Mechanical properties of phormium tenax reinforced natural rubber composites

The introduction of natural fibers as a filler in a natural rubber (NR) matrix can be of relevance for their eco-friendly and sustainable nature as the substitute for carbon-based fillers. In this work, short Phormium tenax fibers were introduced in random orientation into a NR matrix in different lengths (6, 10, and 14 mm) and various amounts (10, 20, and 30%, taking 100 as the NR weight). The composite was fabricated using a two-roll mill according to American Society for Testing and Materials (ASTM) D3184-11 standard. Several properties were determined, namely tensile and tear characteristics, hardness, and abrasion resistance. The results suggest that the shortest fiber length used, 6 mm, offered the best combination between loss of mechanical (tensile and tear) properties and hardness and the most acceptable resistance to abrasion, with the properties increasing with the amount of fibers present in NR. As a consequence, it is indicated that a higher amount of fibers could be possibly introduced, especially to achieve harder composites, though this would require a more controlled mixing process not excessively reducing tensile elongation at break

Animal fiber characterization and fiber loading effect on mechanical behaviors of sheep wool fiber reinforced polyester composites

© 2020 Taylor & Francis. This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Natural Fibers on 06/12/2020, available online: https://doi.org/10.1080/15440478.2020.1848743.This study presents animal fiber characterization and the influence of various fiber loadings on mechanical properties of sheep hair fiber-reinforced polymer (SHFRP) composites. The sheep hair fibers (SHF) characterization was carried out using X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM) and non-contact surface roughness machine. The functional group and chemical bond were analyzed using FTIR techniques. The crystallinity index and thermal stability of the SHF were characterized, using XRD and TGA techniques, respectively. The composites were fabricated using a compression molding technique and a varying weight percentage of 20, 30 and 40 fiber. The composite plates were cut into test samples according to ASTM standard methods for their mechanical (tensile, flexural and impact) behaviors to be extensively analyzed. The surface morphology of the fractured samples was examined with aid of an SEM. From the results obtained, it was evident that the SHFRP composite recorded a significantly increased tensile strength property when fiber loading was increased from 20 to 40 wt%. The optimum 40 wt% SHFRP composite sample recorded better flexural and impact strength, when compared with other counterparts. This was attributed to a better fiber-matrix interfacial adhesion, as established fromSEM micrographs.Peer reviewedFinal Accepted Versio

Effect of chemical treatment on physico-chemical properties of a novel extracted cellulosic Cryptostegia grandiflora fiber

© 2023 The Author(s). Published by IOP Publishing Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/The increasing global need to achieve sustainability in product development demands the use of biodegradable materials from renewable resources in many engineering applications. Accordingly, various natural fibers were explored as suitable reinforcement in polymer matrixes due to their low density and biodegradability. Hence, in this present work, a novel fiber reinforcement was extracted from the stem of the Cryptostegia grandiflora (CG) plant through a retting process and manual intervention. The extracted Cryptostegia grandiflora fibers(CGFs)were chemically treated using NaOH and silane. Various properties like crystal structure, chemical composition, surface morphology, and thermal degradation were studied using x-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR) Scanning electron Microscopy (SEM) and Thermogravimetric analysis (TGA). The increasing cellulose content and the removal of hemicellulose after the chemical treatment indicate the potential for this CGfiber as a better reinforcement element in polymers. The increasing trend of tensile strength was observed for the CGfiber in the following order: silane > NaOH > untreated conditions. Two-stage thermal degradation was observed in all the cases where the maximum thermal degradation was found at the silane-treated CGfibers. Based on their performance, the chemically treated CGfibres can be made into composites and used for structural applications.Peer reviewe

Travertine crystal growth ripples record the hydraulic history of ancient Rome’s Anio Novus aqueduct

Travertine crystal growth ripples are used to reconstruct the early hydraulic history of the Anio Novus aqueduct of ancient Rome. These crystalline morphologies deposited within the aqueduct channel record the hydraulic history of gravity-driven turbulent flow at the time of Roman operation. The wavelength, amplitude, and steepness of these travertine crystal growth ripples indicate that large-scale sustained aqueduct flows scaled directly with the thickness of the aqueous viscous sublayer. Resulting critical shear Reynolds numbers are comparable with those reconstructed from heat/mass transfer crystalline ripples formed in other natural and engineered environments. This includes sediment transport in rivers, lakes, and oceans, chemical precipitation and dissolution in caves, and melting and freezing in ice. Where flow depth and perimeter could be reconstructed from the distribution and stratigraphy of the travertine within the Anio Novus aqueduct, flow velocity and rate have been quantified by deriving roughness-flow relationships that are independent of water temperature. More generally, under conditions of near-constant water temperature and kinematic viscosity within the Anio Novus aqueduct channel, the travertine crystal growth ripple wavelengths increased with decreasing flow velocity, indicating that systematic changes took place in flow rate during travertine deposition. This study establishes that travertine crystal growth ripples such as those preserved in the Anio Novus provide a sensitive record of past hydraulic conditions, which can be similarly reconstructed from travertine deposited in other ancient water conveyance and storage systems around the world

Capturing the Surface Texture and Shape of Pollen: A Comparison of Microscopy Techniques

Research on the comparative morphology of pollen grains depends crucially on the application of appropriate microscopy techniques. Information on the performance of microscopy techniques can be used to inform that choice. We compared the ability of several microscopy techniques to provide information on the shape and surface texture of three pollen types with differing morphologies. These techniques are: widefield, apotome, confocal and two-photon microscopy (reflected light techniques), and brightfield and differential interference contrast microscopy (DIC) (transmitted light techniques). We also provide a first view of pollen using super-resolution microscopy. The three pollen types used to contrast the performance of each technique are: Croton hirtus (Euphorbiaceae), Mabea occidentalis (Euphorbiaceae) and Agropyron repens (Poaceae). No single microscopy technique provided an adequate picture of both the shape and surface texture of any of the three pollen types investigated here. The wavelength of incident light, photon-collection ability of the optical technique, signal-to-noise ratio, and the thickness and light absorption characteristics of the exine profoundly affect the recovery of morphological information by a given optical microscopy technique. Reflected light techniques, particularly confocal and two-photon microscopy, best capture pollen shape but provide limited information on very fine surface texture. In contrast, transmitted light techniques, particularly differential interference contrast microscopy, can resolve very fine surface texture but provide limited information on shape. Texture comprising sculptural elements that are spaced near the diffraction limit of light (∼250 nm; NDL) presents an acute challenge to optical microscopy. Super-resolution structured illumination microscopy provides data on the NDL texture of A. repens that is more comparable to textural data from scanning electron microscopy than any other optical microscopy technique investigated here. Maximizing the recovery of morphological information from pollen grains should lead to more robust classifications, and an increase in the taxonomic precision with which ancient vegetation can be reconstructed

An overview of burst, buckling, durability and corrosion analysis of lightweight FRP composite pipes and their applicability

© 2019 Elsevier Ltd. All rights reserved.The main aim of this review article was to address the performance of filament wound fibre reinforced polymer (FRP) composite pipes and their critical properties, such as burst, buckling, durability and corrosion. The importance of process parameters concerning merits and demerits of the manufacturing methods was discussed for the better-quality performance. Burst analysis revealed that the winding angle of ±55° was observed to be optimum with minimum failure mechanisms, such as matrix cracking, whitening, leakage and fracture. The reduction of buckling effect was reported in case of lower hoop stress value in the hoop to axial stress ratio against axial, compression and torsion. A significant improvement in energy absorption was observed in the hybrid composite pipes with the effect of thermal treatment. However, the varying winding angle in FRP pipe fabrication was reported as an influencing factor affecting all the aforementioned properties. Almost 90% of the reviewed studies was done using E-glass/epoxy materials for the composite pipe production. By overcoming associated limitations, such as replacing synthetic materials, designing new material combinations and cost-benefit analysis, the production cost of the lightweight FRP composite pipes can be decreased for the real-time applications.Peer reviewe

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Not AvailableSorghum with its remarkable adaptability to drought and high temperature provides a model system for grass genomics and resource for gene discovery especially for abiotic stress tolerance. Group 3 LEA genes from barley and rice have been shown to play crucial role in abiotic stress tolerance. Here, we present a genome-wide analysis of LEA3 genes in sorghum. We identified four genes encoding LEA3 proteins in the sorghum genome and further classified them into LEA3A and LEA3B subgroups based on the conservation of LEA3 specific motifs. Further, expression pattern of these genes were analyzed in seeds during development and vegetative tissues under abiotic stresses. SbLEA3A group genes showed expression at early stage of seed development and increased significantly at maturity, while SbLEA3B group genes expressed only in matured seeds. Expression of SbLEA3 genes in response to abiotic stresses such as soil moisture deficit (drought), osmotic, salt, and temperature stresses, and exogenous ABA treatments was also studied in the leaves of 2-weeksold seedlings. ABA and drought induced the expression of all LEA3 genes, while cold and heat stress induced none of them. Promoter analysis revealed the presence of multiple ABRE core cis-elements and a few low temperature response (LTRE)/drought responsive (DRE) cis-elements. This study suggests non-redundant function of LEA3 genes in seed development and stress tolerance in sorghum.Not Availabl

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Not AvailableModification of lignin composition and content are important to enhance the saccharification potential of lignocellulosic biomass. Brown midrib (bmr) mutants with altered lignin and enhanced glucose yields are a valuable resource for modification of the lignin biosynthetic pathway in sorghum (Sorghum bicolor (L.) Moench). Of the 38 bmr mutants reported in sorghum, some have been classified into four independent groups, namely bmr2, bmr6, bmr12 and bmr19, based on the allelic test, and a few have been characterized at the molecular level. The bmr2, bmr6 and bmr12 groups have mutations that impair 4-coumarate: coenzyme A ligase (4CL), cinnamyl alcohol dehydrogenase (CAD2) and caffeic O-methyltransferase (COMT), respectively. The molecular basis of bmr19 is unknown. In the present study, four spontaneous bmr mutants of sorghumwere analyzed for allelic variation at two candidate gene loci. cDNAs of CAD2 andCOMTgeneswere cloned and sequenced fromthese mutants. Sequence analysis revealed that two of these mutants, IS23789 and IS23253, share a new allele of CAD2. These mutants have a G-to-C transversion at position 3699 of the genomic sequence that leads to glycine-to-arginine (G191R) substitution in the CAD2 protein sequence. This mutation lies in the highly conserved glycine-rich motif 188G(X)GGV(L)G193 that participates in the binding of the pyrophosphate group of NADP? cofactor and hence might impair the activity of CAD2. Phloroglucinol staining of midribs of these mutants also showed a dark wine-red color that is characteristic of the bmr6 group. These twomutants can be distinguished by an intron length polymorphic marker developed based on the COMT gene sequence in this study. Mutant IS23549, which has also been assigned to the bmr6 group, was found to have another new allele with alanine-to-valine (A164V) substitution inCAD2.Alanine-164 is highly conserved amongMDR proteins in plants and hence may be necessary for the activity of the enzyme. Inmutant IS11861, there was no mutation that led to a change in amino acid in CAD2, while a threonine-to-serine (T302S) substitution was found in COMT. This single nucleotide polymorphism (SNP) at position 2645 in theCOMTgenewas converted into a cleaved amplified polymorphic sequence marker that can be used for its identification. In addition, additional SNP- and/or indel-based markers were developed, which can be used for exploiting these alleles in the molecular breeding of sorghum for dedicated bioenergy feedstock.Not Availabl

Investigation of abrasive water jet machining parameters on turkey fibre reinforced polyester composites

Polymer based composites are finding wide variety of application in industries due to the excellent strength to weight ratio and better mechanical properties. In this wok an effort is made to fabricate unsaturated polyester composites using 20% turkey fibre as reinforcement materials. Methyl Ethyl Ketone Peroxide (MEKP) and Cobalt Naphthalene (CN) is castoff as catalyst and accelerator. The composite is fabricated using compression molding machine and curing is done within the machine itself. Machinability study of the fabricated composites is studied using Abrasive Water Jet Machine (AWJM). Corollary of three parameters namely pressure (P), standoff distance (SoD) and feed rate (fr) on surface roughness (Ra) and taper angle (Ta) of the composite is studied and reported. It is observed from the results of experiments, working with higher pressure increases the Ra of the composites irrespective offr and SoD. But in case of taper angle reverse trend is observed increase in pressure decrease the taper angle irrespective of SoD and f r. Multi-objective Optimization by Ratio Analysis (MOORA) is employed to optimize the machining parameter and to improve the process capability. It is observed that the optimal machining parameters are A3, B2 and C2. (c) 2021 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 2nd International Conference on Materials, Manufacturing, and Machining for Industry 4.0

Template free synthesis of vacancy tailored, highly mesoporous one-dimensional δ-MnO2 for energy storage applications

This work involves the synthesis of highly conducting, ultra-thin, mesoporous manganese dioxide, nanotubes and nanowires, using a sol–gel technique. This is a template-free method for preparing mesoporous (3.3 to 5.4 nm) nanotubes and nanowires of 10–15 nm radius with surface area (221.19 m ^2 /g-102.09 m ^2 /g). In the MnO _2 lattice, oxygen and cationic vacancies are tailored by changing the reducing agent for improved energy storage. X-ray photoelectron spectroscopic studies are conducted to quantify the oxygen and cationic vacancies. The tailored one-dimensional δ -MnO _2 is used as an electrode material for symmetric and asymmetric supercapacitor designs. A non-toxic, less volatile aqueous neutral electrolyte is used for the supercapacitive measurement, giving a specific capacitance of 460.75 F g ^−1 at 2 mV s ^−1 with symmetric mode at 1 V. With activated carbon, this material can also produce asymmetric supercapacitors with a specific capacitance of 107.38 F g ^−1 at 10 mV s ^−1 at 1.7 V