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High-pressure membrane dehumidification is of interest for aircraft environmental control system (ECS) applications. Typically, membrane dehumidifier (MD) modules are characterized by manufacturers over a range of mass flow rates, temperatures, and pressures at saturation conditions. However, to evaluate the suitability of high-pressure membrane dehumidification for aircraft applications, the performance must be characterized over the broader range of psychrometric conditions that could be encountered. Moreover, the practical integration of an MD into an environmental control system necessitates reconsideration of the traditional product sweep approach, where some of the dry air produced is removed and supplied to the other side of the membrane to enhance mass transfer. In an environmental control system, using product sweep would require excessive bleed air from the engine and cause unbalanced flow in the turbomachinery. To avoid this, alternate sources of sweep must be considered, and their effects on dehumidification must be evaluated. This work conducts an experimental investigation of an MD module using product sweep under a range of psychrometric conditions, then compares product and humid sweep modes to understand the effects of sweep conditions on dehumidification performance. Concurrently, a numerical model of an MD is implemented and validated--first against the module specification sheet, then against the empirical results that represent moderate altitude aircraft conditions. Ultimately, the feasibility of a hot and humid sweep source to maintain sufficient dehumidification performance under realistic altitude conditions is demonstrated. [ABSTRACT FROM AUTHOR]

A numerical method using advanced nonlinear shear is used to study the thermal vibration of functionally graded material (FGM) thick circular cylindrical shells. The third-order shear deformation theory (TSDT) of displacements is applied and the equations are derived of the motion of cylindrical shells and the expression of the advanced nonlinear varied shear factor. The expressions of stiffness of thick composited two-layer FGM circular cylindrical shells with sinusoidal rising temperature are applied. The partial differential equation (PDE) in dynamic equilibrium of thick FGM circular cylindrical shells is derived with respect to shear rotations and displacements under terms of thermal–mechanical loads and density inertia terms. Important parametric effects of the advanced nonlinear varied shear factor, power law index, and temperature on the stress and displacement of thick FGM circular cylindrical shells are studied. Additionally, the advanced nonlinear varied shear factor effect is included and studied for a vibrating frequency using a fully homogeneous equation. [ABSTRACT FROM AUTHOR]

In this research, a numerical model for simulating dam break floods was developed utilizing ArcGIS 10.8, 3ds Max 2021, and Flow-3D v11.2 software, with the aim of accurately representing the dam break disaster at Tianchi Lake in Changbai Mountain. The study involved the construction of a Triangulated Irregular Network (TIN) terrain surface and the application of 3ds Max 2021 to enhance the precision of the three-dimensional terrain data, thereby optimizing the depiction of the region's topography. The finite volume method, along with multi-block grid technology, was employed to model the dam break scenario at Tianchi Lake. To evaluate the severity of the dam break disaster, the research integrated land use classifications within the study area with the simulated flood depths resulting from the dam break, applying the natural breaks method for hazard level classification. The findings indicated that the computational fluid dynamics (CFD) numerical model developed in this study significantly enhanced both the efficiency and accuracy of the simulations. Furthermore, the disaster assessment methodology that incorporated land use types facilitated the generation of inundation maps and disaster zoning maps across two scenarios, thereby effectively assessing the impacts of the disaster under varying conditions. [ABSTRACT FROM AUTHOR]

Due to the variety of engines in volume, number of cylinders and power, turbochargers on the market are often generally made for a specific range of engine power. This research shows one of the ways to improve the performance of a turbocharger with a wide range of performance in a specific engine. In this article, by changing the inlet angle of the turbocharger turbine blade compared to the turbine blade inlet angle of a selected turbocharger and three-dimensional flow simulation inside it, the goal is to improve turbine performance. A real model of a turbocharger turbine, including a volute and blades, has been photographed by precise devices and an image has been prepared in the form of a cloud of points. This image is modified by the software and a three-dimensional model is prepared from it and edited in different software environments, and finally the three-dimensional flow inside the turbine is simulated. For validation, the engine and turbocharger assembly placed on the test bench and the performance parameters of the turbocharger turbine has been measured at different engine speeds and compared with the simulation results. The results showed that changing the inlet blade angle of the turbine to the value of 4.7° compared to the initial entry angle of the blade in all engine speeds leads to the optimization of the values of the performance parameters of the turbine. This angle change, improves the pressure ratio of the turbine by about 11% and the efficiency and power by about 18%. At high speeds, due to the surge phenomenon in compressor, this pressure ratio may not be practical, but at low speeds, when the energy of exhaust gases from the engine is not enough for good turbine operation, this increase in power can be very beneficial. [ABSTRACT FROM AUTHOR]

Chloride transport is one of the most serious problems facing reinforced concrete structures, and coatings can effectively block the intrusion of chloride ions. In order to evaluate the resistance of coatings to chloride ion erosion more quickly and accurately, based on the transport mechanism of chloride and water in coated concrete, a two-dimensional mesoscale model of concrete containing coating, aggregate, and matrix was established in this paper. In response to the transport mechanism of chloride ions in coated concrete, a coupled convection–diffusion numerical model considering the binding effect of chloride, temperature effect, and hydration effect is established. The idealized service life conditions of the coating are introduced, and the influence of coating type, coating thickness, and coating service life on the distribution of erosive agents inside the coated concrete is analyzed. After analysis and research, it is recommended that coating concrete exposed to 3.5% NaCl erosion use a film-forming coating with an expected life of more than 10 years and a coating thickness of at least 1.5 mm, preferably chlorinated polyvinyl chloride (CPVC) and chlorinated polyethylene (CPE) coatings. [ABSTRACT FROM AUTHOR]

This paper presents over-current protective relays for electric distribution systems. The objective is to determine the reliability of the system by comparing the performance of numerical and electromechanical relays. Electromechanical over-current protective relay on 33kV Itire-Ijesha distribution feeder was analyzed and modeled using MATLAB/Simulink. A numerical relay was proposed and also modeled using the real data of the existing Itire-Ijesha 33kV distribution feeder. While electromechanical relay was simulated as an instantaneous relay, the numerical relay was programmed and simulated as an IEEE moderately inverse definite minimum time (IDMT) relay. The simulation was for single line-to-ground fault with the red phase, double line-to-ground fault using red and blue phase as well as line-to-line fault using red and blue phase. Comparing the performances of the two different models, numerical relay tripped in mini-seconds while the electromechanical relay model tripped in seconds. In conclusion, therefore, the numerical relay proved to be superior, smarter, and more reliable than electromechanical relays. [ABSTRACT FROM AUTHOR]

The high penetration of voltage-source converter (VSC) based resources poses stability challenges to modern power systems due to introducing new dynamics with broad time-scale and frequency-coupling. The so-called impedance-based modeling (IBM) is widely used for the dynamic characterization and stability analysis of grid-connected VSCs. In this article, it is first shown that using IBM, the analytical aggregation of interconnected VSC-based systems results in very high-order transfer matrices, which are not conducive to stability analysis. As an alternative, a numerical recursive aggregation technique is proposed for interconnected VSC-based power systems. Using the proposed method, the individual multi-input multi-output transfer matrices of the IBM of VSCs can be readily used for aggregation across a range of discrete frequencies. Moreover, an algorithm is proposed to automate the aggregation of multiconverter-based systems. The proposed technique is illustrated on a VSC-based power system with multiple converters considering the interconnecting line impedances. The time-domain simulations and frequency analysis verify the accuracy and effectiveness of the proposed method, demonstrating that it is over 990 times computationally more efficient than the small-signal injection method for calculating the aggregated load admittance while also offering almost 80 times higher frequency resolution.

Abstract This study presents a simplified numerical modeling approach that estimates the local scour depths around bridge supports based on the bed shear stresses. It is developed using 3D computational fluid dynamics and coding through ANSYS workbench scripting along with C++ language. The proposed model is called SCFDS (Simplified Computational Fluid Dynamics Scour). The model’s main idea is to lower the bed bathymetry at the locations affected by flow obstruction until the shear stresses reach stable target values. The developed model is assessed by applying it to a complex pier of a real bridge over the Nile-River, and its scour data is calculated using the Hec-18 empirical equations. The outcomes of the model’s assessment show that it can depict the local scour around complex bridge supports. The developed approach is a novel and efficient tool that can help the designers in simulating local scour in the vicinity of flow obstructions. However, more verification studies are necessary to reach a generalized conclusion.

The dynamic of the heat transfer analysis constitutes an important factor that has drawn the attention of many researchers. Heat transfer is evaluated by considering the heat transfer coefficient, the surface area, and the temperature difference between the surface and the surrounding fluid. The computation of the temperature difference across various surface areas shows that increased heat transfer enhances the proportion of the heat conduction rate. In most cases, the system becomes unstable because inappropriate structural elements and outside disturbances, like ambient temperature can readily change the yielding temperature. As a result, the heat exchanger's efficiency needs improvement. A numerical simulation analyzing the performance of a shell and tube heat exchanger indicates that an increase in the surface area leads to a corresponding increase in the heat transfer rate. To optimize system performance, mathematical models were employed for the stability analysis of temperature changes. MATLAB simulations computed temperature differences in quantities of heat and area, thereby obtaining valuable insights for improving heat exchanger design and operation.

This study investigated the effects of magnetic field on pressure drop and heat transfer enhancement of nanofluid in a pipe containing porous medium by a 2D simulation. The study involves modeling the flow of nanofluid as a single-phase flow and simulating fluid flow through the porous medium using the Darcy–Brinkman–Forchheimer equation. A constant uniform heat flux around the pipe is used as the thermal boundary condition. The simulations evaluate the effect of several parameters, such as Reynolds number, porosity, thermal conductivity of the porous medium, and nanofluid material. The findings show that utilizing a magnetic field increases heat transfer in nanofluid. Based on the simulations, both pressure drop and heat transfer rates increase with increasing Reynolds number. The rate of heat transfer increases as the thermal conductivity of porous medium increases, and among the selected materials, Ag has the greatest impact on heat transfer, followed by copper, gold, aluminum, and steel. By comparison of metallic ( Al , Cu ) and metallic oxide ( Si O 2 , Ti O 2 , CuO ) nanoparticles it is observed that using Al provides the highest heat transfer. Moreover, increasing porosity (0.8–0.98) decreases heat transfer coefficient. The performance evaluation criteria (PEC) are also examined as a determinant term to select the desirable condition. (The aluminum water nanofluid that is subjected to a magnetic field and moves through a silver-porous medium with a porosity of 0.9 has the highest PEC.) [ABSTRACT FROM AUTHOR]

This study presents a simplified numerical modeling approach that estimates the local scour depths around bridge supports based on the bed shear stresses. It is developed using 3D computational fluid dynamics and coding through ANSYS workbench scripting along with C++ language. The proposed model is called SCFDS (Simplified Computational Fluid Dynamics Scour). The model's main idea is to lower the bed bathymetry at the locations affected by flow obstruction until the shear stresses reach stable target values. The developed model is assessed by applying it to a complex pier of a real bridge over the Nile-River, and its scour data is calculated using the Hec-18 empirical equations. The outcomes of the model's assessment show that it can depict the local scour around complex bridge supports. The developed approach is a novel and efficient tool that can help the designers in simulating local scour in the vicinity of flow obstructions. However, more verification studies are necessary to reach a generalized conclusion. [ABSTRACT FROM AUTHOR]

With advancements in gravitational wave detection technology, an increasing number of binary neutron star (BNS) merger events are expected to be detected. Due to the narrow opening angle of jet cores, many BNS merger events occur off-axis, resulting in numerous gamma-ray bursts (GRBs) going undetected. Models suggest that kilonovae, which can be observed off-axis, offer more opportunities to be detected in the optical/near-infrared band as electromagnetic counterparts of BNS merger events. In this study, we calculate kilonova emission using a three-dimensional semi-analytical code and model the GRB afterglow emission with the open-source Python package afterglowpy at various inclination angles. Our results show that it is possible to identify the kilonova signal from the observed color evolution of BNS merger events. We also deduce the optimal observing window for SVOM/VT and JWST/NIRCam, which depends on the viewing angle, jet opening angle, and circumburst density. These parameters can be cross-checked with the multi-band afterglow fitting. We suggest that kilonovae are more likely to be identified at larger inclination angles, which can also help determine whether the observed signals without accompanying GRBs originate from BNS mergers. [ABSTRACT FROM AUTHOR]

The need for faster communication in today's world has led to the need for antennas with high bandwidth and gain. A novel THz MIMO antenna based on metamaterial is presented in this manuscript for high-speed communication applications with broad bandwidth and high gain. The THz MIMO metamaterial antenna is designed using a C-shaped metamaterial resonator. The metamaterial antenna is also compared with a simple square patch MIMO antenna design for different antenna parameters like gain, reflection, and transmission coefficients. The metamaterial MIMO antenna gives a higher bandwidth of around 1.95 THz, three operating bands and a maximum isolation of about 80 dB. The maximum gain of the metamaterial MIMO design is 20.4 dB. The metamaterial MIMO antenna is also optimized for its geometrical parameters like slot length, slot width, substrate thickness and ground layer thickness. The optimized value of slot length, slot width, substrate and ground layer thicknesses are obtained as 10 µm, 10 µm, 1.5 µm and 1 µm, respectively. The MIMO parameters like ECC, DG, MEG, CCL and TARC are analyzed. All these parameter values fall within the standard requirement for MIMO antennas. The designed metamaterial MIMO antenna can be a good pick for 6G/TWPAN communication devices. [ABSTRACT FROM AUTHOR]

Numerical simulations are essential for predicting the mechanical properties of different structures like gyroids that center this study. Three different methods are explored: shell elements, solid elements, and homogenization. Results reveal that homogenization is only suitable for obtaining the properties in the elastic zone, whereas solid models can determine also the behaviors in the plateau zone and the densification point. In the case of shell elements model, it can predict the elastic behavior model and the levels of stress in the plateau zone but with a lower accuracy than the solid element, but it cannot predict the densification point. [ABSTRACT FROM AUTHOR]

Thermosyphons are passive heat exchanger devices that use the latent heat of vaporization of a working fluid to intensify heat transfer. They consist of a metallic tube, passed through a vacuum process, and filled with a working fluid, and use the action of gravity to circulate the fluid internally. They are used to enhance heat transfer in many industrial areas, such as aerospace, electronics, and telecommunications, among others. In the literature, several studies are related to the subject under study, both experimental and numerical analyses. Still, there is not validation of the results, especially when obtaining the boiling heat transfer coefficient. Thus, the main objective of the present work consists of determining an experimental test bench, from Dirichlet's Condition, varying an evaporator wall temperature (303.15 K, 313.15 K, and 323.15 K) and water filling ratio (50% and 100% of the evaporator's volume) into stainless-steel thermosyphon, providing experimental data for validation of numerical simulations carried out using the ANSYS® FLUENTTM software. The comparison between numerical and experimental results demonstrated good agreement validating the numerical methodology. [ABSTRACT FROM AUTHOR]

Technological advancements necessitate efficient electronic heat management, driving the need for effective cooling solutions. This study investigates the application of MXene-based nanofluids across varying concentrations in microchannel heat sinks to enhance electronic cooling performance. Utilizing numerical simulations, we analyze nanofluid concentrations, flow dynamics, and performance evaluation criteria (PEC) using an Eulerian model to characterize the inhomogeneous flow properties. Concentrations ranging from 0.01 to 0.04 vol% are incrementally examined, with validation against experimental data to ensure accuracy. Key findings reveal that at a Reynolds number (Re) of 300, a 0.04 vol% nanofluid fraction yields a 20.1% reduction in thermal resistance compared to pure water. Moreover, at Re 1000, the heat transfer coefficient improves by 29.4% compared to the 0.04 vol% concentration. These results underscore the potential of MXene nanoflakes as adequate heat sink working fluids for electronics cooling. Applications of this research extend to various electronic devices and systems requiring efficient cooling mechanisms. By leveraging MXene nanofluids, manufacturers can enhance thermal management in microelectronic components, such as integrated circuits, LEDs, and power electronics. Additionally, this study's insights can inform the design and optimization of cooling systems in high-performance computing, automotive electronics, and aerospace applications, where heat dissipation is critical for maintaining device reliability and performance. [ABSTRACT FROM AUTHOR]

Beach erosion and coastal protection are complex and interconnected phenomena that have a substantial impact on coastal environments worldwide. Among the various coastal protection measures, seawalls have been widely implemented to mitigate erosion and protect coastal assets. However, the interrelationship between beach erosion and seawalls remains a critical topic for investigation to ensure effective and sustainable coastal management strategies. Seawalls impact the shoreline, particularly through the "end effect", where the seawall functions similarly to a groin, causing erosion on the downdrift side relative to the direction of wave approach. This study provides a detailed analysis of the interplay between beach erosion and seawall structures in Loc An, Vietnam, employing both remote sensing and numerical approaches. Sentinel-2 images were employed together with an analytical solution to observe the shoreline change at the Loc An sand spit and to determine input values for the numerical model. Based on the shoreline dynamics, a numerical scheme was employed to study the shoreline evolution after the construction of a seawall. Our findings show that the shoreline evolution can be divided into three stages: (1) The first stage corresponds to the elongation of the sand spit without interference from coastal structures. (2) The second stage shows the effect of jetties on the shoreline, as signaled by the buildup of sand updrift of the jetties. (3) The third stage shows the effectiveness of the seawall, where the shoreline reaches its equilibrium condition. The study provides a quick and simple method for estimating shoreline diffusivity (ε) in situations where measured data is scarce. [ABSTRACT FROM AUTHOR]

Simulation is one of the most widely used methods for process optimization towards improved part quality in Additive Manufacturing (AM), particularly for metal parts. However, due to the nature of the AM processes and the complex phenomena that occur, simulations that are capable of providing a detailed overview of the physical mechanisms demand considerable computational resources and time. In this study, a numerical approach is presented, which can be applied to any implicit numerical thermal simulation for AM, allowing for a significant decrease in computational time (higher than 70%) with minimal impact on accuracy. This is achieved by combining space partitioning, enabled by a boundary condition that was developed, with dynamic mesh adaptation in the x-, y-, and z-axis. The methodology is described in detail and both the decrease in computational time and the accuracy of the developed approach are validated in a computational case study, as well as using experimental results.

The extensive modification in different land operations fueled by rapid urbanization is a matter of great concern. It is not just a simple process of exchange within different classes as we think; moreover, it is one of the most responsible factors for the change in biological rotations of the natural system. India, one of the fastest-urbanizing nations, is expected to be the home of the most urban residents by 2050, likely resulting in various undesirable issues in emerging and existing cities. The review highlights the apprehensive sides of sprawl and land use/land cover (LULC) changes in the Indian context. It also aims to assist the researchers in exploring the scope and relevance of sprawl measurement techniques for emerging urban settlements through the collected literature. A multi-stage sampling method is used to scrutinize the secondary source-based information regarding the research work. In total, 58 studies of recognized journals have been appraised systematically from 1981 to 2022. The findings reveal that increasing accidental growth caused by rapid urbanization is the leading cause of the change in LULC and irreparable environmental loss. 77.58 percent of studies have reported that geospatial technology, models, and numerical methods are more relevant to urban planners and officials for sprawl measurement and LULC change detection. So, the administration should address the accidental urban growth in its initial phase with a priority for sustainable urbanization.

AbstractOptimizing the efficiency of metal powder production through brush atomization necessitates a comprehensive understanding of the interaction between the brush bristles and the molten metal, as well as its consequential effects on the fragmentation of the melt. Thus this study presents Computational Fluid Dynamics (CFD) models of the brush-melt interplay during the atomization of molten metals. The volume-of-fluid method was used to examine the various stages of melt fragmentation, from when the melt is discharged to when it settles on the brush bristles. The results revealed that the first breakup occurred close to the discharge orifice due to aerodynamic instability and fell within 13 < [Formula: see text]< 40.3. The nature of this breakup depends on the brush speed, bristle length, bristle diameter, brush density, and melt properties. A second breakup was observed when the melt contacted the rotating bristles. The melt bridges formed between two or more bristles due to attractive forces between the closely packed bristles induced by the capillary force of the melt and the surface tension of the meniscus surface are also overcome due to brush rotation. These results are in agreement with the experimental observations and are therefore sufficient for demonstrating the system.

Music education is a realm of study concerned with the teaching and learning of music. This music education will develop affective, motor skills in students who play instruments and expand cognitive development through reasoning and interpretation of musical notation. However, many people still underestimate music education. In the education and teaching system of music arts, especially in the last years of the 20th century, new methods emerged. One of the methods that will be discussed is the Tonika-Do Method. This article is a type of literature study and uses the exposition method in presenting the concepts contained in previous studies. The sources used contain the results of discussions about art education, music, and music education. The application of fixed "do" is not carried out as it should be from the meaning of fixed "do" itself. The reading system used in this lesson is not an fixed "do", but a system taken from the basic idea of an fixed "do" system, where 'Do' is not understood as a C, D, E note or something else, but is more understood as a number 1, which is the tone of writing in numerical notation. This fixed “do” reading system is carried out with the aim of avoiding moving 1 ('do') which is generally found in how to read numerical notation, which of course tends to make it difficult for students in a notation recognition. The learning process can include practicing the C scale, followed by the chromatic scale, etude, then entering the song.

This study aimed to investigate the nonlinear structural behavior of concrete deep beams internally reinforced with glass fiber-reinforced polymer (GFRP) reinforcing bars and containing a web opening of various sizes and locations within the shear span. Three-dimensional (3D) numerical simulation models were developed for large-scale GFRP-reinforced concrete deep beams (300 mm × 1200 mm × 5000 mm) with a shear span-to-depth ratio (a/h) of 1.04. Predictions of the numerical models were validated against published experimental data. A parametric study was conducted to examine the effect of varying the opening size and location on the shear response. Results of the numerical analysis indicated that the strength of the deep beam models with an opening in the middle of the shear span decreased with an increase in either the opening width or height. The rate of the strength reduction caused by increasing the opening height was, however, more significant than that produced by increasing the opening width. Placing a web opening in the compression zone close to the load plate was very detrimental to the beam strength. Conversely, a negligible strength reduction was recorded when the web opening was placed in the tension side above the flexural reinforcement and away from the natural load path. Data of the parametric study were utilized to introduce simplified analytical formulas capable of predicting the shear capacity of GFRP-reinforced concrete deep beams with a web opening in the shear span. [ABSTRACT FROM AUTHOR]

Crosswind can reduce the operability of an aeroengine significantly at static or near static operating conditions. Computational fluid dynamics predictions of the flow at crosswind conditions will play an important part in future designs, however, accurate numerical predictions of the flow within the intake remain challenging even for simulations of cases with intake only. The main objective of this paper is to demonstrate the importance of numerical setup and to determine an optimal computational model for crosswind investigations that can be used by other researchers. By considering the flow to be inherently unsteady, the influence of inlet and exit boundary conditions, and grid sensitivity is studied by using unsteady Reynolds-average Navier-Stokes (URANS) simulations. Numerical predictions of the time-averaged intake pressure recovery (IPR) and the motion of the vortex on the ground are compared against the existing experimental data. The results show that for an intake under crosswind, the ground vortex that forms under the intake and the in-duct separation, when present, exhibit unsteady behavior that become stronger as the crosswind velocity is increased. The steady-state simulation is only representative at lower crosswinds. The intake flow separation and ground vortex predictions are influenced by the inlet boundary layer profiles. Moreover, acoustic reflection was observed at the intake exit boundary which propagates upstream, creating artificial unsteady frequencies in IPR. The reflection is generated from the use of uniform boundary conditions at the intake exit and is not dissipated in the grid due to the long wavelength; this can be mitigated by using a choked nozzle at the intake exit. Acoustic reflection was also observed at the far-field exit boundary. These reflections are caused from interaction of trailing vortex and far-field boundary. [ABSTRACT FROM AUTHOR]

We present SPICE , a new suite of radiation-hydrodynamic, cosmological simulations targeting the epoch of reionization. The goal of these simulations is to systematically probe a variety of stellar feedback models, including 'bursty' and 'smooth' forms of supernova energy injection, as well as poorly explored physical scenarios such as hypernova explosions and radiation pressure on dust. We show that even subtle differences in the behaviour of supernova feedback drive profound differences in reionization histories, with burstier forms of feedback causing earlier reionization. However, we also find that some global galaxy properties, such as the dust-attenuated luminosity functions and star formation main sequence, remain degenerate between models. In particular, we show that stellar feedback and its strength determine the morphological mix of galaxies emerging by |$z \, = \, 5$| and that the reionization history is inextricably connected to intrinsic properties such as galaxy kinematics and morphology. While star-forming, massive discs are prevalent if supernova feedback is 'smooth', 'bursty' feedback preferentially generates dispersion-dominated systems. Different modes of feedback produce different strengths of outflows, altering the interstellar/circumgalactic medium in different ways, and in turn strongly affecting the escape of Lyman continuum (LyC) photons. We establish a correlation between galaxy morphology and LyC escape fraction, revealing that dispersion-dominated systems have escape fractions 10–50 times higher than their rotation-dominated counterparts at all redshifts. At the same intrinsic luminosity, dispersion-dominated systems should thus preferentially generate large H  ii regions as compared to their rotation-dominated counterparts. Since dispersion-dominated systems are more prevalent if stellar feedback is more explosive, reionization occurs earlier in our simulation with burstier feedback. We argue that statistical samples of post-reionization galaxy morphologies (using both stellar and gaseous components) probed with telescopes such as JWST , ALMA, and MUSE can constrain stellar feedback at z > 5 and models of cosmic reionization. [ABSTRACT FROM AUTHOR]

Collatz Conjecture (3x+1) or in some literature as 3N+1 is a problem because it works in the way that if you take any positive number, if it is an odd number you multiply it by three (3) then add one (1). On the other hand, if it is an even number, you divide it by two (2). Eventually, all positive numbers decrease to one (1). One (1) is odd, so multiply it by three (3) is three (3) and add one (1) is four (4). Four (4) is even, so divide it by two (2) is two (2). Two (2) is also even, so divide it by two (2) is one (1) again. All positive numbers end up in the loop (4-2-1). This loop is like a numerical lock. Therefore, the solution of this problem will have to be a numerical key results to all positive numbers. [ABSTRACT FROM AUTHOR]

In this innovative study, a unique approach was engaged to simulate the flow characteristics of nanofluid inside a tank featuring a surface subjected to uniform flux. The testing fluid for this investigation was fabricated by incorporating alumina powders with varying shapes into water. The derivation of the final equations involved the application of Darcy’s law and the formulation of the stream function. The container experienced the combined efficacy of both the Lorentz force and gravity forces. The incorporation of additives resulted in a significant enhancement of the Nusselt number (Nu), demonstrating an increase of 19.8% and 40.28%, contingent on the magnitude of the Hartmann number (Ha). Moreover, an elevation in the shape factor led to a notable rise in Nu by 14%. Remarkably, as the Ha increased, there was a substantial reduction in the cooling rate by 51.33%. Furthermore, in the absence of the Ha, an escalation in the Rayleigh number (Ra) caused Nu to surge by 65.8%. This study holds paramount importance as it introduces a novel technique for simulating nanofluid flow with a sinusoidal surface, providing valuable insights into the complex interplay of forces within the container. The utilization of varying shapes of alumina powders adds a layer of sophistication to the experimentation, making this investigation a noteworthy contribution to the existing body of knowledge. The findings not only enhance our understanding of heat transfer dynamics but also offer practical implications for applications involving nanofluids in containers with nonuniform surfaces subjected to heat flux. [ABSTRACT FROM AUTHOR]

Vertical impervious membrane has been widely used in seepage control of levee engineering, but there are still issues of low calculation accuracy in seepage calculation of hydraulic gradient field around impervious membrane. In order to study the distribution law of seepage field at discontinuous interface including material interface, impermeable body and impermeable membrane, the numerical manifold method of node continuous weight function was introduced. By comparing the distribution law of water head and hydraulic gradient with finite element method and numerical manifold method, the superiority of numerical manifold method in solving seepage issue with discontinuous interface was verified. Compared with the finite element method, the numerical manifold method was simpler and the improved method could calculate the hydraulic gradient at the discontinuous interface more accurately. Taking Diversion of Huaihe River into Yihe River Rectification Project as an example, using the numerical manifold method of node continuous weight function, the influence law of whether there was vertical film laying, film laying length and film laying defect position on the seepage of dike was studied. The results show that the anti-seepage effect increases obviously after the film is inserted into the clay layer. The influence degree of membrane damage on seepage field mainly depends on the stratum where the damage is located. Reasonable measures should be taken to avoid the damage of membrane in permeable stratum. [ABSTRACT FROM AUTHOR]

The transition to more environmentally friendly steel production methods has intensified research into hydrogen-based direct reduction (HyDR) of iron oxide pellets. The aim of this study is to systematically investigate the kinetics of the reduction process, the evolution of porosity and the resulting microstructural changes on the reduction behavior of high-quality pellets during HyDR of iron ore at different temperatures. A modified mathematical model is developed based on the shrinkage kernel model, taking into account both mass and heat transport in a hydrogen atmosphere. The effects of temperature, particle size and time on the reduction behavior of the pellets are investigated. The simulated results are validated and discussed by the results of a batch of iron oxide pellets consisting of ten almost spherical pellets subjected to the direct reduction process with pure hydrogen. The results show that the total energy input to the HyDR process is a complex balance of factors, including chemical reaction rates, diffusion dynamics and entropy generation. The increase in free volume and simultaneous decrease in pore diameter reflect the dynamic nature of the microstructure, which includes additional free volume and defects due to the volume discrepancies and associated stresses between the reactant and product phases. Furthermore, the data show that higher temperatures accelerate the reduction reactions, especially the transformation of wustite into metallic iron. This phase transition is characterized by a significant volume change that cannot be accommodated by elastic deformation alone, leading to the development of lattice defects such as cracks, creep pores and dislocations that serve as stress relief mechanisms. The trends for porosity change at 950 °C and 1000 °C observed in the experimental results are correct and in good agreement with the numerical and simulated results. [Display omitted] • Development of a model to evaluate HyDR kinetics and microstructural changes in iron oxide pellets. • Higher temperatures accelerate HyDR, which affects phase transitions and defect formation. • Temperature-induced porosity affects kinetics and gas diffusion despite tortuosity. • HyDR leads to stress defects and increased porosity in the microstructure. • The interaction of kinetics and entropy in the optimization of the HyDR process for steel was highlighted. [ABSTRACT FROM AUTHOR]

AbstractThis study aims to enhance the performance of the air-cooled hybrid battery thermal management system (BTMS) by using fins under extreme discharge conditions such as 7C, 9C, and 11C. In this context, five different fin structures, Type-I (no fin), Type-II (rectangular), Type-III (extended), Type-IV (blade), and Type-V (triangular), were modeled, and numerical analyses of the developed BTMSs were performed using COMSOL Multiphysics software. In the numerical analysis, three different phase change materials (PCM-1, PCM-2, and PCM-3) with three different thicknesses (tPCM) of 4, 6, and 8 mm were considered, and the airflow was supplied to the system at three different Reynolds (Re) numbers of 100, 200, and 400. In this way, the effects of the BTMS types, tPCM, PCM types, and air velocity on the battery pack temperature distribution (ΔT), PCM melting uniformity (ΔF), and maximum battery cell temperature (Tmax) in the hybrid BTMS were investigated. As a result of the analyses, the maximum ΔT was found to be 5.58 °C for the case involving Type-II and PCM-1 with tPCM of 4 mm at 11C. PCM-2 exhibited the best performance for all BTMS types with a tPCM of 4 mm at 9C. However, at 11C, only the case involving PCM-3 with a tPCM of 6 mm and Type-V could maintain the Tmax under 60 °C. Moreover, the results obtained from the numerical analysis revealed that the use of fins significantly increased the PCM melting uniformity. [ABSTRACT FROM AUTHOR]

An experiment-supported simulation process chain is set up to perform numerical forced response analyses on a transonic high-pressure compressor front stage at varying operating conditions. A wake generator is used upstream of the rotor to excite a specific resonance within the operating range of the compressor. Thereby, extensive aerodynamic and structural dynamic experimental data, obtained from state-of-the-art rig testing at the Transonic Compressor Darmstadt test facility at the Technical University of Darmstadt, are used to validate numerical results and ensure realistic boundary conditions. In the course of this, five-hole-probe measurements at steady operating conditions close to the investigated resonance enable a validation of the steady aerodynamics. Subsequently, numerically obtained aeroelastic quantities, such as resonance frequency, and damping, as well as maximum alternating blade stresses and tip deflections, are compared to experimental blade tip timing data. Experimental trends in damping can be confirmed and better explained by considering numerical results regarding the aerodynamic wall work density and secondary flow phenomena. The influence of varying loading conditions on the resonance frequency is not observed as distinctly in numerical, as in experimental results. Generally, alternating blade stresses and deflections appear to be significantly lower than in the experiments. However, similar to the aerodynamic damping, numerical results contribute to a better understanding of experimental trends. The successive experimental validation shows the capabilities of the numerical forced response analysis setup and enables the highlighting of challenges and identification of potential further adaptations. [ABSTRACT FROM AUTHOR]

This study investigates the impact of initial injection conditions on colloid transport and retention in porous media. Employing both uniform and flux‐weighted distributions for the initial colloid locations, the research explores diverse flow scenarios, ranging from simple Poiseuille flow to more complex geometries. The results underscore the pivotal role the injection mode plays on the shape of colloid retention profiles (RPs), particularly those that display anomalous non‐exponential decay with distance. Broadly, uniform injection yields multi‐exponential profiles, while flux‐weighted injection can lead to nonmonotonic profiles in certain conditions. The study identifies preferential flow paths as a key factor in producing nonmonotonic RPs. Notably, variations in fluid velocity, colloid size, and ionic strength affect attachment rates near the inlet but do not significantly alter the qualitative transition between multi‐exponential and nonmonotonic profiles. The study emphasizes that the chosen injection mode dictates retention profile shapes, highlighting its crucial role in porous media colloid transport. These insights provide a possible partial explanation of previously observed anomalous transport behaviors, urging consideration of injection conditions in interpretations of experiments, where they can be difficult to accurately control and measure with high precision. Key Points: The study finds that initial injection conditions strongly influence colloid transport and retention profilesDifferent injection methods lead to varied retention patterns, revealing insights into anomalous transport in porous mediaThe findings underscore the importance of injection conditions in experimental design to better understand colloid transport behavior [ABSTRACT FROM AUTHOR]