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Electrospun is a unique class of porous and heterogeneous materials with multi-length-scales constituents that offer a rich variety of surface functionalities to serve a host of applications. Upscaling the electrospun materials from the laboratory to the industry is often limited by the lack of understanding of their mechanical properties. Herein, we developed a theoretical framework to predict the elastic constants of the electrospun mats that hinges on the concept of elastic properties of constituent fibers, three-dimensional (3D) alignment of fibers, and local fiber curvature. Enabled by continuum-based micromechanical approaches, this framework successfully pre-dicted the elastic moduli regardless of bead-string morphology and local architectural heterogeneities present within the electrospun mats. The 3D fiber orientation distribution obtained using X-ray nano-computed tomography (nanoCT) analysis served as a key input for the validation of the analytical model. In general, the predicted elastic moduli are in reasonably good agreement with the experimental data of randomly oriented and preferentially aligned polylactic acid (PLA)-based electrospun mats. To demonstrate our analytical model's versatility and reliability, another set of PA6(3)-based electrospun mats has been chosen from the literature for validation purposes. The parametric analysis has been performed to provide a roadmap to improve the elastic moduli of electrospun mats and justify the assumed values of some of the key attributes.

Hypothesis Self-similarity is a scale-invariant irregularity that can assist in designing a robust superhydrophobic material. A combinatorial design strategy involving self-similarity and dual-length scale can be employed to create a new library of a doubly re-entrant, disordered, and porous network of superhydrophobic materials. Asymmetric wettability can be engineered in nonwoven materials by rendering them with superhydrophobic characteristics on one side. Experiments A facile, scalable, and inexpensive spray-coating technique was used to decorate the weakly hydrophobic stearate-treated titanate nanowires (TiONWs) over the self-similar nonwoven material. Laser scanning confocal microscopy was employed to image the impalement dynamics in three dimensions. With the aid of X-ray microcomputed tomography analysis, the three-dimensional (3D) nonwoven structural parameters were obtained and analyzed. The underwater superhydrophobic behavior of the prepared samples was investigated. Findings A classic 'lotus effect' has been successfully endowed in self-similar nonwoven-titanate nanostructured materials (SS-Ti-NMs) from a nonwoven material that housed the air pockets in bulk and water repellent TiONWs on the surface. The finer fiber-based SS-Ti-NMs exhibited lower roll-off angles and a thinner layer of water on its surface. An asymmetric wettability and the unusual display of underwater superhydrophobic behavior of SS-Ti-NMs have been uncovered.

Computer code plays a vital role in modern science, from the conception and design of experiments through to final data analyses. Open sharing of code has been widely discussed as being advantageous to the scientific process, allowing experiments to be more easily replicated, helping with error detection, and reducing wasted effort and resources. In the case of psychology, the code used to present stimuli is a fundamental component of many experiments. It is not known, however, the degree to which researchers are sharing this type of code.To estimate this, we conducted a survey of 400 psychology papers published between 2016 and 2021, identifying those that openly share stimulus presentation code. For those that did, we established if it would run following download and also appraised the code’s usability in terms of style and documentation.It was found that only 8.4% of papers shared stimulus code, compared to 17.9% sharing analysis code and 31.7% sharing data. Of shared code, 70% ran directly or after minor corrections. For code that did not run, the main error was missing dependencies (66.7%). The usability of the code was moderate, with low levels of code annotation and minimal documentation provided.These results suggest that stimulus presentation code sharing lags behind other forms of code and data sharing, potentially due to less emphasis such code in open-science discussions and in journal policies. They also highlight a need for improved documentation to maximise code utility.

Serogroup B meningococcal disease (MenB) causes almost 60% of meningitis cases among adolescents and young adults. Yet, MenB vaccine coverage among adolescents remains below 10%. Since parents are the primary medical decision makers for adolescents, we examined MenB vaccination rates and parent attitudes about meningitis and the MenB vaccine. In 2018, in conjunction with a county-wide, school-based immunization campaign, we conducted a mixed methods study among parents of 16- to 17-year-olds. We facilitated focus groups asking parents about their knowledge of meningitis and reactions to educational materials and sent behavioral surveys based on Health Belief Model constructs to parents through the county high school system. Parents in three focus groups (n = 8; participation rate = 13%) expressed confusion about their child’s need to receive the MenB vaccine in addition to the meningococcal conjugate vaccine (MenACWY), but conveyed strong trust in their physicians’ recommendation. Among survey participants (n = 170), 70 (41%) had heard of the MenB vaccine. Among those 70 parents, the most common barriers to vaccination were concerns about side effects (55%) and uncertainty of susceptibility due to receipt of the MenACWY vaccine (30%). The percentage of teens that received at least one dose of the MenB vaccine was 50% (n = 35) by parent report and 23% (n = 16) by state vaccination records. Parents demonstrated uncertainty and confusion about the MenB vaccine particularly due to the existence of another meningitis vaccine and limited health care provider recommendations. Confirmatory studies of parent confusion about the MenB vaccine are needed to develop interventions.

With the recent emergence of highly transmissible variants of the novel coronavirus SARS-CoV-2, the demand for N95 respirators is expected to remain high. The extensive use of N95 respirators by the public is susceptible to demand‐supply gaps and raises concern about their disposal, threatening the environment with a new kind of plastic pollution. Herein, we investigated the filtration performance of the N95 respirator by specifically analyzing the structure in the key filtration layers of meltblown nonwoven after decontamination with one and five cycles of liquid hydrogen peroxide, ultraviolet radiation, moist heat, and aqueous soap solution treatments. With the aid of X-ray microcomputed tomography (microCT) analysis, the local structural heterogeneity of the meltblown nonwoven has been unfolded and subsequently correlated with their filtration performance at a face velocity that matched with speaking conditions (∼3.89 m/s). The filtration efficiency results of the N95 respirator remain unaltered after performing one cycle of treatment modalities (except autoclave).

van Wyk put forward a compression model of fibrous materials utilizing a library of analytical approaches, including the continuum mechanics, stereological, geometrical probability, least square method, and excluded area concept. In this letter, we wish to point out a key error noted in van Wyk’s work with the objective of correcting misconceptions that are held by the majority of us. Through this contribution, we question the “inverse cube” pressure-volume relationship of random fibrous materials. The pressure-volume relationship has been revisited by modifying the formulation of the mean length of a fiber element between consecutive contacts projected on the compression direction.

Filtering facepiece respirators (FFRs) provide effective protection against diseases spread through airborne infectious droplets and particles. The widespread use of FFRs during the COVID-19 pandemic has not only led to supply shortages, but the disposal of single-use facemasks also threatens the environment with a new kind of plastic pollution. While limited reuse of filtering facepiece respirators has been permitted as a crisis capacity strategy, there are currently no standard test methods available for decontamination before their repeated use. The decontamination of respirators can compromise the structural and functional integrity by reducing the filtration efficiency and breathability. Digital segmentation of X-ray microcomputed tomography (microCT) scans of the meltblown nonwoven layers of a specific N95 respirator model (Venus-4400) after treatment with one and five cycles of liquid hydrogen peroxide, ultraviolet radiation, moist heat, and aqueous soap solution enabled us to perform filtration simulations of decontaminated respirators. The computed filtration efficiencies for 0.3 µm particles agreed well with experimental measurements, and the distribution of particle penetration depths was correlated with the structural changes resulting from decontamination. The combination of X-ray microCT imaging with numerical simulations thus provides a strategy for quantitative evaluation of the effectiveness of decontamination treatments for a specific respirator model.

The plant products are best option for the treatment of cancer due to its lower side effects. In the present study, it was planned to evaluate the chemopreventive and anticarcinogenic activity of Cuscuta reflexa extract in experimental rats. The hydroalcoholic extract was prepared, and acute toxicity, anticarcinogenicity activity and Chemopreventive effect were evaluated. The hydroalcoholic extract was free from toxicity upto dose of 5000 mg/kg body weight. The present investigation showed significant effect of the hydroalcoholic extract (250 and 500 mg/kg) in preventing melanoma tumor by B16F10 cell line in experimental animals. The result of micronucleus assay indicate that hydroalcoholic extract (250 and 500 mg/kg) have preventive potential against cyclophosphamide induced micronucleus formation in experimental animals. The findings suggested that the anticarcinogenicity and chemopreventive activity of Cuscuta reflexa may be due to antioxidant activity.

Valve regulated lead acid (VRLA) battery constitutes towards the largest part of the worldwide secondary battery market share. Indisputably, absorptive glass mat (AGM) is a key component in a VRLA battery that is often engineered utilizing the synergy that exists between fiber and structural parameters. Over the past few decades, a considerable progress has been made in designing and tailoring the AGM separators but often limited by ‘trial-and-error’ approach. Here in, we present a comprehensive review that specifically targets the design of AGM separators by bridging a gap between fiber-structure-property relationships. The critical review on various experimental and theoretical studies aims to present a template for ‘designer’ AGM separator to fulfill the demands of any application of VRLA batteries. The review surveys important functions and various properties of AGM separators, which have been related with a key set of fiber and structural parameters. Several challenges presented in the form of failure modes of the VRLA battery can be overcome by leveraging the synergy between key set of fiber and structural parameters. This review also highlights the structural commonalities between AGM separators and the other nonwoven materials. This opens up an opportunity to utilize the existing theoretical models of nonwovens to the AGM separators.

Mechanical metamaterials are an extraordinary class of materials that harness their unusual characteristics from the geometrical features. Herein, we report a design strategy to decipher anisotropic and aperiodic nonwovens as auxetic metamaterials by carefully decorating with the slit perforations in a stochastic manner. These slit perforated nonwoven materials have been tested under uniaxial tensile deformation by altering the aspect ratio of the specimen dimensions. Ostensibly, the slit perforations in nonwovens created the invariant behavior towards the test direction and the aspect ratio of the specimen dimensions. These slit perforations have led to the geometrical frustration-free structures that are of paramount importance to avoid any hindrance to the desired functionality.

Valve regulated lead acid (VRLA) batteries are traditionally classified on the basis of gel and absorptive glass mat (AGM) separators. To fulfill the desired functions of AGM batteries, a key design feature of the separator relies on the uptake of the electrolyte in shortest transport time. Herein, we present a three-dimensional (3D) analytical model to predict the fastest electrolyte uptake in AGM separators based upon the optimal set of fiber and structural parameters. The predictive model has utilized 3D data of fiber orientation in AGM separators, obtained via X-ray micro-computed tomography analysis. Such realistic structural information of AGM has assisted in simulating the separators made up of cheaper coarser glass fibers, which was subsequently benchmarked with the experimental samples consisting of finer fibers for attaining the fastest electrolyte uptake. Through theoretical modeling, a design criterion has successfully evolved for the fastest electrolyte uptake by mapping the key effects of the fiber diameter, 3D fiber orientation distribution and porosity of AGM separators. In general, high-density AGM separators comprising of preferentially aligned coarser fibers tend to attain the fastest electrolyte uptake.

Needlepunched nonwovens represent a special class of three-dimensional (3D) fiber networks that successfully generated a host of applications but the rationale of their design involving the intricate microstructure and understanding of the mechanics of the relevant deformation is still lacking. Herein, the micromechanical behavior of needlepunched nonwoven materials possessing out-of-plane auxetic characteristics has been investigated by unraveling the anisotropic structure. The evolution of the 3D intricate architecture of anisotropic nonwoven materials under prescribed levels of tensile strain has been determined using a 3D optical profiler. Most importantly, the analytical models expressed in terms of the initial modulus and in-plane Poisson's ratio of the nonwoven materials are presented. A comparison between the theory and experiments revealed a satisfactory agreement for the modulus and in-plane Poisson's ratio. Further, a comparative analysis of well-known analytical models of in-plane Poisson's ratio with the experimental data clearly demonstrated that the plausible mechanism of deformation of fibers is bending and not stretching.

Objective: At a large public university, we aimed to evaluate an intervention designed to increase serogroup B meningococcal (MenB) vaccine uptake and awareness. Methods: Using a pretest-posttest design with a double posttest, we evaluated an intervention conducted by a local foundation and the Florida Department of Health that distributed MenB vaccine on campus and conducted an educational campaign. Prior to intervention activities, we recruited students to complete a survey about their MenB knowledge and attitudes. For survey participants who provided contact information, we sent two follow-up surveys and assessed MenB vaccine records. We used chi-square tests, adjusted for nonindependence, to compare preintervention to postintervention (three-month and one-year) vaccination and attitudes. Results: Among the 686 students with accessible vaccine records, MenB vaccine initiation increased 9% (from 24% to 33%) and completion increased 8% (from 13% to 21%) from before the intervention to one year after the intervention. When restricting to students who completed the relevant follow-up surveys, the percentage of students who heard of the MenB vaccine increased by 15% (p > .001) from before the intervention to three months after (n = 188 students) and maintained a 10% increase (p > .001) one year after the intervention (n = 261 students). Among students that heard of the MenB vaccine, the percentage of students who thought they needed the MenB vaccine even though they received the MenACWY increased 14% (p = .03) by the three-month postintervention survey and up to 18% by the one-year follow-up (p = .002). Conclusions: A university-wide, on-campus vaccination and educational campaign increased college students’ MenB vaccine initiation, completion, and knowledge. Clinicaltrials.gov ID: NCT02975596.

Visual statistical learning (VSL) occurs when participants are exposed to spatially or temporally ordered stimuli, and become increasingly sensitive to them without explicitly realizing the hidden regularities. In the temporal domain of VSL, participants are usually exposed to shape-triplets, followed by the use of familiarity judgments and recognition tasks to directly probe VSL. Other methods, such as the rapid serial visual presentation (RSVP) task, indirectly probe the learning of temporal sequences, and provide evidence of learning within the triplets. Despite the RSVP's success, however, previous implementations of the RSVP task have only pseudorandomized the triplets to form the test sequence, such that the task permits only two stream locations for a given target shape (belonging to a certain within-triplet position), out of six available locations. These fixed locations may result in confounded response time (RT) findings and potentially lead to an overestimation of a weak (or nonexistent) VSL effect. In this study, we conduct 4 experiments and show that the previously reported VSL effect in RSVP is eliminated when the RSVP stream is fully counterbalanced (Experiment 1), and resurfaces again when the RSVP stream returns to its original pseudorandomized design (Experiment 2). Importantly, in both, we observe a "stream location effect," where RT gradually becomes faster to reflect the hazard rate of target appearance, which may have been the factor driving previously reported VSL effects. Follow-up experiments show that results from Experiment 1 are not due to the absence of implicit learning (Experiment 3), although the stream location effect can occur without any learning, suggesting that it is something inherent to the RSVP task (Experiment 4). Together, these results identify an influential effect, the stream location effect, inherently present in the RSVP task, and show how misinforming the RSVP task can be, when not used with properly controlled parameters, and demand a reexamination of the effects found in previous studies which could have been the effect of detection stream locations, misconstrued as VSL. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Electrospun mats with targeted wettability are a way forward to diversify their mainstream applications and can facilitate in creating a platform for a remarkable set of properties. Limited control over the fiber morphology and surface chemistry, along with the complex architecture of electrospun mats, pose some of the key challenges for maneuvering the wettability. Herein, we present the design principles that underpin the key determinants responsible for a metastable state of a water droplet on electrospun mats possessing wrinkled surface topography. A ‘first-of-its-kind’ analytical model of apparent contact angle based on the modified Cassie-Baxter state has been proposed that accounts for the dual-scale roughness originating from fiber wrinkles and protuberances created by fiber–fiber contacts. Three-dimensional (3D) fiber and structural parameters obtained via X-ray microcomputed tomography (microCT) analysis served as key inputs for predictive modeling. The analytical model of the apparent advancing and receding contact angles has been validated with electrospun mats having well-defined orientation characteristics. In general, the theory and experiments are in reasonable agreement. Although similar magnitudes of static and advancing contact angles of water on surfaces of randomly and aligned electrospun mats have been experimentally observed, the receding contact angles differed significantly.

Biomaterials are porous and three-dimensional (3D) templates, which are used as biological substitutes in tissue engineering. Targeting the optimal design of biomaterials requires a synergy between mechanical, porous, mass transport, and biological properties. To address this challenge, we propose a non-periodic meta-biomaterial in the form of an out-of-plane auxetic nonwoven scaffold that possesses a 3D interconnected highly porous structure with remarkable mechanical properties corresponding to conventional nonwoven material. A design strategy of utilizing larger fiber diameters to enhance the porosity and permeability characteristics successfully devised the nonwoven scaffold with an extraordinary out-of-plane auxetic effect. In situ tensile-X-ray microcomputed tomography (microCT) analysis has been carried out to monitor the variation in the morphological characteristics.

Self-similar materials can assist in the transition of hydrophobic to hydrophilic state in a well-controlled manner. Herein, we report an ensemble of carboxylic functionalized carbon nanotubes (CNTs) decorated on the self-similar nonwoven surface using a facile, scalable and inexpensive vacuum filtration process for tunable surface wettability. Increasing the amount of CNTs combined with the vacuum assisted nonwoven material reduced the apparent equilibrium contact angle systematically. A simple analytical model has been proposed to predict the apparent equilibrium contact angle by formulating a direct relationship with the structural parameters of CNTs and nonwoven materials. In general, a satisfactory agreement was observed between the theoretical and experimental apparent equilibrium contact angles of CNT decorated nonwoven materials.

Nonwoven geotextiles made from hybridization of natural and synthetic fibers can potentially offer distinct advantages in terms of uniformity and improved mechanical properties. To further enhance the mechanical properties of hybrid nonwoven geotextiles, natural fibers such as jute must be treated with a minimal amount of alkali, such that the treatment process becomes scalable, cost-effective and environmentally friendly. Herein, we report a comparative analysis of physical and mechanical properties between the corresponding samples of untreated (UT) jute/polypropylene (PP) and mild alkali-treated (MAT) jute/PP nonwoven geotextiles in both virgin and damaged conditions. The constituent jute fibers were treated with 0.5 wt.% of sodium hydroxide solution under ambient temperature conditions for 24 h duration. Such mild treatment of jute fibers with alkali solution resulted in considerable improvement in the mechanical properties of MAT jute/PP nonwoven geotextiles corresponding to the sets of UT jute/PP nonwoven geotextiles. Various types of damage, including circular holes, horizontal cuts, vertical cuts and inclined cuts at an angle of 45°, were artificially induced in hybrid nonwoven geotextiles to investigate the reduction in tensile properties. Further, the Poisson's ratio in virgin and damaged states was determined to make a comparison between the UT and MAT jute/PP nonwoven geotextiles. In general, lower Poisson's ratio values were observed for mechanically damaged MAT jute/PP nonwoven geotextiles corresponding to the samples of UT jute/PP nonwoven geotextiles. Surprisingly, the vertical cuts induced in MAT jute/PP nonwoven geotextiles yielded tensile strength comparable to that of virgin samples.

Absorptive glass mat (AGM) separator is a vital technical component in valve regulated lead acid (VRLA) batteries that can be tailored for a desired application. To selectively design and tailor the AGM separator, the intricate three-dimensional (3D) structure needs to be unraveled. Herein, a toolkit of 3D analytical models of pore size distribution and electrolyte uptake expressed via wicking characteristics of AGM separators under unconfined and confined states is presented. 3D data of fiber orientation distributions obtained previously through X-ray micro-computed tomography (microCT) analysis are used as key set of input parameters. The predictive ability of pore size distribution model is assessed through the commonly used experimental set-up that usually apply high level of compressive stresses. Further, the existing analytical model of wicking characteristics of AGM separators has been extended to account for 3D characteristics, and subsequently, compared with the experimental results. A good agreement between the theory and experiments pave the way to simulate the realistic charge-discharge modes of the battery by applying cyclic loading condition. A threshold criterion describing the invariant behavior of pore size and wicking characteristics in terms of maximum permissible limit of key structural parameters during charge-discharge mode of the battery has also been proposed.

Contemporary understanding of fiber-fiber contacts is vital in diversifying the applications of fiber networks. Various properties of fiber networks rely on the architecture, which essentially requires encapsulating realistic features arising from excluded volume effects. Herein, an architectural-based interfiber spacing model of ‘generalized’ fiber networks has been proposed by combining the geometrical probability, stochastic, and excluded volume approaches. The interfiber spacing model features the classical work of excluded volume approach of Onsager, superimposed on Komori and Makishima's theory of fiber-fiber contacts. The significance of the interfiber spacing model relies on its ability to systematically demystify the anomalies in Onsager's work for random networks composed of exceedingly low-aspect-ratio fibers. Nevertheless, a good agreement between the theory and experiments justified that Onsager's excluded volume approach is sufficiently robust to predict the interfiber spacing of moderate to high-aspect-ratio fiber networks.

Articular cartilage possesses unique structure and composition giving rise to unusual mechanical behavior. Typically, it is a structurally graded material that displays variation in mechanical properties along the depth. In this communication, the geometrical probability approach has been used for predicting the in-plane Poisson’s ratio in the surface and middle zones of articular cartilage. The presented model has formulated a relationship between the Poisson’s ratio and collagen fibril alignment. A comparison has been made between the theoretical and experimental findings of Poisson’s ratio in the surface and middle zones of human patella cartilage, as obtained from the literature.

Absorptive glass mat (AGM) separators are widely used for valve regulated lead acid (VRLA) batteries due to their remarkable fiber and structural characteristics. Discharge performance and recharge ...

Unprecedented sign change of Poisson’s ratio not only paves the way for diverse applications, but it provides a sense of deep understanding of ‘hidden’ mechanics, yet to be discovered. Stochastically distributed multi-walled carbon nanotubes in the form of buckypaper can possess negative Poisson’s ratio, but the underlying design principles are still unclear. Herein, we explored analytical approaches, namely, energy minimization, structural modeling, and force-balance as a means to target negative Poisson’s ratio in the buckypaper. Though ‘zero’ Poisson’s ratio is still achievable, the controlling parameters could not be identified. Guided by a ‘keyed-brick’ structure, a simple geometrical model is then constructed to account for sliding effects in carbon nanotubes for contemporary understanding of auxetic behavior (negative Poisson’s ratio). The alignment of carbon nanotubes plays a prominent role in augmenting the magnitude of negative Poisson’s ratio.

Buckypaper (BP) is a planar film that consists of random network of multiwall carbon nanotubes (MWCNTs) held together by weak van der Waals interactions at tube-tube junctions. Although individual ...

Hierarchical roughness and low surface energy are the main criteria for designing superhydrophobic surfaces with extreme water repellency. Herein, we present a step-wise approach to devise three-dimensional (3D) superhydrophobic disordered arrays of fibers in the form of nonwoven mats exhibiting hierarchical surface roughness and low surface energy. Key design parameters in the form of roughness factors at multiple length scales for 3D nonwoven mats have been quantified. The contact angles have been predicted for each of the wetting regimes that exists for nonwoven mats with predefined level of hierarchical surface roughness and surface energy. Experimental realization of superhydrophobic mats was attained by decorating the highly hydrophilic nonwoven viscose fibers with ZnO rods that effectively modulated the surface roughness at multiple length scales and subsequently, the surface energy was lowered using fluorocarbon treatment. Synergistic effects of hierarchical roughness and surface energy have systematically increased the static water contact angle of nonwoven mat (up to 164°) and simultaneously, lowered the roll-off angle ( ≈ 11°).

Fiber networks with out-of-plane auxetic behavior have been sporadically investigated. One of the major challenges is to design such materials with giant negative Poisson’s ratio over large deformations. Here in, we report a systematic investigation to create three-dimensional (3D) fiber networks in the form of needlepunched nonwoven materials with out-of-plane auxetic behavior over large deformations via theoretical modeling and extensive set of experiments. The experimental matrix has encapsulated the key parameters of the needlepunching nonwoven process. Under uniaxial tensile loading, the anisotropy coupled with local fiber densification in networks has yielded large negative Poisson’s ratio (up to −5.7) specifically in the preferential direction. The in-plane and out-of-plane Poisson’s ratios of fiber networks have been predicted and, subsequently, compared with the experimental results. Fiber orientation was found to be a core parameter that modulated the in-plane Poisson’s ratio of fiber networks. A parametric analysis has revealed the interplay between the anisotropy of the fiber network and the out-of-plane Poisson’s ratio based upon constant volume consideration.

In this communication, a stochastic approach based upon Komori and Makishima’s work has been used for predicting the electrical percolation threshold of cylindrical nanofillers with three-dimensional (3D) spatial orientations in a typical nanocomposite system. Specifically, the proposed model was able to predict the volume fraction based percolation threshold of nanofillers with a wide range of aspect ratios (10–1000), which was substantiated with a variety of experimental data sets obtained from the literature. The anisotropic behavior of 3D aligned nanofillers was successfully introduced via in-plane and out-of-plane orientation distributions. The percolation threshold values of nanofillers were also found to be comparable with those obtained from the stochastic model that has incorporated the excluded volume effect.

Anterior cruciate ligament (ACL) is one of the most susceptible ligaments of the knee that can suffer injury. These ruptured ligaments can be treated through surgical intervention using a braided structure that either acts as a substitute graft in isolation or an augmentation device alongside the biological tissue. Therefore, the main objective of the research work is to present an analytical model for predicting the complete set of tensile properties of braided prosthesis consisting of multifilament strands based upon predefined braid geometry and constituent material properties. The model has also accounted for the kinematical changes under defined loading conditions. The research findings have been confirmed by making a comparison between the theoretical and experimental results. The tensile properties of braided prostheses predicted via analytical route matched reasonably well with the experimental results.

In this communication, an analytical model for predicting the compression induced electrical resistance of bulk assemblies of carbon nanomaterials has been presented. The model is based upon the stereological and stochastic approaches for computing the structural parameters of the assembly together with classical Hertzian contact mechanics and constriction resistance techniques to predict the compression induced electrical response. The model has been validated with the experimental data of carbon nanofibers (CNFs) obtained from the literature. The electrical response of CNFs was found to be tunable by varying the fiber orientation distribution within the assembly specifically under lower amount of compressive stresses.

Anterior cruciate ligament (ACL) is a key fibrous connective tissue that maintains the stability of a knee joint and it is the most commonly injured ligament of the knee. A synthetic prosthesis in the form of a braided structure can be an attractive alternative to biological grafts provided that the mechanical properties can be tailored to mimic the natural ACL. In the present work, the polypropylene based structurally gradient braided prostheses have been designed and developed by understanding their tensile properties. Circular braiding process was employed to fabricate structurally gradient braided prostheses by systematically placing different types of braids in defined set of layers. An analytical model for predicting the tensile properties of structurally gradient braided prostheses has been presented by modifying and combining the existing models available in the literature. Specifically, the full set of stress-strain behaviour of structurally gradient braided prostheses has been computed based upon braid structural characteristics, constituent strand properties and braid kinematics. A triaxial braid in the outer layer of braided prostheses was found to withstand higher tensile stresses in comparison to a biaxial braid having same structural characteristics. A comparison has been made between the theoretical and experimental results of tensile properties of structurally gradient braided prostheses. The tensile properties of structurally gradient braided prostheses predicted through analytical route matched reasonably well with the experimental results.

Drawing on antifragility as a lens, we explore UK-based entrepreneurs’ accounts of their behaviours and choices to theorise how they managed to bounce back from bankruptcy to restart their new firm...

Solid/ liquid interaction strongly depends, among other things, on the chemical and physical properties of fluids, therefore, there are unexploited analytical possibilities in investigating the surface wetting and evaporation behavior. Strongly hydrophobic rough surface thin films were prepared by spray-coating a fluoropolymer film with incorporated layered double oxide (LDO) microparticles. We studied the evaporation of ethanol–water mixtures from the low energy (8.4 ± 2.6 mJ/m2) composite surfaces by simultaneous high-speed visible imaging, infrared imaging and weight loss monitoring. The wetting behavior changed from Cassie's wetting mode (pure water) to Wenzel's (pure ethanol) as a function of solvent composition. The vaporization process could be divided into three stages described by constant evaporate rates and the heat transfer coefficient between the studied layer and water is KT = 1768 W/(m2K). We have found strong correlations between parameters of the measured evaporation profiles and certain physical properties of the solvents. It is possible to estimate the viscosity, the boiling point, or the surface tension of a studied liquid merely from the total evaporation time. This novel solvent identification method can serve as a new application field for such low energy hybrid surfaces.

The valve regulated lead acid (VRLA) battery is a predominant electrochemical storage system that stores energy in a cheap, reliable and recyclable manner for innumerable applications. The absorptive glass mat (AGM) separator is a key component, which is pivotal for the successful functioning of the VRLA battery. Herein, the intricate three-dimensional (3D) porous structure of AGM separators has been unveiled using X-ray micro-computed tomography (microCT) analysis. X-ray microCT has quantified a variety of fiber and structural parameters including fiber orientation, porosity, tortuosity, pore size distribution, pore interconnectivity and pore volume distribution. A predictive model of hydraulic tortuosity has been developed based upon some of these fiber and structural parameters. Moreover, the pore size distribution extracted via X-ray microCT analysis has served as a benchmark for making a comparison with the existing analytical model of the pore size distribution of AGM separators. Pore size distributions obtained via the existing analytical model and through X-ray microCT analysis are in close agreement.

Triaxial braided structures have proliferated in many applications and specifically, they are extensively used as main constituent materials in various biomedical and composite systems. The topological nature of triaxial braids provides significant enhancement in mechanical properties which can be further tuned by elucidating the most important geometrical and material parameters. In this study, the geometrical models of various braid parameters of triaxial braided structures have been developed for predefined strand geometries. These braid parameters were then used for computing various tensile properties of triaxial braids. Particularly, the elastic properties of triaxial braided structures and their composites have been analysed by including the effect of axial strand crimp. Furthermore, the full set of stress–strain characteristics of triaxial braided structures has been predicted based upon braid topological characteristics, constituent strand properties and braid kinematics. The research findings of stress–strain characteristics of triaxial braids have been confirmed by making a comparison between the theoretical and experimental results.

Braiding is a highly versatile and cost-effective method of producing structures that has been successfully used for numerous applications ranging from ropes, composites, biomedical uses, insulation to sports and recreation activities, and the list of applications of braided structures is ever-increasing. The prediction of tensile property is a pre-requisite for the success of deployment of braided structures in these applications. This paper reviews the key parameters that control the tensile properties of biaxial and triaxial braided structures along with the models developed for these braids by various researchers with different fields of interest. In general, the tensile properties of braided structures are strongly dependent upon their architecture and the kinematics and mechanics involved in the braid formation. Furthermore, various approaches and methodologies have also been presented for the tensile models of braids consisting of an elastic core and multi-layered structures.

Success of tissue engineering relies on the architecture and properties of porous scaffolds. Electrospun nonwoven scaffolds in the form of mats are unique materials due to large surface area to volume ratio, high porosity, versatility in surface functionalities and excellent mechanical properties. Maneuvering the mechanical behavior of the electrospun mat is a major challenge both from theoretical and experimental perspectives. Herein, we report a two-dimensional (2D) analytical model of normalized elastic moduli of electrospun mats by formulating a relationship with the governing fiber and structural parameters. The analytical model of normalized mat modulus has also accounted for fiber curvature in the form of sinusoidal curve along with the specimen dimensions considered during the uniaxial tensile test. A comparison has been made between the magnitudes of normalized mat modulus obtained through predictive modeling and the experimental results adapted from the literature. In general, a good agreement has been found between the theoretical and the experimental results of normalized moduli of electrospun mats. An interplay of some of the governing parameters has been analyzed through parametric analysis. Through theoretical modeling, the normalized amplitude of fiber crimp via fiber diameter along with the aspect ratio of specimen dimensions are observed to be the dominant factors responsible for modulating the normalized mat modulus.