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Lithium-ion batteries are widely used for their high energy density, high power density, long lifetime, and safety which are crucial for the environmentally friendly future energy system. Electrodes are the key component of LIBs that determines battery performance. LiFePO4 is a common electrode used in battery technology due to its long cycle life and good safety. Laser structuring of electrodes has recently been considered a promising approach to increase energy density. In this work, LiFePO4 electrodes were structured into a grid-type pattern by varying the laser power, resulting in different aspect ratios. To evaluate the effects of the structuring, wettability and electrochemical performance were tested. The wetting property was investigated using spread area, wetting time, and contact angle measurements. Besides, the wetting rate was measured using the wetting balance test and capillary rise test. Lucas Washburn model and Zhmud extended model were used to quantitatively express the wetting rate. The influence of gravity on the wetting performance was also investigated by comparing those models. Furthermore, an electrochemical test was performed to see the cyclic stability, rate capability, and charge–discharge profile with a C rate up to 1C.

Shaped-Tube Electrolytic Drilling (STED) is an electrochemical dissolution-based process able to fabricate high aspect-ratio (AR) holes rapidly on the superalloys. The electrolyte flowing in the side gap between the tool's lateral surface and hole wall in the presence of an electric field during the entire process duration leads to non-uniform dissolution and stray-cutting. The localization of anodic dissolution mitigates the stray cutting, which contributes to the non-uniformity of micro-holes. The enhanced localized anodic dissolution is attainable by using neutral electrolytes mixed with the alkaline electrolytes that promote passivation on the surface of Inconel 718. The hole roundness error is crucial for the dimensional accuracy of micro-holes due to the overcutting constraints. Therefore, the present research investigates the feasibility of using electrolyte solutions of dissimilar anionic activity mixed with alkaline electrolytes to mitigate hole roundness error in high AR micro-holes. The effects of process parameters, such as applied voltage, tool feed rate, supplementary electrolyte concentration, and electrolyte entry temperature on the hole roundness error were studied to understand the dissolution behavior with different electrolyte solutions. The investigation results revealed that adding alkaline electrolytes in NaCl and NaNO3 based electrolyte solutions mitigate hole roundness error, whereas the KBr-based electrolyte solution performs unsatisfactorily. [ABSTRACT FROM AUTHOR]

The demand for improved performance and higher energy density of LIBs is growing due to their wide range of applications and advancement in the energy storage market for electric vehicles. Three-dimensional (3D) structured electrodes have recently been considered the best and most promising approach to improve battery performance as they exhibit high areal and specific capacity. In the work described here, a nanosecond pulsed fiber laser was used to generate four types of surface patterns named: line, grid, triangular end, and rectangular end patterns with an equal amount of ablated active material volume. A study on wettability was performed using the spread area, wetting time, wetting balance, and capillary rise measurements. Moreover, the Lucas Washburn and extended wettability models were used to quantitatively express the wetting behavior using the term wetting rate. In all approaches, line-patterned electrodes show better wettability along with a higher wetting rate, while poor behavior is seen with an unstructured electrode. Galvanostatic tests were used to examine how these electrode surface patterns influence the electrochemical performance of the battery. The capacity retentions, discharge capacity efficiencies, and cyclic stabilities were improved on cells with line, triangular end, and rectangular end patterned electrodes. [Display omitted] • Laser structuring of Li-ion battery electrodes was performed using line, rectangular, triangular, and grid patterns. • Laser structuring increases the active surface area for enhanced Li-ion diffusion. • Gravity is negligible in the initial period of wicking during electrolyte wetting. • Capacity retentions, discharge capacity efficiencies, and cyclic stabilities were improved for the structured electrodes. [ABSTRACT FROM AUTHOR]

Previously, tokamak research has been focused mainly on large aspect ratio devices where the vessel/plasma major radius is about a factor three larger than the plasma radius. This research culminated in the design and construction of the international thermonuclear experimental reactor, ITER. Spherical tokamaks (ST), with aspect ratio below two, represent an attractive alternative to large aspect ratio tokamaks as, in our opinion, provide a faster, more economical and compact solution on the path to a fusion reactor. STs are the focus of research at Tokamak Energy Ltd with its present device ST40 in operation and the first ST reactor being designed, taking advantage of the high temperature superconductor (HTS) technology. HTS allow to design a ST with magnetic field/comparable or exceeding that of present-day large aspect ratio tokamaks. However, plasma studies carried out so far on compact, low aspect ratio tokamaks have been limited to small, low magnetic field, low plasma-current devices and therefore the data available for extrapolating to large scale ST plasmas is limited. This paper addresses the problem of scaling the results of large aspect ratio tokamak and existing ST plasmas to a high field ST reactor using plasma-similarity arguments in order to mitigate its design and operational risks. The role of the plasma aspect ratio in scaling burning plasmas as well as conventional experiments in deuterium is highlighted. We find that the scaling for fusion-reactor plasmas exhibit a stronger dependence on the magnetic field and aspect ratio than the one of conventional non-burning plasmas. The parameters of a ST having the same fusion gain Q fus of ITER under different confinement assumptions and for different aspect ratios are presented and discussed. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DESs), a novel generation of solvents, have recently been described as efficient and timesaving fibrillation agents for proteins. In this context, the present work aims at assessing the effect of the hydrogen bond donor (HBD) of cholinium chloride ([Ch]Cl):carboxylic acid based DESs on the dimensions (length and width) of lysozyme nanofibers (LNFs). Mono-, di- and tri-carboxylic acids (acetic, lactic, levulinic, malic and citric acids) were used to prepare different DES formulations, which were successfully used on the fibrillation of lysozyme. The results showed that the carboxylic acid (i.e. the HBD) plays an important role on the fibrillation efficiency and on the length of the ensuing LNFs with aspect-ratios always higher than those obtained by fibrillation with [Ch]Cl. The longest LNFs were obtained using lactic acid as the HBD with an average length of 1004 ± 334 nm and width of 31.8 ± 6.8 nm, and thus an aspect-ratio of ca. 32. The potential of these protein nanofibers as reinforcing additives was evaluated by preparing pullulan (PL)-based nanocomposite films containing 5% LNFs with different aspect-ratios, resulting in highly homogenous and transparent films with improved mechanical performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Laser structuring of LiFePO 4 electrode material. • Effect of the aspect ratio of structured electrodes on wettability and its comparison with unstructured electrodes. • Comparative study of wetting rate with the capillary rise and wetting balance test between structured and Unstructured electrodes. • Usage and comparison of Lucas Washburn model and Zhmud extended model for quantifying the wetting rate. • Electrochemical analysis for cyclic stability, rate capability, and charge–discharge profile. Lithium-ion batteries are widely used for their high energy density, high power density, long lifetime, and safety which are crucial for the environmentally friendly future energy system. Electrodes are the key component of LIBs that determines battery performance. LiFePO 4 is a common electrode used in battery technology due to its long cycle life and good safety. Laser structuring of electrodes has recently been considered a promising approach to increase energy density. In this work, LiFePO 4 electrodes were structured into a grid-type pattern by varying the laser power, resulting in different aspect ratios. To evaluate the effects of the structuring, wettability and electrochemical performance were tested. The wetting property was investigated using spread area, wetting time, and contact angle measurements. Besides, the wetting rate was measured using the wetting balance test and capillary rise test. Lucas Washburn model and Zhmud extended model were used to quantitatively express the wetting rate. The influence of gravity on the wetting performance was also investigated by comparing those models. Furthermore, an electrochemical test was performed to see the cyclic stability, rate capability, and charge–discharge profile with a C rate up to 1C. [ABSTRACT FROM AUTHOR]

• The mechanical behavior of steel fiber reinforced recycled fine aggregate concrete (RAC) was systematically studied. • The effect of steel fiber parameters on the fresh and hardened properties of RAC was investigated. • The high aspect ratio steel fibers significantly improved the toughness of the RAC. In order to solve the problem of low toughness and easy cracking of recycled aggregate concrete, steel fibers were incorporated to recycled fine aggregate concrete (RAC) to prepare a sustainable fiber-reinforced concrete. Steel fibers of various contents (20, 35, 50 and 65 kg/m3) and aspect ratios (l/d = 40 and 55) were incorporated to the RAC, and their fresh properties, mechanical properties and microstructure were investigated. The results show that the slump of RAC decreases with increasing fiber aspect ratio and content. Meanwhile, incorporating a small amount of steel fibers (l/d = 40, 20 kg/m3) improves the 28-d compressive strength of RAC, but with further increase in fiber aspect ratio and content, the compressive strength of RAC decreases. The incorporation of steel fibers greatly improves the splitting tensile strength and flexural strength of RAC, and the steel fibers with high aspect ratio have a higher gain in strength. The 28-d flexural strength of concrete with 65 kg/m3 steel fibers (l/d = 40) increases by 148.11 % relative to plain RAC, while the 65 kg/m3 steel fibers with an aspect ratio of 55 makes RAC with increases by 243.78 %. The mass loss of fiber-reinforced RAC under abrasion is also lower than that of plain RAC, and the steel fiber with high aspect ratio performs better. For the load–deflection response, the incorporation of fibers increases the peak load, and also increases the flexural toughness and post-cracking toughness, with the greatest gain for high aspect ratio fibers. [ABSTRACT FROM AUTHOR]

Projections for the next thirty years predict a rapid growth in urban population, particularly in the less developed regions. Constructing and updating GIS databases of 3D urban form is essential for analyzing spatial phenomena related to urbanization. One of these phenomena, urban climate, is influenced by urban morphology. A prerequisite for representing urban morphology is 3D data including the height of urban features. In cases where no city plans or field survey data are available, a viable option is to use remotely-sensed data for recognition of urban features. Often, the output of automated object recognition consists of footprints of urban features. A known method for calculating a feature's height for reconstructing 3D urban morphology is to use the shadows cast by those features. A GIS-based method for constructing 3D geodatabases of urban morphology from cast shadows and analyzing geometrical parameters for urban-climate analysis was developed. The method focuses on the aspect-ratio of inner courtyards and its relation to solar access. A case-study is presented to demonstrate the feasibility of this method. Results demonstrate that the method offers a reliable and low-cost process for constructing 3D geodatabases that can be applied to the analysis of urban-climate parameters in less developed regions, where costly data and sophisticated processing practices are less accessible. This method can enhance the understanding of microclimatic conditions and facilitate climate conscious and sustainable future urban planning in sprawling urban centers. [ABSTRACT FROM AUTHOR]

The in-situ radical bulk polymerization technique has been proved to be the most efficient strategy for the inorganic/polymer nanocomposites due to its facile mass-production and excellent interfacial properties. However, the inevitable gelation in this approach might cause negative influence on the processing performance of the nanocomposites. Here, the effects of the length and organic modification of the attapulgite nanorods on the performance of the attapulgite/polystyrene (ATP/PS) nanocomposites synthesized via the in-situ radical bulk polymerization technique were studied. The relative molecular weight of polystyrene, percentage of grafting (PG%), particle size of the ATP-PS micro-gels, and glass transition temperature (T g ) of the resultant ATP/PS nanocomposites were discussed. And the processing property of the ATP/PS nanocomposites was also preliminarily investigated by comparing their melting index (MI). Such understanding would lead to a better design to high-performance inorganic/polymer nanocomposites based on high aspect-ratio nanomaterials. [ABSTRACT FROM AUTHOR]

A systematic parametric study has been made in pulsed Nd:YAG laser welding to understand the energy transfer modes. Four different energy transfer zones, namely conduction, transition, penetration, and keyhole, have been identified. The traditional classification of energy transfer modes based on the power density value of 106 W/cm2is not strictly applicable as the transfer mode varies with pulse duration. The threshold power density to form keyhole is not constant, but the threshold energy density has been found to be invariant around 2.4 kJ/cm2. The pulse duration has been optimized to be of about 8 ms to achieve welds of higher aspect ratio. [ABSTRACT FROM PUBLISHER]

The paper deals with reinforced soil structures used in critical infrastructures for ecological landfills. During the last 17 years in Romania 28 such landfills were completed. Romania is however a country where strong earthquakes often occur. About 60% of its territory feels the seismic actions which combine with the existing ones. During earthquakes in the massive structures of landfills, huge inertial forces are developing. Due to uncontrolled movements and deformations, the protective layers of isolation could yield, producing ecological disasters of unforeseen proportions and consequences. Since prevention measures are preferable as opposed to those of repairment, the paper presents a comparative analysis between the safety levels reached in four compatible scenarios of loading. For this purpose three phenomena of instability are considered: lateral sliding, overturning and settlement. These three phenomena correspond to the degrees of freedom by which typical cross sections are endowed. The numerical analysis was carried out with the WinWall Program under Tensar license whilst the results were displayed analytically, in tables, and graphically, in axonometric views. By this study, those parameters allowing physical or structural interventions for enhancing the level of safety were identified. The study is also of high interest for the cost evaluations of the reinforced soil structures currently used in critical infrastructures. [ABSTRACT FROM AUTHOR]

This paper investigates the aspect-ratio locking of the isoparametric 8-node quadrilateral (QUAD8) element. An important finding is that, if finite element solution is carried out with in exact arithmetic (i.e., with no truncation and round off errors), the locking tendency of the element is completely avoided even for aspect-ratios as high as 100000. The current finite element codes mostly use floating point arithmetic. Thus, they can only avoid this locking for aspect-ratios up to 100 or 1000. A novel method is proposed in the paper to avoid aspect-ratio locking in floating point computations. In this method, the offending terms of the strain-displacement matrix (i.e., B-matrix) are multiplied by suitable scaling factors to avoid ill-conditioning of stiffness matrix. Numerical examples are presented to demonstrate the efficacy of the method. The examples reveal that aspect-ratio locking is avoided even for aspect-ratios as high as 100000. [ABSTRACT FROM AUTHOR]

The eyes of stalk-eyed flies (Diopsidae) are positioned at the end of rigid peduncles (‘stalks’) protruding laterally from the head. Eye-stalk length varies within the family and, in some species, varies between males and females. Larger eye-stalks in males result from sexual selection for longer stalks, a trait that increases male reproductive success. In the present study, we examined whether an increase in eye-stalk length results in an adjustment of wing size and shape to deal with the burden of bearing an exaggerated ‘ornament’. We compared wing morphology among ten species of stalk-eyed flies that differ in eye-span and the degree of sexual dimorphism. Mass-specific wing length differed between males and females in seven out of the ten species. Nondimensional wing shape parameters differed between the species ( P < 0.001), but mostly did not differ between males and females of the same species. Dimorphism in eye-span closely correlated with dimorphism in wing length ( r = 0.89, P < 0.001) and the correlation remained significant (r = 0.81, P = 0.006) after correcting for phylogenetic relationships. Once corrected for phylogenetic relatedness, the mass-specific wing length of males (but not females) was weakly correlated with mass-specific eye-span ( r = 0.66, P = 0.042). We propose that the observed proportional increase in wing length associated with increased eye-span can facilitate aerial manoeuverability, which would otherwise be handicapped by the elevated moment of inertia imposed by the wider head. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 860–871. [ABSTRACT FROM AUTHOR]

Abstract: Recently, the need for super-repellent surfaces has been increasing, with applications ranging from material science to Lab-on-a-Chip diagnostics and microfluidics. We propose a novel and simple method to engineer super-hydrophobic surfaces using commercially available negative-tone resists, namely SU-8 and the photodefinable spin-on silicone elastomer, PDSE. The surface energies of fabricated materials were investigated and applied to the transition from the super-hydrophobic to hydrophilic states, occurring during liquid phase evaporation. [Copyright &y& Elsevier]

This paper presents a new topological structure for use in the context of hierarchical radiosity combined with discontinuity meshing. This is most useful for a new strategy adopted for subdividing the elements of a scene consisting of convex polygons. The subdivision is done in a local optimization manner keeping the aspect ratios of produced polygons low. The generated meshes give high visual accuracy. [ABSTRACT FROM AUTHOR]

• The influence of noble metal-coated magnetic Co@M (M=Au, Ag, Au-Ag) core-shell nanoparticles for the formation of the spherical and spheroidal core-shell nanostructures is studied. • The observed spectra are found between 336-698 nm on the wavelength spectrum. • The line width & peak position of LSPR spectra is enhanced by changing the core size and shell thickness in the core-shell spherical nanostructures and aspect ratio as well as shell thickness in spheroidal core-shell nanostructures. • Thus, tunability in core size, shell thickness, aspect ratio, and configuration opens new potential use with desired applications in biomedical fields. In this paper, the optical properties of magnetic-plasmonic core-shell nanoparticles are studied using the Mie theory and DDA method. DDA results are compared with Mie theory results for spherical core-shell NPs as it gives the exact solution. It is observed that the position of LSPR peak in core-shell nanostructures is tuned by changing the cores and shell thickness in the core-shell spherical nanostructures and aspect ratio as well as shell thickness in spheroidal core-shell nanostructures. In addition, the yolk-shell nanostructures exhibit enhancement of LSPR peaks, bandwidth, and their corresponding intensities, as compared to spherical core-shell nanostructures. The calculated absorption spectra at λ max are obtained in the wavelength range of 336-698 nm. This study opens up the new potential of appropriate core-shell nanostructures in bio-imaging, drug delivery, biomedicine, and therapeutic uses. [ABSTRACT FROM AUTHOR]

• Enhanced damage in reinforced concrete columns is due to 2D blast wave propagation. • The 2D wave propagation transitions into 1D wave propagation in walls. • A 500 g TNT contact explosion on square column resulted in damage index of 1. • 67% increase in width reduced damage index to 0.71 when subjected to 500-g TNT. • 140% in width reduced damage index from 1 to 0.48 when subjected to breach charge mass. The response of reinforced concrete (RC) members subjected to contact explosion effects is more severe than the response to non-contact explosions due to local material failure. The shock-wave reflection within the RC member causes severe local material damage. The resulting loss of concrete cross-section reduces the axial load and bending capacity of the RC member. It is hypothesized that the concrete loss from the sides can be prevented by increasing the aspect ratio of the cross-section. In a low aspect ratio RC column, the reflection is from three faces whereas in RC slabs and high aspect ratio columns the shock-wave reflection from the back-face only is significant. This study experimentally investigates the response of rectangular RC columns with varying widths of the cross-section, subjected to contact explosion effects. A range of aspect ratios was investigated to preclude the side face damage for a given depth of rectangular RC column. High fidelity numerical models were developed to predict the blast-response and the residual axial capacity of the blast-damaged rectangular columns. The numerical models were validated, and the results show a good correlation with the experimental results. Using a rectangular RC column aspect ratio with a width that precludes the side face spall significantly improves the residual axial capacity of the blast-damaged columns. Furthermore, parametric analyses were performed to numerically investigate the influence of the width on the residual axial load carrying capacity of rectangular RC columns subjected to contact explosion effects of breach-charge mass required for the provided depth. An increase in the width of the column improved the damage resistance even though the rectangular column was breached around the point of detonation. Hence, increasing the width of the rectangular RC columns can be effectively used to mitigate contact explosion effects. [ABSTRACT FROM AUTHOR]