Values Of Bending Modulus Research Articles

Indocyanine green and iohexol loaded hydroxyapatite in poly(L-lactide-co-caprolactone)-based composite for bimodal near-infrared fluorescence- and X-ray-based imaging.

This study aimed to develop material for multimodal imaging by means of X-ray and near-infrared containing FDA- and EMA-approved iohexol and indocyanine green (ICG). The mentioned contrast agents (CAs) are hydrophilic and amphiphilic, respectively, which creates difficulties in fabrication of functional polymeric composites for fiducial markers (FMs) with usage thereof. Therefore, this study exploited for the first time the possibility of enhancing the radiopacity and introduction of the NIR fluorescence of FMs by adsorption of the CAs on hydroxyapatite (HAp) nanoparticles. The particles were embedded in the poly(L-lactide-co-caprolactone) (P[LAcoCL]) matrix resulting in the composite material for bimodal near-infrared fluorescence- and X-ray-based imaging. The applied method of material preparation provided homogenous distribution of both CAs with high iohexol loading efficiency and improved fluorescence signal due to hindered ICG aggregation. The material possessed profound contrasting properties for both imaging modalities. Its stability was evaluated during in vitro experiments in phosphate-buffered saline (PBS) and foetal bovine serum (FBS) solutions. The addition of HAp nanoparticles had significant effect on the fluorescence signal. The X-ray radiopacity was stable within minimum 11 weeks, even though the addition of ICG contributed to a faster release of iohexol. The stiffness of the material was not affected by iohexol or ICG, but incorporation of HAp nanoparticles elevated the values of bending modulus by approximately 70%. Moreover, the performed cell study revealed that all tested materials were not cytotoxic. Thus, the developed material can be successfully used for fabrication of FMs.

Sustainable Use of Biomass Boiler Ash as a Reinforcement Filler for Polyamide 6 Composite

The use of biomass combustion ash as a reinforcing filler has taken the attention in recent years to reduce the overall production cost and increase the mechanical properties of plastics. This study evaluates the effect of biomass boilers ash (BBA) as a reinforcing filler on polyamide 6 composites (PA6). The chemical composition and thermal stability of BBA were analyzed by X-ray fluorescence (XRF), Thermogravimetric analysis (TGA), and Differential thermal analysis (DTA) thermographs. Test samples were prepared by varying the ash content (2.5%, 5%, 7.5%, and 10%), and also samples were prepared without adding ash as a control. Moreover, surface modification was carried out by using N-2 (Aminoethyl) 3-aminopropyl triethoxy diamino-silane as a possible coupling agent for BBA and it was tested by varying the coupling agent concentration (0.5%, 1%, and 2%) by dry process and the samples were prepared by extrusion and injection molding processes. Comparative analysis of the degree of crystallinity, mechanical properties including tensile, flexural, and thermal properties were tested. The highest degree of crystallinity was obtained with 7.5% BBA-filled composites. The addition of 2% surface-modified BBA (SBBA) filled composites (PA6 / 10% Ash 2% CA) showed an increase of tensile strength and elongation at break than the 10% unmodified BBA (UBBA) (PA6/ 10% Ash) filled composites. Stress at peak and bending modulus values in the flexural test data were increased up to 10%. But it was significantly reduced with the increasing of modifying agent concentration due to the increment of stiffness of the composite.

Effect of Botulinum Toxin Type A on Mandibular Fracture Healing: An Experimental Study in Rabbits

The effect of botulinum toxin type A (BTX-A) on fracture healing of the long bones is controversial, and no controlled clinical or experimental study has investigated the effect of BTX-A on mandibular fractures. The purpose of this study was to investigate whether BTX-A injection into the masseter muscles affects bone healing by reducing the displacing forces in an unfavorable mandibular fracture model. Forty-eight male New Zealand white rabbits were used. Ten units of BTX-A was injected into each masseter muscle in the animals in the BTX-A group, whereas saline solution was injected in the animals in the control group. A unilateral osteotomy and fixation with a microplate were performed. Bone healing was evaluated by radiodensitometric, biomechanical, histologic, and histomorphometric methods after 21days. The mean bone mineral density in the fracture area was significantly higher in the BTX-A group (P=.038). The mean failure load and bending modulus values were significantly higher in the BTX-A group than in the control group (P=.032 and P=.005, respectively). The mean histologic bone healing scores, bone volume-total volume values, and trabecular diameter values were significantly higher in the BTX-A group than in the control group (P=.001, P=.001, and P=.026, respectively). BTX-A application into the masseter muscles improves bone healing of a unilateral mandibular fracture in rabbits.

Fast and accurate bending modulus prediction of 3D woven composites via experimental modal analysis

Abstract An original mixed numerical-experimental identification method was proposed and used to predict the bending modulus of 3D woven composites. Four kinds of textile composites were utilized as specimens to verify the correctness of this method. Firstly, the vibration test was conducted to obtain key vibration parameters (natural frequency, damping factors, damping shapes) of the composite; Secondly, the cantilever beam model about the relationship between the natural frequency and modulus was adopted to predict the bending modulus; Finally, to verify the correctness of predicted values, three-point bending test was carried out to acquire the experimental values of bending modulus. The comparison results show that the relative error between experimental results and predicted values based on the first natural frequency for the four kinds of composites were all lower than 8%. Therefore, the experimental modal analysis technique as a nondestructive manner is reasonable and safe to understand the bending modulus of complex textile composites using the first natural frequency of their cantilever beam.

Abstracts

Extracellular vesicles (EVs) are important mediators of intercellular communication, being involved both in maintaining normal physiology as well as spreading of a wide range of diseases. In order to successfully deliver their cargo, EVs need to be taken up by the target cells. Several studies suggest that successful cellular uptake of nanoparticles is affected by their mechanical properties. We propose that mechanical properties of EVs are important with respect to their function. We study mechanics of vesicles from red blood cells (RBC), both healthy and malaria parasite infected. Moreover, we examine the effect of cell temperature treatment on the mechanical properties of the secreted vesicles. To do so we perform a detailed AFMforce spectroscopy study and analyze our results using a Helfrich-model based theoretical framework to estimate the bending modulus of different vesicle populations. By simultaneously performing a systematic analysis of EV protein and lipid composition, we find that bending modulus values are significantly decreased upon increase in EV membrane protein content. Our results can provide better understanding of EVs function and new insights into the vesiculation process in health and disease.

Mechanical properties and structure of rapidly solidified bulk Fe89 − xHf4Ta1Cu1Gd1SixB4 (x = 0–15) and Fe74Hf4Ta1Cu1Gd1LaySi15 − yB4 (y = 7) alloys

Authors investigated mechanical properties of microcrystalline Fe89−xHf4Ta1Cu1Gd1SixB4 (x=0–15) and Fe74Hf4Ta1Cu1Gd1LaySi15−yB4 (y=7) alloys obtained by copper mold injection casting to a form of rods, 3mm in diameter. Structure of the samples was analyzed by Cu K-α powder X-ray diffractometry and the unit cell parameters of identified h-Fe2Hf0.8Ta0.2 (C14 Laves), fcc-Fe16Hf6Si7 (D8a) and bcc-Fe phases were calculated. The study revealed that ascending Si content leads to reduction in values of both unit cell parameters of C14 phase in the alloys studied while causes the expansion of D8a lattice; decrease in secondary dendrite arm spacing in the middle of the rods; stepwise improvement of yield and compressive strength at the expense of plastic deformation region, what was attributed to the precipitation of C14 Laves/D8a in the interdendritic regions of bcc-Fe; decrease in flexural strength with no effect on deflection-at-yield and exponential increase in hardness of the studied alloys. There is also clear correlation between unit cell volume of fcc-Fe16Hf6Si7 phase, yield and compressive strength on Si content. For the alloys with x=0–13, relation between yield strength and Vickers hardness was described with logarithmic function. It was found, that the lattice expansion of bcc-Fe and, in lesser extent, C14 Laves phase is correlated with the value of bending modulus in the whole composition range.

Synergistic effects of zinc oxide in montmorillonite flame‐retardant polystyrene nanocomposites

ABSTRACTIn this study, two‐dimensional organic montmorillonite (OMMT) and one‐dimensional needlelike ZnO were used as flame retardants of polystyrene (PS). Polystyrene/organic montmorillonite (PMT) and polystyrene/organic montmorillonite/zinc oxide nanocomposites (PMZs) with different weight ratios were prepared by melt intercalation. Information on the morphologies and structures of the PS nanocomposites was obtained with Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results indicate that a mixed exfoliated–intercalated structure was observed in the PMT and PMZs. Dynamic mechanical thermal analysis showed that both the storage modulus and glass‐transition temperature values of the PMT and PMZs were significantly improved compared with those of the neat PS. The mechanical property tests showed that the bending modulus values of both PM5 (PS/OMMT weight ratio = 95:5) and PMZs increased compared with that of pristine PS. PMZ1 (PS/OMMT/ZnO weight ratio = 94:5:1) provided no decrease in the tensile strength in comparison with PS. A synergistic effect was observed between OMMT and ZnO; this resulted in improvements in the flame retardancy and dynamic mechanical properties in the PMZs. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43047.

Characterization of prickle tactile discomfort properties of different textile single fibers using an axial fiber-compression-bending analyzer (FICBA)

This research contributes to the study of prickle sensation in terms of single fiber bending modulus and flexural rigidity, which are important factors for fabric-evoked prickle for garment tactile comfort. In this study, a novel technique was used to study the flexural buckling behavior of single fibers using an axial fiber-compression-bending analyzer (FICBA). The bending behavior and bending equivalent modulus of different single fibers were measured and analyzed. The bending properties of single fibers were quantified by calculating the equivalent bending modulus, and the flexural rigidity via measurement of the protruding length ( l), diameter ( d) of single fiber, and its critical force ( Pcr), obtained from the peak point of the force–displacement curve. The experimental results indicate that ramie single fiber has the highest bending modulus, while cotton has the lowest bending modulus. However, hemp, jute, wool, flax, and cashmere fiber have bending modulus values lower than ramie but higher than cotton. On the other hand, the flexural rigidity of jute fiber is higher than that of wool followed by ramie, hemp, flax, cashmere, and cotton consecutively. Therefore, jute, wool, and ramie are stiffer than the other fibers, especially jute fiber. Thus, jute, wool, and ramie are uncomfortable single fibers because the fabric-evoked prickle, which is caused by short, coarse, and stiff fibers protruding from the fabric surface, generate sufficient force to evoke a low level of activity on a human nociceptors, but insufficient to penetrate the human skin so as to cause itchiness.

Robust Measurement of Membrane Bending Moduli Using Light Sheet Fluorescence Imaging of Vesicle Fluctuations

The mechanical rigidity of lipid membranes is a key determinant of the energetics of cellular membrane deformation. Measurements of membrane bending moduli remain rare, however, and show a large variance, a situation that can be addressed by the development of improved techniques and by comparisons between disparate techniques applied to the same systems. We introduce here the use of selective plane illumination microscopy (SPIM, also known as light sheet fluorescence microscopy) to image thermal fluctuations of giant vesicles. The optical sectioning of SPIM enables high-speed fluorescence imaging of freely suspended vesicles and quantification of edge localization precision, yielding robust fluctuation spectra and rigidity estimates. For both lipid-only membranes and membranes bound by the intracellular trafficking protein Sar1p, which lowers membrane rigidity in a concentration-dependent manner, we show that the resulting bending modulus values are in close agreement with those derived from an independent assay based on membrane tether pulling. We also show that the fluctuation spectra of vesicles bound by the mammalian Sar1A protein, which stiffens membranes at high concentrations, are not well fit by a model of homogeneous quasi-spherical vesicles, suggesting that SPIM-based analysis can offer insights into spatially inhomogeneous properties induced by protein assemblies.

Mechanical Properties of Polymer Composites with Sugarcane Bagasse Filler

Natural fibers reinforced polymer composites have gained more interest because of their biodegradable, light weight, less expensive sources, easy processing, high specific modulus and also environmentally friendly appeal. This paper presents an overview of a study aimed at showing on how the bio-composites which is bagasse fibers combined with resins as an alternative of bagasse-fiber-based composites panel. Transforming bagasse fibers into panel products provides a prospective solution. Bagasse-fiber-based composites offer potential as the core material replacing high density and expensive wood-based fiberboard. Biodegradable composites reinforced with bagasse fibres after being modified or treated by alkali treatment were prepared and also the mechanical properties were investigated. The bio-composites panel samples were processed by hot press machine. All panels were made with aspect ratios between bagasse fibers and polystyrene thermoplastics resins and also the sieve size of bagasse fibers which has short fibers and combination of short fiber and granules fibers. The polystyrene was added as a modified from natural fibers to determine the effect it had on physical and mechanical properties of the panel. Resin content level and panel density were very important in controlling the strength properties of the panels. Surface hardness value, compressive strength, bending strength and bending modulus values all increases in resin content level and panel density. Bagasse-based-panel products can be commercialize successfully if have good development of a cost manufacturing process on an establishment of a market base for the products.

Preparation and bending properties of three dimensional braided single poly (lactic acid) composite

New three dimensional (3D) braided single poly (lactic acid) composites (PLA–SPCs) were obtained by combining 3D and five (5)-direction braiding technique and hot-compression technical process. 3D and 5-direction braided preforms with different braiding angles, thicknesses and fiber volume fractions were prepared. Preforms were preheated in the specially designed die system in order to make all of the fibers partially melted. In the next stage, the preforms were consolidated under a certain pressure (from 7.8 to 10MPa) at temperatures ranging from 130 up to 150°C. Under the controlled processing conditions, one part of fiber body formed matrix while the other part retained its fibrous form.At the same consolidation temperature, the maximum bending stress values resulted to be substantially dependent on the fiber volume fraction of PLA–SPCs, while the bending modulus values were largely subjected to the fiber content in the length direction. The increases of consolidation pressure gave rise to better fusion of neighboring fibers with the result that the maximum stress and modulus were increased. As the consolidation temperature increases, the fusion bonding was improved, the bending failure feature was converted from plastic to brittle, both maximum bending stress and modulus values were increased. It is expected that this study could provide a new approach for the manufacture of high-performance single polymer composites (SPCs) by using thermoplastic polymer fibers.

Complex estimation of bending elasticity of hemp woven fabric after washing treatment

PurposeThis paper aims to investigate the elasticity of hemp woven fabric under action of bending force, before and after washing treatment.Design/methodology/approachBending elasticity was monitored in three different ways: through the value of bending modulus, on the basis of fabric's resistance to creasing expressed through the value of quality number, and through the value of bending deformation components. On the basis of the results obtained from the mentioned three types of investigations, the complex criterion of quality of washed and unwashed hemp fabric, from the aspect of their elasticity, was formulated.FindingsValues of complex criterion as well as the values of bending modulus, quality number and total recurrent deformation pointed to the conclusion that investigated hemp fabric has, not good, but satisfied bending elasticity, especially after washing treatment. The values of bending deformation components served for establishing Frenkel's model of elastic behaviour under action of bending force of washed as well as unwashed hemp fabric.Practical implicationsShows that the way on which Frenkel's model was established might be interesting because of its simplicity.Originality/valueProvides information on the elasticity of hemp woven fabric before and after washing.

Mechanical behaviour of femoral bones in bending loading

A series of 33 human femoral bones have been subjected to a four point bending test at high strain rates. Two different failure modes were recognized. A Y shaped fracture at the middle region induced by a pure bending moment yielded a zone of non-linearity at the load vs deformation curve and a higher bending force, more deformation of the structure and higher strain energy to fracture compared with the less frequently occurring oblique fracture at the distal third of the structure resulting in a failure without a ‘plastic’ portion at the load-deformation curve. Estimated values of bending modulus and maximum bending moment based upon a simple uniform beam model showed high correlation coefficients with the experimentally determined values. Scanning electron microscopic examination of the Y fracture showed distortion and void formation of the material at the structural level. This could explain the extensive non-elastic deformation prior to failure.