Aspect Ratio Research Articles

Developments in Localized Surface Plasmon Resonance

AbstractLocalized surface plasmon resonance (LSPR) is a nanoscale phenomenon associated with noble metal nanostructures that has long been studied and has gained considerable interest in recent years. These resonances produce sharp spectral absorption and scattering peaks, along with strong electromagnetic near-field enhancements. Over the past decade, advancements in the fabrication of noble metal nanostructures have propelled significant developments in various scientific and technological aspects of LSPR. One notable application is the detection of molecular interactions near the nanoparticle surface, observable through shifts in the LSPR spectral peak. This document provides an overview of this sensing strategy. Given the broad and expanding scope of this topic, it is impossible to cover every aspect comprehensively in this review. However, we aim to outline major research efforts within the field and review a diverse array of relevant literature. We will provide a detailed summary of the physical principles underlying LSPR sensing and address some existing inconsistencies in the nomenclature used. Our discussion will primarily focus on LSPR sensors that employ metal nanoparticles, rather than on those utilizing extended, fabricated structures. We will concentrate on sensors where LSPR acts as the primary mode of signal transduction, excluding hybrid strategies like those combining LSPR with fluorescence. Additionally, our examination of biological LSPR sensors will largely pertain to label-free detection methods, rather than those that use metal nanoparticles as labels or as means to enhance the efficacy of a label. In the subsequent section of this review, we delve into the analytical theory underpinning LSPR, exploring its physical origins and its dependency on the material properties of noble metals and the surrounding refractive index. We will discuss the behavior of both spherical and spheroidal particles and elaborate on how the LSPR response varies with particle aspect ratio. Further, we detail the fundamentals of nanoparticle-based LSPR sensing. This includes an exploration of single-particle and ensemble measurements and a comparative analysis of scattering, absorption, and extinction phenomena. The discussion will extend to how these principles are applied in practical sensing scenarios, highlighting the key experimental approaches and measurement techniques.

Utilization finite element and machine learning methods to investigation the axial compressive behavior of elliptical FRP-confined concrete columns

Nowadays, elliptical sections are among the geometric shapes that are becoming more and more popular in the architecture world. Finite element analysis (FEA) software, such as ABAQUS, is used to simulate elliptical concrete columns confined with fiber reinforced polymer (FRP) jackets based on experimental data published in the literature. The validity of the finite element modeling (FEM) approach was confirmed by comparing it to experimental data obtained from 45 specimens in existing studies, demonstrating a favorable agreement. Additionally, a parametric study was also carried out, which included simulating 40 more specimens, resulting in a total of 85 specimens for analysis. The effect of various test variables such as sectional aspect ratio, the amount of FRP layers, and concrete strength on the elliptical column’s behavior is investigated. The axial compressive strength is predicted using current models from the literature. The outcomes revealed that the higher unconfined concrete strength decreased FRP confinement efficacy. Insufficient confinement with post-peak softening is more likely in FRP-confined high strength concrete columns, especially if the confinement was not stiff enough. Also, by adding more FRP layers, the stress and strain capabilities of elliptical concrete columns confined with FRP composites are improved. Physical experiments require a significant investment of time and resources, but they can produce valuable results. Finite element analysis, on the other hand, depends heavily on the modeler's competence and can minimize the number of experiments required by employing computer simulation, but it also requires high computer settings. In recent years, there has been a major advancement in the usage of machine learning (ML) algorithms in the applications of FRP composites with different concrete components. Taking this into consideration, this investigation is extended to estimate the compressive strength of elliptical FRP-confined columns using four tree-based ML algorithms including Decision Tree, Random Forest, Gradient Boosting and XGBoost. The XGBoost model achieved the highest predictive accuracy with the R2 values of 0.95 for both the compressive strength and axial strain targets.

Effect of Rolling Process Parameters on Transverse Cracks on the Surface of Q345 Steel

This article examines the evolutionary behavior of transverse surface cracks in Q345 steel during the hot‐rolling process under various rolling conditions. “V”‐shaped cracks are prefabricated on the billet surface for laboratory hot‐rolling tests, and a corresponding rolling model is developed to validate its accuracy. The slab rolling model is established based on actual onsite rolling process parameters. The aim is to analyze the effects of different rolling conditions on the surface crack morphology and aspect ratio. The results indicate that variations in roll diameter (1400, 1300, and 1200 mm) influence crack propagation, with cracks unfolding earlier when the roll diameter is 1400 mm. At varying initial rolling temperatures (1300, 1200, and 1100 °C), cracks begin to unfold earlier at the highest temperature of 1300 °C. When examining different friction coefficients (0.4, 0.5, and 0.6), cracks unfold earlier at the highest coefficient of 0.6. Similarly, at different rolling speeds (3, 4, and 5 m s−1), cracks unfolded earlier at the highest speed of 5 m s−1. Analysis of changes in crack depth and aspect ratio during rolling shows that the initial few passes have a greater influence on crack depth and unfolding. In the later stages of rolling, cracks continue to unfold, though the depth shows minimal variation, and the aspect ratio tends to approach zero.

Presentation of representative shape parameters of porous media based on mathematical computation on images

The shape parameters of porous media are really important to describe the petrophysical and geomechanical parameters of reservoirs. In addition, shape analysis can provide essential information about the origin, transport, deposition history of particles, etc. Because macroscopic properties (such as permeability, diffusion, etc.) are influenced by microscopic properties (such as pore size, grain shape, etc.). So far, various studies have been conducted to calculate some shape parameters, however, there is no comprehensive study that first includes most of the geometric parameters of the shape and then presents the representative shape parameters. Therefore, the aim of this study is to present representative shape parameters of porous media based on mathematical computation on images. The shape parameters studied included roundness, circularity, angularity, convexity, compactness, sphericity, aspect ratio, elongation, eccentricity, shape factor, and regularity. Calculation of shape parameters is done digitally using the developed program. The necessary data for the desired analysis are obtained from real sandstone samples. To develop this research, first, the mentioned shape parameters are calculated using the developed program for all rock samples. Then, by establishing a relationship between the mentioned parameters, the representative parameters that can show the shape of the porous medium are expressed. The results of this study show that the representative shape parameters of the porous medium are compactness, shape factor-round, and aspect ratio, which are good indicators for the shape of the porous medium.

Impact analysis of particle sphericity on the properties of porous materials via particle packing method for hydrogen fuel and electrolysis cells

This study focuses on the impacts of particle's sphericity on the properties of porous materials crucial to electrochemical devices. Three-dimensional structures with spherical and cylindrical particles were generated to simulate porous granular and fibrous materials. The constructed particle geometries are as follows: a sphere and cylinders with different aspect ratios (height-to-diameter) of 0.1, 0.5, 1.0, 2.5, 5.0, 10, and 20. Every model exhibits a porosity of 0.500 ± 0.001 to exclude the effects of porosity. The structures were binarized with 200×200×200 dimensionless voxels, which were analyzed with the specific surface area, grain and pore size distributions, geometrical tortuosity, conductivity, and diffusivity across the through- and in-planes. As a result, the particle geometry significantly impacts on tortuosity, conductivity, and diffusivity, with the absolute value of Spearman's correlation coefficient of up to 1. It may imply the necessity to consider particle geometry as an ex-situ characterization for better electrochemical performance.

A novel trajectory planning method for mobile robotic grinding wind turbine blade

As the core component of wind turbine, wind turbine blade requires two grinding processes in the production. However, mobile robotic automation grinding of wind turbine blades is considered to be a challenging task due to the high aspect ratio and compound surface of the wind turbine blade. The trajectories generated by most robotic grinding trajectory planning algorithms are often found to be inferior in grinding large compound surface workpieces, as they are typically designed for robotic machining with a fixed base. In this paper, a novel iso-planar algorithm based on oriented bounding box (OBB) of the workpiece is developed to plan the grinding trajectories by taking into consideration the characteristics of blade. The constant chord length algorithm employing Taylor quadratic expansion is then developed to discretize trajectory into grinding points. Considering the characteristics of compound surface, a post-processing strategy is proposed to eliminate redundant grinding points and generate consistent tool orientations on compound surface. Based on these three steps, a workstation location optimization model for improving robot manipulability is introduced to determine a series of workstation locations. Furthermore, the grinding and movement synchronization strategy based on mobile platform trajectory interpolation is proposed to enhance the efficiency of machining large workpieces. The simulation and experiments demonstrate the effectiveness of the proposed trajectory planning method for mobile robotic grinding wind turbine blade, the rationality of the optimization model and the feasibility of grinding and movement synchronization strategy.

Low phosphorus causes hepatic energy metabolism disorder through Dynamin-related protein 1-mediated mitochondrial fission in fish

BackgroundLow phosphorus (LP) diets perturb hepatic energy metabolism homeostasis in fish. However, the specific mechanisms in LP-induced hepatic energy metabolism disorders remain to be fully elucidated. ObjectivesThis study sought to elucidate the underlying mechanisms of mitochondria involved in LP-induced energy metabolism disorders. MethodsSpotted seabass were fed diets with 0.72% (S-AP, control) or 0.36% (S-LP) available phosphorus for 10 weeks. Drp1 was knocked down or protein kinase A (PKA) was activated using 8Br-cAMP (5 μM, a PKA activator) in spotted seabass hepatocytes under LP medium. Zebrafish were fed Z-LP diets (0.30% available phosphorus) containing Mdivi-1 (5 mg/kg, a Drp1 inhibitor) or 8Br-cAMP (0.5 mg/kg) for 6 weeks. Biochemical and molecular parameters, along with transmission electron microscopy and immunofluorescence, were used to assess hepatic glycolipid metabolism, mitochondrial function and morphology. ResultsSpotted seabass fed S-LP diets showed reduced ATP (0.52-fold) and cyclic adenosine monophosphate (cAMP) (0.52-fold) levels, along with reduced Drp1 (s582) (0.38-fold) and PKA (0.61-fold) phosphorylation levels in the liver compared with those fed S-AP diets (P < 0.05). Drp1 knockdown elevated ATP levels (1.99-fold), decreased mitochondrial DRP1 protein levels (0.45-fold), and increased mitochondrial aspect ratio (1.82-fold) in LP-treated hepatocytes (P < 0.05). Furthermore, 8Br-cAMP-treated hepatocytes exhibited higher PKA phosphorylation (2.85-fold), ATP levels (1.60-fold), and mitochondrial aspect ratio (2.00-fold), along with decreased mitochondrial DRP1 protein levels (0.29-fold) under LP medium (P < 0.05). However, mutating s582 to alanine mimic Drp1 dephosphorylation decreased ATP levels (0.63-fold) and mitochondrial aspect ratio (0.53-fold) in 8Br-cAMP-treated hepatocytes (P < 0.05). In addition, zebrafish were fed Z-LP diets containing Mdivi-1 or 8Br-cAMP had higher ATP levels (3.44-fold or 1.98-fold) than that fed Z-LP diets (P < 0.05). ConclusionsThese findings provide a potential mechanistic elucidation for LP-induced energy metabolism disorders through the cAMP/PKA/Drp1-mediated mitochondrial fission signaling pathway.

Conjugate heat transfer simulations of a radially cooled gas turbine blade leading edge using a vortex-based fluidic oscillator for sweeping jet impingement

The turbine blades of aero engines are subjected to extremely high temperatures, particularly at the leading edge, where temperatures can reach approximately 1800–2000 K. Therefore, effective heat load management is crucial. A vortex-based fluidic oscillator for sweeping jet impingement was proposed as an innovative cooling method to enhance heat transfer at leading edge of high-pressure gas turbine blades. This numerical investigation evaluates the cooling performance of a vortex-based sweeping jet compared to steady and conventional sweeping jets in a radially cooled high-pressure turbine blade. In this study, a conjugate heat transfer model based on three-dimensional unsteady Reynolds-averaged Navier–Stokes (URANS) equations is employed. The shear stress transport (SST k–ω) model is specifically selected to predict the flow field and heat transfer characteristics of a vortex-based fluidic oscillator applied to the leading edge. To verify the accuracy of numerical calculations, two sets of experimental data were used as benchmark. The results demonstrated strong qualitative and quantitative agreement with experimental data. Various parameters, including coolant mass flow rates (0.171, 0.514, and 0.857 g/s), aspect ratios (0.5, 0.65, and 1), jet-to-wall spacings (H/D = 2, 4, and 6), and pressure drop, were examined to assess overall cooling effectiveness and heat transfer performance. Time-averaged and time-resolved flow field measurements revealed that vortex-based fluidic oscillator significantly enhanced cooling effects and covered a larger impinging area compared to a steady jet. Notably, the vortex-based fluidic oscillator achieved a 24.3% higher heat transfer performance than the steady jet at H/D = 2, with an average temperature decrease in approximately 21 K at leading edge.

Thermal management optimization strategy for lithium-ion battery based on phase change material and fractal fin

In order to solve the problem of temperature control of lithium-ion battery (LB) in electric vehicles, a new battery thermal management system (BTMS) based on phase change material (PCM) coupled fractal fin (FF) was proposed. The effects of latent heat, thickness, and thermal conductivity of PCM (paraffin) on the thermal properties of BTMS were investigated. Subsequently, the fin structure was added to the BTMS to improve the heat transfer capacity, and the number of fins, aspect ratio, material and structure morphology were explored. The results show that when the latent heat of PCM is 200 kJ/kg, the thickness is 2 cm, and the thermal conductivity is 0.8 W/(m·K), the temperature of LB is 34.9 K lower than that of LB without the BTMS at 4C. In addition, the BTMS has the best performance when FF-II with a fin count of 5, aspect ratio of 7:1, and material of carbon steel are used. The temperatures of LB are 301.8 K, 303.9 K, 305.4 K, and 307.3 K at 1 to 4C, respectively, and the temperature difference in BTMS can be controlled within 2.5 K. This study provides some guidance for the optimization of BTMS.

Combining Simple Deformations to Elicit Complex Motions and Directed Swimming of Smart Organic Crystals with Controllable Thickness

The lack of control over the crystal growth in a systematic way currently stands as an unsurmountable impediment to the preparation of dynamic crystals as soft robots; in effect, the mechanical effects of molecular crystals have become a subject of scattered reports that pertain only to specific crystal sizes and actuation conditions, often without the ability to establish or confirm systematic trends. One of the factors that prevents the verification of such performance is the unavailability of strategies for effectively controlling crystal size and aspect ratio, where crystals of serendipitous size are harvested from crystallization solution. Here we devised a water‐assisted precipitation method to prepare crystals of chemical variants of 9‐anthracene derivative (chemical substitution of the 9th carbon) crystals with various thicknesses that respond to ultraviolet light with simple mechanical effects, including bending, splintering, and rotation. By capitalizing on the robust mechanical flexibility and deformability of crystals, we demonstrate systematic variations in crystal deformation that are further elevated in complexity to construct crystal‐based robots capable of motions reminiscent of controllable sailing and humanoid movements. The results illustrate an approach to eliminate a critical obstacle towards complete control over the motility of dynamic molecular crystals as microrobots in nonaerial environments.

Asymmetric Sample Shapes Complicate Planar Biaxial Testing Assumptions by Intensifying Shear Strains and Stresses

Planar biaxial testing offers a physiologically relevant approach for mechanically characterizing thin deformable soft tissues, but often relies on erroneous assumptions of uniform strain fields and negligible shear strains and forces. In addition to the complex mechanical behavior exhibited by soft tissues, constraints on sample size, geometry, and aspect ratio often restrict sample shape and symmetry. Using simple PDMS gels, we explored the unknown and unquantified effects of sample shape asymmetry on planar biaxial testing results, including shear strain magnitudes, shear forces measured at the sample’s boundary, and the homogeneity of strains experienced at the center of each sample. We used a combination of finite element modeling and experimental validation to examine PDMS gels of varying levels of asymmetry, allowing us to identify effects of sample shape without confounding factors introduced by the nonlinear, spatially variable, and anisotropic properties of soft tissues. Both biaxial simulations and experiments, which showed strong agreement, revealed that sample shape asymmetry led to significantly larger shear strains, shear forces, and overestimation of principal stresses. Excluding these shear forces resulted in an underestimation of shear moduli during inverse mechanical characterizations. Even in the simplest of deformable biomaterials, sample shape asymmetry should be avoided as it can induce drastic increases in shear strains and shear forces, invalidating traditional planar biaxial testing analyses. Alternatively, sample shape asymmetry may be exploited to generate more robust estimates of constitutive parameters in more complex materials, which could lead to a refined understanding and inference of mechanical behavior.

Rockery morphology based on quantitative analysis of shading

The rockeries of classical Chinese gardens are masterpieces of classical Chinese garden art and form a key element of garden heritage. Consequently, a quantitative study of “rockery shadows” is of considerable importance to the study of “rockery forms.” In this study, we selected the representative North Rockery in Zhanyuan Garden of Nanjing and Ruiyunfeng, Guanyunfeng, and Yulinglong as the objects of the study. This study aims to explore the shadow images of rockeries using image extraction and targeted quantitative analysis methods. Macroscopically, the overall shape of rockery shadows was described using fractal dimensions; microscopically, the aspect ratio, angle, and refinement indexes of each shadow based on each observation angle of the rockery were measured using the PAT-GEOM plug-in in ImageJ software. SPSS Statistics was used for the normal distribution test of the angular distribution data. Consequently, the shadow data of the North Rockery in Zhanyuan Garden and Ruiyunfeng, Guanyunfeng, and Yulinglong, respectively, were analyzed and compared, and four rockery-shadow laws were derived. Finally, the results were applied to the design of the rockery morphological translation based on quantitative analysis of the shadows. The approach presented here will enhance landscape design, support environmental planning, and preserve cultural heritage.

Combining Simple Deformations to Elicit Complex Motions and Directed Swimming of Smart Organic Crystals with Controllable Thickness.

The lack of control over the crystal growth in a systematic way currently stands as an unsurmountable impediment to the preparation of dynamic crystals as soft robots; in effect, the mechanical effects of molecular crystals have become a subject of scattered reports that pertain only to specific crystal sizes and actuation conditions, often without the ability to establish or confirm systematic trends. One of the factors that prevents the verification of such performance is the unavailability of strategies for effectively controlling crystal size and aspect ratio, where crystals of serendipitous size are harvested from crystallization solution. Here we devised a water-assisted precipitation method to prepare crystals of chemical variants of 9-anthracene derivative (chemical substitution of the 9th carbon) crystals with various thicknesses that respond to ultraviolet light with simple mechanical effects, including bending, splintering, and rotation. By capitalizing on the robust mechanical flexibility and deformability of crystals, we demonstrate systematic variations in crystal deformation that are further elevated in complexity to construct crystal-based robots capable of motions reminiscent of controllable sailing and humanoid movements. The results illustrate an approach to eliminate a critical obstacletowards complete control over the motility of dynamic molecular crystals as microrobots in nonaerial environments.

Vertical Variability in morphology, chemistry and optical properties of the transported Saharan air layer measured from Cape Verde and the Caribbean.

The structural properties of the Saharan air layer (SAL) including chemical, morphological and optical properties were measured during the Saharan Aerosol Longrange TRansport and Aerosol Cloud interaction Experiment (SALTRACE- June/July 2013). Flight measurements were done from Cape Verde and the Caribbean. Changes happening with the chemical composition, mixing, shape and absorption of aerosol single particles (particle diameter range 0.5-3.0 µm) inside SAL during its transport are detailed. Dust-dominated SAL (relative number abundance >90%) and generally low mixing (<1% with sea-salt and sulphates) are observed at both locations. The change in shape (determined as aspect ratio (AR)) after transatlantic transport was statistically not significant. The iron oxide fraction, important for light absorption, contributed 6.0-6.8% to SAL dust. A lower amount of Fe oxides was observed in transported SAL, especially for the size range 0.5-1.5 µm. This reduction in Fe oxide content resulted in a 4% decrease (0.0046-0.0044) in dust imaginary refractive index and a 1% decrease in single scattering albedo (0.802-0.809) at 520 nm. Our work suggests including the size distribution of iron oxides and their particular behaviour in future experiment/model studies.

Web Shear Buckling of Steel-Concrete Composite Girders – Advanced Numerical Analysis

Load-bearing capacity of plate girders, often used in design of bridges and high-rise buildings, is limited by the shear capacity of connected slender plate elements subjected to shear buckling. To quantify this, experimental investigations on five large-scale steel and steel-concrete composite plate girders loaded solely in shear, with a minimal influence of bending moments, have been conducted and evaluated. In this paper, the phenomenon of web shear buckling is investigated within the numerical analysis using the ABAQUS Software. An advanced numerical model has been developed and results validated against existing experimental findings. One of the focal points of this study represents the methodology of developing such a comprehensive numerical model, implementation of suitable analysis procedures, material models, boundary conditions, finite elements and interactions, in order to correctly replicate the observed response in the tests. In addition, case studies tackling the influence of web slenderness, aspect ratio, initial imperfections, shear connection and concrete classes on the structural-mechanical behavior of steel-concrete composite girders in shear as well as the applicability and suitability of the existing analytical model are also presented and analyzed.

Experimental research on the bubble dynamic characteristics during carbon capture in the novel prepared functionalized porous ionic liquids

Porous ionic liquids have received widespread attention as one of the novel CO2 absorbers to reduce CO2 produced by the combustion of fossil fuels. Based on this, the CO2 capture experiments are conducted in ionic liquids ([TEP][MIm] and [TEP][FA]), and the porous ionic liquid (ZIF-8/[TEP][MIm]). The dynamic characteristics of CO2 bubbles in different concentrations of ZIF-8/[TEP][MIm] liquid are researched. The results show that the CO2 capture capacity of the aqueous solution with a concentration of [TEP][MIm] of 20 wt% reaching 2.06 mol/mol ILs. The optimal addition amount of ZIF-8 in the porous ionic liquid using the ethylene glycol as a cosolvent is 1.0 g/100 g, and the maximum CO2 capture amount is about 2.22 mol/mol. Furthermore, the aspect ratio and cross-sectional ratio of CO2 bubbles generated by the four nozzles decrease with the increase of ZIF-8 and [TEP][MIm] concentrations, and the difference between the extreme values of CO2 equivalent diameter under experimental conditions is about 0.513 cm. In addition, the Eo number decreases with the rise of CO2 bubble, and the maximum different value is about 2.94. This work explores the dynamic characteristics of CO2 bubbles in ZIF-8/[TEP][MIm] within a bubbling tower, aiming to optimize the CO2 capture process and provide a valuable reference for advancements in the carbon capture, utilization, and storage technology.

Improving interface joining strength of Ti6Al4V/AZ91D bimetal prepared by compound casting via Ni-coated Ti6Al4V lattice structure

The joining of titanium/magnesium (Ti/Mg) bimetals presents challenges due to the low mutual solubility and absence of metallurgical reactions between Ti and Mg. Herein we utilized the Ni-coated Ti6Al4V lattice structure to enhance the interfacial property of Ti6Al4V/AZ91D bimetal prepared by compound casting. The Box-Behnken design (BBD) was employed to optimize the lattice design. The resulting structure featured struts with a diameter (ds) of 2.4 mm, an aspect ratio (l/ds) ratio of 5.4, a tilt angle (ω) of 57°, and a node-to-strut diameter ratio (dn/ds) of 2.4. The optimized Ti6Al4V lattice structure manufactured by selective laser melting (SLM) exhibited α′ martensite with a high dislocation density, conferring exceptional tensile strength. The rough texture of the lattice surface enhanced adhesion with the Ni coating and improved wetting and reactivity between Ni and AZ91D alloy melt. This resulted in the formation of a serrated metallurgical interface with AZ91D alloy, which was primarily composed of α-Mg + Mg2Ni eutectic structure+τ-Ni2Mg3Al ternary phases. An impressive joining strength of 116.1 MPa was obtained under the optimized lattice structure, and the bimetal joint predominantly fails through the damage of AZ91D, aligning closely with simulated failure predictions.

Tectonomagmatic evolution of Pune – Nasik Deccan Dykes: Insights from structure and dimension scaling

The Deccan Continental Flood Basalt of the Indian Peninsula is characterized by extensive basaltic eruptions ornamented with three spectacular distinct dyke swarms: the Pune – Nasik, Narmada – Tapi, and Western Coastal dyke swarms. Our study area is the Pune – Nasik dyke swarm, which has ~465 mappable dykes. These dykes exhibit different orientations with a predominant trend of N101° and vary in length from less than 1 km to ~64 km. These dykes are massively jointed and occasionally contain vesicles filled with secondary minerals like quartz and calcite. The host rock is weathered basalt of various older Deccan flows. In this study, we have calculated magmatic overpressures and magma chamber depths using the aspect ratios (length/thickness) of the dykes. The average estimated source depth is ~13 km, based on an average Young's modulus for the host rock basalt (Eavg, 7.5 GPa). Additionally, we compared the inferred magma source depths of the Pune – Nasik, and Narmada-Tapi dyke swarms which include the Nandurbar – Dhule, and Pachmarhi dykes of the Deccan Flood Basalt Province. Our findings indicate that the magma chamber source depth is greater in the Pune – Nasik dyke swarm compared with other dyke swarms. The variation in strike distribution of the Pune-Nasik dyke swarm may be attributed to several factors, including a larger magma chamber, local stress fields generated by shallow magma chamber, or the superimposition of tectonic stress fields (N-S and E-W extension) during the emplacement of dykes. This contrasts with the commonly held belief that the dykes are solely connected to a central edifice of the Reunion hotspot.

Functional organic adlayers for controlling the adhesion strength of electrolessly deposited copper on super-engineering plastics

Effective metallization of super-engineering plastics such as liquid crystal polymers (LCP) and polyphenylene sulfides (PPS) via electroless deposition of copper thin films is an important step in the manufacturing of a wide range of devices. Copper deposition typically requires a pre-treatment step involving chemical and/or mechanical roughening to ensure high adhesion at the polymer/Cu interface; however such treatments are detrimental to patterns and topographic features of the polymer that possess µm resolution and/or high aspect ratio. Herein, we demonstrate that it is possible to regulate and improve adhesion of electrolessly deposited copper thin films at LCP and PPS materials via multilayer functionalization with aryldiazonium cations of a p-aminobenzoic acid precursor. We first demonstrate that aryldiazonium grafting conditions can be optimized to overcome the chemical inertness of LCP/PPS without resorting to harsh oxidative or mechanical treatments. We then show that the density of Ar-COOH groups can be regulated by modifying the number of functionalization cycles. X-ray photoelectron spectroscopy studies shows that this has a clear impact on the composition of the catalytic nanoparticle layer required for copper deposition. Adhesion strength studies demonstrate that such changes translate into improved adhesion strengths without any adverse effects on surface roughness. Control experiments with alternative chemical moieties suggest that specific chemical interactions between catalytic seeds and grafted carboxylate groups play an important role in the observed improved adhesion.

Enhancing Aerodynamic Performance of Double Rectangular Cylinders through Numerical Analysis at Varying Inclinations

In the present work, numerical simulations are conducted for external flow through a double rectangular cylinder with different inclinations at Reynolds number (Re) 50 to 200 based on free stream velocity. The cylinder aspect ratio is considered to be fixed at 0.25. During the numerical simulations, one cylinder is kept fixed, and the other cylinder is inclined at ‘θ = 20o’ first clockwise and then in an anticlockwise direction alternatively for both cylinders. Because of the inclined cylinder, the vortex dynamics lead to significant changes in flow-induced forces. In this article, the focus is given to how Re and inclination in the cylinder influence the flow structures and associated aerodynamic properties. It is shown that when any of the cylinders are inclined, a significant decrease in the average drag coefficient is noticed as compared to the parallel cylinder case. In a similar manner, the lift coefficient also decreases when any one of the cylinders is inclined at θ = 20o either clockwise or counterclockwise as compared to the parallel cylinder case.