Matrix Layer Research Articles

Semi-analytical mechanical model for FRCM-to-substrate shear bond tests

The debonding process of an FRCM reinforcing system from the substrate is studied in a semi-analytical fashion. FRCM is modeled considering independently the central elastic fiber grid and the two thick upper and lower matrix layers, assumed elasto-fragile; matrix and fiber are considered in a monoaxial state of stress; they mutually exchange shear stresses at the interface, this latter characterized by a softening stress-slip relationship; the reinforcement system is then bonded with a rigid substrate by means of a further elastic interface. Under such hypotheses, a simple system of first order non-linear and coupled differential equations is derived and solved by means of a semi-analytical approach. Independent variables are the axial displacements of the three layers (upper and lower matrix, central fiber) and the corresponding axial stresses. The approach is successfully validated against two experimental datasets available in the literature, relying into different FRCM strengthening systems bonded to rigid substrates and subjected to single lap shear tests. The model is able to capture not only the global debonding behavior but also the local one, with a precise prediction along the bond length of the shape of the axial stresses into the different layers, of the interface shear stresses and of the location of the cracks inside the matrix.

Novel slow-release nanohybrid from zinc hydroxysalt intercalated with dicamba herbicide

Dicamba was intercalated by co-precipitation into a zinc-layered hydroxide salt (LHS) to create a slow-release nanohybrid weed control without leaching. The X-Ray Powder Diffractometry (XRPD) patterns of the LHS intercalated with dicamba showed a basal spacing of 20.48 Å and 26.10 Å, confirming its allocation as a monolayer and bilayer interdigitated arrangement, respectively. The Fourier Transformant Infrared (FTIR) spectrum showed bands typical of dicamba and provided information about its bridging bidentate coordination to the matrix layer. The thermogravimetric analysis (TGA) estimated the compound's formula as Zn5(OH)8(dicamba)2·4.14H2O. The thermal stability of the LHS/dicamba system, the stages of mass loss, the characterization of the compounds released in the pyrolysis, the activation energy (Ea), and the kinetics were all analyzed. The average activation energy for decomposition of intercalated dicamba indicates that the thermal degradation occurred with the breakage of covalent bonds. Controlled release of dicamba from its nanohybrid in water was observed for 962 h (40 days). The pseudo-second-order model described the release process satisfactorily from its linear fitting, suggesting intraparticle diffusion or surface diffusion control. In summary, the intercalation of dicamba in the zinc LHS produced a slow-release material that can aid in weed control.

Mechanical analysis and machinability evaluation of a new EDM-turning hybrid machining process

This study developed an accurate electrical discharge-assisted turning (EDAT) technique for Ti–6Al–4 V alloy and a precise EDAT cutting force prediction model considering theoretical multi-physics fields with metallurgical transformation. A heat-fluid coupled model of multi-pulse discharge in the EDAT process was developed to obtain the thickness of the removal layer (RL) and modified layer (ML) together with the temperature field of the cutting layer. Subsequently, the shear flow stresses under different machining parameters were obtained using the oblique cutting and flow softening constitutive models. Within the cutting layer, the pure thermal softening effect reduces the flow stresses by more than 25% in the unmodified matrix layer (UML) and by more than 60% in the ML, which is dominated by the metallurgical transformation softening (MTS) effect. Finally, the cutting force model of EDAT under multi-physical fields was established and the accuracy was verified by relevant experiments. The results showed that the increase in discharge number accelerated the rise of workpiece surface temperatures, and the small cutting parameters were favorable to the machining performance of the EDAT. The MTS effect significantly reduces cutting forces while improving the quality of the machined surface.

Fatigue crack propagation of the gradient surface-modified layer of high-strength steel

A gradient modified layer can be produced on the high-strength steel surface by carburizing heat treatment. In this study, microstructure characterization and fatigue crack propagation test were carried out on the gradient surface-modified layer of the 18CrNiMo7-6 high-strength steel. With increasing depth of the surface-modified layer, the yield strength and the kernel average misorientation value decrease, and the equivalent grain size of the slatted martensite structure and the number of the large-angle boundaries increase. The orientation difference angle of the point to point pre- and post-fatigue at the crack of the transition layer and the matrix layer increases from less than 2° to approximately 10° and about 4°, respectively. With the increase of the depth of the surface-modified layer, the degree of deformation inside the martensitic packet decreases, while the extent of macroscopic deformation of the material increases. Deformation occurs inside the martensitic packet at the main crack, and there is essentially no deformation inside the martensite packets away from the main crack. On both sides of the main crack, a large number of extrusions parallel to the martensitic lath appear. The large-angle boundaries of the original austenite grain boundary and martensite boundary hinder the propagation of the fatigue crack.

Simulation of the role of agglomerations in the tunneling conductivity of polymer/carbon nanotube piezoresistive strain sensors

A 3D Monte Carlo method paired with a percolation model is carried out to predict the electrical resistivity and piezoresistive sensitivity of carbon nanotube (CNT)-polymer piezoresistive sensors. CNTs are randomly dispersed into the insulating layer of a polymer matrix having agglomerated morphologies in some parts. The electrical resistivity of nanocomposite with a defined agglomeration state is determined by considering the tunneling effect between each connected pair of CNTs. The influence of various parameters such as agglomeration radius, percentage, intrinsic properties and geometries of CNTs are investigated. A comparison was made between the analytical results and experimental data. Considering the tunneling behavior in the vicinity of the percolation transition, a good agreement is obtained between the analytical results and experimental data. Monte Carlo simulations indicated that the tunneling resistance with a random distribution of CNTs depends on the level of agglomeration. Results revealed that piezoresistive sensitivity was diminished by larger agglomerations.

Structure-based lead optimization to improve potency and selectivity of a novel tetrahydroimidazo[1,2-a]pyridine-5-carboxylic acid series of heparanase-1 inhibitor

Heparanase-1 (HPSE1) is an endo-β-d-glucuronidase that is the only mammalian enzyme known to cleave heparan sulfate (HS) of heparan sulfate proteoglycans (HSPG), a key component of the glycocalyx layer of the vascular endothelium matrix. Inhibition of HPSE1 has therapeutic potential for cancer and proteinuric kidney diseases. We previously reported that 2 showed a moderate potency as an HPSE1 inhibitor and an issue of selectivity against exo-β-d-glucuronidase (GUSβ) and glucocerebrosidase (GBA) remained. A structure-based lead optimization of 2 using X-ray co-crystal structure analysis and fragment molecular orbital calculation resulted in 4e, which showed a more than 7-fold increase in HPSE1 inhibitory activity. The subsequent introduction of a methyl group into the 6-hydroxy group of 4e resulted in 18 with reduced inhibitory activities against GUSβ and GBA while maintaining the inhibitory activity against HPSE1. The inhibitory activities of 18 against serum HPSE1 in mice were significant and lasted for 4 h at doses of 3, 30, and 100 mg/kg. Compound 18 could be a novel lead compound for HPSE1 inhibitors with improved inhibitory activity against HPSE1 and increased HPSE1 selectivity over GUSβ and GBA.

Development and Characterization of Gel-Based Buccoadhesive Bilayer Formulation of Nifedipine.

A promising controlled drug delivery system has been developed based on polymeric buccoadhesive bilayered formulation that uses a drug-free backing layer and a polymeric hydrophilic gel buccoadhesive core layer containing nifedipine. The DSC thermogravimetric analysis confirms the drug's entrapment in the gel layer and reveals no evidence of a potential interaction. Various ratios of bioadhesive polymers, including HPMC K100, PVP K30, SCMC, and CP 934, were combined with EC as an impermeable backing layer to ensure unidirectional drug release towards the buccal mucosa. The polymeric compositions of hydrophilic gel-natured HPMC, SCMC, and CP formed a matrix layer by surrounding the core nifedipine during compression. Preformulation studies were performed for all of the ingredients in order to evaluate their physical and flow characteristics. Ex vivo buccoadhesive strength, surface pH, swelling index, in vitro and in vivo drug release, and ex vivo permeation investigations were performed to evaluate the produced gel-based system. Rapid temperature variations had no appreciable impact on the substance's physical properties, pharmacological content, or buccoadhesive strength during stability testing using actual human saliva. It was clear from a histological examination of the ex vivo mucosa that the developed system did not cause any irritation or inflammation at the site of administration. The formulation NT5 was the best one, with a correlation coefficient of 0.9966. The in vitro and in vivo drug release profiles were well correlated, and they mimic the in vitro drug release pattern via the biological membrane. Thus, the developed gel-based formulation was found to be novel, stable, and useful for the targeted delivery of nifedipine.

Water absorption behavior and physico‐chemical and mechanical performance of PLA‐based biopolymers filled with degradable glass fibers

AbstractPoly(lactic acid) (PLA)‐based biopolymers filled with degradable glass fibers were submitted to real life conditions, selected based on their potential applications as beverage containers, to evaluate the feasibility of their usage at the required operational conditions. To do so, several media (i.e., buffer solutions at pH = 3, 5, 7.5, 12 and alcoholic solution) and temperatures (25, 37, 55 and 70°C) were applied to mimic the storage of food, beverage, and detergents inside or in direct contact with the bio‐based prototypes. Their mechanical, spectroscopic (FTIR) and morphological (SEM) features were evaluated and compared with samples after immersion. Water absorption increased with the increasing temperature, with maximum values achieved in alcoholic solutions indicating a more severe interaction of media with the functional groups of the samples. The diffusivity, D, increased with temperature, indicating faster water diffusion rate, especially in strong alkaline media. Treatments at pH 12 led to the most relevant degradation. This behavior was confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis that evidenced a strong decrease of the ester band at 1755 cm−1 and the dissolution of the external layer of the polymeric matrix, which became more evident at higher temperatures, where several glass fibers emerged from the bulk. Tensile and flexural tests indicated a softening of the material and an increase in the plasticity of the samples with the increasing temperature. Evident embrittlement of samples was observed at higher temperatures, suggesting an increase in the crystallinity degree of the biopolymer. The obtained results showed the suitability of the PLA‐based biocomposites for applications that do not require high temperatures for long periods of time. Also, the tested materials were proved to resist washing with mild detergents. These results will help in the designing of the new improved PLA‐based biocomposites to meet with the target objectives on their applications.

Ablation resistance of Ti2AlC ceramics at 1600 °C in nitrogen plasma flame

In this study, the ablation behaviors of high-purity and dense Ti2AlC ceramics were investigated using a nitrogen plasma flame at 1600 °C. The macromorphology, microstructure, and phase compositions of the Ti2AlC ceramics were systematically investigated at ablation times of 60–180 s. At the longest ablation time of 180 s, the linear ablation rate and mass ablation rate are 3.09 μm/s and −0.473 mg/s, respectively, which indicate noteworthy ablation resistance. The ablated cross-sections of the samples can be classified into three layers: a surface oxide layer, transition decomposition layer, and matrix layer. The surface oxide layers formed at different ablation times are composed of Al2TiO5 and TiO2, and the transition decomposition layer comprises mainly TiC and Al2O3 with pores and cracks. The high ablation resistance of the Ti2AlC ceramics is primarily due to the formation of the surface oxide layer, which effectively prevents oxidation and plasma flow erosion.

Engineering of extracellular matrix from human iPSC-mesenchymal progenitors to enhance osteogenic capacity of human bone marrow stromal cells independent of their age.

Regeneration of bone defects is often limited due to compromised bone tissue physiology. Previous studies suggest that engineered extracellular matrices enhance the regenerative capacity of mesenchymal stromal cells. In this study, we used human-induced pluripotent stem cells, a scalable source of young mesenchymal progenitors (hiPSC-MPs), to generate extracellular matrix (iECM) and test its effects on the osteogenic capacity of human bone-marrow mesenchymal stromal cells (BMSCs). iECM was deposited as a layer on cell culture dishes and into three-dimensional (3D) silk-based spongy scaffolds. After decellularization, iECM maintained inherent structural proteins including collagens, fibronectin and laminin, and contained minimal residual DNA. Young adult and aged BMSCs cultured on the iECM layer in osteogenic medium exhibited a significant increase in proliferation, osteogenic marker expression, and mineralization as compared to tissue culture plastic. With BMSCs from aged donors, matrix mineralization was only detected when cultured on iECM, but not on tissue culture plastic. When cultured in 3D iECM/silk scaffolds, BMSCs exhibited significantly increased osteogenic gene expression levels and bone matrix deposition. iECM layer showed a similar enhancement of aged BMSC proliferation, osteogenic gene expression, and mineralization compared with extracellular matrix layers derived from young adult or aged BMSCs. However, iECM increased osteogenic differentiation and decreased adipocyte formation compared with single protein substrates including collagen and fibronectin. Together, our data suggest that the microenvironment comprised of iECM can enhance the osteogenic activity of BMSCs, providing a bioactive and scalable biomaterial strategy for enhancing bone regeneration in patients with delayed or failed bone healing.

A coupling strategy for excellent mechanical properties and enhanced interfacial performance of polyimide/carbon fiber composite with metal-free catalyzed-curing route

The structure and properties of carbon fiber reinforced composites (CFRC) depend on main factors, especially the unpredictable interface. In this work, a kind of thiocarbonyl disulfide compound is introduced to achieve the catalyzed-cure of phenylethynyl terminated polyimide (PI) and plays the role of coupling medium to constitute covalent-bonded structure at the PI/CF interface. The organocatalyzed cure not only follows the free radical mechanism with an initial curing temperature down to 260.4 °C, but also endows the composite with reduced internal thermal stress and enhanced interface structure. Due to both CF surface-initiated free radical curing reaction and coupling reaction between thiocarbonyl-containing PI matrix and hydroxyl-rich sizing layer, the composite performs an improved interfacial shear strength (IFSS) of 123.9 MPa, being 2.47 times as the thermally cured ones, plus the anti-bacterial reinforcement of the PI matrix. Besides, the interface enhancement brings the CFRC specimen improved electrical properties, performing a 92.6% increase of transverse electrical conductivity to 367.6 S/m. This study gives perspective for improving the interfacial performance of high-temperature processed CFRC with “as-received” fiber reinforcers, plus a clear outlook to future research directions and open challenges to prepare high-performance CFRC.

Multistage Anticoagulant Surfaces: A Synergistic Combination of Protein Resistance, Fibrinolysis, and Endothelialization.

Anticoagulant surface modification of blood-contacting materials has been shown to be effective in preventing thrombosis and reducing the dose of anticoagulant drugs that patients take. However, commercially available anticoagulant coatings, that is, both bioinert and bioactive coatings, are typically based on a single anticoagulation strategy. This puts the anticoagulation function of the coating at risk of failure during long-term use. Considering the several pathways of the human coagulation system, the synergy of multiple anticoagulation theories may provide separate, targeted effects at different stages of thrombosis. Based on this presumption, in this work, negatively charged poly(sodium p-styrenesulfonate-co-oligo(ethylene glycol) methyl ether methacrylate) and positively charged poly(lysine-co-1-adamantan-1-ylmethyl methacrylate) were synthesized to construct matrix layers on the substrate by electrostatic layer-by-layer self-assembly (LBL). Amino-functionalized β-cyclodextrin (β-CD-PEI) was subsequently immobilized on the surface by host-guest interactions, and heparin was grafted. By adjusting the content of poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA), the interactions between modified surfaces and plasma proteins/cells were regulated. This multistage anticoagulant surface exhibits inertness at the initial stage of implantation, resisting nonspecific protein adsorption (POEGMA). When coagulation reactions occur, heparin exerts its active anticoagulant function in a timely manner, blocking the pathway of thrombosis. If thrombus formation is inevitable, lysine can play a fibrinolytic role in dissolving fibrin clots. Finally, during implantation, endothelial cells continue to adhere and proliferate on the surface, forming an endothelial layer, which meets the blood compatibility requirements. This method provides a new approach to construct a multistage anticoagulant surface for blood-contacting materials.

Chitosan-based mixed matrix composite membranes for CO2/CH4 mixed gas separation. Experimental characterization and performance validation

Membrane technology is acknowledged as one of the most efficient for biogas upgrading, separating simultaneously CH4 and CO2 in the retentate and permeate streams, respectively. The sustainability would still be improved by using renewable and environmentally friendly materials for membrane fabrication. Specifically, this study is focused on laboratory-scale mixed gas separation tests of composite membranes prepared from chitosan (CS), a hydrophilic, biodegradable and biocompatible polymer from abundant natural resources, with good adhesive and film forming properties and high affinity for CO2 due to the primary amine and hydroxyl groups functionalities in CS. To improve mechanical resistance and CO2/CH4 separation, CS was hybridized by a 5 wt% loading of non-toxic ionic [emim][acetate] liquid (IL), and variable loadings of compatible inorganic fillers, such as 3D zeolite 4A and NaETS-10, and layered AM-4 titanosilicate. The CS-based mixed matrix layer was coated on porous polyether sulfone (PES) support. The CO2 permeance and CO2/CH4 separation were measured at different feed concentrations to evaluate the membranes performance in the treatment of different streams. This separation behavior was explained by the wet thickness, water uptake, morphology and ionic resistance of the composite membrane. As such, the 5 wt% Zeolite 4A and NaETS-10-filled ILCS/PES membranes provided a good dispersion in the ILCS matrix and the mixed matrix layer a good adhesion with the porous PES support, leading to high CO2 permeances and separation factors up to 30, whereas the more hydrophilic lamellar AM-4 titanosilicate-filled ILCS layer showed cluster agglomeration in the matrix and a faster detachment of the coated layer from the PES substrate. With increasing filler loading, an increase of the permeance of both CO2 and CH4 gas components was, although selectivity decreased upon increasing AM-4 filler loading. The CO2/CH4 mixed gas separation performance was validated by a custom-built model for a wide range of feed composition, to cover such processes as natural gas sweetening, biogas upgrading and enhanced oil recovery with acceptable relative error below 10% (absolute value), except for the AM-4 titanosilicate-filled ILCS membranes, showing morphological fabrication defects.

Lysosome pH-regulated H+ /K+ switching channel involved in maintaining lysosomal homeostasis.

Lysosomal pH setpoint and H+ homeostasis is key to the lysosome's functions. The Parkinson's disease-risk protein TMEM175, originally identified as lysosomal K+ channel, works as a H+ -activated H+ channel and discharges the lysosomal H+ store when it is hyper-acidified. Yang etal. indicate that TMEM175 is permeable for both K+ and H+ in the same pore and charges the lysosome with H+ under certain conditions. The charge and discharge functions are under regulation of the lysosomal matrix and glycocalyx layer. Their presented work indicates that TMEM175 performs as a multi-functional channel regulating lysosomal pH in response to physiological conditions.

Expression of 20 SCPP genes during tooth and bone mineralization in Senegal bichir.

The African bichir (Polypterus senegalus) is a living representative of Polypteriformes. P. senegalus possesses teeth composed of dentin covered by an enameloid cap and a layer of collar enamel on the tooth shaft, as in lepisosteids. A thin layer of enamel matrix can also be found covering the cap enameloid after its maturation and during the collar enamel formation. Teleosts fish do not possess enamel; teeth are protected by cap and collar enameloid, and inversely in sarcopterygians, where teeth are only covered by enamel, with the exception of the cap enameloid in teeth of larval urodeles. The presence of enameloid and enamel in the teeth of the same organism is an opportunity to solve the evolutionary history of the presence of enamel/enameloid in basal actinopterygians. In silico analyses of the jaw transcriptome of a juvenile bichir provided twenty SCPP transcripts. They included enamel, dentin, and bone-specific SCPPs known in sarcopterygians and several actinopterygian-specific SCPPs. The expression of these 20 genes was investigated by in situ hybridizations on jaw sections during tooth and dentary bone formation. A spatiotemporal expression patterns were established and compared with previous studies of SCPP gene expression during enamel/enameloid and bone formation. Similarities and differences were highlighted, and several SCPP transcripts were found specifically expressed during tooth or bone formation suggesting either conserved or new functions of these SCPPs.

Three patterns for identifying the posterior plane of a lenticule during SMILE

PurposeTo describe three patterns of posterior plane edge identification in small-incision lenticule extraction and to prevent lenticule mis-dissection.MethodsFemtosecond laser application was performed for small-incision lenticule extraction (SMILE) by one surgeon. The surgical videos of SMILE were recorded and re-watched by the surgeon after operation.ResultsSmall-incision lenticule extraction was performed in 52 eyes of 28 patients, and no patient had cap-lenticular adhesion. Three patterns of posterior plane of lenticule were noticed when the surgical videos were re-watched. A “double lines” attached to the dissector were visible, signifying the reflective tape of the edge of the lenticule and the cap. During the expansion of the posterior lamellar separation, a fusiform opening between the lenticule edge and the underlying matrix layer was assumed to be a “leaf sign.” With some unintentional operation, the posterior lamella was pushed away from the surgeon. The edge of the lenticule away from the anatomical part, the marking of the femtosecond laser cut, and the edge of the cap layer showed three reflective bands, which formed a “triple lines.” The “double lines,” “leaf sign,” and “triple lines” were observed in 30 eyes (57.7%), 21 eyes (40.4%), and 1 eye (1.9%), respectively.ConclusionThese three signs cover possible situations and provide visual landmarks to identify the correct dissection of the posterior plane, which can help shorten the learning curve of novice doctors.

Effects of nonlinear hyper‐viscoelasticity and matrix/fiber debonding on the mechanical properties of short carbon fiber/styrene‐butadiene rubber composites under cyclic uniaxial loading using a multiscale finite element model

AbstractA multiscale finite element analysis was performed for short carbon fiber (SCF) reinforced rubber composites under uniaxial tensile loading with periodic geometries and random distributions of the short fibers. Three different zones were considered, including the rubber matrix, SCF as the inclusion phase, and a thin matrix layer as the interphase. A nonlinear hyper‐viscoelastic model was selected for the matrix, while linear viscoelastic and elastic models were considered for the interphase and reinforcing phases, respectively. The analyses were carried out on an incremental basis from a lower loading‐unloading rate of 10 mm/min to a higher rate of 100 mm/min. Two interface conditions were considered between the polymer matrix and the SCF phases: perfect bonding and partial debonding. The partial debonding was modeled via extended FEM (XFEM) with a crack initiation criterion. An integral averaging technique was employed to predict stress and strain at the macro‐scale. Based on the observations in this work, hysteresis and energy dissipation decrease with the addition of the short fibers to the neat rubber and surface modification of the fibers under three‐cycle loading. For example, in the first cycle and for a constant stress of 0.45 MPa, the strain value decreases from 0.25 to 0.17 MPa at the loading‐unloading rate of 10 mm/min. The high‐fidelity model developed in this work for short fiber/rubber composites is able to predict the stress and strain responses of the SCF/SBR composites, confirming the accuracy of the utilized multiscale approach.

Hybrid homogenization theory with surface effects: Application to columnar nanoporous materials

Nanocomposites, including nanoporous ceramics, metals and polymers, are being widely used in various engineering applications. At the nanoscale, surface/interface effects have significant influence on the homogenized properties and local stresses. To account for these nanoscale effects, the well-established Gurtin–Murdoch theory of surface elasticity is typically incorporated into classical elasticity-based micromechanics schemes and numerical approaches based on the finite-element and most recently finite-volume methods. Whereas the classical micromechanics models either neglect the interactions of adjacent fibers/pores or account for the interactions in an average sense, the finite-element and finite-volume based approaches require high discretization to capture the large stress/strain gradients around the interface/surface. In contrast, the recently proposed hybrid homogenization theory (HHT) combines elements of locally-exact elasticity and finite-volume approaches and is both accurate and efficient, enabling rapid generation and analysis of ordered and quasi-random fiber or pore arrays. Herein, a continuous bulk matrix layer of arbitrary size endowed with a two-dimensional energetic surface is introduced between fiber/pore and discretized matrix region that enables exact calculation of stress jump conditions in the Young–Laplace equations of the Gurtin–Murdoch model. The enhanced HHT with interface/surface effects is validated by comparison with the stress concentration factors obtained using a classical elasticity solution and point-wise stress fields predicted by the locally-exact and finite-volume homogenization theories, exhibiting stable solutions even for very thin bulk matrix layers. The enhanced theory is then employed to study the influence of random nanopore microstructures with random pore radii on the complete set of homogenized moduli of porous silicon used in the electronics industry.

Dislocation in a Strained Layer Embedded in a Semi-Infinite Matrix

Abstract The misfit stress in a thin layer embedded in a semi-infinite matrix has been first determined near the free surface of the structure, using the virtual dislocation formalism. From a Peach–Koehler force analysis, the different equilibrium positions (unstable and stable) of an edge dislocation gliding in a plane of the layer inclined with respect to the upper interface and emerging at the point of intersection of the upper interface and this free surface have been then characterized with respect to the lattice mismatch and the inclination angle of the gliding plane. It has been found that the dislocation may exhibit stable equilibrium position near the interface and/or near the free surface. A diagram of the position stability has been then determined versus the misfit parameter and the inclination angle. The energy variation due to the introduction of an edge dislocation from the free surface until the matrix layer interface has been finally determined, when the dislocation is gliding in the plane inclined with respect to the interface horizontal axis. A critical thickness of the layer beyond which the formation of the dislocation in the interfaces is energetically favorable has been finally determined as well as its position with respect to the free surface in the lower interface.

Waste Coir Nanofiller Fused Gallus-Gallus Fibres Reinforced PMC

This research aims to increase the utility of globally and abundantly available waste natural fibres of Gallus-Gallus fibres coir waste from mattress and car seat manufacturing factories. The composite samples were prepared with a rally round of polyester resin of grade GP500 bio-epoxy by synthesizing specially treated Gallus-Gallus fibres selectively used for reinforcement and characterizing them through static and dynamic mechanical analyses to identify their wide range of applicability. The Gallus-Gallus fibres are preprocessed with sodium oxidative and a half per cent of potassium manganate (VII) chemical solution. The selective use includes 5 mm, 10 mm, 15 mm, and 20 mm length of the Gallus-Gallus fibre, and the quantity of reinforcement was 10%, 20%, and 30%. Five alternate layers of matrix and fibres, with vertical and horizontal orientation, are considered; 12 different samples of Gallus-Gallus fibres reinforced polyester polymer composites and a neat polyester composites were synthesized and characterized for moisture absorbability, tensile strength, tensile modulus, flexural strength, flexural modulus, wear resistance, and outperformed composites were included in microscopic examination and dynamic Mmchanical analysis. The interesting results are the preferred resin, supported for good surface finish, interface bonding, and totally in the enhancement of Composite properties. The composites are strong in tension (760.89 MPa) and sufficiently flexible (flexural modulus 5441.32 MPa), absorbed less moisture (5.8 g), high wear-resistant (least weight loss upon abrasion with a value of 0.1989 g), secured good results in dynamic analysis, and ensured homogeneous distribution of fibres in the matrix through a scanning electron microscopy image. The composites CPPC10, CPPC11, and CPPC12 performed well but composite CPPC12 outperformed.