Split Model Research Articles

RELAP5/mod3.3 Analysis of Natural Circulation Cooldown with One Inactive Loop for Nuclear Power Plant Krško (NEK)

The paper presents the RELAP5/mod3.3 analysis of natural circulation cooldown with one inactive loop for Nuclear Power Plant Krško (NEK). The aim of the analysis is to determine the limiting cooldown rates during operator recovery actions to minimize the effect of flow stagnation in inactive loop. Since this is typical asymmetrical transient, the RELAP5/mod3.3 NEK model with split reactor vessel model was developed (models of the reactor vessel and core were axially divided in two parts) and used for this analysis. The several transients of cooldown, with one inactive loop, for different time after shutdown (different decay heat) were performed. The extreme conservative assumptions were applied for the analyses, i.e. the complete loss of feedwater (FW) and auxiliary feedwater (AF), including turbine driven (TD) AF pump, and the cooldown has started after the SG is completely dry (inactive). The analyses show that the cooldown rate shall be significantly reduced, and, based on the results the procedure ES-0.2 “Natural Circulation Cooldown” was modified.

A conservative particle splitting and merging technique with dynamic pattern and minimum density error

Splitting and merging technique is one of the effective refinement tools to increase the resolution in particle methods. However, it still has many challenges in stability, accuracy and conservation issues. In this research, a pair splitting technique with minimum density error, as well as with mass, momentum and energy conservations, is proposed. Instead of using a fixed splitting pattern adopted in previous researches, the splitting angle and distance in this research are dynamically obtained by achieving the total minimum density error of splitting particles and their surrounding particles. Regarding the merging algorithm, a triplet particle merging model with two small particles and one large particle is proposed to maintain angular momentum conservation. A minimum merging distance limitation is developed to ensure mass, momentum and energy conservations at the same time. A set of cases are investigated to validate the effectiveness, stability and conservation of the present splitting and merging model. The results show that the present model decreases large oscillations and avoids sudden disturb caused by irregular particle distribution due to splitting and merging.

Broadband near-infrared luminescence in erbium ion single-doped tellurite glass for optical amplification.

This Letter proposes a simple approach for the realization of a broadband near-infrared (NIR) luminescence source in erbium ion single-doped tellurite glass, which is bent on tailoring the network structure. Under the collective action of multiple broadening mechanisms and fluorescence capture, broadband fluorescence with a full width at half maximum (FWHM) of 132 nm (1500-1632 nm) was achieved. To the best of our knowledge, this is the largest FWHM reported for erbium single-doping of tellurite glass materials. Meanwhile, this fiberglass exhibits excellent thermal stability and high visible to NIR transmittance. Furthermore, a novel equivalent five-level Stark splitting model is proposed that can effectively explain the spectrum broadening. This study is beneficial for the further development of broadband optical amplification.

Increasing the Efficiency of Photocatalytic Water Splitting via Introducing Intermediate Bands.

Photocatalytic water splitting is a potential way to utilize solar energy. To be practically useful, it is important to have a high solar-to-hydrogen (STH) efficiency. In this study, we propose a conceptually new photocatalytic water splitting model based on intermediate bands (IBs). In this new model, introducing IBs within the band gap can significantly increase the STH efficiency limit (from 30.7% to 48.1% without an overpotential and from 13.4% to 36.2% with overpotentials) compared to that in conventional single-band gap photocatalytic water splitting. First-principles calculations indicate that N-doped TiO2, Bi-doped TiO2, and P-doped ZnO have suitable IBs that can be used to construct IB photocatalytic water splitting systems. The STH efficiency limits of these three doped systems are 10.0%, 12.0%, and 19.0%, respectively, while those of pristine TiO2 and ZnO without IB are only 0.9% and 1.6%, respectively. The IB photocatalytic water splitting model proposed in this study opens a new avenue for photocatalytic water splitting design.

Evaluation of instrumentation and pedicle screw design for posterior lumbar fixation: A pre-clinical in vivo/ex vivo ovine model.

Stabilization procedures of the lumbar spine are routinely performed for various conditions, such as spondylolisthesis and scoliosis. Spine surgery has become even more common, with the incidence rates increasing ~30% between 2004 and 2015. Various solutions to increase the success of lumbar stabilization procedures have been proposed, ranging from the device's geometrical configuration to bone quality enhancement via grafting and, recently, through modified drilling instrumentation. Conventional (manual) instrumentation renders the excavated bony fragments ineffective, whereas the "additive" osseodensification rotary drilling compacts the bone fragments into the osteotomy walls, creating nucleating sites for regeneration. This study aimed to compare both manual versus rotary Osseodensification (OD) instrumentation as well as two different pedicle screw thread designs in a controlled split animal model in posterior lumbar stabilization to determine the feasibility and potential advantages of each variable with respect to mechanical stability and histomorphology. A total of 164 single thread (82 per thread configuration), pedicle screws (4.5× 35 mm) were used for the study. Each animal received eight pedicles (four per thread design) screws, which were placed in the lumbar spine of 21 adult sheep. One side of the lumbar spine underwent rotary osseodensification instrumentation, while the contralateral underwent conventional, hand, instrumentation. The animals were euthanized after 6- and 24-weeks of healing, and the vertebrae were removed for biomechanical and histomorphometric analyses. Pullout strength and histologic analysis were performed on all harvested samples. The rotary instrumentation yielded statistically (p= 0.026) greater pullout strength (1060.6N ± 181) relative to hand instrumentation (769.3N ± 181) at the 24-week healing time point. Histomorphometric analysis exhibited significantly higher degrees of bone to implant contact for the rotary instrumentation only at the early healing time point (6 weeks), whereas bone area fraction occupancy was statistically higher for rotary instrumentation at both healing times. The levels of soft tissue infiltration were lower for pedicle screws placed in osteotomies prepared using OD instrumentation relative to hand instrumentation, independent of healing time. The rotary instrumentation yielded enhanced mechanical and histologic results relative to the conventional hand instrumentation in this lumbar spine stabilization model.

Comparing simulated and experimental spectral line splitting in visible spectroscopy diagnostics in the HL-2A tokamak

We established the passive-visible spectroscopy diagnostics (P-VSD) and active-VSD (A-VSD) spectral splitting models for the HL-2A tokamak. Spectral splitting due to the influence of electromagnetic fields on the spectra in VSD is studied. Zeeman splitting induced by the magnetic field ( B ) is used to distinguish reflected light overlap in the divertor for P-VSD. Stark splitting caused by the Lorentz electric field ( E Lorentz) from the neutral beam injection particle’s interaction with the magnetic field ( V beam× B ) is used to measure the safety factor q profile for A-VSD. We give a comparison and error analysis by fitting the experimental spectra with the simulation results. The distinguishing of edge (scrape-off layer and divertor) hydrogen/deuterium spectral lines and the q profile derived from the spectra provides a reference for HL-2M VSD.

Logical Mechanism and Practical Exploration of Integrating Divided Classroom Education Model into Physical Education Teaching in Colleges and Universities

With the change of times, the reform of higher education continues to develop in depth, and the importance of physical education courses in colleges and universities is also increasing. The reform of physical education teaching is also being carried out in full swing in various colleges and universities. Many new teaching methods have been applied to college physical education, and the classroom teaching model is an inevitable development trend of higher education reform. This paper uses research methods of literature and logical analysis to elaborate on the split classroom education model, analyzes the logical mechanism of the split classroom education model in college physical education classes, explores the practical application of the split classroom education model in college physical education classes, and proposes corresponding strategies, hoping to help college physical education teachers apply the split classroom teaching method more scientifically and reasonably to college physical education classes, Improve the teaching effect of college physical education, and promote the cultivation of students' comprehensive quality on this basis.

Synthesis, crystal structure and thermal properties of tetra-kis-(3-methyl-pyridine-κN)bis-(thio-cyanato-κN)nickel(II).

Reaction of Ni(NCS)2 with 3-methyl-pyridine in water leads to the formation of crystals of the title compound, [Ni(NCS)2(C6H7N)4]. All of them are of poor quality and non-merohedrally twinned but a refinement using data in HKLF-5 format leads to a reasonable structure model and reliability factors. The crystal structure of the title compound consists of discrete complexes, in which the nickel cations are sixfold coordinated by two terminal N-bonded thio-cyanate anions and four 3-methyl-pyridine ligands within slightly distorted octa-hedra. One of the 3-methyl-pyridine ligands is disordered and was refined using a split model. The discrete complexes are arranged into layers. X-ray powder diffraction proves that pure samples have been obtained, and in the IR spectrum, the CN stretching vibration is observed at 2072 cm-1, in agreement with the presence of only terminally coordinated thio-cyanate anions. Comparing the calculated powder pattern with those of the residues obtained by solvent removal from several solvates already reported in the literature proves that, in each case, this crystalline phase is formed. Assessing the crystal structures of the solvates in comparison with that of the ansolvate reveals some similarities.

A PRODUCTION SPLITTING MODEL OF HETEROGENEOUS MULTI-LAYERED RESERVOIRS WITH COMMINGLED PRODUCTION

Production splitting is the basis for a proper understanding of the development effect of reservoirs when multiple layers are commingled to produce, and it is a difficult part of the development evaluation of this type of reservoir. Reservoirs with multiple layers are usually developed through commingled production. However, due to interlayer interference, the total output of commingled production is lower than the sum of individual production of each subordinate layer. It's significant to clarify the interlayer interference mechanism during layers with commingled production, establish an accurate splitting model of the production from subordinate layers, split the commingled production into each subordinate layer, and effectively understand the production level and remaining potential of the subordinate layers during commingled production. It is expected to develop a theoretical basis for the rational and effective development of multi-layered commingled production reservoirs. In this paper, a combination of multi-tube parallel displacement experiments and numerical simulations of a multi-layered reservoir with commingled production is used to analyze the influence of factors such as permeability ratio, production pressure difference, and crude oil viscosity on the interlayer interference mechanism. According to the research results, the interference coefficient is firstly introduced on the basis of the theoretical production formula of seepage flow. The change rate of the oil production splitting coefficient at the stage when the water cut is more than 80% is also proposed, and the production splitting model of subordinate layers in heterogeneous reservoirs is established, considering multiple factors. Taking multi-layered Reservoir A with commingled production as an example, this model is used to split the production of commingled wells. Results show that interlayer interference can be reduced by decreasing the permeability ratio and high permeability laminar fluidity, and increasing the production pressure difference. When the water content is greater than 80%, the oil production segmentation coefficient of the layers with high permeability decreases sharply with the increase of the water content. For the low-permeable layer, the situation is just the opposite. At the same time, based on the study of the interlayer interference mechanism coupled with the oil well radial flow production formula, the interference coefficient and the oil production segmentation coefficient change ratio are introduced. The findings of this study can help develop a more accurate model for production of subordinate layers in heterogeneous multi-layered reservoirs. The established splitting model is carried out using the data from two wells and four subordinate layers in Reservoir A, indicating that the accuracy of the proposed model is close to 90%.

Unveiling the reconstructed active phase of Ni3Se2model for water splitting

The dynamical evolution of Ni3Se2was studied with real active sites for oxygen evolution and hydrogen evolution reactions in alkali media.

Optimization of emergency supplies paths based on dynamic real-time split deliver

A multi-objective dynamic demand split delivery emergency material distribution model is developed to enhance the efficiency of emergency material distribution and facilitate the smooth progress of safety rescue operations during unconventional emergencies. This model incorporates the psychological view of those affected by disasters. The issue of dynamic demand may be transformed into a static demand problem by dividing the distribution time window into time domains of equal length. The optimization process is thereafter executed in real-time with the timed batch methodology. A refined ant colony method has been developed to address the model by integrating the attributes of the mathematical model, followed by doing an arithmetic case analysis. The findings indicate that the algorithm and mathematical model suggested in this study are efficacious in addressing the emergency material distribution issue, offering valuable decision-making advice and reference.

Microbiota fúngica do ar ambiente em uma unidade de terapia intensiva em Rio Branco, Acre, Amazônia Ocidental, Brasil

Abstract Fungi exhibit three adverse effects on human health: inflammatory, allergic and toxic effects, these implications affect mainly immunodepressed patients. The objective of this work was to analyze the fungal microbiota of the ambient air of an Intensive Care Unit. Three collections were carried out in an Intensive Care Unit in the city of Rio Branco, Acre, Western Amazon, Brazil from March to May 2017. 126 Petri dishes were exposed with the culture medium Agar Sabouraud with chloramphenicol and Agar Mycosel, considering the distribution of the 21 air conditioners, split residential model. The plates were incubated for seven days at room temperature and the growth of Colony Forming Units was observed. Colony counting and isolation for the morphological characterization of the granted fungi was performed. After quantification, the concentration of fungi per cubic meters of air (CFU.m-3) was settled. The third collection had a larger number of colony forming units with 48.6%. In the total of the analyzed samples, filamentous fungi (85.5%) and yeasts (14.5%) were isolated. Thirteen genera of fungi were identified, with the most frequent filaments being Cladosporium spp. 33.0%, Aspergillus spp. 30.4% and Penicillium spp. 19.6%, and yeasts Candida spp. 52.6%, Trichosporon spp. 36.9%. The colony-forming unit per cubic meter (CFU.m-3) did not shown any difference between the Cores in the same collection period, however in the 1st and 3rd collection, Core 1 had the highest average. The fungal microbiota of this Unit presented thirteen different genera potentially pathogenic, revealing the need for monitoring microorganisms and prevention actions.

Split modeling approach to non-cooperative strategic games

Split modeling approach to non-cooperative strategic games

Топологічні аспекти моделювання паралельних обчислень при розв’язанні динамічних задач на базі інтерфейсу передачі повідомлень

The article deals with the development, substantiation and research of analytical models of data transmission when solving complex multidimensional dynamic problems. Models of interprocessor exchange are obtained for computing systems with distributed memory and topological architectures: ring, 2D-torus, hypercube, etc. The application of double arithmetic based on the GMP-library and its effect on the temporal characteristics of parallel applications are considered. The dependence of the parallelism characteristics of numerical algorithms when using the streaming SIMD-extension is analyzed. The modern stage of development of computer and information technologies has one of its directions - the use of the idea of parallelism in order to reduce the time of solving multidimensional problems that have a high temporal complexity or are even NP-complete. Despite the significant increase in the productivity of existing parallel systems, reducing the cost of components for their construction, development and implementation of parallel methods remains the most difficult problem due to the lack of study of the internal structure of algorithms and their properties. Thus, the introduction of parallel computing requires not so much the mastering of parallel data processing as the development of parallel algorithms based on the parallelization of sequential ones or the construction of fundamentally new, more efficient parallel methods. That is why the analysis of existing parallel algorithms, studying the possibilities of improving their characteristics is an important, promising and practically demanded task. The purpose of the work is to increase the efficiency of solving complex multidimensional dynamic problems implemented on parallel architectures of distributed memory using the message passing interface (MPI) due to the reduction of communication time. Tasks of the work: firstly, it is the development of analytical models of multiple data transfer operations for different topologies of connection of processors, substantiation of the models and research of the quality of parallel calculations of various classes of numerical methods for cluster systems. The possibility and effectiveness of using double arithmetic (GMP-library) and its influence on the temporal characteristics of parallel implementation are separately investigated. Additionally, the paper analyzes the dependence of the parallelism characteristics of the methods on the use of Streaming SIMD-Extension (SSE). The scientific novelty of the field lies in the development and development of analytical models for processes of interprocessor exchange given by cluster systems, which allow to increase the efficiency of parallel implementations of numerical methods in rich dynamic tasks for a short period of time on a communication warehouse. The practical significance of the field is in the development of split models for the analysis of the efficiency of collective operations of multiple data transfer within the MPI interface, which is the current standard for software implementation of robots with shared memory. Possibility of arranging floating arithmetic based on the GMP library was added, which is especially important for the development of folding problems of dynamic problems with singularities.

Ratification of the ISDS Provisions in CETA – Current Court and Legislative Challenges – an Overview

This article considers the recent rejection of challenges to the ratification of the Comprehensive Economic Trade Agreement with Canada (CETA), by both the German Constitutional Court in March 2022, the Irish High Court and the Irish Supreme Court decision in November 2022, and the likely future path towards ratification. It considers the background to these court challenges, including the request from the Kingdom of Belgium to the Court of Justice of the EU (CJEU) on the compatibility of the ISDS provisions of CETA with EU law, the underlying themes in the German and Irish court challenges, and the position on ratification across other countries in the EU. It concludes that the path to ratification is unclear and that the EU may be forced in the future to adopt a split model to any Free Trade Agreement with Canada.

Development and comparison of local solar split models on the example of Central Europe

Solar radiation influences many and diverse fields like energy generation, agriculture and building operation. Hence, simulation models in these fields often rely on precise information about solar radiation. Measurements are often restricted to global irradiance, whereby measurements of its single components, direct and diffuse irradiance, are sparse. However, information on both, the direct and diffuse irradiance, is necessary for simulation models to work reliably. In this study, solar separation models are developed using 10-min training data from two different locations in Austria. Direct horizontal irradiance is predicted via regressing the direct fraction using several objective functions. The models are first trained on a data set including data from both locations, and evaluated regarding root mean squared deviation (RMSD), mean bias deviation (MBD), and coefficient of determination (R2) on measured and estimated direct normal irradiance. The two best performing models are then selected for further analysis. This analysis comprises of an evaluation of the models per season, transferability of trained modes between two locations in Austria, a transferability and generalisability study conducted for four more locations in Central Europe, and a comparison with the trusted Engerer model. The solar separation model with polynomial terms up to order three and Ridge regularisation outperforms the second model based a logistic term in combination with mixed quadratic terms as well as the Engerer model.

Load Distribution and Dynamic Response in Torque Split Applications

This study consists of constructing and analyzing gear mathematical models of torque split systems for contact pressure distribution and dynamic transmission error at different gear positions concerning phase angles. According to the method specified in the AGMA 927 standard, load distribution is calculated by considering shaft torsion and bending deformations. Partial contact loss may occur as a result of shaft bending with asymmetric gear positioning on a long shaft. The contact separation can be decreased by reaction force balancing if the driven gears are in the opposite position with respect to the drive gear. In the calculation of the dynamic transmission error of the torque split model, a parametric phase difference for the gear positions is proposed using gear geometry parameters. The variation of the dynamic response according to the change in the parametric phase angle in the torque split system is analyzed for the same values of each gear. Small changes in the phase values change the system response significantly. To obtain lower dynamic transmission error amplitude, the phase difference and gear positions are examined. The contact pressure distribution is validated by the finite element method, and the dynamic transmission error is compared with the experimental study in the literature.

Comprehensive US database and model for ethanol blend effects on air toxics, particle number, and black carbon tailpipe emissions

Light-duty vehicles produce exhaust air toxic species in addition to regulated pollutants. Although numerous studies have evaluated the impacts of fuel composition on air toxics, there has been no comprehensive modeling study that considered data from all available sources. To examine the effects of real-world fuel composition on air toxics, black carbon (BC), and particle number (PN) emissions, we conducted a thorough evaluation of US emission studies, pooled data from the Federal Test Procedure (FTP) and Unified Cycle (LA92) driving schedules, and developed models based on fuel and vehicle properties. To address nonlinear blend property responses to ethanol concentration, we built separate linear models (split models) for low (up to 10% ethanol by volume) and mid blends. We then estimated differences in emissions from expected market fuel compositions. We observed differences between the operation of port fuel injection (PFI) and gasoline direct injection (GDI) engines and between test cycles and phases. Results showed that aromatics raised 1,3-butadiene, benzene, toluene, ethylbenzene, and xylene emissions, while ethanol raised acetaldehyde and lowered 1,3-butadiene. Ethanol raises octane number and enables reduction of reformate (and hence aromatics) in a blend. For aldehydes, 1,3-butadiene, and BC the effects differed between PFI and GDI vehicles. For ethanol and acetaldehyde production by PFI and for BTEX, BC, and PN from GDI vehicles, there were differences between comprehensive (i.e., single linear fit) and split models, confirming nonlinearity of the actual ethanol relationships and supporting use of separate models for ethanol blends above and below 10%. To the extent that PFI and GDI models differ, emissions inventory calculations should treat them separately. Estimated market fuel blend compositions for summer regular gasoline yielded quantitative projections of ethanol blend levels on air toxics, BC, and PN emissions. Projections were consistent for all projected fuel grades (summer regular, winter regular, and premium). • Thorough evaluation of US toxic species, BC, and PN emission studies. • Produced and tested emission models based on engine types and fuel compositions. • Different blending behavior of ethanol below and above E10. • Different market fuel effects between PFI and GDI vehicles. • Aromatics raised BTEX while ethanol raised acetaldehyde and lowered 1,3-butadiene.

Fracture modeling by the eigenfracture approach for the implicit material point method framework

AbstractThe material point method (MPM) is efficiently applied for the simulation of structures undergoing large deformations where fracture and crack initiation are expected. The eigenfracture approach is introduced in the paper at hand for the implicit MPM to model crack development and propagation in static and dynamic fracture of brittle elastic materials. Eigenfracture is an energetic fracture formulation applied in the postprocessing step of the implicit MPM, making its implementation relatively straightforward. Furthermore, the driving energy used to check crack propagation is evaluated using the representative crack elements (RCE), by which the crack is modeled as a discrete phenomenon. The RCE approach shows more realistic results compared to other split models. Additionally, the fracture description of reinforced materials within the MPM is also presented in this article by coupling truss finite elements to the MPM, considering the bond stress‐slip constitutive model. Two‐ and three‐dimensional problems in static and dynamic applications are presented to assess the efficacy of the approach.

ObfusX: Routing obfuscation with explanatory analysis of a machine learning attack

This is the first work that incorporates recent advancements in “explainability” of machine learning (ML) to build a routing obfuscator called ObfusX. We adopt a recent metric—the SHAP value—which explains to what extent each layout feature can reveal each unknown connection for a recent ML-based split manufacturing attack model. The unique benefits of SHAP-based analysis include the ability to identify the best candidates for obfuscation, together with the dominant layout features which make them vulnerable. As a result, ObfusX can achieve better hit rate (97% lower) while perturbing significantly fewer nets when obfuscating using a via perturbation scheme, compared to prior work. When imposing the same wirelength limit using a wire lifting scheme, ObfusX performs significantly better in performance metrics (e.g., 2.2 times more reduction on average in percentage of netlist recovery).