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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]

In this paper, a finite volume (TPFA) method is employed to simulate a degenerate breast cancer model that captures the progressive mutations from a normal breast stem cell to a tumor cell. The model incorporates a degenerate parabolic equation to represent the interaction between solid tumor growth and its environment, which involves the release of degradative enzymes governed by a partial differential equation. The discrete maximum principle is verified to be satisfied by the proposed finite volume scheme, and the convergence of the existing discrete solutions to a weak solution is proven. Additionally, the development of breast cancer is demonstrated through a numerical experiment. [ABSTRACT FROM AUTHOR]

With the increase of antenna aperture and frequency, the influence of solar heat on its performance becomes more and more serious. In this paper, the thermal model of the 110 m aperture radio telescope to be built in Xinjiang is established to study its temperature field characteristics on the summer solstice. The results are as follows: during the day, the highest temperature of the main reflector can reach 42.86 ∘ C, which appears at 14 o'clock, and the temperature of the legs also reaches the peak of 41.74 ∘ C at the same time. The horizontal temperature difference of the back frame will exceed 1 ∘ C at 5, 18, and 19.5 o'clock, the antenna pointing performance will be greatly affected. The temperature field at night is also not uniform, and the temperature difference of the pitching structure is significantly higher than that of other components, with the maximum temperature difference of 6.42 ∘ C. Through the method of numerical simulation and test, it is proved that the wall thickness difference of components is the main reason for the large temperature difference at night. [ABSTRACT FROM AUTHOR]

This paper examines options for orbit configurations for a space interferometer. In contrast to previously presented concepts for space very long baseline interferometry, we propose a combination of regular and retrograde near-Earth circular orbits in order to achieve a faster filling of (u , v) coverage. With the rapid relative motion of the telescopes, it will be possible to quickly obtain high quality images of supermassive black holes. As a result of such an approach, it will be possible for the first time to conduct high quality studies of the supermassive black hole close surroundings in dynamics. • A new configuration for the space interferometer is proposed. • This configuration uses near-Earth regular and retrograde orbits. • Calculated orbits are stable more than 10 years. • The supermassive black hole can be imaged within 20 h. • Synthetic simulations show observations of black holes are possible in dynamics. [ABSTRACT FROM AUTHOR]

Classical methods for initial orbit determination (IOD) include Laplace method, Gauss method, and their variations. In addition to this, based on the characteristic of optical observation data nowadays, experts propose some other IOD methods, like Double- r method and admissible region method. One of the ways to determinate the orbit through double- r method is to guess distances of the target from the observer at two epochs—usually at the first and the last one. By doing so, we can solve the Lambert problem, and use its solution as the initial guess of the orbit. Furthermore, we can improve the initial guess by iterations to reduce the root mean square (RMS) of the observations. The admissible method is based on the concept of attributable (longitude, latitude, and their rates). With some conceptions, the admissible region described by the range and range rate from the observer is characterized. Using triangulation we can find the nodal point that makes the RMS minimal. In our work, we apply one intelligent optimization method—the particle swarm optimization method to the two methods, based on simulated and real data, and compare the results with that of modified Laplace method. At last, we briefly discuss the possibility of applying the double- r method to the orbit link problem. [ABSTRACT FROM AUTHOR]

Comets are the primitive planetesimals left in the solar system. Studying the evolution of comet nucleus is of great significance for understanding the formation and evolution history of other celestial bodies in the solar system. Under the action of solar radiation, the volatile components of comets sublimate and drive the dust movement, resulting in the loss of comet nucleus material. Therefore, the activity of comet nucleus affects the surface morphology and even the overall shape evolution. The orbit data were obtained from IAU (International Astronomical Union) MPC (Minor Planet Center), and the spin and precession of comet nucleus were taken into account. The shape evolution model of Mass loss-driven shape evolution model (MONET) was used to simulate the short period comet. The distribution of solar radiation energy and surface erosion depth of short-period comet 1P/Halley, 9P/Tempel 1, 19P/Borrelly, 67P/C-G (Churyumov-Gerasimenko), 81P/Wild 2, and 103P/Hartley 2 in one orbital period is calculated. Combined with its dynamic parameters, the effects of rotation, precession, and revolution on the sublimation distribution of surface water ice and the possibility of causing the difference in erosion between north and south are discussed. [ABSTRACT FROM AUTHOR]

Instrumental polarization is a vital factor for the accurate measurements of the solar magnetic field. It is necessary to optimize the optical design of the large solar telescope to obtain high accuracy solar magnetic field information. In this paper, an optimal design scheme based on four-mirror polarization compensation optics for the 8-meter giant solar telescope is presented. The polarization effect of pupil and field of view are analyzed by the polarization ray tracing programming, the telescope motion and wavelength properties of the field-effect are investigated detailedly. The result shows that, in the near infrared waveband which includes the magnetic sensitive spectral lines of He I 1.083 μ m and Fe I 1.565 μ m, the polarization-free field size is 0.91 ′ , and the polarization-free field size in the visible band is 0.5 ′ , in which the instrumental polarization of telescope is smaller than 2 × 10 − 4 . [ABSTRACT FROM AUTHOR]

In the smooth mass distribution model, the critical curve represents a line with magnification divergence on the image plane in a strong gravitational lensing system. Considering the microlensing effects caused by discrete masses, the magnification map in the source plane exhibits a complex structure, which offers a promising way for detecting dark matter. However, simulating microlensing near the critical curve poses challenges due to magnification divergence and the substantial computational demands involved. To achieve the required simulation accuracy, direct inverse ray-shooting would require significant computational resources. Therefore we applied a GPU-based code optimized with interpolation method to enable efficient computation on a large scale. Using the GPU of NVIDIA Tesla V100S PCIe 32GB, it takes approximately 7000 seconds to calculate the effects of around 13,000 microlenses for a simulation involving 10 13 emitted rays. Then we generated 80 magnification maps, and select 800 light curves for a statistical analysis of microcaustic density and peak magnification. [ABSTRACT FROM AUTHOR]

In this paper, the forced convection of forced convection of ferro-nanofluid in a U-shaped tubed subjected to a magnetic field is investigated. Modeling is performed in three sizes of the bending radius. The Reynolds number and Hartmann number ranges are 600 ≤ Re ≤ 1200 and 2 ≤ Ha ≤ 12, respectively. The ferro-nanofluid is composed of water-based Fe 3 O 4 particles that vary in volume fraction from 0.01 to 0.03. The simulation is carried out under a 3-D model, incompressible, laminar and steady-state by using the finite volume method. The results show that at a constant bending radius, as the Hartmann number increases, the current density increases. In addition, in all cases, as the Hartmann number increases, the coefficient of friction increases, and the presence of a magnetic field reduces the velocity of the fluid flow. Also, the maximum and minimum friction coefficients are related to the minimum Reynolds number and the maximum Reynolds number, respectively. The results also show that the effect of flow velocity on the heat transfer rate is much more significant than the intensity of the magnetic field and increasing the bending radius of the tube leads to a further reduction of fluid energy and the fluid receives less heat flux from the wall. [ABSTRACT FROM AUTHOR]

When a liquid contacts a solid, physicochemical reactions form an electrical double layer (EDL) at the interface. Understanding the EDL is crucial to prevent electrical device failures, but few experimental methods can access this charge distribution. Recently, the pressure wave propagation (PWP) method has been explored. This paper presents simulations of current generated by a pressure wave through the EDL using the finite difference time domain (FDTD) method. A parametric study investigates the effects of EDL parameters and stimulus properties on the signal. Simulations with EDL data obtained experimentally for both conductive and dielectric liquids are carried out. [ABSTRACT FROM AUTHOR]

Solar water collectors (SWCs) are the major element of any solar power system. Evacuated tube solar water collectors (ESWCs) contain multiple evacuated tubes formed between the tubular absorber and the glass cover in each tube to reduce heat losses. In this survey, it is aimed to improve the thermal performance of a heat pipe evacuated tube water solar collectors (HP-ESWCs) by using quartz nanofluid as the working fluid and experimentally and numerically obtained results are explained in detail. The numerical simulation of the heat pipe part of the system aims to present a general view of energy gain by the heat pipe, evaporation of the working liquid inside the pipe and condensation of the vapor by releasing its energy in the condenser section. Also, the performance of the whole collector was experimentally examined utilizing four different working fluids. The outcomes indicate that the thermal efficiency of the HP-EWSC using deionized water varied between 29.63 and 55.78 %, 36.50–61.13 %, 40.73–64.35 % and 32.81–75.92 % at 0.008, 0.016, 0.033 and 0.050 kg/s flow rates, respectively. Also, the efficiency of HP-EWSC using quartz/water changed between the ranges of 43.87–71.95 %, 50.86–78.22 %, 46.37–79.66 % and 55.60–85.64 % at 0.008, 0.016, 0.033 and 0.050 kg/s flow rates, respectively. Average exergy efficiency enhancement by utilizing quartz/water nanofluid in the present work varied in the range of 34.23–99.97 %. General findings of this study clearly showed the positive impacts of using quartz/water as working fluid in the HP-ESWCs on the overall performance. [ABSTRACT FROM AUTHOR]

Current research on Taylor bubble flow heat transfer mainly focuses on straight channels, with less emphasis on the transport characteristics and heat transfer regimes of Taylor bubble flow in branching channels. Understanding the flow and heat transfer regimes of Taylor bubble flow in branching channels is crucial for enhancing microfluidic and microchemical applications. Numerical simulations can provide detailed flow information that experiments might miss, deepening our understanding of Taylor bubble flow for enhanced heat transfer. The research results indicate the presence of three bubble breakup regimes at the T-junction: Non-breakup (NB), Tunnel breakup (TB), and Obstructed breakup (OB). The phase diagrams were established based on Capillary number and bubble length to predict the transitions between these three breakup regimes. Pressure within the channel increases with bubble deformation but decreases after breakup. Bubble breakup converts potential energy to kinetic energy, enhancing the heat transfer coefficient in the branching microchannels. The stagnation of bubbles at the T-junction temporarily reduces the heat transfer coefficient but increases after the breakup. Up to 115 % of the best performance improvement was achieved for Taylor bubble flow when the channel width ratio was 1.2. When the channel width ratio was greater than or equal to 1, the TB regime influenced bubble breakup within the channel, resulting in asymmetric breakups and uneven heat transfer. When employing tree-like branched microchannels and Taylor flow for enhanced heat transfer, a channel width ratio of 0.8 is recommended. [ABSTRACT FROM AUTHOR]

Efficient electronics cooling has always been a perpetual challenge, with the limits of single-phase cooling almost being reached. Two-phase cooling in the form of pool boiling is an attractive next step, with much research being devoted to it. While refrigerants operating at lower saturation temperatures are key to achieving effective cooling, surface modifications have been shown to also affect bubble dynamics and enhance nucleate pool boiling heat transfer. A simple, easy to implement fabrication method was sought, with the goal of expanding the knowledge of bubble dynamics. To this end, single bubble growth on structured surfaces that are achievable on a lathe, with an average roughness of 75 μm and differing indentation angles between 90° and 46°, was studied numerically using an OpenFOAM multiphase library. Conjugate heat transfer was applied, with heat fluxes ranging between 7.6 and 28 kW/m2 for pure refrigerants R32 and R1234yf. By comparing the bubble equivalent diameter with that of a smooth surface at a fixed heat flux, it was found that the bubble growth rates of structured surfaces were largely independent of indentation angles less than 90°, but lower than for smooth surfaces. For structured surfaces, a critical indentation angle of approximately 60° was identified which affected the bubble dynamics. For angles greater than the critical angle the bubble growth time was up to 150 % longer, which also resulted in larger departure diameters. However, the opposite trend was observed as the indentation angle was decreased below the critical angle. From a force analysis, it was found that the physical limitation imposed on the bubble growth was responsible for the critical indentation angle behaviour, with the most acute angle of 46° showing the shortest departure time. Furthermore, the bubble growth from a single cavity corresponded better with the trends of a smooth surface than a structured surface with comparable indentation angles. On a structured surface, once the bubble reached the edge of the cavity, its base diameter was limited by the physical characteristics of the surface. For the single cavity surface, however, bubble growth was uninhibited beyond the cavity, mimicking a completely smooth surface. The marked difference between results of a fully structured surface and the single cavity implies that future research will have to take the structural limitations on bubble growth imposed by a roughened surface into account. [Display omitted] [ABSTRACT FROM AUTHOR]

• Numerical modeling is useful for assessing options to improve landfill gas collection. • Effects of higher vacuum and/or more horizontal collectors are quantified. • Accurate measurement of the fugitive emission rate is a key calibration parameter. • Emission rate measurements conducted using airborne matter mapping method. A two-dimensional landfill gas flow model using the FEFLOW numerical code was developed to assess the potential improvement in landfill gas (LFG) collection and the reduction in greenhouse gas emissions at a landfill due to increases in the vacuum of horizontal collectors and/or installation of additional LFG collection infrastructure. A key calibration input parameter for the model, the fugitive methane emission rate from the study area, was measured using the airborne matter mapping method. The measurement showed that, at the time, the methane collection efficiency for the study area was approximately 37 %. The model indicated that increasing the vacuum of the existing collection system by 0.75 kPa could result in an improvement in collection efficiency from 37 % to 49 % within the selected study area. A similar increase of collection efficiency could be obtained by either doubling the number of horizontal collectors on a platform or installing a layer of permeable demolition waste on that level, without an increase in collection system vacuum. Combining the addition of collection infrastructure with an increase in collection system vacuum by 1 kPa was predicted to improve the collection efficiency for the study area to about 74 %. [ABSTRACT FROM AUTHOR]

In this study a novel compound parabolic collector (CPC) with an asymmetric reflector and an evacuated U-pipe tubular receiver was examined numerically and experimentally. The thermal operation of the system was tested in a range of 22–70 °C inlet temperature in the city of Athens in Greece, using water as the working fluid. The collector was oriented towards the sun in each case, while the measurements where conducted for 10 min regarding each operating point. The data acquisition as regards the solar irradiation intensity, the inlet, the outlet and the ambient temperature was conducted every 30 s. The experimental results were also validated by developing a numerical model in SolidWorks Flow Simulation environment. Particularly, it was found that the numerical results diverge from the experimental one by 3% on average, with the maximum declination to take the value of 5.17%. By this simulation it was possible to estimate the temperature of the receiver and the convection regime at the interior of the U-pipe. The convective coefficient at the interior of the flow tube was also validated through a theoretical model. Last but not least, the collector was compared with three other designs taken from literature as regards the optical performance. [ABSTRACT FROM AUTHOR]

This study analyzes the characteristic numerical analysis of membrane electrode assembly in Proton Exchange Membrane Fuel Cell (PEMFC) with bipolar plate, flow channel, gas diffusion electrode, and proton exchange membrane. The numerical solution focuses on discussing the effects of different parameters, including permeability, porosity, and operation voltage, on various mass fractions, current-voltage curve, and power-voltage curve. The results show that as the porous medium with high gas permeability is an important factor that affects the mass fraction of hydrogen. Regarding the analyses of various porosities, the fuel cell performance can be effectively promoted with larger ratio of porosity and permeability. However, increasing the porosity will affect the electrical conductivity and increase the flooding of water, which will block the flow channel and reduce efficiency. • Increasing the permeability will improve PEMFC performance. • High porosity can be effectively associated and allow the gas to flow through. • High voltages will increase the hydrogen mass fraction and affect the electrochemical reaction. [ABSTRACT FROM AUTHOR]

The equilibrium dynamics of the post-Newtonian circular restricted three-body problem (PNCRTBP), in the case of two massive stars or even stellar remnants, are investigated. Numerical methods are deployed for determining the points of equilibrium, as well as their linear stability. Our systematic and rigorous analysis reveals the role and influence of the transition parameter ∊ and the radiation pressure factor q on the dynamics of the system. It is revealed that the amount of equilibria increases with increasing value of the radiation pressure factor. On the other hand, as the value of the transition parameter tends to its maximum value the number of libration points is reduced, implying that in the case of strong post-Newtonian gravity the system degenerates. [ABSTRACT FROM AUTHOR]

In this paper, we provide a numerical study of laminar flow in a micro-sized backward-facing step channel for water-based nanofluids containing Al 2 O 3 and TiO 2 nanoparticles and investigate the impact of the temperature differences between the inlet and the downward wall temperatures. The present work is the first study to introduce a temperature-dependent separation flow model. The velocity increases with increasing concentration of nanoparticles. However, when comparing Al 2 O 3 and TiO 2 nanofluids, Al 2 O 3 has a velocity and shear stress higher than TiO 2 for 0.04 volume fraction. Increasing the volume fraction of nanofluid led to an increase in the rate of heat transfer from the wall to the fluid, as the thermal properties improved as the volume ratio increased. The performance efficiency index (PEI) decreases as the volume fraction of the particle increases after a certain amount of nanoparticles. The simulation results of the nanofluid separation flow in the recirculation and reattachment shows that the velocity increases as the temperature difference increases, the size of the primary and secondary recirculation regions behind the step is significantly influenced with the temperature difference, a larger temperature difference means a larger recirculation zone. [ABSTRACT FROM AUTHOR]

As the wind industry expands into remoter and deeper areas of the open sea with abundant wind energy, environmental loadings become harsher. This increases the requirements for submarine power cables (SPCs), which serve as the 'lifeline' for transporting electricity. Consequently, a more advanced design based on a thorough understanding of this structure is needed. However, the complex configuration and intensive contact issues within SPCs limit our understanding and make them black boxes for cable engineers. To gain more insights, methods for performing local mechanical analysis of SPCs are necessary. Despite this need, a comprehensive review of existing methods for local mechanical analysis of SPC is still lacking. Therefore, it is essential to review the available methods and provide guidelines for utilizing and developing these methods. • Comprehensive Review: This paper presents a systematic review of experimental, analytical, and numerical methods for local mechanical analysis of submarine power cables (SPCs), filling a significant gap in the existing literature. • Practical Guidelines: By evaluating the strengths and weaknesses of each method, the paper provides practical guidelines for engineers and researchers to effectively apply these methods in SPC design and analysis. • Identification of Critical Challenges: The review identifies key challenges such as complex contact pressures, simplification of helical wires, and handling of combined loading scenarios, offering valuable insights for future research. [ABSTRACT FROM AUTHOR]

• A three-dimensional conjugate heat transfer numerical model for slug flow was developed. • Dry patches are more likely to form in rectangular channels than in circular channels during slug flow. • Internal circulation within the liquid slug during boiling enhances heat transfer in the liquid phase. • An increase in wall superheat leads to liquid film evaporation and the formation of dry patches. • Increasing the inlet mixture velocity enhances heat transfer. • Heat transfer in slug flow is optimized when the liquid slug length equals the channel width. In recent years, flow boiling heat transfer in microchannels has been extensively studied as an efficient cooling solution, with slug flow considered the optimal operating condition for microchannels. Current research on slug flow boiling primarily focuses on circular channels and isolated bubbles modeled with 2D axisymmetric geometries. This paper investigates flow boiling in three-dimensional rectangular microchannels based on conjugate heat transfer. Superheat, velocity, and bubble generation frequency affect slug flow heat transfer by influencing the internal circulation within the liquid slug, the length and thickness of the liquid film, dry patches, and bubble length. In this study, the two-phase flow with a Peclet number (Pe) ranging from 355 to 1780 is in the transition zone, where the diffusion effects between the fluids cannot be ignored. The main mechanism for enhancing heat transfer within the liquid slug is the internal recirculation flow. In comparison to the heat transfer of single-phase flow within the channel, the average Nusselt number for two-phase flow boiling exhibits a significant enhancement, increasing by as much as 85 % and not less than 62 % concomitant with the increase in superheat. Accompanying the increment in inlet velocity, there is a notable augmentation in the Nusselt number for two-phase flow boiling, escalating by as much as 63 % and at a minimum of 29 %. Consequent to the elevation in bubble generation frequency, a substantial rise is observed in the heat transfer coefficient, surging by up to 80 % and not falling below 28 %. When the length of the liquid slug equals the width of the channel, slug flow achieves the highest heat transfer coefficient. This study provides theoretical guidance for flow pattern control within microchannels. [ABSTRACT FROM AUTHOR]

Thermal models are essential for studying airless planetary surfaces, as the interaction between topography and thermophysical properties plays a crucial role in determining a surface's response to localized illumination. Accurate temperature distribution calculations require a comprehensive investigation of sunlight scattering, a process that, despite its computational challenges, cannot be overlooked, especially when high resolution is necessary. Furthermore, thermal analysis is fundamental for assessing the stability of volatiles in polar regions. In this study, we introduce a novel approach by discretizing the Sun into 100 individual elements, allowing for a highly precise simulation of solar flux—an innovation crucial for accurately capturing temperature distributions in Mercury's polar craters, given the planet's proximity to the Sun. This level of discretization significantly enhances the accuracy of the thermal model, ensuring a more realistic depiction of how sunlight interacts with crater topography. We developed a dual-model approach that simulates both direct solar illumination and its scattering on two craters, Laxness and Fuller, located at Mercury's north pole. The illumination and thermal model predict temperature distribution and heat transfer based on the material's thermal properties and topography. The study examines the interaction between direct sunlight, causing localized heating, and scattered light, which influences the thermal response of surface materials. Detailed illumination maps and temperature profiles were generated over two Hermean years, revealing the significant impact of the self-heating effect on temperature distribution. The results show that specific regions experience indirect solar flux due to the craters' morphology, particularly in permanently shadowed regions (PSRs) that are heated exclusively by scattered radiation. Maximum temperature profiles for the Laxness and Fuller craters show a substantial temperature increase within PSRs compared to areas exposed to direct illumination. However, while self-heating does not affect the stability of water ice in the Laxness crater, in the Fuller crater, a section within the radar-bright material reaches temperatures of up to 210 K, potentially threatening the stability of water ice. Further investigation with the onboard SIMBIO-SYS instrument on the BepiColombo mission will help to better understand the current state of these craters and their volatile deposits. • Novel Sun Discretization Method: Tool discretizes the Sun into 100 elements for accurate flux modeling. • Enhanced Thermal Modeling: Refined temperature distribution approach includes self-heating. • Application to Mercury's Polar Craters: Model reveals PSR temperature variations due to self-heating. • Potential Impact on Water Ice Stability: Fuller crater temperatures may threaten ice stability. • Future Exploration: Findings highlight the need for BepiColombo mission to study crater thermal states. [ABSTRACT FROM AUTHOR]

The integration of phase change materials (PCMs) presents a promising possibility for enhancing the thermal management of supercapacitors (SCs), which are vital components in various energy storage systems. This research focuses on investigating the thermal behavior of SCs with integrated PCM, employing finite element method (FEM) simulations to solve the transient thermal problem. Through a comparative analysis at various time instants, the transient thermal response of SCs is examined, shedding light on the efficacy of PCM-based thermal management strategies. Moreover, parametric studies are conducted to investigate the influence of PCM key characteristics, like melting temperature and layer thickness on the SC thermal response. Additionally, the impact of enhanced PCM thermal conductivity is explored by integrating high-conductive short carbon fibers (CF) within the PCM matrix. This investigation encompasses various PCM melting points, allowing for a comprehensive understanding of the interplay between PCM properties and SC thermal response. The results indicate that a notable decline in the highest temperatures of the SC can be achieved, leading to a reduction of about 9 °C depending on the PCM melting temperature and the improved thermal conductivity. The obtained results emphasize the effectiveness and practical feasibility of the proposed thermal management strategy. The modeling approach presented provides a robust tool with significant efficiency in reducing computational time for analyzing the thermal behavior of large models, as the utilization of the homogenization technique notably decreases the computational time. The findings of this study not only provide insights into optimizing PCM-based thermal management strategies for SCs but also contribute to advancing the design and performance of energy storage systems by addressing crucial thermal challenges. [ABSTRACT FROM AUTHOR]

Multilayer composite sandwich panels with corrugated cores have the potential for structural applications requiring high stiffness and strength-to-weight ratios. This study aims to experimentally and numerically investigate the bending response of sandwich panels with novel square and trapezoidal corrugated core configurations fabricated from E-glass fiber-reinforced epoxy composites, both with and without polyurethane foam filling. Quasi-static three-point bending tests were conducted to evaluate and compare the flexural stiffness and maximum load capacity of the panel designs. The cores were manufactured using vacuum-assisted resin transfer molding. Key results showed that changing the core geometry from square to trapezoidal improved the bending stiffness by up to 26 %. Incorporating polyurethane foam further increased the bending stiffness by up to 41 % and maximum load by up to 47 % compared to solid cores. Failure initiation and progression were governed by matrix cracking in the face sheets and cores, followed by core cell wall buckling and delamination. Finite element modeling using ABAQUS captured the progressive damage behavior, exhibiting good agreement with experimental force-displacement responses. Failure modes included matrix cracks, fiber fractures, core buckling and delamination. This study provides valuable insights into the mechanical performance of innovative corrugated core sandwich panel designs under quasi-static bending loads. The validated FE approach also enables virtual testing and optimization of composite sandwich structures. • Novel corrugated sandwich panels tested in bending. Trapezoidal cores 27% stiffer than square cores. • Polyurethane foam cores boosted bending stiffness 41% and max load 47% over solid cores. • Tests and models examined damage progression from cracking to buckling to delamination. • ABAQUS FEA matched tests, validating computational analysis of new sandwich designs. • Optimized multi-layer corrugated cores enhanced flexural strength while maintaining light weight for engineering uses. [ABSTRACT FROM AUTHOR]

Photovoltaic-thermal (PVT) collectors developed over the years have achieved reduced photovoltaic (PV) panel temperature and improved electrical efficiency mostly based on single-tube spiral and serpentine configurations of the cooling pipes. However, the design and analysis of PVT collector configurations incorporating multiple serpentine tubes, capable of simultaneously reducing both the average PV panel temperature and temperature non-uniformity within the panel, are rare. The present work introduces two novel designs PVT collector systems by incorporating dual-tube arrangements, namely, the Dual-Tube Uni-Directional (DTUD) and the Dual-Tube Opposite-Directional (DTOD) systems. The new collectors' performance is numerically analysed through three-dimensional (3D) simulations. The highest net powers are obtained with 32 cooling loops in both the DTUD and DTOD designs for the given flow rate and panel area. The DTUD-based PVT system yields up to 10.39 % and 10.36 % gains in electrical efficiency and net power, respectively. On the contrary, the DTOD system also results in gains of these parameters, albeit marginally less than the DTUD arrangement. However, the DTOD arrangement results in reduced maximum PV panel temperature, which can positively impact the panel's life span. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • An investigation of ventilated PCM roof in a mono-zone building was performed. • Roof configurations were evaluated experimentally and numerically in a Bsh climate. • Ventilation stabilized the time the PCM remained in each melting–solidification phase. • PCM roof reduced indoor temperature fluctuations between 1.94 and 10.4 %. • PCM reduced the thermal loads by up to 92.9 % with small ducts open 24 h/day. The effect of incorporating phase change material (PCM) into roofing systems combined with natural ventilation is numerically and experimentally investigated. Four roof configurations, including ventilated and unventilated options with and without an air gap between the PCM and the insulation material, are subjected to experimental research during the winter season in a semi-arid climate using two fully instrumented modules. A sensitivity analysis is conducted through annual transient simulations for different air gap dimensions and schedule openings. The experimental campaign demonstrates a decrease in the maximum peak indoor air temperature of between 1.9 and 4.4 % when the PCM is employed. Additionally, an increase in the minimum indoor air temperature between 4.4 and 10.4 % is achieved. Similarly, an improvement in the thermal performance of the PCM is observed when natural ventilation occurs, and it positively influences the interior surface temperature of the roof. Furthermore, the numerical results show almost zero annual thermal balance in the scenario where natural ventilation is allowed in the combination of 12 and 24 h per day through ducts with a diameter of 15 and 20 cm, respectively. Finally, this demonstrates that PCM roofs enhanced with natural ventilation could be an energy-efficient alternative for semi-arid climates under well-configured ventilation schedules and roof layers. [ABSTRACT FROM AUTHOR]

Numerical modeling of slope failures seeks to predict two key phenomena: the initiation of failure and the post-failure runout. Currently, most modeling methods for slope failure analysis excel at one of these two but are deficient in the other. For example, the Finite Element Method (FEM) models the initiation of instability well but quickly loses accuracy when modeling large deformations because of mesh distortion, restricting its ability to predict runout. Conversely, the Material Point Method (MPM) utilizes material points which move freely across a background grid, allowing for indefinite deformations without computational issues. However, MPM is restricted in its ability to model slope failure initiation due to limitations of the available boundary conditions and reduced accuracy of its stress distributions. The sequential hybridization of these two methods, initiating a model in FEM and then transferring to MPM, presents an opportunity to accurately capture both initiation and runout by a single model. The exact time for this transfer is not self-apparent, but it must be conducted after the initiation mechanism and before excessive mesh distortion. By simulating two granular column failures and two slope failures, we demonstrate the effectiveness of this hybrid FEM-MPM method and identify the appropriate time to transfer. [ABSTRACT FROM AUTHOR]

Computational efficiency of the recursion of eccentricity functions is investigated, and a kind of batch recursion method is given. Its computational efficiency is significantly superior to the direct calculation method. Moreover, this kind of batch recursion is forward so that the magnitudes of eccentricity functions experience from small to large change in the recursive process. Hence in this way the high accuracy of the recursion of eccentricity functions can be guaranteed. [ABSTRACT FROM AUTHOR]

In order to investigate redshift space distortion effect on voids, VIDE (Void Identification and Examination toolkit) algorithm is used to find cosmic voids in real space and redshift space based on a mock galaxy catalog produced by the semi-analytical galaxy formation model. The voids can be divided into "collapsed" type and "expanded" type, according to the galaxy velocity on the void wall. The results show that the fraction of the "collapsed" voids decrease as the voids' size grows, while "expanded" voids are contrary. The effective radius of two type voids differs by 20% in real space, and the mean radial density profile of "collapsed" voids is significant higher than that of "expanded" voids. Using the member galaxies to match the voids in two spaces, the comparison of the voids' number distributions of two spaces shows that the difference of voids' number between them is related to the voids' size, and half of the voids in redshift space can not matched to the voids in real space. For the matched voids, the redshift space distortion has stronger effect on the density profile of the "collapsed" voids. For the unmatched ones, their density profile is clearly different, and the infall movement of galaxies on their shell is more obvious in real space. [ABSTRACT FROM AUTHOR]

• Finite element model predicts HSR concrete fatigue life. • Model assesses impact of load frequency, stress ratio, and level. • Fatigue life of environmentally damaged concrete analyzed. High-speed railways have become a critical component of modern transportation, and ensuring the stability and durability of high-speed railway concrete under environmental and train fatigue loads is essential for ensuring project safety. This paper employs a numerical simulation method to predict the performance and lifespan of high-speed railroad concrete under fatigue loading with environmental damage. The study analyzes the effects of stress level (0.5–0.8), stress ratio (0.1–0.9), and load frequency (5 Hz–40 Hz) on the fatigue performance and lifespan of railway concrete during bending fatigue loading. A four-point bending numerical model of concrete is developed in this paper, which considers elastic modulus decay and surface cracking, in order to quantify the degradation of concrete properties in response to environmental and load-induced cracks. The numerical model is well-validated with experimental results, and the study establishes a correlation between concrete degradation and environmental and load-induced cracks, as well as the fatigue resistance of high-speed railroad concrete. The bending fatigue frequency of concrete should not exceed 25 Hz at high stress levels of 0.7. This study also shows that environment-induced initial damage will greatly reduce the fatigue resistance of concrete, and fatigue life degradation and elastic modulus decay have a nearly linear relationship. This research provides a crucial foundation for the fatigue design of concrete materials for high-speed railroads. [ABSTRACT FROM AUTHOR]

• Casson-Maxwell fluid flow in the gap of the disk and cone system is considered for heat and mass transfer applications. To the best of our knowledge and belief, it is the pioneer attempt to consider the combination of two fluids for this unique kind of geometry. The combination of non-Newtonian and viscoelastic nature properties plays a vital role in heat and mass transfer analysis. • Magnetic field in combination with the Casson-Maxwell fluid flow over the rotating con and disk is also a new addition. • The Artificial Neural Network (ANN) strategy is used to solve the problem. The results are validated through error estimation. • The various cone and disk rotations are considered to analyze the flow behavior. The Casson-Maxwell nanofluid is affected by the same and opposite rotations of the devices, which are also derived and discussed in detail. The Casson-Maxwell model is particularly useful for studying viscoplastic fluids or fluids with yield stress, making it applicable to various engineering applications, including extrusion processes, coating applications, and biomedical fluid dynamics. Casson-Maxwell fluid flow enhances mass transfer rates due to the combined effects of non-Newtonian viscosity and viscoelastic behavior. This is particularly useful in processes where mass transfer limitations play a significant role, such as in multiphase reactions or reactive distillation systems. In the context of the above applications the present model, is the combination of Casson- Maxwell fluids that flow through the varying gap of the spinning cone and disk system (CDS) for the heat transfer enhancement. The magnetic field is also imposed in the upright direction to the flow field. The solution of the transform equations has been obtained through artificial neural networks (ANN). The skin friction, heat transfer rate, and comparative analysis have been done. The Casson-Maxwell parameters that depend on the viscoelastic behavior and high viscosity term, causes the fluid to slow down and tends to store the temperature, for a long time as compared to traditional fluids. The radial component of velocity decreases due to the increase in magnetic field. The relative error of the reference and targeted dates is calculated to demonstrate the best precision efficiency of ANN, with a range of 10−3 to 10−4. [ABSTRACT FROM AUTHOR]

This work provides insights into the possible origin of comet P/2003 T12 (SOHO) and the dynamics of comet fragmentation events. We studied the hypothesis of the origin of the comet P/2003 T12 (SOHO) as a fragment of the Jupiter family comet 169P/NEAT. We studied the recent dynamical evolution of the comet pair and determined the epochs of relative minimum distance and velocity as well as the similarity between the orbits using different criteria following Rożek et al. (2011) and Kholshevnikov et al. (2016). We generated 6000 clones of both comets with orbital elements compatible with the observational uncertainties of the actual orbits and found that their evolution is stable for the past ∼ 5000 years. We found four epochs where the relative distance and velocity exhibit simultaneous minima. We studied possible fragmentation events in these epochs by applying a simple break-up model for the generation of fictitious fragments at different relative speeds. Analyzing the orbital distance between the fragments, we found some fragments that exhibit noticeable stable behavior at a very low mutual orbital distance according to several distance definitions, which suggest that those fragments evolve in orbits very similar to that of the P/2003 T12 (SOHO). We conclude that comet P/2003 T12 (SOHO) could be a fragment of comet 169P/NEAT and the most likely epoch for such fragmentation would be at least 2000 years ago (around 94 A.D.), given that the fragments that best resemblance comet P/2003 T12 (SOHO) are found in this epoch. • Orbits 169P/NEAT and P/2003 T12 (SOHO) remained stable for the latest 10000 years • Four simultaneous relative distance and velocity minima are found in the last 2000 years • Several minima that occurred before 2000 years are found but are not well defined • We found simulated fragments that evolve similar to actual P/2003 T12 (SOHO) orbit [ABSTRACT FROM AUTHOR]

We introduce the Python program THALAS (TensorFlow Hydrodynamics Analysis for Lyman-Alpha Simulations), which maps baryon fields (baryon density, temperature, and velocity) to Ly α optical depth fields in both real space and redshift space. Unlike previous Ly α codes, THALAS is fully differentiable, enabling a wide variety of potential applications for general analysis of hydrodynamical simulations and cosmological inference. To demonstrate THALAS's capabilities, we apply it to the Ly α forest inversion problem: given a Ly α optical depth field, we reconstruct the corresponding real-space dark matter density field. Such applications are relevant to both cosmological and three-dimensional tomographic analyses of Lyman Alpha forest data. [ABSTRACT FROM AUTHOR]

• Hybrid nanofluid was used in cooling applications of PV/T systems. • 3D model was used for examining conduction and convection heat transfer mechanisms. • It was seen that hybrid nanofluid has better performance than mono nanofluid. Photovoltaic thermal systems (PV/T) are system that simultaneously turn solar energy into electricity and thermal energy. Through the working fluids (water, ethylene glycol) used in the solar collector, PV/T systems aiming to reduce solar cell temperature come to the fore with increase in electrical efficiency. In recent years, the use of mono nanofluid with superior to heat transfer properties comparison conventional fluids as working fluid in photovoltaic thermal systems has become widespread. The main purpose of this study is to investigate the improvements in the use of hybrid and mono nanofluid on the performance of sheet and tubes based PV/T systems compared to water. In numerical analysis, different velocity inlet (0.02–0.08 m/s) of base fluid, CuO + Fe/water and CuO/water (50:50) are investigated via ANSYS Fluent 18.2 software. The three dimensional geometry used includes serpentine channel, absorber plate and solar cells to examine heat transfer mechanisms via conduction and convection. The results indicate that increase in inlet fluid velocity positively affects the thermal efficiency, but also increases pressure drop. However, there is no significant effect in terms of electrical efficiency. The increase after 0.06 m/s velocity gradually decrease and a more stable value is reached. The maximum increase of electrical and thermal efficiency for (φ = 2%) hybrid nanofluid is 2.14% and 5.4% comparison to water. While this value for mono nanofluid is 1.32% and 3.33%. Using hybrid nanofluid, the pressure drop was 214.78 Pa. As a consequence of the study, it is determined that the using hybrid nanofluid improves the PV/T system performance. [ABSTRACT FROM AUTHOR]

In this study, three-dimensional numerical analyses were carried out to investigate the effects of reinforcement pullout resistance including facing connection strength on the behavior of geosynthetic-reinforced soil (GRS) piers under a service load condition. Three different piers were investigated in this study, which simulated different levels of reinforcement pullout resistance. Each pier had two cases with different reinforcement stiffness J and reinforcement spacing S v but the same ratio of J / S v. Numerical results showed that reinforcement pullout resistance had a significant effect on the behavior of GRS piers. When the pullout mode prevailed, the case with small S v and low J had smaller lateral facing displacements and vertical strain of the pier under the same applied pressure as compared to the case with large S v and high J when the ratio of J / S v was kept constant. When the pullout mode did not prevail, two cases with the same ratio of J / S v showed similar performance despite different combinations of S v and J were used. To more effectively mobilize reinforcement strength and improve GRS pier performance, small reinforcement spacing or high-strength facing connection should be considered when sufficient reinforcement pullout resistance cannot be guaranteed otherwise. [ABSTRACT FROM AUTHOR]

• S-CO 2 properties are strongly temperature-dependent in the operating conditions of PTC. • S-CO 2 properties vary considerably while passing through the receiver tube. • The net heat flux from one half of the heat collecting element is always negative. • The thermal efficiency of PTC varies slightly during a typical summer day. • Change of available solar incidence dramatically alters the outlet temperature of PTC. Recently, supercritical carbon dioxide, S-CO 2 , has been suggested for utilization as the working fluid in solar thermal power plants. Replacing current working fluids with S-CO 2 , however, is not a straightforward task. This work numerically investigates the heat transfer and flow filed in a parabolic trough solar collector which carries S-CO 2. A full-scale three-dimensional model of the parabolic trough is developed and analyzed using the Star CCM + software. The variation of carbon dioxide's thermophysical properties inside the receiver tube is considered. The computational model is validated against a set of experimental data published by Sandia National Laboratories with no more than a 2.81% error margin. The numerical experiment is carried out at five different times during a typical summer day in Albuquerque, NM. Numerical results confirm that in all cases, heat loss from the upper half of the receiver tube is more than the absorbed solar incidence on that side. At noon, when the absorbed heat flux on the lower surface of the receiver tube reaches its maximum at 29810 W/m2, the net heat loss flux from the upper half of the receiver tube reaches 2622 W/m2. Consequently, the heat transfer from the upper half of the receiver tube unfavorably impacts the thermal efficiency of the parabolic trough. Additionally, while from 8 AM to 12 PM thermal efficiency drops less than 2.4%, the S-CO 2 temperature increment grows over 182%. A reverse trend occurs from noon to 4 PM, mainly due to the change in the available solar incidence. [ABSTRACT FROM AUTHOR]

The temperature rise of hydrogen tank during fast fill poses challenge on the safety of hydrogen-powered vehicles. Researchers have been continuously looking for methods to mitigate the challenge of overheating. In this paper, we proposed an innovative solution by introducing porous infill in gas tanks to slow down gas-to-wall heat transfer. The porosity of the infill is no less than 97% to maintain the volume capacity of gas tanks. To evaluate the impact of infill heat capacity, we modelled the filling process with a lumped-parameter model and obtained various time-independent temperature evolution curves. Then, we set up a 2D and a 3D finite volume model and investigated the spatial distribution of temperature rise. Four cases with different infill properties were simulated and compared. At the end of the fast fill, the infill resulted in lower tank wall temperature at the cost of higher gas temperature. The combined effect of internal gas temperature and gas-phase effective thermal conductivity largely determines the final temperature distribution. The presence of infill effectively slowed down convective heat transfer, yet overly resistive porous infill may overly slow down the gas flow and result in thermal stratification. Further studies on infill design can be done to seek more effective solutions. Image 1 • Proposed the innovative use of porous infill in gas tanks to control heat transfer. • Achieved significantly lower average tank wall temperature during fast fill. • Explained the roles of gas temperature and convective heat transfer. • Demonstrated the interaction among the infill, the gas flow and temperaturefield. • Obtained theoretical limits of using heat absorber in gas tanks. [ABSTRACT FROM AUTHOR]

The article is focused on a deep and detailed study on available Ordinary Differential Equations (ODEs) numerical solvers for biochemical and bioprocesses purposes, which are an important part of the renewable energy sector. A wide selection of algorithms is tested - starting from simple, single-step explicit methods, ending with implicit multi-step techniques. These include MATLAB, Python, C++, and C# implementations. The test configuration is an ODEs based model that simulates a biogas production reactor. The research shows that most of the tested solvers pass the accuracy-test (the difference didn't exceed 0,07%), however only selected are efficient. Most of Runge-Kutta based methods are slow and require an enormous number of steps (more than 2.5 × 108). Only multi-step implicit methods are long term solutions - they provide great accuracy while dealing well with stiff, non-smooth ODEs sets. The best from tested solutions were two MATLAB solvers - ode23s and ode15s, as well as a python solver - the LSODA. The first needed averagely 84,051s of calculation time, and 96465 steps, while ode15s required just 11,529s, performing over 20-times fewer steps. The LSODA is ranked somewhere between them with 18,806s of calculation time and the total number of 23730 steps for tested ODEs set. • The mathematical modeling as support in the design of bioenergy generation. • A wide selection of ODE solvers is evaluated. • Implicit methods are the most efficient for bioprocess models. • Different calculation environment can be utilized – MATLAB, Python, C++, C#. [ABSTRACT FROM AUTHOR]

Several new types of electrostatic precipitators consisted of conventional discharge electrode and novel collection electrode are proposed, in which the wet rope arrays replace the conventional metal plate to be used as collection electrodes. The corona discharge, gas flow, and particle migration processes in these electrostatic precipitators are numerically simulated to investigate the effect of rope array configuration on pressure drop and particle collection efficiency. It is found that the parallel-flow rope array configuration has comparable collection efficiency as the wire-plate configuration and the pressure drop is negligible. The cross-flow rope array configuration provides higher collection efficiency than wire-plate configuration if the rope layer number is larger than 2. The configuration with both parallel-flow and cross-flow rope arrays is the optimal configuration to provide higher collection efficiency than wire-plate configuration and the pressure drop is moderate. Results indicate that the wet rope array is a promising collection electrode configuration. Unlabelled Image • Wet rope arrays are used to construct several electrostatic precipitator models. • Effect of ropes configuration on the particle migration is numerically studied. • Combination of parallel and cross flow configuration is optimal. • Wet rope array provides better performance than plate collection electrodes. [ABSTRACT FROM AUTHOR]

In this research, a 3D (three dimensional) modified in-pipe hydro Savonius turbine with a deflector is studied experimentally and numerically. The new Savonius turbine has two blades, consisting of a large number of semicircles with different diameters and its axis is perpendicular to the flow direction. The turbine and a deflector are constructed 3D printing, and then tested in a laboratory rig in several operating conditions. The same conditions as in the experiments are simulated numerically. The validity of numerical results is proved by comparison with experimental results. Hence, numerical simulation is developed to investigate the effects of deflector and turbine geometry. Moreover, a theoretical consideration to evaluate output power is provided. In this study, the deflector geometry is defined by two parameters: blockage coefficient, and angle, which with turbine aspect ratio are considered as three variable parameters. The effect of changing these three parameters on the flow rate, output torque, and turbine efficiency is determined and described graphically using 3D streamlines and pressure contours. The results indicate a positive effect of increasing turbine height. However, the increase in deflector parameters is positive only up to a certain amount and beyond it that has an adverse effect on turbine performance. • New in-pipe Savonius turbine and a deflector are designed and examined experimentally and numerically. • Effect of three important parameters of the turbine and deflector on the turbine performance are focused, numerically. • The deflector and turbine geometry to obtain the highest efficiency are defined. • A theoretical consideration to evaluate output power is provided. • Turbine behavior is described by 3D streamlines and pressure contours. [ABSTRACT FROM AUTHOR]

The application of innovative technologies in the manufacture of wind turbines (WT) has produced more efficient WT that can operate successfully in low wind speed (LWS) environments. This technology has not been implemented in many LWS parts of the world due to the paucity of enabling technical information (wind resource availability and wind turbine configuration). This study uses ten years wind speed data from twelve Nigerian cities and their population densities, remote sensing, and the configuration of some commercially available LWS turbines in generating technical information suitable for data-backed decision-making on low-speed turbine deployability, operational conditions, and energy yield at 50 and 400 m. Five different numerical and metaheuristic procedures were randomly selected and utilized to estimate Weibull parameters used in computing wind energy development (WEDP) parameters (effective wind power density, EWPD, and wind available time). WT with low cut-in speeds (∼2 m.s−1) can be installed in all the cities. With the highest EWPD and WEDP ratings (100%) at both 50 and 400 m, Obudu is the most suitable location for the development of wind power infrastructure. • Wind has been accepted globally as the most dependable renewable energy source. • Site-specific wind speed regimes have to be subjected to some form of analysis. • Scale and shape parameters generated from numerical and metaheuristic procedures. • metaheuristic procedures outperform the numerical procedures at all the locations. • Wind resource appreciates such that all the sites fall into Classes 5, 6 and 7. [ABSTRACT FROM AUTHOR]

The Two-Tube heat exchangers due to their uncomplicated structure and high performance, have extensive use in the thermal engineering industries. Therefore, raising the performance and efficiency and the heat transfer capability is always a popular concept. Thus, the present paper has focused on the simulation and optimization of the application of the spiral-shaped turbulator in this kind of heat exchanger. A Computational Fluid Dynamic (CFD) code, which is 3D, is developed to solve the flow governing equations. So, 12 different cases (c1 to c12) are modeled with different spiral radii (R = 2 mm, 6 mm, and 9 mm) and pitches (500 mm, 250 mm, 100 mm, and 50 mm) to find the optimal position and configuration of the turbulator. The results indicated that c10 and c11 with R = 9 and with pitch = 250 mm and 100 mm can rise 168 % and 183.5 %, respectively, in Nusselt while increasing the pressure slippage compared to the base case. In the next part, it is endeavored to find the optimal base profile shape for the turbulator. Various profile shapes are examined and as a result, it is found that increasing the edge of the base shape increases the friction coefficient. On the other hand, the triangular base profile shape has the best thermal and hydraulic performance. [ABSTRACT FROM AUTHOR]

PTHs are massively deployed for disaster-relief after various natural disasters. Following a previous experimental study on applying PCMs to an experimental PTH, where only a very limited number of designs were experimentally examined, in this paper, different designs of applying PCMs to a disaster-relief PTH were numerically examined and the best one identified for guiding future practical applications. A numerical model for a full-scale PTH was established using EnergyPlus and experimentally validated. Using the validated model, a two-part numerical study was carried out. In the first part, a total of 16 different designs were defined and D10 identified as the most effective one, resulting in the highest number of acceptable hours at 90. In the second part, increasing PCM's thickness to beyond 20 mm would lead to negligible effects on further improving indoor thermal environment. Hence, 20 mm thickness was recommended as a reference value for future practical applications. Furthermore, the developed EnergyPlus based model for the experimental PTH may be adapted for other types of PTHs used in different climates. Hence, the outcomes of the numerical study may also guide the future applications of PCM to disaster-relief PTHs of various configurations, and located in different climates. • A mathematical model of a PTH was built and validated using EnergyPlus. • 17 different designs of applying PCM to PTHs were numerically studied. • Locating PCM on the indoor side on a movable basis was the most effective. • A PCM thickness of 20 mm was recommended for future practical application. [ABSTRACT FROM AUTHOR]

The growth of thermally grown oxide (TGO) always induces large deformation and growth stress in thermal barrier coating systems (TBCs), which play a major role in the initiation and propagation of interfacial cracks. In the present work, the influence of TGO non-uniform growth on stress evolution and interfacial crack initiation is investigated by the finite element method. The results demonstrate that, compared with a uniform growth model, the non-uniform growth of TGO increases the magnitude of residual stress in the TC layers and leads to the early initiation of interfacial cracks. Moreover, the difference in maximum stress between uniform and non-uniform growth increases with the increase in interfacial roughness. However, the change in TGO growth mode and interfacial roughness does not change the location of crack initiation, which remains at off-peak locations. • The TGO growth rate of peak location was different from that of valleys. • The uniform growth of TGO was considered in the other FE models. • Effects of TGO non-uniform growth on cracking behaviors were numerically investigated. • The non-uniform growth would lead to early cracking. • The non-uniform growth will not change the cracking location. [ABSTRACT FROM AUTHOR]

• A tapered-straight shrink (STS) tube is proposed for energy absorption. • A theoretical model is developed for the STS tube to predict its plateau force. • The deformation modes of the tapered-straight shrink tube are classified and the effects of geometric parameters on crashworthiness are discussed. This paper proposes a new straight-tapered shrink (STS) circular tube, which is planned to be applied on railway coupler for energy absorbing and overload protection. Quasi-static experiment and finite element (FE) simulation were adopted to investigate the crashworthiness performance of the STS tube. In the FE analysis we found that the compressive material properties were more suitable for accurately modeling the STS tube. The results showed that the STS tube can develop two deformation modes, i.e., shrink mode (S-mode) and buckling mode (B-mode), and the B-mode cannot meet the application requirement. Moreover, the distribution of deformation modes under different geometric parameters, namely, wall thickness (t), slope angle (α) and straight zone length (L 1), were obtained. It was found that the B-mode mainly occurs when t, α and L 1 are all large. The force-displacement characteristics showed that a plateau force occurred in some STS tubes. A theoretical model for predicting the plateau force was then proposed. Finally, the effects of geometric parameters on the peak crush force (F max) and specific energy absorption (SEA) were performed. It was found that the increases in the three parameters all result the increases in SEA and F max , and α has the most significant effect on the crashworthiness performance of the STS tube. Image, graphical abstract [ABSTRACT FROM AUTHOR]

• The advantages of pulsed flow in different applications and need of further studies. • Enhancing fluidizing fine and cohesive particles and preventing agglomeration. • Better mixing and boosting the rates of heat and mass transfer. • Preserving upward momentum and increasing maximum spoutable bed height. • Shift from dominance of experimental work to numerical studies in recent years. This paper reviews the application of pulsed flow in fluidized and spouted beds, widely used in various industries. A number of pulsing studies have been performed to improve the performance of these beds, enhance mixing and promote homogeneity. One effective way to increase the efficiency is to pulse the incoming flow, removing inactive or dead zones, thereby preventing agglomeration and settling. Although numerous studies have been carried out on conventional beds, little has been written on pulsed beds, in spite of their proven advantages. The role of pulsations in hydrodynamics, mixing, segregation, heat transfer, drying, and agglomeration are among the topics addressed. Future needs are identified and projected. [ABSTRACT FROM AUTHOR]

Abstract The use of fibre metal laminates (FMLs) offers significant improvements over more traditional materials applied in aircraft structures, such as metallic alloys. The use of this type of materials offers weight reduction, improved damage tolerance characteristics and enhanced safety due to a synergetic combination of the advantageous properties of both composites and metallic alloys. The main objective of this work was to study the effect of reinforcing a basic carbon fibre reinforced polymer (CFRP) joint with titanium laminates and/or with additional adhesive layers in the interfaces between titanium and composite, following different lay-up configurations. The lay-up configuration that led to the best results in terms of failure mode and failure load, was found to be the configuration using titanium laminates on a basic CFRP substrate and additional layers of film adhesive in between the metal laminate and the CFRP. A numerical model using finite element analysis with cohesive zone elements was also developed, with the aim of studying the performance of the different proposed configurations, correlate the models with the experimental results, and to aid the identification of the optimal material to use for reinforcement of the CFRP adherend. [ABSTRACT FROM AUTHOR]