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Polymer electrolytes (PEs) are widely used in the field of flexible energy storage due to their high safety, good flexibility, and ease of processing. Developing PEs with both high mechanical properties, high ionic conductivity and wide electrochemical stability window (ESW) for lithium‐metal batteries (LMBs) is an urgent issue to be addressed. In this work, we designed and synthesized the poly (vinyl alcohol) (PVA)‐polyacrylic acid (PAA)‐LiCl electrolyte for LMBs with a high ionic conductivity, wide ESW, high modulus and puncture resistance simultaneously. Through the construction of dual cross‐linking networks, the PVA‐PAA‐LiCl exhibits a wide ESW (6.2 V), achieves a notable ionic conductivity (1.08 × 10−4 S cm−1) at room temperature and can realize a high cycle stability of Li symmetric battery more than 300 h at 1 mA cm−2/1 mA h cm−2. Furthermore, it demonstrates exceptional puncture resistance, capable of withstanding pressures up to 5.73 × 108 Pa exerted by a steel nail, while simultaneously exhibites a commendable tensile strength of 4.9 MPa. Hence, this conceptual framework featuring dual‐crosslink network structure offers profound implications for the progression of next‐generation flexible energy storage. [ABSTRACT FROM AUTHOR]

Ceramic nanofibrous sponges are attractive for their broad applications in high-temperature air filtration, thermal insulation, sewage treatment, and catalyst support. However, the present ceramic sponges usually show brittle fracture even under tensile stresses. Herein, a ceramic sponge assembled by ultralong and crimped Si 3 N 4 nanofiber nanofibers is designed and prepared to achieve temperature-invariant reversible from liquid nitrogen to 1200 °C and large elongations (ductile failure over 100 %) as well as excellent compressive anti-puncturing property. Moreover, the ceramic sponge illustrates a high filtration efficiency of 99.6 % for PM 2.5 and a low-pressure drop of 32 Pa during a long-term test under high-speed gas flow. It can also support photocatalyst g-C 3 N 4 nanoparticles, yielding a high efficiency of photodegradation of nitrogen oxide gases. The well-designed ceramic nanofiber sponge with good comprehensive mechanical performances thus shows promising applications in air purification under extreme working conditions. [ABSTRACT FROM AUTHOR]

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Shear thickening fluids (STF) are the materials of future to be used in numerous high-tech applications, including protection against impact. The researchers have investigated the effect of particle size and their shape on the impact resistance of fabrics using the fixed concentration of particles for STF preparation. In addition to particle shape and size, particle concentration may be an important factor that can contribute to the yarn-to-yarn friction and ultimately enhancing their impact resistance. The objective of this study is to compare the mechanical performance of para-aramid fabric treated with non-Newtonian STF made by using three diffrent percentages of silica particles. The para-aramid fabric was impregnated with STF and needle penetration, tensile strength, and energy absorption were checked in dry and wet state. The microparticles percentage in STF has a direct relation with the mechanical performance of samples. Fabric impregnated in STF with 7% of silica microparticles has higher tensile strength puncture resistance, and impact resistance, 1.4, 3 and 1.75 times respectively as compared to the fabric sample without STF. [ABSTRACT FROM AUTHOR]

Textiles-fibres, yarns and fabrics are omnipresent in our daily lives, with unique mechanical properties that fit the design specifications for the tasks for which they are designed. The development of yarns and fabrics with negative Poisson’s ratio (NPR) is an area of current research interest due to their potential for use in high performance textiles (e.g., military, sports, etc.). The unique braiding technology of interlacement for preparation of braided helically wrapped yarns with NPR effect with later development of auxetic woven fabric made it possible to avoid the slippage of the wrapped component from the core. The applied geometrical configuration and NPR behaviour of the braided helical yarn structure with seven different angles comprising of monofilament elastomeric polyurethane (PU) core with two wrap materials that include multifilament ultra-high molecular weight polyethylene (UHMWPE) and polyethylene terephthalate (PET) fibres were investigated and analysed. The mechanically stable 2D woven textile auxetic fabrics (AF) with various weave patterns such as 2/2 matt and 3/1 twill were developed from the auxetic yarn with PU elastomer core having maximum NPR effect of −1.70 using lower wrapped angle of 9° to study and compare their mechanical responses. The auxetic yarn was used in weft direction and multifilament UHMWPE yarn in warp direction, using semi-automatic loom. Auxeticity of AF was analysed and its various mechanical properties such tensile strength, impact energy absorption, in-plane, and out-of-plane auxeticity, and puncture resistance were studied. Higher energy absorption of 84 Nm for matt fabric was seen compared to twill fabric having an energy of 65 Nm. The puncture resistance capability of matt fabric was better than twill fabric. While twill fabric exhibited better auxetic effect in both in-plane and out-of-plane mode compared to matt fabric. In short, both the twill and matt design AF’s showed unique characteristics which are beneficial in making various protective textiles such as protective helmets, bullet proof shields, cut resistance gloves, blast resistant curtains, and puncture tolerant elastomeric composites.

Investigation was performed to evaluate the puncture resistance of multi-walled carbon nanotubes (MWCNTs)/glass fibre epoxy laminate composites using different indenters (conical, elliptical, flat, and hemispherical). For the puncture tests, MWCNT weight percentage and indenter type were varied. Furthermore, the impact of MWCNT on tensile, flexural, and interlaminar shear strength was evaluated. Ultrasonic C-scan provided insights into the damage evolution and failure mechanisms of the laminates under puncture. The results indicate that the flat indenter exhibits prolonged indentation time and enhanced energy absorption, resulting in a disc-shaped failure pattern. On the other hand, the conical indenter demonstrates rapid penetration due to its smaller contact surface area. The elliptical indenter generates higher frictional energy, leading to bulging damage. The hemispherical indenter showed an even distribution of force across the impacted surface, minimizing force concentration and reducing the extent of damage. These findings shed light on the puncture mechanisms of MWCNT/Glass fibre epoxy laminate composites, paving the way for more precise glass fibre laminate composite design and optimisation in practical applications such as aerospace, automotive, and sporting goods, where puncture loading is a critical consideration.

Featured Application: This research paper promotes green engineering in slope stabilization. The results of this study can serve as a reference in understanding the strength performance of natural fiber geotextile, specifically coir geotextile, as an alternative material for slope stabilization. Slope stability is one of the crucial factors to consider in every civil engineering project. One widely used method to stabilize slope is the use of polymeric products called geosynthetics. Natural fiber geosynthetics used for geotechnical applications have attracted attention because of their environmental and economic benefits. Coir fibers made into nonwoven geotextiles are utilized in this study as an alternative material for slope stabilization. One drawback of coir fiber geotextiles is their low tensile strength and limited life span due to their susceptibility to environmental factors. This study was conducted to evaluate the effect of mercerization and bleaching treatment on the strength performance of nonwoven coir geotextiles after exposure to conditions simulating biological and chemical degradation. Microscopic images of treated coir geotextiles show the removal of surface impurities that altered the physical components in the fiber. The grab tensile strength results prove that the mercerized coir geotextiles are suitable for field conditions and groundwater exposure. The untreated coir geotextiles showed superior puncture resistance relative to the chemically treated geotextiles. The chemical treatments improved the tensile strength; however, they weakened the puncture resistance of the coir geotextile due to the decrease in thickness. A slope stability simulation conducted using Rocscience Slide2 version 9.017 software proved that coir geotextiles can effectively reinforce slopes, with strength performance almost comparable to that of synthetic geotextiles. [ABSTRACT FROM AUTHOR]

This study examines the resistance of three-dimensional (3D) weft-knitted fabrics to mechanical risks to determine the influence of varying percentage contents of high molecular weight polyethylene and basalt on cut, puncture, abrasion, and tear resistance. The three-dimensional weft-knitted fabrics are designed by separating functional layers: the outer (protective) layer contains varying percentage contents of high molecular weight polyethylene and basalt; the inner layer (suitable for contact with the skin) contains polyester; both layers are connected using polyamide. The strength properties of knits in response to mechanical impact were evaluated by performing cut, puncture, abrasion, and tear resistance tests. Basalt was found to improve the cut resistance of knits significantly, even with its content as low as 5% in the outer layer. The knit with the highest high molecular weight polyethylene content in the outer layer demonstrated the best puncture and tear resistance. No correlation was established between the varying percentage contents of high molecular weight polyethylene and basalt and the maximum number of abrasion cycles, as the three-dimensional weft-knitted fabrics showed no noticeable wear. The test results show that the structure of three-dimensional weft-knitted fabric with the outer layer designed to withstand mechanical impact and the inner layer suitable for direct contact with the skin protects against a wide range of mechanical impacts. This applies even when varying percentage contents of high molecular weight polyethylene and basalt are used only in the outer layer. [ABSTRACT FROM AUTHOR]

ABSTRACTIt remains a challenge to achieve rapidly recoverable hydrogels by molecular hydrogen-bonding interaction because of its slow interaction kinetics. This work for the first time reports a trehalose (Tre)-based molecular movement mechanism inside a single network of polyacrylamide (PAM) that accelerates the kinetics of hydrogen-bonding interaction, and thereby endows the hydrogel with high toughness and rapid shape and mechanical recoverability. The resultant PAM@Tre hydrogel is capable of full shape recovery after 10,000 loading/unloading cycles at a strain of 500%. Even after being stretched at a strain of 2500%, it can recover to its original shape within 10 seconds. Moreover, the molecular movement of trehalose also endows the PAM@Tre hydrogel with fracture energy and toughness as high as ~9000 J m–2 and ~1600 kJ m–3, respectively, leading to strong resistance to both static and dynamic piercing. The PAM@Tre hydrogel is thus believed to have enormous potentials in protection devices, bionic skin, soft actuator, and stretchable electronics.

Biodegradable jute geotextiles (JGTs) are an effective reinforcing material for unpaved roads, but its serviceability is limited because of faster microbial degradation. Different methods are in use to improve the serviceability of jute geotextiles. In this paper, the influence of CA-chitosan treatment, road design, and rainfall intensity on the time-dependent serviceability of JGTs has been studied. Chemically treated jute geotextiles are laid in unpaved road designs with and without sand layer, for 30, 60, and 90 days’ duration, and are exposed to simulated rainfall intensities of 50 and 100 mm/hr. With an increase in time of usage, breaking load and puncture resistance decrease due to microbial attack, and pore size decreases due to clogging of soil in JGTs. Chemical treatment is observed to have a greater influence on the serviceability, followed by the presence of a sand layer in road design and the rainfall intensity and shows retention % in tensile strength of 87.42% and 91.21% after 30 days duration. Further, the overall performance of CA-chitosan treated JGTs is observed to be better than untreated JGTs.

Lightweight and soft puncture-resistant fabrics have great applications in professional clothing. A soft composite fabric was fabricated by coating a water-soluble polyacrylate emulsion (PAE) on the surface of aramid fabric (AF; AF/PAE). The areal weight of AF/PAE fabric was only 7.1% higher than that of AF ones. Under spike stabbing, both the maximum load and energy absorption capacity of AF/PAE were about 4.5 times higher than those of AF. The puncture resistance of AF/PAE was superior to those of shear thickening fluid (STF)-impregnated AF (AF/STF) and polyurethane (PU)-sprayed AF (AF/PU) under the same areal weight or thickness. Carboxylic multi-walled carbon nanotubes (MWCNTs-COOH; 0.4 wt %) were then added to AF/PAE to further enhance the puncture resistance of the composite fabric. The spike punching resistance of AF/PAE increased by about 49.2% after the addition of MWCNTs-COOH. MWCNTs-COOH created a bridge effect between fibers to enhance friction between yarns. In addition, MWCNTs-COOH on the fiber surface can form a network protective membrane, which can effectively disperse stress and reduce fiber fibrillation, thus improving the puncture resistance of the fabric. This study provides an efficient method for the development of lightweight and flexible anti-stabbing equipment. [ABSTRACT FROM AUTHOR]

Shear thickening fluids (STFs) have been shown to improve the effectiveness of fabrics used in soft body armor applications. They are used to increase the puncture and ballistic impact resistance of Kevlar® fabrics. However, the effect of using STFs with natural fabrics such as flax appears to have never been studied. Similarly, the hybridization of different fabric types impregnated with STF has also only undergone limited study. The rheology of STFs at varying concentrations of nanosilica dispersed in polyethylene glycol (PEG) was studied at different temperatures. It was found that the STFs behave as a non-Newtonian fluid in response to changes in shear rate. In this study the effectiveness on the puncture and ballistic impact resistance of impregnating flax fabric with STF at concentrations of 30%, 50%, and 70% w/w of nanosilica in PEG was investigated. The effect of hybridization of flax and Kevlar® fabrics impregnated with STF was also investigated. The puncture resistance of both flax fabrics treated with STFs and hybrids treated with STFs was found to increase significantly and can be controlled by STF concentration. The ballistic impact resistance was also found to increase in the hybrid samples when STF concentration was at least 50%. The flax treated with STFs showed either a decrease in specific energy absorption per layer for the lower STF concentration, or a very small increase at 70% STF concentration. [ABSTRACT FROM AUTHOR]

We evaluated the effects of chitosan of different molecular weights on the quality of Kamchatka berries after harvest and storage. Chitosan with lower molecular weights (from 3 to 21 kDa) positively influenced the soluble solid content after harvest. However, chitosan had no significant effect on titratable acidity after harvest. Regardless of the chitosan molecular weight, the berries contained from 7.4% to 30% more total polyphenols compared with the control (162 mg per 100 g) after harvest. After storage, the total phenolic content decreased slightly and depended on the storage conditions. The L-ascorbic acid content was the highest after harvest and storage after treatment with the highest molecular weight of chitosan (950k kDa). Chitosan 50 kDa positively influenced the firmness and puncture resistance of the berries after harvest (146% of control) and storage (135% of control). [ABSTRACT FROM AUTHOR]

It remains a challenge to achieve rapidly recoverable hydrogels by molecular hydrogen-bonding interaction because of its slow interaction kinetics. This work for the first time reports a trehalose (Tre)-based molecular movement mechanism inside a single network of polyacrylamide (PAM) that accelerates the kinetics of hydrogen-bonding interaction, and thereby endows the hydrogel with high toughness and rapid shape and mechanical recoverability. The resultant PAM@Tre hydrogel is capable of full shape recovery after 10,000 loading/unloading cycles at a strain of 500%. Even after being stretched at a strain of 2500%, it can recover to its original shape within 10 seconds. Moreover, the molecular movement of trehalose also endows the PAM@Tre hydrogel with fracture energy and toughness as high as ~9000 J m–2 and ~1600 kJ m–3, respectively, leading to strong resistance to both static and dynamic piercing. The PAM@Tre hydrogel is thus believed to have enormous potentials in protection devices, bionic skin, soft actuator, and stretchable electronics. [ABSTRACT FROM AUTHOR]

This study investigates the resistance of three-dimensional (3D) weft-knitted fabrics to mechanical risks in order to determine the impact of the percentage content of raw materials in the knits on mechanical loads. For this purpose, 3D weft-knitted fabrics, consisting of a front side, binding, and back side layers, were designed and produced on an E20 circular weft-knitting machine using organic multifilament yarns (high molecular weight polyethylene, HMWPE) and inorganic multifilament (basalt, BS) yarns for the front and back side layers and conventional polyamide yarns for the binding layer. The cut, puncture, abrasion, and tear resistance tests were performed to assess the resistance of 3D weft-knitted fabrics to mechanical risks. According to the testing results, basalt in the structure of 3D weft-knitted fabrics significantly increases the cut resistance, even in cases of a small basalt content in the knit. The puncture, abrasion, and tear resistance testing results showed that the highest HMWPE percentage content in the knitted structure provided the highest resistance to these risks, while increasing the basalt content in the knit did not improve the resistance testing results. Based on the testing results and the assessment of the protection levels provided by the knitted fabrics, the conclusion can be made that the use of HMWPE multifilament yarns and basalt multifilament yarns in the structure of 3D weft-knitted fabrics contributes to the achievement of the highest levels of performance. All the designed 3D weft-knitted fabrics provide complex protection against different mechanical risks (cut, puncture, abrasion, tear). The tests performed may be useful for further development of knitted fabrics designed to provide protection against mechanical risks. [ABSTRACT FROM AUTHOR]

Increasing levels of textile waste have become a matter of great concern for the environment and the circular economy movement. Synthetic or man-made fibers are not decomposed in landfills and also generate toxic gases if incinerated. Waste of high-performance fibers has enormous potential to be used in the development of technical products. In this study, carding waste of para-aramid fibers was blended with virgin polyester fibers to produce needle punched nonwoven felts to be used in the development of protective gloves. Nonwoven webs of different blend ratios and three different weights (GSM) (100, 150, 200 g/m2) were produced. The nonwoven webs were then quilted with knitted polyester fabric to produce gloves. Cut resistance, abrasion resistance, tear resistance and heat resistance of the felts increased with the increase in GSM (g/m2). Particularly at lower GSM, an increasing percentage of aramid fibers showed significant enhancement in cut resistance. The nonwoven felts comprising aramid/polyester blends of 75/25 and 60/40 yielded level 3 cut resistance at 100 GSM which reduced to level 2 with a further decrease in aramid fiber content. The abrasion resistance and tear resistance of the gloves were at level 3 to 4 and showed little dependence on blend ratio but were relatively higher at higher GSM. At 100 GSM, the felts exhibited heat resistance level 1 which increased to level 2 at 200 GSM. The findings of this study suggest that waste of high-performance fibers can be used as cost control and environmentally friendly strategy in the development of protective textiles. [ABSTRACT FROM AUTHOR]

Biodegradable jute geotextiles (JGTs) are an effective reinforcing material for unpaved roads, but its serviceability is limited because of faster microbial degradation. Different methods are in use to improve the serviceability of jute geotextiles. In this paper, the influence of CA-chitosan treatment, road design, and rainfall intensity on the time-dependent serviceability of JGTs has been studied. Chemically treated jute geotextiles are laid in unpaved road designs with and without sand layer, for 30, 60, and 90 days' duration, and are exposed to simulated rainfall intensities of 50 and 100 mm/hr. With an increase in time of usage, breaking load and puncture resistance decrease due to microbial attack, and pore size decreases due to clogging of soil in JGTs. Chemical treatment is observed to have a greater influence on the serviceability, followed by the presence of a sand layer in road design and the rainfall intensity and shows retention % in tensile strength of 87.42% and 91.21% after 30 days duration. Further, the overall performance of CA-chitosan treated JGTs is observed to be better than untreated JGTs. [ABSTRACT FROM AUTHOR]

The present study intended to develop improved biopolymer film from seaweed polysaccharides. The quantity optimization of polysaccharides for the composite film was sought by empirical response surface methodology. To achieve the goal, Box–Behnken model was applied to the concentration of three independent variables, viz. agar (1.0–2.0% w/v), alginate (1.0–2.0% w/v) and carrageenan (1.0–2.0% (w/v). The glycerol was used as a plasticizer and kept constant (25% w/w) for total solid mass. The overall desirability function fits with the quadratic model at 99.78% level of significance for the optimization of agar (1.99% w/v), alginate (1.45 w/v) and carrageenan (2.0% w/v) to reach minimum water vapor permeability and maximum tensile strength, elongation at break and puncture resistance. The absolute residual error (1.04–3.37%) of experimental and predicted response was also validated. Attenuated total reflection-Fourier transform infrared spectroscopy confirmed the interactions such as stretching at 2900 cm−1 region corresponded to C–H stretching vibration and an intensity peak observed at 1200 cm−1 of AAC film corresponded to sulfate ester groups. The shift in crystalline nature of composite film was confirmed by XRD. The 3D image of atomic force microscopy showed layer-by-layer assembly of intermolecules at 310-nm resolution, and the characterized smooth surface has more functional application. The carrageenan and agar are found to be more responsible for the film properties such as moisture content, thickness, whiteness index, transparency, swelling and erosion than alginate. [ABSTRACT FROM AUTHOR]

Slope stability is one of the crucial factors to consider in every civil engineering project. One widely used method to stabilize slope is the use of polymeric products called geosynthetics. Natural fiber geosynthetics used for geotechnical applications have attracted attention because of their environmental and economic benefits. Coir fibers made into nonwoven geotextiles are utilized in this study as an alternative material for slope stabilization. One drawback of coir fiber geotextiles is their low tensile strength and limited life span due to their susceptibility to environmental factors. This study was conducted to evaluate the effect of mercerization and bleaching treatment on the strength performance of nonwoven coir geotextiles after exposure to conditions simulating biological and chemical degradation. Microscopic images of treated coir geotextiles show the removal of surface impurities that altered the physical components in the fiber. The grab tensile strength results prove that the mercerized coir geotextiles are suitable for field conditions and groundwater exposure. The untreated coir geotextiles showed superior puncture resistance relative to the chemically treated geotextiles. The chemical treatments improved the tensile strength; however, they weakened the puncture resistance of the coir geotextile due to the decrease in thickness. A slope stability simulation conducted using Rocscience Slide2 version 9.017 software proved that coir geotextiles can effectively reinforce slopes, with strength performance almost comparable to that of synthetic geotextiles.

[Display omitted] • Fusion of covalent adaptable networks (CANs) with different mechanical properties using the diverse dynamic chemical bond. • CANs containing bi-dynamic bonds illustrate synergism and variable activation energy. • CANs exhibit outstanding puncture resistance properties and mechanical properties. Covalent adaptable networks (CANs) are widely used because of their outstanding mechanical properties and reprocessibility. However, these materials can only be recycled with mono-dynamic bonding networks during recovery. Here, we report that fused polymer CANs containing bi-dynamic bonds with adjustable mechanical properties are achieved through the dynamic behavior of the β -amino ester bond and the enamine-one bond. The β -amino ester bond-based CANs (P1) and the enamine-one bond-based CANs (P5) were prepared using tris(2-aminoethyl)amine (TREN) and m-xylylenediamine (MXDA) with hexanediol diacrylate and hexane-1, 6-diyl dipropiolate via click reaction, respectively. The mechanical and thermal properties of the fused films obtained after grinding and mixing at room temperature were comparable to those of CANs containing bi-dynamic bonds obtained by pre-mixing TREN and MXDA. Dynamic exchange and topological bond formation by the β -amino ester and the enamine-one at the interface are shown at the molecular level and with high uniformity. CANs containing bi-dynamic bonds showed synergism in stress relaxation experiments, demonstrating variable activation energies over a range of the temperature window. Owing to their excellent puncture resistance, the prepared materials can be used in flexible devices, energy-storage equipment, and various other applications. [ABSTRACT FROM AUTHOR]

The puncture resistant fabrics find use in most of industrial and normal life applications. Traditionally, it is believed that the fabrics woven in plain weave and higher GSM are best solution for the puncture resistant applications. This study presents an innovative fabric solution for puncture resistant applications by varying/combining the fabric architecture. The fabric structural parameters (weave design and cover factor) were varied and the puncture resistance of resulting fabrics was investigated. Double face fabrics were developed, and their puncture resistance was compared with conventional woven fabrics (Plain, Matt and Satin). The outcome of this study showed that the 2/2 matt weave performs well against the puncture force, followed by the double face fabrics. The effect of cover factor was found to be significant in case of some weaves and not prominent in case of other weaves. Hence, it was concluded that while designing the fabric for puncture resistance, all the parameter including material, cover factor, and weave design need to be considered carefully. [ABSTRACT FROM AUTHOR]

Fleshy fruits have evolved to be attractive to frugivorous seed dispersers. As a result, many fruit traits like size, color, scent and nutritional content are assumed to be the result of selective pressures exerted by frugivores. At the same time, fruit traits are also subjected to a set of other selective pressures and constraints. One such trait is fruit hardness. On one hand, haptic cues have been suggested to play a role in frugivore behavior, potentially driving selection on fruit skin traits, including hardness. On the other hand, fruit skin traits also interact with antagonists, e.g. seed predators and microbes, which can also impose selective pressures, particularly with respect to fruit hardness. Yet skin hardness may also be driven not by adaptive response to biotic pressures, but rather a mechanical constraint: fruits are packed with water‐rich pulp and seeds which exert mechanical pressure on the skin. Skin hardness may simply result from the need for fruits to withhold internal pressure to maintain fruit integrity. We test the fruit mechanical constraint hypothesis on a set of 95 native Malagasy plant species. We used a theoretical structural formula to model internal pressure experienced by fruit skins to test whether variation in pulp weight predicts fruit hardness. We find that, while positively correlated, internal stress explains very little of the variance in fruit hardness. This suggests that mechanical constraints play a minor role in driving fruit hardness, and that biotic factors may therefore contribute substantially to variation in fruit hardness. [ABSTRACT FROM AUTHOR]

Mechanical properties of sugar beet roots are related to their damage susceptibility and storability. For selection in breeding, it is beneficial to identify stable traits that can be measured in young plants. Ten genotypes, nine sugar beet and one fodder beet, were grown in the field (harvest in August and November) and in the glasshouse for 14 weeks. The puncture resistance was measured using a texture analyser. Furthermore, the dry matter content was determined. Genotypic differences in puncture resistance of sugar beet roots could be determined in early growth stages and showed no relevant interaction to environment/growing conditions. The puncture resistance was closely related to the dry matter content of the root. Genotypic differences in puncture resistance are independent of growing conditions (field/glasshouse) and age of the plants (harvest date/growth stage). Puncture resistance is thus a potential trait for selection of genotypes with a high tissue strength. The dry matter content was identified as an easy‐to‐measure parameter for the preselection of genotypes. Key message: Puncture resistance of sugar beet roots is a stable genotypic trait independent of growing conditions (field/glasshouse) and age of the plants and is closely related to the dry matter content. [ABSTRACT FROM AUTHOR]

Aim of the study: The aim of the article was to present the results of the analysis of puncture strength of shielding and sealing geosynthetics. Standard qualification tests were carried out on a rigid support in accordance with PN-EN 14574: 2015-12. Four types of protective geotextiles with different thicknesses and weights as well as three types of geomembranes differing in thickness were used for the tests. Individual materials were examined separately and in the form of geocomposites. Material and methods: Two groups of geosynthetics were used in the study. The first group were four types of geotextiles whose function is to separate materials with different grain sizes, filtration in engineering constructions. Geotextiles were characterized by different thickness, basis weight or production technology. The second group were impermeable geomembrane with sealing properties, made of smooth-rolled polyethylene on three sides, with three heights. To test the geosynthetics for puncture with a pyramid (PN-EN 14574:2015-12). Results and conclusions: Among the geotextiles, the most resistant to puncture turned out to be needle-punched non-woven fabric with a thickness of 4 mm. The values for the remaining needle-punched geotextiles 1.5 mm thick depended on their basis weight and differed in strength by 30% in favor of heavier non-woven geotextile. Glued geotextile with a thickness of 0.5 mm turned out to have a similar strength to 1.5 mm geotextile with a heavier weight and 46% more durable than geotextile of the same thickness and a lower weight. In the case of geomembranes, the puncture strength turned out to be 2-5 times higher than the strength of geotextiles.

Knitted fabrics finds wide applications in functional/protective areas, as the advancements in textile Industry happens. These fabrics were famous for their stretchable structure and soft feel. This study investigates the mechanical performance, stability, and puncture of weft knitted structures with and without inlay yarns. Specimens were developed using Jute and Flax yarn as inlay yarn while Kevlar® (para-aramid) and polyester yarn as main yarn. Main and inlay yarn effect on tensile strength, elongation, stretch and recovery, and puncture resistance was characterized. The results reveal that mechanical performance and stability of fabric were significantly increased with inlay yarn in the course direction. On the other hand, expansion was greatly reduced, but higher growth was observed in rib specimens without inlay yarn. [ABSTRACT FROM AUTHOR]

Copyright of China Forest Products Industry is the property of China Forest Products Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bituminous geomembranes (BGM) collaborate in the global challenge of improving water resources management by waterproofing hydraulic works. BGMs are multi-layered composite geomembranes with each of the components providing a technical benefit on large canals projects. These technical advantages include: A very low Manning coefficient for efficient water flow, extreme puncture resistance, which allows rapid deployment on rougher subgrades and permits many types of cover directly on top, excellent resistance to wind uplift due to their high surface mass, meaning installation can be done in strong winds up to 40 km/h. BGMs also have a very low coefficient of thermal expansion and do not wrinkle with changes in temperature like other polymeric membranes do. This is particularly useful in high heat projects when geomembrane is left exposed, providing a more secure project in the long run with less risk of wrinkle-induced cracks and failures. To illustrate this, this presentation will describe the composite structure of bituminous geomembranes and will explain its main advantages in the hydraulic field. All these will be presented with the description of test results in different types of large width canals: Canals for irrigation: in France, for the waterproofing of the Canal de Provence; in India, where the Maharashtra state decided to replace original concrete for a geomembrane lining system in Pench Canal. Navigable canals: in France where VNF (French Waterways) chose the BGM for waterproofing the repairs of its canals. A work near Montargis will be presented as well as waterways in England (Lancaster Canal) and Canada (Chambly Canal). Finally, hydroelectric power canals will be also described: at the Sankt Dyonisen power plant in the Alps in Austria and the Cumpeo power plant in the Maule region in Chile.

Understanding the internal microstructure of silkworm cocoons is beneficial for developing biomaterials. In this study, both domesticated (Bombyx mori) and wild silkworm cocoons (Antheraea pernyi and Antheraea mylitta) were studied using the X-ray micro computed tomography (XCT), and their microstructural characteristics were analyzed quantitatively. It is discovered that fiber widths of the cocoons significantly increased from the inner to the outer layer. It is also detected that for the three cocoons in the core regions, unaffected by the surface condition, from the inner to the outer layer, fiber percentages show significant decrease initially, and then no obvious change, and the fibers in different layers are more aligned towards the short diameter of the cocoon, and Antheraea mylitta fibers display the highest fiber orientation. Fractal dimension of the domestic cocoon was significantly reduced, whereas those of the wild cocoons display no obvious change. The two wild cocoons show significantly higher maximum strength, initial modulus and breaking energy than the domesticated cocoons, and Antheraea pernyi performs better maximum strength and breaking energy than Antheraea mylitta. The tensile property is closely related to fiber percentage, fiber intersectional density and fractal dimension.

The very thin and lightweight silkworm cocoon has outstanding mechanical properties attributed to its specific composite microstructure. However, the microstructures of the cocoons have not been studied quantitatively, and their anti-puncture performance has not been examined as well. In this study, both domesticated (Bombyx mori) and wild silkworm cocoons (Antheraea pernyi, Antheraea mylitta and Samia canningi) were investigated for their microstructures using fractal theory, and their quasi-static puncture resistance was tested and compared. In addition, the effects of cocoon layers and hot-press treatments on the puncture resistance of two cocoon types (B. mori and A. pernyi) were investigated. The three wild cocoons demonstrated significantly higher fractal dimensions, higher fiber intersectional densities and low porosities, indicating their structures are more optimized. They also displayed better puncture resistance than B. mori. Increased layer numbers could significantly increase the puncture resistance of both cocoon types and A. pernyi showed more remarkable increases. Moreover, the two cocoon types showed optimum puncture resistance after heat treatment with hot-press temperature of 135℃ and pressure of 25 MPa, and A. pernyi showed better puncture resistance after such treatment. Finally, both the maximum puncture force and puncture energy of cocoons displayed a linear increase with the increasing fractal dimensions. The new insights can guide the development of novel protective fiber composites with desirable and predictable anti-puncture performance. [ABSTRACT FROM AUTHOR]

Mechanical properties of sugar beet are important during harvesting and processing. To potentially correlate mechanical properties with structural features of cell wall polymers, four different Beta varieties (Beta vulgaris L.) were characterized for their mechanical properties and cell wall composition. In addition, the influence of nitrogen fertilization was analyzed. Additional nitrogen fertilization only slightly influenced mechanical properties and cell wall composition. Hardly any structural differences of cell wall polysaccharides were observed for all Beta varieties. Slight differences in alcohol insoluble residue and protein contents, in amino acid profiles of proteins, and in esterification degree of pectins were found. The Beta varieties differed in their contents of cell wall bound phenolic components, and particularly in their dry matter contents. Analyses of mechanical properties of the Beta varieties demonstrated differences in tissue firmness and compressive strength. However, no evidence was found that the observed differences of cell wall composition are responsible for the divergent mechanical properties, with the exception of water contents that were higher in samples with less compressive strength. [ABSTRACT FROM AUTHOR]

This study examines the performance level of hybrid woven protective clothing (HWPC), manufactured from Kevlar® (K) and Ramie (R) yarns. The weave structures (plain, twill 1/3) and variables fiber ratios were used to produce HWPC. The performance level of HWPC was measured according to EN 388:2016. We came to the conclusion that blade cut resistance of plain and twill structure sustained protection level up to increase of KR 80:20 and KR 70:30, respectively; puncture resistance of K100% and HWPC remained in the same level of protection for plain and twill weaves; Abrasion resistance of K100% and HWPC of plain and twill weaves samples presented abrasive performance of same protection level, but the average number of cycles sustained for twill weave samples was slightly higher than plain weave. However, comparing the plain and twill weaves sample for tear resistance, twill weave samples have higher tear resistance than plain weave. A gray relational analysis and Taguchi method was performed to optimize the performance of two structures with variable fiber ratios. It was established that the article produced with K&R yarns with KR 80:20 ratio and twill weave presented the best performance against all test runs. The main objective of this study is to reduce plastic pollution by reducing the amount of synthetic fiber proportion in personal protective clothing and thereby reducing the dependence on nonrenewable sources for synthetic fiber. The 41 g/m2 reduction of Kevlar® fiber has been made in a conventional PC with ramie fiber, without compromising the protection level. This will enhance the sustainability of HWPC. [ABSTRACT FROM AUTHOR]

Effects of stroke frequency, depth of needle penetration and mass per unit area on properties of needle-punched nonwoven fabrics produced from polypropylene (PP), 50/50 PP/kenaf and kenaf fibres have been studied. Properties of fabrics, such as tensile strength, puncture resistance, pore size, water permeability and transmissivity are analysed. Results obtained show that the higher tensile strength and puncture resistance are achieved in fabrics produced from kenaf fibres at higher stroke frequency, depth of needle penetration and mass per unit area. Fabrics produced from kenaf fibres can be employed in geotextile applications, since they also possess bigger pore size and higher water permeability. [ABSTRACT FROM AUTHOR]

The problem of recycling polymer waste is one of the most actual problems. One way to solve this problem is to create biodegradable food packaging. By mixing solutions of starch and agar at different mass ratios of polymers in the presence of glycerol, biodegradable films are obtained. Their structural and mechanical characteristics are determined. It is shown that the values of strength, modulus of elasticity and puncture resistance of films are maximal at the mass ratio of agar/starch 7-9. A comparison of the roughness of the films obtained from starch, agar and their mixture showed that the greatest roughness is possessed by films based on starch. The introduction of agar into the films of starch leads to a significant reduction in their roughness. To regulate the structural and mechanical properties of films, it is proposed to use Cа and Mg salts. The influence of Ca2+ and Mg2+ ions on the strength and deformation characteristics of biofilms was studied. It is shown that Ca2+ ions monotonically increase the strength characteristics of starch-agar films, while the curves of changes in these parameters in the presence of Mg2+ ions have maxima at a concentration of 0.5 %. The difference in the effect of Ca2+ and Mg2+ ions on the structural and mechanical properties of films is explained by the hydration degree of these ions. The biodegradability of starch-agar films was controlled by changing their IR spectra. The most significant changes are observed in the intensity and localization of peaks corresponding to O-H, C-H and C-C bonds, which can be evidence of changes in the structure of films due to the destruction of the grid of hydrogen bonds and hydrophobic interactions, as well as the break of hydrocarbon chains and the destruction of the skeleton of carbohydrate molecules. [ABSTRACT FROM AUTHOR]

Fracture mechanics are utilized to successfully predict the allowable bend radii achieved through experimentation for ion‐exchanged glass having thicknesses of 25 to 125 microns. The origin of the non‐monotonic relationship between puncture resistance and glass thickness is also described. [ABSTRACT FROM AUTHOR]

Certain features of both extant and fossil anthropoid primates have been interpreted as adaptations to ripe fruit foraging and feeding particularly spatulate incisors and trichromatic color vision. Here, we approach the question of anthropoid fruit foraging adaptations in light of the sensory and mechanical properties of anthropoid-consumed fruits in Kibale National Park, Uganda. We quantify the color, odor, size, and puncture resistance of fruits in Kibale that are consumed by anthropoid primates (N = 44) and compare these with the same traits of fruits that are not consumed by anthropoid primates (N = 24). Contrary to extant hypotheses, color and odor of anthropoid-consumed fruits do not differ from non-anthropoid–consumed fruits. However, we find that anthropoids in this system consume fruits that are significantly larger than non-anthropoid–consumed fruits, and with the exception of elephants that consume very large fruits, are the only dispersers of fruits with a surface area <4032 mm2, and a maximum diameter of 52 mm. While our findings do not support most extant hypotheses for the evolution of derived anthropoid primate traits as adaptations to ripe fruit foraging, we find some evidence to support the hypothesis that spatulate incisors may be an adaptation to foraging on large fruits, which tend to be harder. [ABSTRACT FROM AUTHOR]

The shape of the needle tip that is currently used in the medical field is a "lancet point," which is a diagonally cut cylindrical pipe, further cut on both sides. The shape of the needle shank is typically cylindrical. In this paper, tip and shank shapes that differ from the standard shape are experimentally investigated for the purpose of reducing puncture resistance. Microneedles of various cross-sectional shapes, such as polygonal and star-like, were fabricated using stereo laser lithography. Before the needle penetrates the skin, sharp edges at the needle tip may be effective to generate a stress concentration on the skin, inducing a skin fracture. After the needle penetrates the skin, corners in the cross section of the needle shank may effectively reduce the frictional resistance because the contact area between the skin and needle is limited at the corners. A needle insertion experiment was conducted against an artificial skin made of polydimethylsiloxane. The puncture resistance decreased respectively for the circular needle, polygonal needle, and star-shaped needle. For the star-shaped needles, the maximum resistance decreased as the number of corners (N) decreased. For the polygonal needle, the maximum resistance increased as N increased from 3 to 5; however, there was no observable difference for N from 6 to 8. The experimental results show that a triangular star-shaped microneedle is the most effective in reducing the puncture resistance. [ABSTRACT FROM AUTHOR]

Measurements of the dynamic load of conveyor belts of identical strengths were used to evaluate and compare the data for belts with and without a support system. The goal was to identify the effects of the support system in terms of a relative amount of impact energy absorbed by a conveyor belt. A dynamic model was designed based on selected parameters of the impact process. Damage to conveyor belts, caused by the absorption of impact energy, was evaluated using the applied methods of mathematical statistics.

In the present work, an attempt has been made to study the effect of structural changes on the sustainable properties of needle punch nonwoven geotextile. There are two important process parameters, which influence the structure significantly. The parameters are punch density and depth of penetration of the needle. This research work is designed by considering the two parameters. Whereas, three-levels of each parameter taken and nine samples prepared by using two-factor three-level full factorial design. The structural analysis was carried out by an image analysis technique. All measured physical and mechanical properties of nonwovens have a strong correlation with the structural parameter. The significant effect noticed on fabric thickness, tensile strength, pore diameter, puncture resistance and impact resistance with the varying considered parameters; punch density and needle depth penetration. [ABSTRACT FROM AUTHOR]

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In this research, eight different 3D weft-knitted fabrics were developed and evaluated. 3D fabrics have been knitted on circular weft-knitting machines with two different gauges: 20E gauge and 28E gauge. Three different raw materials were used for the fabric's production: high molecular mass polyethylene (HPPE) yarn and 0.05 mm diameter steel wire in the outer layers (for the front and reverse) and polyamide yarn in the binding layer. The experiments were conducted on the developed 3D knitted fabrics to determine the fabric's resistance to mechanical risks such as circular blade cut, puncture, abrasion, and also to evaluate the comfort parameter, such as air permeability. It was defined that 3D weft-knitted fabrics best results on tests: circular blade cut, puncture and abrasion resistant were achieved using HPPE yarn twisted with steel wire, higher mass per unit area with more significant amount of steel wire. According to the standard EN 388:2003, three samples of developed 3D weft-knitted fabrics had the highest 5th blade cut and the highest (4th) abrasion resistance level. All of them had the highest (4th) level of puncture resistance. 3D fabrics knitted on a circular weft-knitting machine of gauge 28E ensured 1.3–2.1 times greater blade cut and 4.9–12.1 times greater abrasion resistance result, than fabrics knitted on gauge 20E, due to a higher stitch density, higher mass per unit area, density and fabric's thickness. But on the other hand, these parameters lowered air permeability by 20.2–43.0%. [ABSTRACT FROM AUTHOR]

Stab and puncture resistant body armor is widely used by the law enforcement personnel, security and military in many countries. The primary requirement for the armor is to provide protection against various weapons used in an attack. Comfort properties are given increased importance in many countries and considered the second most important requirement. In this research Kevlar was blended with wool and wool–nylon. The resultant fabrics were coated with silica and their stab and puncture resistance in quasistatic conditions was examined using the universal tensile tester. It was hypothesized that the application of coating will generate higher friction to restrict the lateral movement of yarns, and thus present a higher number of yarns for direct resistance to impact during the attack and dissipating the impact energy, whereas the use of wool and nylon will provide the required ergonomics of wearability and stretch. It was observed that the application of the silica coating helped in improving the resistance to the stab and punctures using weapons such as knife (P1, as specified in NIJ 0115.00), ball and pointed impactors. In the quasistatic tests, the highest value of the maximum resistant force was recorded when the ball was used and the lowest was observed for the knife. Furthermore, the application of coating helped in absorbing impact energy. However, the fabric stiffness increased due to the coating, which will negatively impact the ergonomics and wearability. [ABSTRACT FROM AUTHOR]

This study aims to investigate the mechanical properties, far-infrared (FIR) emissivity, and limiting oxygen index (LOI) of FIR ray/low-melting-point (LM) nonwoven fabrics, flame retardant (FR)/LM nonwoven fabrics, and FIR/FR/LM composite nonwoven fabrics, which are with or without heat treatment and also investigating the effect of heat treatment on the LM polyethylene terephthalate (PET) fibers. Test results show that for FIR/LM nonwoven fabrics, applying heat treatment leads to the better mechanical properties and FIR emissivity of 0.90. For FR/LM nonwoven fabrics, unheat-treatment samples have greater mechanical properties and an LOI of 34. For FIR/FR/LM composite nonwoven fabrics, the unheat-treated samples exhibit greater tensile properties, but the heat-treated samples exhibit greater puncture resistance, burst strength, and FIR emissivity. The structural parameters of the composite nonwoven fabrics can be adjusted according to the demand of users in terms of FIR emissivity and flame retardancy, and the composite nonwoven fabrics are thus expected to be used as construction materials for medical systems. [ABSTRACT FROM AUTHOR]

Abstract The objective of this work was to compare the barrier and mechanical properties and shrinkability of coextruded films chlorine-free, with high barrier chlorine multilayer films traditionally used to preserve fresh beef. Four 9-layer barrier-shrink films containing PET, ethylene ionomers, polyamide PA66/6 modified with amorphous PA, 32 or 44 mol% EVOH and PE were produced in a commercial scale triple bubble co-extrusion line. Seal strength, puncture resistance, oxygen and water vapor permeability and film shrink were measured for the four films and compared to the EVA/PVDC/PE film properties. The results obtained under controlled laboratory conditions show that films made with one layer of EVOH 32 mol% of ethylene encapsulated between two layers of PA66/6 modified with amorphous PA have gas barrier properties and puncture resistance better than a typical EVA/PVDC/PE, seal strength and shrinkability comparable to this film and therefore have potential to preserve fresh beef.