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Beam-column joints' behavior is a key research focus due to their critical role in maintaining structural integrity and safety during earthquakes. While concentric joints have been extensively studied, eccentric joints, where beams' centerlines deviate from columns' centerlines, remain relatively unexplored. Beam-column joints exhibit more complex behavior, experiencing a significantly higher shear force (approximately six-fold that of a column), along with flexural moments and normal forces. The joint's eccentricity introduces a torsional moment that amplifies shear stress, and the beam is subjected to an out-of-plane moment (around one-sixth of the primary moment). The out-of-plane moment reduces the joint's resistance mechanism by reducing the confinement provided by beams. To examine the influence of beam eccentricity on the ductility, strength, and failure mechanism of beam-column joints, comprehensive nonlinear finite element (FE) analyses were conducted utilizing experimental eccentric beam-column joints, followed by meticulous validation of the developed model. The models employed incompatible mode mesh element and energy-based models for the concrete material behavior, utilizing an explicit solver. The models were used to examine the impact of various geometric parameters, boundary conditions, and axial load levels on behaviors (global and local) of the beam-column joint subassemblies. The examined geometric parameters encompass aspect ratios of joint and column for both joint types (exterior and interior). Joint behaviors were observed to be significantly influenced by the boundary conditions of the column. Furthermore, the aspect ratio of the joint, representing the beam-to-column depth ratio, played a predominant role in determining the joint failure mechanism by limiting their ability to develop beam hinges. Increasing the aspect ratio of the column had a modest effect on the joint's shear strength but improved the joint subassemblies' ductile behavior, despite increasing the joint's torsional moment. Higher column axial load levels increased the joint's shear strength and led to a shift in cracking patterns from diagonal to vertical. Interestingly, the study found that interior joints experienced higher out-of-plane moments. Exterior and interior joints maintained a level of approximately 62.5 % as a ratio between their shear strength across all models. Moreover, it was observed that yielding of joint stirrups correlated with a shear distortion angle of approximately 0.5 × 10 − 2 rad. Restrictions of ACI provisions on the aspect ratio of the joint seem to be conservative for eccentric interior joints. On the other side, the ACI provisions might overestimate eccentric exterior joint shear strengths as the aspect ratio exceeds unity. [ABSTRACT FROM AUTHOR]

The first phase of this study aimed to validate multi-scale approaches based on Representative Volume Elements (RVEs) for graphene–polyethylene nanocomposites. stress–strain curves of experimental results were compared with numerical homogenization results. The stress amplification obtained from these simulations was used to predict GNP aspect ratios, demonstrating good agreement with permeability results. After validation of the multiscale approach, this study investigates the adhesion between nanoparticles and matrix in anisotropic GNP-HDPE metamaterial nanocomposites, emphasizing the role of the carboxyl (COOH) functional group in improving adhesion. The RVE model is used to investigate the debonding initiation and progression in these anisotropic nanocomposites under tensile and shear loading. Results indicate a variance in debonding onset and growth depending on orientation relative to the GNP axis. In tensile loading, debonding initiates at higher strains along the GNP axis than perpendicularly. Under shear loading within an anisotropic distribution, debonding behaviour varies significantly between planes perpendicular and parallel to the GNP axis. GNP surfaces with fully debonded surfaces slightly exceed 0.6% perpendicular to the GNP axis but increase to over 10.5% parallel to it. [ABSTRACT FROM AUTHOR]

Visual cryptography scheme is initiated to securely encode a secret image into multiple shares. The secret can be reconstructed by overlaying the shares, making it perceptible to the human visual system. Random grid visual cryptography offers key advantages over traditional visual cryptography such as avoiding pixel expansion and the requirement for intricate codebook design. This paper is intended to conduct a critical analysis and implementation of various algorithms in random grid visual cryptography from 2011 to 2022. The focal parameters of this study are theoretical contrast, experimental contrast and visual quality. Experiments were done on binary images for (k, n) algorithms considering different values of threshold. By implementing and analysing the results, the scheme which gives the optimal result is identified. [ABSTRACT FROM AUTHOR]

With advancements in additive manufacturing (AM) techniques, high-quality triply periodic minimal surface (TPMS) structures can now be produced. TPMS walled heat exchangers (HX) hold significant potential for industrial applications and are receiving increasing attention. This paper explores the impact of various TPMS design variables on flow and thermal performance to optimize TPMS heat exchangers for compactness, high efficiency, and low pressure drop. The design variables examined include the type of TPMS lattice, unit cell size, wall thickness, aspect ratio, TPMS orientation, and equivalent thickness. The study reveals that the flow and heat transfer performance of TPMS structures are significantly affected by these design variables. For the Gyroid, Diamond, and SplitP lattices, performance is nearly identical when the surface-to-volume ratio is kept constant. The average velocity of the fluid in the TPMS HX should be 0.3 m/s. The corresponding Re is between 300~800. Thin wall thickness, small equivalent thickness, and flat lattice configurations can significantly reduce pressure drop while maintaining the overall heat transfer coefficient. Additionally, the angle between the flow direction and TPMS orientation can increase pressure drop. Three aluminum heat exchangers were successfully printed using an AM machine, and testing results are comparable with theoretical prediction. [ABSTRACT FROM AUTHOR]

Evaporation‐induced self‐assembly (EISA) is a versatile method for generating organized superstructures from colloidal particles, offering diverse design possibilities through the manipulation of colloid size, shape, substrate nature, and environmental conditions. While some work highlighted the potential of EISA to investigate phase transitions of inorganic liquid crystals, the influence of sample environment to determine their phase diagrams is often overlooked. In this work, the self‐assembly of lyotropic liquid crystals is compared by EISA on substrates, and by acoustic levitation (absence of substrate). The focus is on imogolite nanotubes, a model colloidal system of 1D charged objects, due to their tunable morphology and rich liquid‐crystalline phase behavior. It demonstrates the feasibility to obtain phase transitions in levitating droplets and on soft hydrophobic substrates, whereas self‐assembly is limited on rigid hydrophilic supports. Moreover, the aspect ratio of the nanotubes proves to be a pivotal factor, influencing both transitions and the resulting materials shape and surface. Besides material shaping, acoustic levitation emerges as a promising method for studying phase transitions by EISA, toward the rapid establishment of phase diagrams from diluted to highly concentrated states using a limited volume of sample. [ABSTRACT FROM AUTHOR]

The frequency solutions of finite elements may significantly deteriorate as the mesh aspect ratios become large, which implies a severe element side-length discrepancy. In this work, an aspect ratio dependent lumped mass (ARLM) formulation is proposed for serendipity elements, i.e., the two-dimensional eight-node and three dimensional twenty-node quadratic elements for linear problems. In particular, a generalized parametric lumped mass matrix template taking into account the mesh aspect ratios is introduced to examine the frequency accuracy of serendipity elements. This generalized lumped mass matrix template completely meets the mass conservation and non-negativity requirements. Subsequently, analytical frequency error estimates are developed for serendipity elements, which clearly illustrate the relationship between the frequency accuracy and element aspect ratios. Accordingly, optimal mass parameters are obtained as the functions of element aspect ratios through solving a constrained optimization problem for frequency accuracy. It turns out that the resulting aspect ratio dependent lumped mass matrices yield much more accurate frequency solutions, in comparison to the diagonal scaling lumped mass (HRZ) matrices and the mid-node lumped mass (MNLM) matrices without consideration of the element aspect ratios, especially for finite element discretizations with severe element side-length discrepancy. The superior accuracy and robustness of the proposed ARLM over HRZ and MNLM are consistently demonstrated by numerical examples. [ABSTRACT FROM AUTHOR]

Estimation of the reservoir parameters such as porosity, lithology and saturation from well logs and seismic data would require the shear wave velocity data. The high cost of shear wave well logging and subsequently the lack of the shear velocity log in most wells are the main reasons to estimate the shear velocity log. The routine methods for estimating the shear velocity are empirical relations, regression analysis, intelligent methods and rock physics models. Most of these methods do not include the impact of geometry of pore spaces and minerals (aspect ratio). Excluding geometry of pore spaces and minerals from the estimation procedure would create considerable estimation error in the oil and gas reservoirs, particularly in the carbonates. In the first step, shear velocity log is estimated using empirical relations, regression analysis and neural network methods. The estimated shear velocity log using neural network is better than empirical and regression methods. Subsequently, a new simple equation utilizing rock physics models is developed to estimate the shear velocity log. The Xu–White (Geophys Prospect 43: 91–118, 1995) and as reported by Gassmann (Elasticity of porous media, Vierteljahrsschrde Naturforchenden, Gesellschaft, 1951) relations were employed to include the impact of lithology, fluid, minerals and pore spaces. The estimated shear velocity log using new equation compares well with the original as reported by Gassmann (Elasticity of porous media, Vierteljahrsschrde Naturforchenden, Gesellschaft, 1951) and Xu–White (Geophys Prospect 43: 91–118, 1995) rock physics methods. The average difference between the measured and estimated velocity logs using new method is 12.6 m/s (or 0.41%). This equation includes the impact of major parameters in the rock physics model in the simple form; thus, it would be applicable in the carbonate and clastic reservoirs. [ABSTRACT FROM AUTHOR]

The effects of soluble ions on the morphology and crystal growth of calcium sulfate hemihydrate whiskers are very significant. In order to gain a deeper understanding of the basic theory of regulating whiskers, this paper summarises the progress of research on the effects of different types and concentrations of soluble cations in desulfurization gypsum on the whisker preparation. The low concentration of Na+ has a small effect on the calcium sulfate hemihydrate whiskers and barely affects the morphology and surface smoothness of the whiskers. The content of K+ is suitable to be 3% (mass fraction) or below, and the higher content has a detrimental effect on the growth of calcium sulfate hemihydrate whiskers. Mg2+ makes the whisker surface more homogeneous and crystalline. And the trace amount of selective adsorption of Al3+ has no effect on the whisker length-to-diameter ratio. Similar to K+, Fe3+ also has the optimal concentration, which is lower than 2 mmol / L. Unlike the cations mentioned above, Cu2+ is not from the raw material, but is an additional ion introduced in the doping of the appropriate amount of Cu2+ is conducive to the formation of whiskers with a smooth and uniform surface. [ABSTRACT FROM AUTHOR]

Mathematical modeling plays a diverse and crucial role in the chemical industry and academia. This manuscript describes how the physical and mechanical engineering disciplines help the commercialization of catalysts from evaluation to scale‐up and manufacturing. Forming and shaping the catalyst is the first basic step in the catalyst manufacturing industry. Part A shows some of the classic process methods that are employed for this purpose. Catalyst extrudates require proper engineering and process control of their aspect ratio. Catalyst extrudates with a high aspect ratio tend to yield a low reactor fill due to a loose packing. Catalyst extrudates with a low aspect ratio tend to yield high pressure drop. Part B introduces the tensile strength of the catalyst in order to predict the aspect ratio of catalyst extrudates in commercial plants. A force‐balance between the tensile strength of the catalyst and the impact forces due to collision experienced during manufacture leads to the dimensionless group Be. The group Be allows to introduce and quantify the severity of equipment and the severity of entire commercial plants. [ABSTRACT FROM AUTHOR]

Through exploring the effects of low pH on the composite system of desulfurization gypsum (DG) enhanced by melamine-formaldehyde resin (MF), it is found that the inducing of sulfate-ion, in contrast to chloride and oxalate ions, favors the longitudinal growth of the crystalline form of the hydration product, which was relatively simple and had the highest length to width (L/D) ratio. At the same time, MF can also improve L/D ratio of gypsum hydration products, which favors the formation of hydrated whiskers. Finally, in a composite system composed of hemihydrate gypsum, MF, and glass fibers, when dilute sulfuric acid was used to regulate pH=3–4, the tight binding formed among the components of the composite system compared to pH=5–6. The hydration product of gypsum adheres tightly to glass fiber surface and produces a good cross-linking and binding effect with MF. The flexural strength, compressive strength, elastic modulus, and water absorption of the desulphurized gypsum composite board is 22.7 MPa, 39.8 MPa, 5 608 MPa, and 1.8%, respectively. [ABSTRACT FROM AUTHOR]

In the present work, the efficacy of placing comma-shaped pin fins in a minichannel heat sink is studied. The effect of different geometrical factors as well as fluid additives are evaluated. Pin fins' distance and aspect ratio at five levels were introduced as a geometrical parameter. Moreover, three fluid additives including nanofluid based water, Micro-encapsulated PCM (MPCM) Slurry and MPCM Slurry with nanofluid at different concentrations were added to the base fluid. Water as a base fluid at 300 K and at five different Reynolds number enters the channel. Eight sets of comma-shaped pin fins are attached to the constant heat flux (100 kW/m2) surface of heat sink to enhance the heat transfer. In the numerical analysis, average temperature, Nusselt number, friction factor, and pressure drop are considered as output elements. The models presented in the current study is simulated using ANSYS Fluent software, which employs finite volume method. Results revealed that, as the pin fin distance increases, the average temperature decreases, and both the Nusselt number and the pressure drop rise. This is due to the specific shape of comma pin fins that intensifies the vortex formation along the channel as the fin distance increases. Furthermore, α =0.8 is an optimum aspect ratio in which the Nusselt number is at the highest value that is about 7% higher than the other cases. It is also concluded that altering the fluid additive augments the heat trasnfer in fluid domain. Among different fluid structures, MPCM slurry has the highest Nusselt number at all Reynolds number while the pressure drop is high as well. Blending MPCM slurry with 15% concentration and nanofluid with 0.1% concentration offers lower average temperature up to 311 K compared to 335 K for pure water. [ABSTRACT FROM AUTHOR]

Thin flexible sheets are utilized in numerous engineering applications. In the manufacturing process, the sheets are supported in fluid flow. Then, flutter is generated on the sheet, which results in serious quality defects (wrinkle etc.). Thus, understanding of the flutter characteristics is quite important to prevent these serious defects. In this study, the influence of the aspect ratio of sheets on the post-critical behavior, e.g. flutter amplitude and hysteretic behavior, is investigated by nonlinear numerical simulations and wind-tunnel experiments. As a result of calculations and experiments focused on the aspect ratio, the critical flutter velocity tends to increase as the aspect ratio is decreased owing to the three-dimensionality of the fluid flow. The flutter amplitude increases with increasing aspect ratio. Moreover, no hysteretic behavior is observed regardless of the aspect ratio for a relatively small mass ratio. In contrast, hysteretic behavior is generated with a large aspect ratio for large enough mass ratios. [ABSTRACT FROM AUTHOR]

This work investigates the mixing phenomenon within rectangular cavities of various aspect ratios, all four sides driven at the same speed in a clockwise direction. For the creeping flow regime, an analytical solution using real eigenfunction expansion is derived. Inertia's influence under higher flow rates is then numerically simulated using a built-in finite element technique in the Mathematica software. For a square cavity, the inherent structural symmetry is combined with the dynamical symmetry of the velocity field. However, changing the aspect ratio disrupts this symmetry in the horizontal and vertical velocities. Interestingly, unlike other wall-driven cavity flows found in the literature, the recirculating zone in this system forms a single vortex without any corner eddies at any Reynolds number. This unique feature offers tremendous potential for controlling the mixing process. In the highly viscous regime, the pressure field is dominated by odd functions in both x and y. As inertia increases, even functions in x and y become more significant, causing the velocities near the moving lids to overshoot their steady-state values. The extent of this overshoot depends on the cavity's aspect ratio, and such a fast mixing regime could be valuable for industrial fluid mixing applications. • The flow dynamics within a rectangular cavity of varying aspect ratios are studied. • The clockwise movement of all four lids at a constant speed are considered. • The slow-motion Stokes layer is analytically resolved by an eigenfunction technique. • Finite element simulations within Mathematica are performed. • A single recirculating vortex for mixing within the cavity occurs. [ABSTRACT FROM AUTHOR]

A semi-planing catamaran is a type of marine craft that benefits from high speed, in conjunction with the its inherent characteristics such as a large deck and high transverse stability. The aspect ratio, length over the beam of a demi-hull, significantly affects the hydrodynamic performance of this vessel. In this study, the effects of the aspect ratio on the hydrodynamic performance of a semi-planing catamaran in calm water and waves are investigated using numerical simulations. The numerical simulation of the AUT-SEM00 model itself is validated by its model test results. The results show that increasing the aspect ratio significantly increases the wetted surface, and that the increase in resistance in calm water is negligible. In addition, increasing the aspect ratio radically reduces the amplitude of vertical acceleration in waves at the center of gravity by up to 85%. Consequently, the seakeeping performance is considerably improved, and the risk to crew and equipment is reduced. [ABSTRACT FROM AUTHOR]

In general, pile foundations are utilized to support structures like tall buildings, bridges, and transmission towers, which are frequently subjected to lateral stresses initiated by wind, action of waves, earthquakes, or traffic loads. Several high-rise structures, highway and railroad overpasses, as well as transmission towers, are constructed near slopes and rely on pile foundations for support. Due to the effects of wind and waves, pile foundations are continuously subjected to cyclic loads. For piles supporting tall buildings, transmission towers, offshore structures, or infrastructure in seismic zones, 1-way or 2-way cyclic lateral loads are commonly applied. Therefore, while designing pile foundations, it is essential to understand how piles behave laterally when they are located near a sloping crest. One of the primary challenges in ensuring the efficient functioning of the superstructure is analyzing how the soil and foundations respond when exposed to long-term lateral loads, such as wind, over an extended period on the piles of offshore platforms. Because of the presence of slope, the pile's lateral load capacity decreased due to the reduced ability of the soil to provide passive resistance. This paper presents small-scale 1-g model tests conducted on the sand to assess the loss of pile's lateral capacity when subjected to 100 cycles under 1 and 2-way cyclic loading. The Relative Density (60%) and varying slopes (Horizontal ground, 1V:3H) with varying spacing (5D and 7D) and aspect ratios (L/D) of 25 and 40 were implemented in this study. Cyclic lateral load tests were performed for sloping as well as horizontal ground. A major reduction in lateral capacity, exceeding 60%, was observed due to the application of cyclic loading. Moreover, the transition from horizontal ground (HG) to sloping ground (SG) decreased the maximum bending moment by 25–40%. This study exemplifies the piles' behaviour when subjected to cyclic lateral loading while resting on a sloping crest, which represents a critical scenario in pile foundation design. [ABSTRACT FROM AUTHOR]

Pumping fluid is one of the crucial parts of any microfluidic system. Using electric and magnetic fields as a substitute for moving parts can have many advantages. In this study hydrodynamic and heat transfer characteristics of electroosmotic flow under influence of lateral electric and transverse magnetic field, are studied numerically. Results indicate that the dimensionless parameters such as Hartmann number, intensity of the lateral electric field, pressure gradient parameter and aspect ratio have an important role in controlling flow. It can be implied that the enhancement of pressure gradient leads to the decrease of critical Hartmann number, and this dependency can be reduced from 44% to 7% for S = 0:5 to S = 50 in two pressure gradients of = 1 and = 20. In addition, the reduction of aspect ratio of microchannel section leads to the increment of critical Hartmann number in a specified lateral electric field. At the end, thermal analysis is being done by consideration of the effects of magnetic and electric fields on the Nusselt number. [ABSTRACT FROM AUTHOR]

The distance-aware dynamic label assignment(DDA) algorithm was proposed to address ssues such as the lack of consideration for aspect ratio of metal surface defects and poor localization ability towards target distribution during the allocation of positive and negative samples in training processes of metal surface defect detection model. DDA did not change the structures of original detec¬ion model and did not increase computational expenses. A new distance loss calculation paradigm was proposed based on geometric characteristics of real frame to optimize the regression problem with a wide aspect ratio. The regression offset in iterative processes was decoded as predicted frame coordi¬nates. Finally, the comprehensive intersection and union ratio information were calculated among the predicted frame, anchor frame and real frame, and positive and negative samples were dynamically se¬ected to improve training accuracy. It was verified through the surface defect detection task of cold-olled strip in a steel plant in Wuhan, and a public hot-rolled strip surface defect data set was intro¬duced for generalization testing. The detection results are significantly improved, which has practical pplication values for metal surface quality specifications [ABSTRACT FROM AUTHOR]

The use of thermal energy storage (TES) contributes to the ongoing process of integrating various types of energy resources in order to achieve cleaner, more flexible, and more sustainable energy use. Numerical modelling of hot storage packed bed storage systems has been conducted in this paper in order to investigate the optimum design of the hot storage system. In this paper, the effect of varying design parameters, including the diameter of the packed bed, the storage material, the void fraction, and the aspect ratio of the packed bed, on storage performance was investigated. COMSOL Multiphysics 5.6 software has been used to design, simulate, and validate an axisymmetric model, which was then applied to evaluate the performance of the storage system based on the total energy stored, the heat transfer efficiency, and the capacity factor. In this paper, a novel-packed bed was proposed based on the parametric analysis. This involved a 0.2 void fraction, 4 mm porous media particle diameter, and Magnesia as the optimum storage material with air as the heat transfer fluid. [ABSTRACT FROM AUTHOR]

In recent decades, reinforced concrete (RC) shear walls have been one of the best structural solutions to resist lateral load in high-rise buildings. Shear wall openings are essential for preparations and architectural requirements, which weaken the wall, reducing bearing capacity, energy absorption, and stiffness while also causing stress concentrations. This paper presents a comprehensive finite element (FE) investigation of the behavior and performance of RC shear walls with openings and subjected to lateral loads. The study aims to evaluate the influence of various parameters, such as opening location, size, wall aspect ratio, axial load, and concrete strength, which affect the performance of shear walls. FE models were developed to simulate the seismic response of RC shear walls under the combined effect of constant axial and lateral loads. The obtained results from the FE model showed a successful validation using the experimental data available in the literature. The FE analysis results demonstrate that the inclusion of lower openings leads to a 25% decrease in the bearing capacity of the wall when compared to the upper openings. Moreover, it was observed that augmenting the sizes of the openings and the aspect ratios of the wall resulted in declines in the strength, stiffness, and energy absorption capacity of the wall while simultaneously enhancing the ductility and displacement of the RC shear walls. [ABSTRACT FROM AUTHOR]

This study investigates fiber-reinforced cementitious composites (FRCCs), concentrating on the geometric features of soft micro- and macro-fibers with a lower elastic modulus and higher aspect ratios than steel fibers. There is no literature predicting the ratio of ultimate flexural strength to the initial cracking strength of FRCC. The composites were made using a cement-to-sand ratio of 1:2.5, with 20% fly ash as a partial substitution and two water-to-binder ratios (0.55 and 0.60). Carbon, polypropylene, and natural sisal fibers were added at quantities ranging from 0.4% to 2.27%, with aspect ratios ranging from 71 to 3750. Flexural strength was determined using 75 × 75 × 380 mm3 prisms, whereas compressive strength was evaluated using 50 mm cubes. Load–deflection curves were created to investigate fracture behavior. The post-cracking behavior was determined using the matrix compressive strength, fiber type, amount, and aspect ratio. Regression analysis of data from this work and previous publications yielded an equation for predicting the ratio of the modulus of rupture (MOR) to the initial fracture strength. After cracking, carbon-fiber-reinforced cementitious composites (CFRCCs) were fragile, but their flexural strength was two to three times higher than that of control specimens. This was because the increased fiber volume and aspect ratio made the materials stronger and better at handling load and deflection. [ABSTRACT FROM AUTHOR]

Nanocellulose has emerged as a widely utilized building block in nanostructured materials due to its availability, sustainability, large surface area, and high stiffness and aspect ratio. The wet or dry elastoplastic properties of these materials are determined by the fibrils' stiffness, chemical properties, hemicellulose content, and the number of fibril contacts. However, the specific contributions and relative importance of each factor remain unclear. Therefore, this work was devoted to systematically comparing the material properties of gels, aerogels, and wet and dry sheets prepared from CNFs with different aspect ratios, chemical functionality, and hemicellulose content. The fibrils were prepared by chemical and mechanical processing of different pulps. By preserving the native structure as much as possible, higher aspect ratio fibrils can be obtained, which allows for the development of more mechanically robust materials. The results demonstrate that higher aspect ratios lead to more interconnected networks at a lower solids concentration, resulting in a more evenly distributed stress and longer-range stress transfer, yielding stiffer and more ductile materials. The most important finding was that the aspect ratio influences the network formation, resulting in different network topologies. The results were also compared to earlier published data and integrated into a theoretical beam-bending model for a complete elastoplastic description of the network properties, including the influence of fibril aspect ratio and chemical functionality. This information improves our understanding and description of nanofibril networks for which general models have been missing. It can be used to optimize nanofibril preparation and, hence, the resulting eco-friendly materials. [ABSTRACT FROM AUTHOR]

The morphology and distribution structure of the reinforcement have a significant effect on the mechanical properties and cutting process of composites. In this paper, two-dimensional tensile and cutting models are established respectively, and the validity of the models is verified by comparing with the cutting force and chip morphology in the experiment. The effects of network reinforcement distribution and particle aspect ratio on the mechanical properties and surface quality of SiCp/Al composites were compared and analyzed. Results show that the aggregation of particles can enhance their continuity, thereby improving their bearing capacity. Network structures and the increase in aspect ratios of particles both can enhance the degree of aggregation of particles, thereby improving their bearing capacity. However, an increase in the degree of aggregation of particles will also lead to an increase in cutting forces and a deterioration in surface quality. The hybrid network structure of particles with different aspect ratios was proposed. Compared with the ellipse particle reinforced network composites model, the network structure with hybrid particles improved the surface quality by 41.7%, while ensures the strengthening effect of the composite material. [ABSTRACT FROM AUTHOR]

In this paper, the influence of decreasing Zr content (0.0110 wt%, 0.0044 wt%) on the microstructure, MnS inclusion characteristics, and mechanical properties of medium carbon ferrite-pearlite steel was studied. The results show that the volume fraction of intragranular ferrite (IGF) in steel increases with a reduction in Zr content. The ductility of the steel is reduced by 1.83%, the impact toughness is increased by 2.5 times, and the yield strength is almost unchanged. Compound MnS inclusions are the main inclusions that induce IGF formation. The proportion of heterogeneous nucleation of MnS inclusions using oxides as nucleation sites is increased, which is the main reason for the increase in the volume fraction of IGF. Furthermore, MnS inclusions change from type Ⅲ to type Ⅰ and Ⅱ, and their distribution is gradually uniform. Thermodynamic analysis reveals that the underlying cause for the morphological transformation of MnS inclusions is the rapid surge in the supersaturation of S element in molten steel. The presence of liquid-phase low-melting inclusions (MnS–Al2O3) promotes the formation of type Ⅰ MnS inclusions. The volume fraction and the dimension perpendicular to the fracture surface of the MnS inclusions are increased by at least 33% and 111%, while their aspect ratio is reduced by a maximum of up to 19%. The change in the volume fraction of MnS inclusions is the primary factor contributing to the decrease of tensile plasticity. The toughness of steel is mainly affected by the aspect ratio and the dimension perpendicular to the fracture surface of MnS inclusions.

Abstract In recent years, there has been an increasing use of Microbially Induced Calcite Precipitation (MICP) technology in ground improvement. Adding fiber to bio-cemented sand leads to significant improvements in its properties. This paper examines how coir fiber and microbially induced calcite precipitation (MICP) might be used to improve the engineering qualities of fine sand. The sand was mixed with Coir fiber at varying Fiber Contents (FC) of 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% by weight of sand. Additionally, varied Aspect Ratios (AR) of 45, 90, 136, 182, and 227 were considered. The mixture also included urease-producing bacteria (Sporosarcina Pasteurii), as well as solutions of urea and calcium chloride with 3M molarity. The untreated and treated sand samples were submitted to a Direct Shear Test (DST). The study found that the shear strength parameters, such as the angle of internal friction, increased by 1.1 times compared to standard fine sand. Additionally, the angle of internal friction (ϕ) of fiber-reinforced sand with MICP showed 1.4 times increase, while the cohesion values demonstrated a sixfold increase compared to MICP fine sand. It was determined that the optimal aspect ratio was 182, and the optimal fiber content was 0.3%. Moreover, the Scanning Electron Microscope (SEM) was utilized to examine the calcite formations present in the treated sand samples, and calcite precipitation was observed between the pores of the soils.

In recent decades, reinforced concrete (RC) shear walls have been one of the best structural solutions to resist lateral load in high-rise buildings. Shear wall openings are essential for preparations and architectural requirements, which weaken the wall, reducing bearing capacity, energy absorption, and stiffness while also causing stress concentrations. This paper presents a comprehensive finite element (FE) investigation of the behavior and performance of RC shear walls with openings and subjected to lateral loads. The study aims to evaluate the influence of various parameters, such as opening location, size, wall aspect ratio, axial load, and concrete strength, which affect the performance of shear walls. FE models were developed to simulate the seismic response of RC shear walls under the combined effect of constant axial and lateral loads. The obtained results from the FE model showed a successful validation using the experimental data available in the literature. The FE analysis results demonstrate that the inclusion of lower openings leads to a 25% decrease in the bearing capacity of the wall when compared to the upper openings. Moreover, it was observed that augmenting the sizes of the openings and the aspect ratios of the wall resulted in declines in the strength, stiffness, and energy absorption capacity of the wall while simultaneously enhancing the ductility and displacement of the RC shear walls.

Extrusion of viscous lava produces domes and spines, collapses of which pose a significant local hazard. Understanding extrusion processes and probabilistic hazard estimation require comprehensive datasets of geometric parameters. We introduce Morphology of Viscous Extrusions (MoVE), a collation of 323 observations of height and width from 80 extrusions at 46 volcanoes globally with compositions spanning basaltic through rhyolitic. Filtering this dataset for sample size, age, and time series overrepresentation reduces the composition range to basaltic-andesitic through dacitic, for which we do not identify a statistically significant effect of composition on extrusion geometry. Young (

It is well known that coarse-grained super-elastic NiTi shape memory alloys (SMAs) exhibit localized rather than homogeneous martensite transformation (MT), which, however, can be strongly influenced by either internal size (grain size, GS) or the external size (geometric size). The coupled effect of GS and geometric size on the functional properties has not been clearly understood yet. In this work, the super-elasticity, one-way, and stress-assisted two-way shape memory effects of the polycrystalline NiTi SMAs with different aspect ratios (length/width for the gauge section) and different GSs are investigated based on the phase field method. The coupled effect of the aspect ratio and GS on the functional properties is adequately revealed. The simulated results indicate that when the aspect ratio is lower than about 4:1, the stress biaxiality and stress heterogeneity in the gauge section of the sample become more and more obvious with decreasing the aspect ratio, which can significantly influence the microstructure evolution in the process involving external stress. Therefore, the corresponding functional property is strongly dependent on the aspect ratio. With decreasing the GS and the aspect ratio (to be lower than 4:1), both the aspect ratio and GS can affect the MT or martensite reorientation in each grain and the interaction among grains. Thus, due to the strong internal constraint (i.e., the constraint of grain boundary) and the external constraint (i.e., the constraint of geometric boundary), the capabilities of the functional properties of NiTi SMAs are gradually weakened and highly dependent on these two factors. [ABSTRACT FROM AUTHOR]

Solar air heaters (SAHs) are widely used for drying vegetables and fruits or for domestic heating. Certain sizing parameters are necessary to obtain the right dimensions for the required air temperature, flow rate, and thus useful thermal energy. The well‐known Hottel–Whillier–Bliss equation was used and made dimensionless by applying the collector longitudinal and transversal aspect ratios (rl and rt) of a double‐glazed flat plate solar air heater (DG‐FPSAH). The steady‐state equations are solved to determine the average temperatures. Thereafter, one could calculate the overall loss heat coefficient and efficiency factor, obtained analytically. A Matlab code was developed to estimate primarily unknown temperatures, useful energy, and the Nusselt number. An iterative numerical method is used until convergence occurs. The inlet cross‐sectional area and air flow velocity are defined as input data. The proposed sizing method depends on the output temperature required by the customer. This temperature can be determined from the plotted curves of the dimensionless ratios. Hence, the SAH‐needed dimensions are determined graphically depending on the functional requirements for construction planning, such as technology choice, work breakdown, and budgeting. In the present case study, based on the input parameters, an airflow rate of 1.2 kg/s entering a DG‐FPSAH with an output temperature of 41.5°C yields the dimensions of Lin = 3.824 m, Win = 2.735 m, and Hin = 0.1825, specifying the collector length, width, and air duct height. The gathered energy and thermohydraulic efficiency are: Qu = 7.91 kW, ηcol = 0.752, respectively. [ABSTRACT FROM AUTHOR]

Abstract To address the environmental issues arising from the growing scarcity of natural fine aggregates (NFA) and landfilling of waste glass, research is being conducted globally to utilize waste glass as a sustainable fine aggregate. However, contradictory results have been obtained regarding the effect of the type of waste glass and the physical properties of waste glass fine aggregate (GFA) on concrete, making it challenging to promote the use of GFA in concrete. Therefore, to promote the use of GFA in concrete, it is necessary to examine it under field conditions, such as mass-production processes or real-scale concrete applications. This study introduced a mass-production process for GFA, and the effect of mass-produced GFA on mortar was evaluated. The fine aggregate properties (particle aspect ratio, crushing rate, and solubility) of the GFA and the effects of color, content, and particle size on the mortar properties (compressive strength, flexural strength, and ASR expansion behavior) were analyzed, along with the results reported in previous studies. Consequently, the high aspect ratio and microcracks in the particles of mass-produced GFA led to an increase in the strength reduction and ASR expansion of the mortar. These effects appear to be particularly severe for transparent GFA. Overall, this study proposed the content of GFA within 20% or the replacement of fine particles (

The use of thermal energy storage (TES) contributes to the ongoing process of integrating various types of energy resources in order to achieve cleaner, more flexible, and more sustainable energy use. Numerical modelling of hot storage packed bed storage systems has been conducted in this paper in order to investigate the optimum design of the hot storage system. In this paper, the effect of varying design parameters, including the diameter of the packed bed, the storage material, the void fraction, and the aspect ratio of the packed bed, on storage performance was investigated. COMSOL Multiphysics 5.6 software has been used to design, simulate, and validate an axisymmetric model, which was then applied to evaluate the performance of the storage system based on the total energy stored, the heat transfer efficiency, and the capacity factor. In this paper, a novel-packed bed was proposed based on the parametric analysis. This involved a 0.2 void fraction, 4 mm porous media particle diameter, and Magnesia as the optimum storage material with air as the heat transfer fluid.

Abstract The Ferromagnetic Resonance (FMR) phenomenon, marked by the selective absorption of microwave radiation by magnetic materials in the presence of a magnetic field, plays a pivotal role in the development of radar absorbing materials, high speed magnetic storage, and magnetic sensors. This process is integral for technologies requiring precise control over microwave absorption frequencies. We explored how variations in resonance fields can be effectively modulated by adjusting both the shape and stress anisotropies of magnetic materials on a flexible substrate. Utilizing polyethylene-naphthalate (PEN) as the substrate and Permalloy (Ni79Fe21, noted for its positive magnetostriction coefficient) as the magnetic component, we demonstrated that modifications in the aspect ratio and bending repetitions can significantly alter the resonance field. The results, consistent with Kittel’s equation and the predictions of a uniaxial magnetic anisotropy model, underscore the potential for flexible substrates in enhancing the sensitivity and versatility of RF-based magnetic devices.

In recent years, postharvest loss has been a serious concern. However, knowledge of the mechanical properties is vital to developing any postharvest technology for rice production better. The objective of this research is to conduct a comparative analysis of the mechanical properties of selected paddy rice at different variety-moisture content interactions. The mechanical properties of AGRA rice, CRI-Amankwatia, CRI-Enapa, and CRI-Dartey, four local varieties developed in Ghana, are compared at 11.5%, 13.0% and 16.5% on wet basis moisture content. Tukey's Honest Significant Difference (HSD) comparisons test was conducted during data analysis to compare all possible pairwise combinations of the various varieties and moisture content interaction. From the results, it was concluded that CRI-Dartey, at 16.5%, recorded the highest Sphericity and Aspect Ratio of 0.391 mm3 and 0.298 mm3, respectively. For grain mass, AGRA rice at 13.0% also recorded 0.0312 g as the highest score. The GM1000, Angle of Repose and Bulk density CRI-Amankwatia at 16.5 % moisture content recorded the highest score of 29.33 g, 47.3o, and 654.0 kg/m3, respectively. AGRA rice at 13.0% observed the highest value of 1685.8 for kg/m3 true density, and the highest value for porosity was 70.83%, which was recorded by CRI-Enapa at 11.5 % moisture content. In all cases, the difference in mean value was less than the Least Square Difference. This indicates that there were no significant statistical differences between their mean values, indicating that technologies developed and adapted for one variety can equally be used for all the other varieties.

The performance of ammonia hydrogen fuel cells (AHFCs) with the same activated area but different aspect ratio is quite different. In this paper, based on the diffusion characteristics of hydrogen nitrogen mixture, five different aspect ratios of AHFCs were designed, and the influence of aspect ratio on the performance of AHFCs was studied by combining experiment and simulation analysis. The results reveal that the power of AHFCs reaches the maximum when the aspect ratio is 1, that is, the shortest hypotenuse of the plate. With the extension of the hypotenuse, the output power decreases, and the output power decreases by 19.3% when the aspect ratio is 4. Due to the strong ability of hydrogen diffusion, when the aspect ratio of AHFCs is 4, the proportion of hydrogen and oxygen starvation area at the interface reaches the maximum and minimum, which are 11.8% and 0.3% respectively, which is contrary to the aspect ratio of 0.25. A larger aspect ratio is conducive to the uniform distribution of gas-water-heat. Although the AHFCs with aspect ratio of 0.64 has advantages in power generation efficiency and fuel utilization, the pressure drop loss increases by 43.7%, and the pressure drop loss with aspect ratio of 0.25 increases by 141.2%. • Experimental data of AHFCs with different aspect ratios are obtained. • Power generation efficiency of AHFCs with different aspect ratios is compared. • AHFC with the shortest hypotenuse has the largest output power. • CV is used to characterize the uniformity of gas-heat-water distribution in AHFC. [ABSTRACT FROM AUTHOR]

To address the environmental issues arising from the growing scarcity of natural fine aggregates (NFA) and landfilling of waste glass, research is being conducted globally to utilize waste glass as a sustainable fine aggregate. However, contradictory results have been obtained regarding the effect of the type of waste glass and the physical properties of waste glass fine aggregate (GFA) on concrete, making it challenging to promote the use of GFA in concrete. Therefore, to promote the use of GFA in concrete, it is necessary to examine it under field conditions, such as mass-production processes or real-scale concrete applications. This study introduced a mass-production process for GFA, and the effect of mass-produced GFA on mortar was evaluated. The fine aggregate properties (particle aspect ratio, crushing rate, and solubility) of the GFA and the effects of color, content, and particle size on the mortar properties (compressive strength, flexural strength, and ASR expansion behavior) were analyzed, along with the results reported in previous studies. Consequently, the high aspect ratio and microcracks in the particles of mass-produced GFA led to an increase in the strength reduction and ASR expansion of the mortar. These effects appear to be particularly severe for transparent GFA. Overall, this study proposed the content of GFA within 20% or the replacement of fine particles (< 500 μm) in NFA as a condition for sustainable fine aggregate. [ABSTRACT FROM AUTHOR]

Intake parameters are essential factors that are often overlooked, but can easily change the direct internal reforming solid oxide fuel cell (DIR-SOFC) performance. A three-dimensional model is developed to simulate the effects of intake parameters on the performance of an anode-supported flat-plate DIR-SOFC. The two primary chemical reactions, water gas shift reaction (WGSR) and methane steam reforming reaction (MSR), as well as the electrochemical oxidation of H 2 and CO, are considered in this model. It was found that the aspect ratio corresponding to the peak current density decreases as fuel increases. A moderate air flow rate makes the fuel-to-air ratio (FAR) corresponding to the drastic change in current density relatively small and wide-ranging, resulting in more desirable temperature distribution and fuel utilization. Under the operating conditions of this paper, adjusting the steam-to-carbon ratio (S/C) to between 1.5 and 2 results in both excellent electrical performance and good temperature uniformity. Additionally, adjusting the flow rate by changing the inlet area or velocity has its own advantages in terms of temperature distribution or current density, which must be taken into account when adjusting the flow rate. This study provides a valuable reference on inlet settings of DIR-SOFC, which would help to promote the development of high-performance SOFCs. • A three-dimensional flat-plate DIR-SOFC model has been developed. • Oxidation reaction of CO is included in the mode. • Different flow rates would change the effects of the aspect ratio and S/C. • Impacts of the fuel-air ratio are analyzed fully in terms of both fuel and air sides. • Changing the flow rate by altering the area or speed can make differences. [ABSTRACT FROM AUTHOR]

This paper investigates, experimentally along with three-dimensional CFD simulation, the variation in heat transfer coefficients of a heated plate located with different inclination angles (0 ≤ α ≤ 90°) and aspect ratios (0.25 ≤ AR ≤ 2). The considerate airflow is at different speeds from 4-32 m/s. The CFD model was simulated by Ansys-Fluent, solving the discretized equations using finite volume method. The experimental data align with CFD results with a relative error between 1.09% and 10.74%. Taking into consideration the plate width enhances the heat transfer coefficient compared to 2D study. Regardless of the inclination angle and the aspect ratio, heat transfer is enhanced with high inlet velocity. By increasing the inlet velocity, heat transfer coefficient decreases with the increment of AR at α = 30°. Different average correlations were obtained between heat transfer coefficient with inlet air velocity, and between average Nusselt number with Reynolds number. A relative error of -18% to 15% was obtained between the correlated and calculated Nusselt numbers. A general correlation linking average Nusselt number to Reynolds number, angle of inclination and heated plate aspect ratios, was also elaborated. [ABSTRACT FROM AUTHOR]

In this paper, minimization of delamination effect on laminated composite plates using smart (piezoelectric and magnetostrictive) materials has been investigated. The static and dynamic responses of the smart composite plates with/without delamination have been obtained using the finite element method. The validation and comparison studies of the laminated composite plate have also been performed to show the level of accuracy of the presently adopted model by solving a few examples related to static and frequency cases. For control and minimization of delamination effect, smart materials have been introduced at the various layers of the laminated panel. Further, the influence of delamination size, location, orientation scheme, aspect ratio, modular ratio and different boundary conditions on the dynamic response of the smart delaminated composite plate has been analyzed. Finally, optimization study has been carried out to find the optimal value of these parameters by minimizing the difference between the frequency responses. Here, two optimization algorithms TLBO and PSO have been considered to carry out the optimization study and results obtained from both techniques are validated and compared. [ABSTRACT FROM AUTHOR]

This research highlights that street layouts, including the vegetation ratio, street orientation, and aspect ratio, are key in diminishing urban heat islands (UHIs), building energy use, and carbon emissions. The optimal street layout for minimal building energy consumption, carbon emissions, and maximal outdoor thermal comfort in Tianjin was established via field measurements, ENVI-met 5.6.1, Energy Plus simulations, and correlation analysis. The findings indicate the following: (1) The carbon emissions of winter residential heating energy consumption are 2.9–3.2 times higher than those for summer cooling. Urban design should thus prioritize winter energy efficiency and summer thermal comfort outdoors. (2) The summer street PET (physiological equivalent temperature) inversely correlates with the vegetation ratio and aspect ratio. Winter heating energy use inversely correlates with the street orientation and directly correlates with the aspect ratio. Adequate vegetation and proper orientation can decrease energy and carbon output while enhancing summer outdoor comfort. (3) Streets with an NW–SE orientation, H/W = 0.9, and 50% trees in summer yield the best thermal comfort, while those with an NE–SW orientation, H/W = 0.3, and 50% vegetative trees in winter produce the lowest carbon emissions. These insights are instrumental in refining urban streets and building designs in cold zones. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) are considered an advanced form of carbon. They have superior characteristics in terms of mechanical and thermal properties compared to other available fibers and can be used in various applications, such as supercapacitors, sensors, and artificial muscles. The properties of single-walled carbon nanotubes (SWNTs) are significantly affected by geometric parameters such as chirality and aspect ratio, and testing conditions such as temperature and strain rate. In this study, the effects of geometric parameters and temperature on the mechanical properties of SWNTs were studied by molecular dynamics (MD) simulations using the Large-scaled Atomic/Molecular Massively Parallel Simulator (LAMMPS). Based on the second-generation reactive empirical bond order (REBO) potential, SWNTs of different diameters were tested in tension and compression under different strain rates and temperatures to understand their effects on the mechanical behavior of SWNTs. It was observed that the Young's modulus and the tensile strength decreases with increasing SWNT tube diameter. As the chiral angle increases, the tensile strength increases, while the Young's modulus decreases. The simulations were repeated at different temperatures of 300 K, 900 K, 1500 K, 2100 K and different strain rates of 1 × 10−3/ps, 0.75 × 10−3/ps, 0.5 × 10−3/ps, and 0.25 × 10−3/ps to investigate the effects of temperature and strain rate, respectively. The results show that the ultimate tensile strength of SWNTs increases with increasing strain rate. It is also seen that when SWNTs were stretched at higher temperatures, they failed at lower stresses and strains. The compressive behavior results indicate that SWNTs tend to buckle under lower stresses and strains than those under tensile stress. The simulation results were validated by and consistent with previous studies. The presented approach can be applied to investigate the properties of other advanced materials. [ABSTRACT FROM AUTHOR]

To investigate the improvement induced by horizontal smoke baffles during lateral smoke exhaust, an immersed road tunnel with various horizontal smoke baffles positioned below the lateral exhaust vent was studied numerically. Together with the velocity field characteristics, the temperature distribution was investigated near the lateral smoke exhaust vent, followed by the analysis of lateral smoke exhaust efficiency under different horizontal smoke baffles. Results showed that after installing the horizontal smoke baffle, there was a significant decrease in the extracted cold air, while the high‐temperature smoke in the exhaust vent increases, indicating the plug‐holing is effectively suppressed. It is known that the efficiency of smoke exhaust increases when the length exceedance ratio of the horizontal smoke baffle is smaller than 100%, while it changes slightly when the baffle length continues to increase. When the width ratio of horizontal baffle is smaller than 40%, the efficiency of smoke exhaust increases with the baffle width and then changes slightly with a wider smoke baffle. With a larger aspect ratio, the wider and shorter lateral exhaust vent is beneficial for improving the lateral smoke exhaust. Under the current conditions, the case shows the optimal smoke exhaust performance with a horizontal baffle length exceedance ratio of 100%, a baffle width ratio of 40%, and exhaust vent aspect ratio of 3:1. Finally, an empirical model is developed to describe the improvement of smoke exhaust efficiency caused by horizontal smoke baffle. These outcomes are helpful to the design of lateral smoke extraction system in road tunnels. [ABSTRACT FROM AUTHOR]

Rapid urbanization and increased human activity have negatively impacted the microclimate of cities, leading to unfavorable conditions for human thermal comfort, particularly in outdoor spaces. Thermal comfort can be improved through various means, such as adjusting the height of urban buildings, the aspect ratio of road widths, and the placement of street trees. This study employed the ENVI-met software V5.5.1 to simulate the microclimate based on aspect ratio (H/W = 1.5) and street tree spacing (6 m) similar to actual conditions with different aspect ratios (H/W = 0.5, 1.0, and 2.0) and street tree spacing (2 m) in Seoul, Republic of Korea. Thermal comfort was assessed through a comprehensive predicted mean vote (PMV) evaluation, considering the gender (male and female) and age (8, 35, and 80 years) of residents in the target area, to determine the optimal urban canyon scenario. The results of the study indicated that the height of the building and the percentage of trees had a significant impact on the temperature and PMV results. When comparing PMV results, women have higher thermal vulnerability than men, and based on age, older adults have higher thermal vulnerability. The aspect ratio of 1.5 and tree spacing of 2 m resulted in the lowest temperature of 35.91 °C at 12:00 p.m. at 0° wind direction and 36.09 °C at 90° wind direction, lower than the actual input value of 36.9 °C. The PMV values were also under the same conditions, with an average PMV by gender of 3.87 at 0° and 4.21 at 90° and an average PMV by age of 3.86 at 0° and 4.19 at 90°. This finding is significant because it can inform the development of planned cities that prioritize urban thermal comfort during summer. This can be achieved through the strategic design of urban canyons and incorporation of street trees in both new and existing cities. [ABSTRACT FROM AUTHOR]

To clarify the influence of the serpentine nozzle configurations on the flow characteristics and aerodynamic performance of aircraft, the flow features and aerodynamic performances of the double-ducted serpentine nozzles with different aspect ratios (AR), length–diameter ratios (LDR) and shielding ratios (SR) are numerically investigated. The results show that the asymmetric nozzle flow occurs due to the curved profile of serpentine nozzles, and a local accelerating effect exists at the S-bend, causing the increase in wall shear stress. The unilateral unsymmetrical expansion of the tail jet in the upward direction interacts with the separated external flow of the afterbody, forming an obvious cross-shock wave and shear layer structure. The surface pressure of the afterbody increases along the external flow direction, and decreases sharply in the separation point of the boundary layer. With the increase in AR and LDR, the local accelerating effect of the nozzle flow weakens, while with the increase in SR, the accelerating effect increases. The total pressure recovery coefficient, flow coefficient and axial thrust coefficient all decrease with the increase in AR, LDR, and SR. The thrust vector angle decreases with the increase in AR but is less affected by LDR and SR. [ABSTRACT FROM AUTHOR]

This report is focused on understanding the mixing performance of Newtonian and non‐Newtonian fluids in an SMX static mixer through computational fluid dynamics (CFD) study in Simcenter STAR‐CCM+. For this, the standard SMX mixer with four mixer elements of radius 26 mm was chosen. The aspect ratio (L/D) was taken as 1. The model constructed was compared using pressure drop ratio values available in literature. First, the design was validated for Newtonian fluid, then for shear‐thinning fluid (non‐Newtonian). Mixing patterns produced through particle tracking approach revealed how blending improved as the fluid moved downstream and interacted with increasing number of mixer elements. A sensitivity study was undertaken to investigate the effect of particle injection mechanism on the mixing process. Two injection methods, vertical and horizontal, were explored to check the influence of injection position on mixing. The results indicate that for the given configuration irrespective of the injection location, at least four mixing elements are needed to achieve good mixing for both Newtonian and shear‐thinning fluids investigated in this study. Statistical reports were used to quantify mixing to understand the mixing behaviour for Newtonian and non‐Newtonian fluids with change in Reynolds number. At high Reynolds number, non‐Newtonian fluids exhibited better mixing abilities. Further, efforts were taken to optimize the various design parameters to produce the most optimum solution with a single mixer element for Newtonian fluid. [ABSTRACT FROM AUTHOR]

The Ferromagnetic Resonance (FMR) phenomenon, marked by the selective absorption of microwave radiation by magnetic materials in the presence of a magnetic field, plays a pivotal role in the development of radar absorbing materials, high speed magnetic storage, and magnetic sensors. This process is integral for technologies requiring precise control over microwave absorption frequencies. We explored how variations in resonance fields can be effectively modulated by adjusting both the shape and stress anisotropies of magnetic materials on a flexible substrate. Utilizing polyethylene-naphthalate (PEN) as the substrate and Permalloy (Ni79Fe21, noted for its positive magnetostriction coefficient) as the magnetic component, we demonstrated that modifications in the aspect ratio and bending repetitions can significantly alter the resonance field. The results, consistent with Kittel’s equation and the predictions of a uniaxial magnetic anisotropy model, underscore the potential for flexible substrates in enhancing the sensitivity and versatility of RF-based magnetic devices. [ABSTRACT FROM AUTHOR]

This study investigates the feasibility of deploying aloe vera, banana, and corn husk fibers that have been treated with sodium hydroxide (NaOH) as reinforcements in composites. The application of NaOH treatment resulted in a substantial enhancement in the tensile strength of all fibers. Among them, banana fibers exhibited the greatest value, reaching 189.7 MPa. The fibers that were treated also showed elevated aspect ratios, especially in the case of banana fibers (178.57), indicating an increased potential for reinforcing. The use of scanning electron microscopy (SEM) showed that the treatment resulted in a surface morphology that was roughened. The fibers that were treated showed enhanced thermal stability, as determined by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). FT-IR spectroscopy verified changes in the chemical composition of the fibers, while XRD examination revealed that both untreated and treated fibers had a structure that was both amorphous and polycrystalline. The results emphasize the potential of NaOH-treated natural fibers, particularly banana fibers due to their exceptional strength, as eco-friendly substitutes for synthetic reinforcements in composites. [ABSTRACT FROM AUTHOR]

Pile foundations, known for their distinct horizontal load-bearing characteristics, are widely utilized in excavation support systems for foundation construction. In comparison to circular piles with equal cross-sectional areas, rectangular piles exhibit superior resistance to horizontal loads. Finite element numerical analyses were conducted in this investigation to compare the horizontal bearing capacity of rectangular and circular piles with a same cross-sectional area. The horizontal bearing capacity characteristics of rectangular piles were quantitatively analyzed, in which the effects of aspect ratio and filter cake thickness on bearing capacity were investigated. Results demonstrate that under the identical conditions, rectangular piles show an increase in horizontal bearing capacity by over 12%. With the increase of aspect ratio, the improvement ratio in lateral resistance becomes stabilized at around 17%. However, in the presence of filter cake, the horizontal bearing capacity of rectangular pile is lower than that of circular pile with the same cross-section. Thus, appropriate measures should be implemented during the on-site construction of rectangular piles. This study provides valuable insights for future construction of rectangular piles. [ABSTRACT FROM AUTHOR]

The investigation of entropic variations in the thermal transport mechanism produced by buoyantly driven temperature gradients has attracted significant attention because of excellent physical significance. Therefore, the prime consent to manipulate the current investigation is to explore the impact of change in the aspect ratio of the trapezoidal cavity in the optimization of the entropy phenomenon. After attaining motivation from its practical essence different entropies including thermal, viscous, and local are estimated. Additionally, global quantities such as average Bejan and Nusselt numbers calculated along with total entropy are measured against flow concerning parameters (aspect ratio (AR), Rayleigh number (Ra) and irreversibility ratio (ϕ )). Numerical experiments are performed by implementing a finite element approach using open-source software renowned as COMSOL Multiphysics. Before the accomplishment of the outcomes, confirmation of the numerical technique is assured by establishing grid sensitivity testing. Comparison of results between present and previous studies is also demonstrated. A wide range of involved sundry parameters varying from 10 - 4 ≤ ϕ ≤ 10 - 2 , 10 2 ≤ Ra ≤ 10 5 and 0.25 ≤ AR ≤ 0.75 are accounted. It is concluded that by escalating the aspect ratio from 0.50 to 0.75, the magnitude of the local entropy enhances from 3370 to 3424. It is revealed that the highest value of viscous entropy that is, 45, is achieved at Ra = 105 and by keeping the aspect ratio of enclosure equal to 0.75, whereas, the thermal entropy approaches 2 for the same situation of parameters. The magnitude of the average Bejan number reaches unity at AR = 0.5 and Ra = 105, whereas for low and high aspect ratios it depicts a magnitude less than 1 for the same Rayleigh number. [ABSTRACT FROM AUTHOR]

Previous studies have shown a strong relationship between heat-related fatalities and ambient air temperature. This problem is expected to increase due to constant urbanization and the threat of global warming. Therefore, designing urban street canyons (USC) to be thermally comfortable is essential for a healthy urban life. This paper investigates the correlation between an urban street canyon's aspect ratio and the albedo material of its surrounding buildings. The aim is to study which combination can successfully mitigate urban heat stress and create a thermally comfortable pedestrian microclimate. This research uses a comparative analysis that suggests the optimum albedo for different USC geometries. An ENVI-met model was used to simulate 9 scenarios for an idealized 2D USC with varying aspect ratios and albedo values. Air temperature, mean radiant temperature and Universal Thermal Climate Index (UTCI) were analyzed. Results show that a medium albedo value performs best thermally in all USCs. High albedo had 13.2% more combined thermal stress compared to medium albedo. However, high albedo performed much better in deep canyons than wider ones, with the average UTCI decreasing by about 4.8%-5.7% when used in deep canyons. Medium albedo should be exclusively used in wide canyons for minimal thermal stress. Practical application: This study provides a reference to the use of materials in urban street canyons of different aspect ratios to achieve good outdoor thermal comfort for pedestrians. [ABSTRACT FROM AUTHOR]

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Unbonded post-tensioned rocking walls have demonstrated superior seismic performance with greatly reduced damage and excellent self-centering behavior. Current design guidelines (ACI 550.7) and representative research on rocking walls are summarized in this paper. Some inconsistencies and voids in the major design parameters for rocking walls are identified. A brief description is provided for two rocking-wall specimens tested under quasi-static cyclic loading. Force flow and failure mechanisms of rocking walls observed from the tests were studied, and it is discovered that they are very different from those of special structural walls. The test data showed that the concentration of compressive strain in concrete at the corners of rocking walls was a local behavior such that the need for confinement reinforcement higher above the toe region was diminished. Fiber grout weaker than concrete in rocking walls used as ductile bearing materials at the wall-foundation interface is a reasonable alternative to ACI 550.7. Design recommendations for height and volumetric ratio of confinement reinforcement are provided. A requirement for the aspect ratio of rocking walls stricter than that in ACI 550.7 is proposed to prevent shear sliding of the walls. [ABSTRACT FROM AUTHOR]