitor stations respectively during solar cycle 23. A total of 80 simultaneous small-amplitude FDs were identified from the three stations with a simple coincident computer code. Statistically significant correlations at 95% confidence level exist between the planetary K-index (Kp), disturbance storm time index (Dst), planetary A-index (Ap), and the corresponding simultaneous small-amplitude FDs at OULU station, but not found in HRMS and NWRK data. These significant links between the weak FDs and the geomagnetic indices (Kp, Dst, and Ap) at OULU station suggest that the parameters (Kp, Dst, and Ap) are likely connected with some common solar activities.

Computational biomechanics for a standing human body: Modal analysis and simulation.

We develop computational mechanical modeling and methods for the analysis and simulation of the motions of a human body. This type of work is crucial in many aspects of human life, ranging from comfort in riding, the motion of aged persons, sports performance and injuries, and many ergonomic issues. A prevailing approach for human motion studies is through lumped parameter models containing discrete masses for the parts of the human body with empirically determined spring, mass, damping coefficients. Such models have been effective to some extent; however, a much more faithful modeling method is to model the human body as it is, namely, as a continuum. We present this approach, and for comparison, we choose two digital CAD models of mannequins for a standing human body, one from the versatile software package LS-DYNA and another from open resources with some of our own adaptations. Our basic view in this paper is to regard human motion as a perturbation and vibration from an equilibrium position which is upright standing. A linear elastodynamic model is chosen for modal analysis, but a full nonlinear viscoelastoplastic extension is possible for full-body simulation. The motion and vibration of these two mannequin models is analyzed by modal analysis, where the normal vibration modes are determined. LS-DYNA is used as the supercomputing and simulation platform. Four sets of low-frequency modes are tabulated, discussed, visualized, and compared. Higher frequency modes are also selectively displayed. We have found that these modes of motion and vibration form intrinsic basic modes of biomechanical motion of the human body. This view is supported by our finding of the upright walking motion as a low-frequency mode in modal analysis. Such a "walking mode" shows the in-phase and out-of-phase movements between the legs and arms on the left and right sides of a human body, implying that this walking motion is spontaneous, likely not requiring any directives from the brain. Dynamic motions of CAD mannequins are also simulated by drop tests for comparisons and the validity of the models is discussed through Fourier frequency analysis. All computed modes of motion are collected in several sets of video animations for ease of visualization. Samples of LS-DYNA computer codes are also included for possible use by other researchers.

MODELACION NUMERICA EN DOS DIMENSIONES PARA ANALISIS DE MUROS MECANICAMENTE ESTABILIZADOS UTILIZANDO MACSTARS

For the modeling of mechanically stabilized walls, it involves performing a two-dimensional analysis through numerical methods, given the complexity of variables for their evaluation. One methodology frequently used in the field of geotechnical engineering is that of limit equilibrium, describing in the article the Macstars computer code, this allows to introduce the geometry of the wall, the main reinforcements, the type of front facing, the geomechanical properties of the different soil layers that make up the area to be evaluated, the phreatic layer, the earthquake and the way in which the voussoirs are divided according to the geometry of the slope. It becomes a complementary computational tool, in the determination of stress-strain values, where the introduction of the collected data is focused on the sequence, selection and iteration, to obtain with it, the safety factor that satisfies the conditions for the evaluation of the critical failure surface.

Position paper on high fidelity simulations for coupled processes, multi-physics and chemistry in geological disposal of nuclear waste

This opinion paper describes the major coupled T(Thermal)-H(Hydro)-M(Mechanical)-C(Chemical) processes in geological repository systems and the frontier of related model development. Particular focus is made on the analysis of existing approaches and open research questions with respect to the further development of coupled codes and models for realistic multi-scale simulations of repository systems. These include the use of machine learning and artificial intelligence in acceleration of computer codes; sensitivity analysis, inverse modelling and optimisation; software engineering and collaborative platforms for model development.

POSIT: An automated tool for detecting and characterizing diverse morphological features in raster data - Application to pockmarks, mounds, and craters

Accurate detection and characterization of seafloor morphologies are crucial for marine researchers and industries involved in underwater mapping, environmental monitoring, or resource exploration. Although their detection has relied on visual inspection of detailed bathymetries, few efforts to automate the process can be found in the literature. This study presents a novel MatLab computer code called POSIT (Feature Signature Detection) based on the convolution and correlation with a structural element containing the shape to search for. POSIT is successfully tested on both synthetic and real datasets, encompassing marine and terrestrial digital elevation models of different resolution and on a digital image. The centroids of submarine pockmarks and mounds, terrestrial volcanic craters and lunar craters are calculated with zero dispersion and perfect location, and their geometric parameters and confidence are provided.

Effects of sinusoidal wall temperature on thermal dynamics and irreversibility around an inclined plate embedded in a square cavity

Abstract Effective thermal and flow control within complex geometries is essential for engineering applications. In this study, an in-depth examination of flow dynamics, entropy, and thermal regulation is undertaken within a square cavity featuring sinusoidal wall temperature. To introduce complexity, an inclined plate obstacle is strategically positioned within the cavity with an inclination angle of 45o, and the investigation spans three distinct scenarios: adiabatic, cold, and hot conditions. The initial physical model is developed by formulating a system of partial differential equations, which are then transformed into a dimensionless representation using relevant variables. Subsequently, the Galerkin method is employed for approximated analysis of the simplified fluid flow model, and the computational code is verified in tabular format. The embedded physical parameters are constrained to specific numerical values to ensure the convergence of the physical model in each scenario. The physical characteristics of isotherms, streamlines, Nusselt numbers, entropy, and Bejan numbers are investigated. Notably, the results demonstrate that the introduction of a cold inclined plate leads to peak values in generating the entropy and average heat transfer rates. When comparing the cold inclined plate to the heated inclined plate, an increase of approximately 20% in the average heat transfer rate and a 15% rise in the entropy generation rate was found for the cold inclined plate. Furthermore, the Bejan number showed a 10% decrease for the cold inclined plate compared to the heated inclined plate. Additionally, increasing the amplitude and wavenumber led to a rise in average heat transfer and entropy generation rates, with 25% and 30% increases, respectively.

Computer-controlled electrical stimulation of facial muscles by facial neuromuscular electrical stimulation (fNMES): Hardware and software solutions

BackgroundComputer controlled electrical stimulation of facial muscles is a promising method to study facial feedback effects, though little guidance is available for new adopters. New MethodFacial Neuromuscular Electrical Stimulation (fNMES) offers a spatially and temporally precise means of manipulating facial muscles during experiments, and can be combined with EEG to study the neurological basis of facial feedback effects. Precise delivery of stimulation requires hardware and software solutions to integrate stimulators and a stimulus-presenting computer. We provide open-source hardware schematics and relevant computer code in order to achieve this integration, so as to facilitate the use of fNMES in the laboratory. ResultsHardware schematics are provided for the building of a bespoke control module, which allows researchers to finely control stimulator output whilst participants complete computer tasks. In addition, we published code that new adopters of NMES can use within their experiments to control the module and send event triggers to another computer. These hard- and software solutions were successfully used to investigate the effects of facial muscle activation on felt and perceived emotion. We summarise these findings and discuss the integration of fNMES with EEG and peripheral physiological measures. Comparison with existing methodsOur inexpensive hardware solution allows fNMES parameters to be computer controlled, and thus allows to stimulate facial muscles with high precision. This opens up new possibilities to investigate, for example, facial feedback effects. ConclusionsWe provide tools and guidance to build a control module in order to precisely deliver electrical stimulation to facial muscles using a stimulus computer (while recording EEG or other peripheral physiology).

Radiation shielding potential of cellulose acetate-CdO-ZnO polymer composites in comparison with concrete and gypsum

Radiation shielding using polymer composites is becoming more attractive because of their ease of production, lightness, ruggedness and availability. In this work, linear attenuation coefficient (LAC) and tenth value layer (TVL) of Cellulose Acetate - CdO - ZnO Polymer Composites of different concentrations of CdO and ZnO denoted as PB1, PB2 and PB3 were investigated against concrete and gypsum. Cellulose Acetate-CdO-ZnO Polymer Composites were prepared using the open mold cast technique and have been investigated for x-rays shielding ability. Cellulose acetate is a biodegradable good matrix, while CdO and ZnO are good fillers for absorbing x-rays in the diagnostic energy range. Scanning Electron Microscopy (SEM) technique was used to observe the uniform dispersal of fillers within the matrix. X-rays attenuation coefficients were calculated by XCOM computer code for all the samples using the average energies commonly used in diagnostic radiology practice - 20 keV, 30 keV, 40 keV and 60 keV. The SEM confirmed the dispersal of the fillers (CdO and ZnO) within the matrix. The result of this investigation showed that all the polymer composites (PB1, PB2 and PB3) have higher LACs and lower TVLs over gypsum and concrete at 20 keV, 30 keV, 40 keV and 60 keV. Tenth Value Layers (TVLs) of all the polymer composites is less than 1 cm at 20 keV, 30 keV and 40 keV.

Optimization of roofs with solar panels using Rao algorithms

Steel space truss roof (SSTR) systems are widely used in structures with large spans such as stadiums, sports halls, and shopping malls, as well as in industrial buildings such as factories, workshops, and production facilities. Solar panels are integrated into SSTR systems to enable these structures to generate energy and to increase the use of sustainable energy sources. With the installation of the solar panels, an additional load was placed on the roofs. However, this raises questions regarding whether existing roofs can withstand this additional weight without compromising their design. This study can be an important reference source for future truss roof designs by increasing sustainable energy use and functionally optimizing the SSTR. Another contribution of this study is that it directly contributes to real-world applications by ensuring that SSTR designs are more efficient and economical for engineering projects. For these purposes, this study presents the size optimization of the SSTR with and without solar panels using the Rao-1 and Rao-2 algorithms, which are metaheuristic algorithms known as the Rao algorithms. Thus, information can be provided regarding whether existing roofs can safely carry solar panels. To optimize the SSTR system, a computer code was created in MATLAB, which works effectively with Rao algorithms and SAP2000-s Open Applicable Programming Interface (OAPI) features and allows repetitive analysis. For size optimization of the SSTR, which consists of 1728 elements, the roof system was divided into three and six groups. Changes in the weight of the SSTR system in the different groups were investigated. The optimum design of both the three-group and six-group SSTR systems with and without solar panels was performed. Based on the results obtained from this study, it was concluded that the Rao-1 algorithm achieved more robust and stable results than the Rao-2 algorithm in both three and six-group SSTR. The SSTR system divided into six groups achieved the minimum weight compared with the SSTR system, which was divided into three groups. In this case, increasing the number of groups provided better results.

Exploring the use of zwitterionic liquids for hydrogen desorption and release from calcite rock oil reservoirs. A theoretical study

A theoretical model is presented to describe the processes of release and desorption of molecular hydrogen from the depths of calcite rock oil fields via surfactants such as zwitterionic liquids. This model is based on molecular mechanics and dynamics, for which we built a supercell with a calcite crystalline unit cell in order to model the {1,0,4} surface and volume of the calcite rock; 42 H2 molecules adsorbed and interacting strongly with the calcite surface stone were analyzed in this work; the effect of crude oil is simulated with an asphaltene macromolecule model. Finally, a branched geminal zwitterionic liquid (ZL) molecule is applied to initiate the process of hydrogen desorption and release. The aqueous medium of the oil field is simulated by the dielectric constant of water. The most stable molecules were obtained using forcite computational code. While the interaction energies were calculated by classical molecular mechanics using Dreiding force field. The dynamics of the H2 desorption and release process from calcite rock of oil well is studied using the classical molecular dynamics. The purpose of the work is to theoretically demonstrate that ZL substances are capable of releasing and desorb hydrogen from the calcite surface in the depths of oil fields. The results indicate that ZL polar groups form cation-π interactions with the asphaltene benzene rings structure, and that, the carbonated chains of the former trap the latter to release molecular hydrogen. Finally, the aqueous medium desorbs hydrogen from the calcite surface and transports it to the surface of the oil field.

Photonuclear reactions on 59Co at bremsstrahlung end-point energies of 40–130 MeV* *Supported in part by the Ministry of Science and Higher Education of the Russian Federation (075-15-2021-1360), and by the project of the National Center for Physics and Mathematics (NCPM) No. 6 ''Nuclear and Radiation Physics,'' direction 6.5.1

Relative yields were measured in the 40−130 MeV bremsstrahlung induced reactions of 59Co. The experiments were performed with the beam from the electron linear accelerator LINAC-200 using the activation and off-line γ-ray spectrometric techniques. The bremsstrahlung photon flux was calculated with the Geant4 program. The cross sections were calculated by using the computer code TALYS-1.96 with different models and were found to be in good agreement with the experimental data.