Young Modules Research Articles

Molecular dynamics method to investigate the interaction energy and mechanical properties of the reinforced graphene aerogel with paraffin as the phase change material in the presence of different external heat fluxes

BackgroundGraphene aerogels (GA), known for their exceptional lightweight and sturdy characteristics, present a promising avenue for improving thermal energy (TE) storage and transfer efficiency. It might be possible to make better thermal management systems in fields like electronics, aerospace, and energy storage by studying how heat flux (HF) affects the strength and stability of graphene aerogels. MethodsThe study used molecular dynamics (MD) simulation to investigate how the mechanical properties of graphene aerogels strengthened with paraffin as phase change material (PCM) change in response to external heat flux (EHF). These simulation methods provided a detailed view of molecular interactions and dynamics at the atomic level, allowing researchers to understand the behavior of materials under various conditions. The change in toughness, interaction energy (IE), Young's modules (YM), and ultimate strength (US) was examined for this reason. Significant findingsThe results indicate that when the HF increased from 0.1 to 0.3 W/m2, the ultimate strength and Young's modules increased from 8.91 and 5.37 GPa to 14.546 and 8.59 GPa, respectively. These values declined when HF increased by more than 0.3 W/m2. When EHF went up to 0.3 W/m², these graphene aerogel properties went up. This was because the atoms moved around more and there were more bonding contacts among the graphene sheets, which made the structure of material stronger. However, at heat flux levels exceeding 0.3 W/m², excessive thermal energy may lead to thermal degradation, causing bond breakage and loss of structural integrity, ultimately resulting in a decrease in these mechanical properties. Also, the results reveal that interaction energy increased from -1522.098 to -1546.325 eV as external HF increased to 0.3 W/m2. The thermal motion of atoms enhanced as the HF increased, enabling closer clustering and better alignment of graphene sheets, thereby strengthening their interactions. This study gave us useful information about how to improve the mechanical properties of graphene aerogels in different HF conditions. This made it more likely that these materials can be used in energy storage systems and thermal management.

Fabrication of heparinized bi-layered vascular graft with PCL/PU/gelatin co-electrospun and chitosan/silk fibroin/gelatin freeze-dried hydrogel for improved endothelialization and enhanced mechanical properties

Fabricating a biocompatible small-diameter vascular graft (< 6 mm) with mechanical properties similar to the natural vein and adding good anti-thrombogenic, endothelialization, and hyperplasia properties remains a challenge. To this end, we fabricated a heparinized bilayer graft to address this problem. The proposed bilayer sample consisted of a heparinized polycaprolactone (PCL), polyurethane (PU), and gelatin (G) co-electrospun inner layer and chitosan, gelatin, and silk fibroin freeze-dried hydrogel crosslinked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) outer layer. The samples exhibited great ultimate stress, Young's module, and suture retention of 4.16±0.25MPa, 8.24±2.59MPa and 4.83±0.31N, respectively. The heparin release assay indicated a sustained release profile of around 70% after 4weeks, which can be attributed to the excellent control via emulsion. Furthermore, the heparinized samples demonstrated good anti-thrombogenic properties investigated in the platelet adhesion assay. For the outer layer, the hydrogel crosslinked with non-toxic materials was prepared through the freeze-drying method to achieve high porosity (64.63%), suitable for smooth muscle cell activity. Moreover, inner and outer layers showed high cell viability toward endothelial (78.96%) and smooth muscle cells (57.77%), respectively. Overall, the proposed heparinized graft exhibited excellent potential for vascular graft regeneration.

Pervaporation and Gas Separation Properties of High-Molecular Ladder-like Polyphenylsilsesquioxanes.

This paper presents the results of studies on the pervaporation properties (for benzene/hexane mixtures) and gas permeability (for He, H2, N2, O2, CO2, CH4, C2H6, and C4H10) of ladder-like polyphenylsesquioxanes (L-PPSQ) with improved physical and chemical properties. These polymers were obtained by condensation of cis-tetraphenylcyclotetrasiloxanetetraol in ammonia medium. The structure of L-PPSQ was fully confirmed by a combination of physicochemical analysis methods: 1H, 29Si NMR, IR spectroscopy, HPLC, powder XRD, and viscometry in solution. For the first time, a high molecular weight of the polymer (Mn = 238 kDa, Mw = 540 kDa) was achieved, which determines its improved mechanical properties and high potential for use in membrane separation. Using TGA and mechanical analysis methods, it was found that this polymer has high thermal (Td5% = 537 °C) and thermal-oxidative stability (Td5% = 587 °C) and good mechanical properties (Young's module (E) = 1700 MPa, ultimate tensile stress (σ) = 44 MPa, elongation at break (ε) = 6%), which is important for making membranes workable under various conditions. The polymer showed a high separation factor for a mixture of 10% wt. benzene in n-hexane (126) at a benzene flow of 33 g/(m2h).

Gelatin-based films incorporated with buriti oil (Mauritia flexuosa L.) as active packaging for artisanal cheese conservation

Active and biodegradable materials have attracted interest in the food packaging area for better product safety and quality. In this study, a gelatin-based film was developed incorporating buriti oil extracted by pressurized propane to preserve the coalho artisanal Brazilian cheese. The GC/qMS analysis of buriti oil revealed unsaturated fatty acids, polyphenols, and carotenoids high content. No significant differences in film thickness, elongation at break, tensile strength, and Young's module were observed between oil-based and oil-free gelatin films. However, oil incorporation into the film decreased the water vapor permeability. Oil-incorporated gelatin-based films displayed antioxidant, bacteriostatic properties and pH responsivity during cheese storage compared to control groups. This trial revealed a significant growth decrease of Salmonella spp., P. aeruginosa, and E. coli, over 14-day storage at 5 °C, indicating the minimized microbial cheese spoilage during storage and the promising application of films for food-active packaging.

Особливості дослідження деформаційної поведінки матеріалів при випробуваннях на згин

The application of bending tests is due to the widespread use of this load scheme in real operating conditions and its greater softness compared to tensile strength. This makes it possible to assess the properties of materials that are brittle when tensile. Bending tests are convenient for estimating the transition temperatures from brittle to plastic (for example, in cold-brittle BCC metals and intermetallics). The issue of determining the elastic characteristics, in particular the measurement of deflections, needs to be clarified. The aim of this work is to improve experimental methods for determining the characteristics of elasticity, in particular to determine the ratio of movement of internal rollers relative to external and deflection between internal rollers, as well as accurate determination of absolute deformation of the test machine depending on load. To obtain the deformation curve of the sample without the deflection meter, a method of subtracting from the total load curve the yield curve of the test machine, which can be obtained after testing the sample with a high axial moment of inertia to minimize its deflection. To test this technique, a ceramic sample based on Al2O3 was tested. After the adjustments, it was found that the modulus of elasticity was 371.3 GPa, which corresponds to the tabular values. The proposed technique allows to accurately measure the modulus of elasticity and obtain curves of microdeformation of low-plastic materials at different test temperatures in the absence of a deflector. The deflection of the central part of the sample relative to the inner rollers by four-point bending is 3/8 of the movement of the inner rollers relative to the outer ones. The improved method of determining the deflections allows to obtain diagrams of deformation of the samples without the deflection meter, as well as to measure the modulus of elasticity and obtain curves of microdeformation of low-plastic materials at different test temperatures. Comparison of the results of determining the modulus of elasticity by methods without a deflector and with it allows you to assess the accuracy of measuring the modulus of elasticity. It is experimentally established that the difference between the values of the Young's modules calculated by the proposed method and the corresponding values calculated taking into account the directly measured deflections does not exceed 1%. Keywords: bending, stress, deformation, deflection, angle of rotation, radius of curvature, axial moment of inertia, deflection meter.

The structural, mechanical, thermal, electronic and optical properties of halide perovskites [formula omitted]: First-principles investigations

The structural, mechanical, thermal, electronic and optical properties of inorganic Pb-free double perovskites Cs2TiX6(X=Cl,Br,I) compounds are investigated. Using the first-principles with full-potential linearized augmented plane wave (FP-LAPW) method, supported the density functional theory, and therefore the generalized gradient approximation (GGA-PBE) and Hybrid exchange-correlation functionals with and without spin-orbit coupling. The computation of the lattice constants showed an honest agreement between our results and the experimental results and the theoretical data available. Using the three independent elastic constants C11, C12 and C44, various mechanical and thermal properties are obtained such as: bulk modules B, shear modules G, Young's modules Y, Pough's ratio B/G, Frantesvich ratio G/B, Poisson's ratio υ, Shear anisotropy character A and Debye temperature ΘD for Cs2TiI6, Cs2TiBr6 and Cs2TiCl6 respectively. Our calculated elastic constant results show that Cs2TiI6, Cs2TiBr6 and Cs2TiCl6 are mechanically stable, anisotropic and ductile in nature. Furthermore, the Cs2TiCl6 compound has the highest Debye temperature, which indicates the highest melting temperature. The electronic band structures reveal the semiconductor conductivity of the three compounds, with a band gap suitable for photovoltaic applications, within the range of 1.5–2.96 eV. Finally, Cs2TiCl6(X=Cl,Br,I) HPs compounds exhibit excellent optical properties like optical absorption, conductivity and refraction index.

Critical Loads of Uniformly Compressed Orthotropic Rectangular Plate on an Elastic Base

Introduction. The problem of critical loads of a compressed orthotropic rectangular plate on an elastic base was considered. The following orthotropy parameters were set for the plate: Poisson coefficients, Young's modules for the main directions, and the shear modulus of the plate material. The components of the compressive load were uniformly distributed along two opposite edges of the plate and acted parallel to the coordinate axes. The edges of the plate were loosely pinched or pivotally supported. Cases were also considered when two parallel edges of the plate were free from loads, and the other two were freely pinched or pivotally supported.Materials and Methods. The problem was studied on the basis of a system of nonlinear Kármán-type equilibrium equations. The critical values of the load parameter were determined from a linearized problem based on a trivial solution. At the same time, the variational method in combination with the finite difference method was used to solve the boundary eigenvalue problem.Results. The problem was reduced to solving a parametric linear boundary eigenvalue problem. In case of boundary conditions of a movable hinge support, exact formulas of eigenvalues and eigenfunctions were given. While in case of free edge pinching, a variational method was used in combination with a finite-difference method, and a computer program for solving the problem was built. It was established that one or two eigenfunctions expressing the deflection of the plate could correspond to the critical value of the compressive load parameter at which the stability of the compressed plate was lost. The results of numerical calculations of the critical values of the compressive load at different values of the orthotropy parameters were presented, and graphs of the corresponding equilibrium forms were constructed. For the case of a long orthotropic plate on an elastic base, it was established that the main term of the asymptotic expansion of the solution to the linear eigenvalue problem was determined from the problem of critical loads of a compressed beam on an elastic base with an elastic modulus that coincides with the elastic modulus of the plate in the longitudinal direction.Discussion and Conclusions. The problem of critical loads of an orthotropic plate compressed in two directions lying on an elastic base was investigated. As the compressive load component increased along one direction, the critical value of the load compressing the plate along the other direction decreased. If an orthotropic plate was compressed by a load along a direction that corresponded to a greater bending stiffness, then the critical value of the loss of stability was greater than the critical value of the compressive load acting along the direction of a lesser bending stiffness. The presence of an elastic foundation increased the bearing capacity of the compressed plate.

Synthesis, characterization, and heavy-ion rejection rate efficiency of PVA/MWCNTs and Triton X-100/MWCNTs Buckypaper membranes

Buckypaper membranes were prepared through the dispersion of multi-walled carbon nanotubes (MWCNTs) in the presence of surfactants (Triton X-100) and (PVA) in a separate manner. The dispersed solutions were vacuum filtered and Buckypapers, which are self-supporting membranes were obtained. The results revealed that the incorporation of both Triton X-100 and PVA surfactants increased the permeability and rejection efficiency of the MWCNTs. The rejection performance for the heavy metal ions of both membranes is investigated for the first time. The physico-chemical and morphological characteristics of the membranes were reported. PVA and Triton X-100 BP membranes displayed electrical conductivity (32.749 ± 2 S cm−1 and 58.3072 ± 1 S cm−1), contact angle (58 ± 3° and 34 ± 3°), water permeability (20 ± 2 Lm−2 h−1 bar−1 and 79 ± 4 Lm−2 h−1 bar−1), surface area (67.7 and 88.5 m2/g) and mechanical properties (Young's module was found to be 10.25 ± 0.2 and 6.07 ± 0.7) respectively. Both PVA/MWCNTs BP and Trix-100/MWCNTs BP membranes significantly reject Cu+2, Cd+2, Co+2, Ba+2, Ni+2, and Pb+2 at PH = 6–8 from aqueous medium. Furthermore, the rejection of metal ions was more efficient in PVA-based membranes compared to Trix-based membranes.

Individualizing Mechanical Ventilation: Titration of Driving Pressure to Pulmonary Elastance Through Young's Module in an Acute Respiratory Distress Syndrome Animal Model

Individualizing Mechanical Ventilation: Titration of Driving Pressure to Pulmonary Elastance Through Young's Module in an Acute Respiratory Distress Syndrome Animal Model

Моделирование кристаллографической текстуры феррит / мартенситной стали при прокатке: уровень и анизотропия прочностных свойств

This paper presents the results of studies of the level and anisotropy of strength properties in ferritic / martensitic steel during warm rolling based on the data on crystallographic texture. The features of texture formation processes in the initial and UFG samples subjected to flat rolling are analyzed by the method of texture analysis and computer modeling. In particular, the analysis of the orientation distribution function (ODF) made it possible to establish the change in the main preferential orientations (Brass, Goss, Copper, Cube, TC, Y, Z and Rotated Cube) depending on the degree of reduction. It is shown that in flat rolling, a stable rolling texture is formed only after 70 % reduction, at which H {001}<011>, Goss {001}<110>, Cube {100}<001> and TC {255}<511> orientations become the main ones. At high degrees of flat rolling, the sharpness of the above textural maxima increases, which is accompanied by the activation of a smaller number of slip systems, and the misorientations between adjacent grains become predominantly high-angle ones. Within the framework of modeling of crystallographic textures, deformation mechanisms were established, two-dimensional projections of yield contours, Young's module and Lankford coefficients (r-value) were constructed. In particular, the results of computer simulation of the yield contours of steel after tempering the coarse-crystalline and UFG states showed that at low degrees of flat rolling reduction, an increased level of anisotropy of strength properties is associated with the residual crystallographic texture in the workpiece, and an increase in the degree of flat rolling leads to alignment of the strength anisotropy in sheets. It was found that the quantitative ratio of the main textural components of the type H {001}<011>, Goss {001}<110>, Cube {100}<001> and TC {255}<511> during rolling determine the anisotropy of the strength properties of steel.

Potential use of glycerol- and/or spermidine-plasticized secalin films as leaf surface coatings for sustainable plant disease management

The effects of spermidine (SPD) on the properties of both secalin (SCL)-based film-forming solutions (FFSs) and their resultant films were studied in the absence or presence of glycerol (GLY) used as primary plasticizer. The average size of SCL particles significantly increased with the increase of SPD concentration, mainly in the presence of GLY, while the negative zeta potential values parallely decreased suggesting a greater stability of the FFSs containing SPD concentrations lower than 1.0 mM. In addition, the decreased contact angle value, compared to water and ethanol solution, indicated that SCL FFSs were highly hydrophobic and that it might be spreaded easily on hydrophobic biological surfaces. SPD could replace GLY in obtaining handleable, homogeneous and performing SCL-based films. The film tensile strength and the Young's module strongly increased in the absence of GLY, reaching values higher than 5 times with respect to controls, whereas elongation at break value of GLY-plasticized films containing 5.0 mM SPD was twice of that of the films prepared without SPD. Conversely, the film moisture content, water solubility and swelling ratio progressively decreased, both in the presence and absence of GLY, up to a SPD concentration of 1.0 mM, whereas the film contact angle increased, confirming the enhancement of its hydrophobicity determined by SPD incorporation. SPD also increased the film barrier properties to gases and water vapor, while the presence of GLY hindered these effects. Finally, SEM analysis of the cross-sections of the SPD containing films showed heterogeneous microstructures, whereas their surfaces appeared rougher than those of the control films. Preliminary experiments carried out by Rosa chinensis Jacq. leaf coating suggest the potential use of SCL-based FFSs spraying in plant disease control. High spreading of the SCL-based FFSs on the entire leaf surfaces, both in the presence and absence of Bordeaux mixture tested as agrochemical, was observed, and the SEM images showed the formation of an evident coating of the leaves. Therefore, these findings suggest the possibility to coat the leaf surface also in vivo with different SCL-based FFSs, giving rise to films possessing tailored functional properties and able to carry and release different agrochemicals.

Biomechanical Properties of the Porcine Trachea before and after Decellularization for Airway Transplantation

<h3>Purpose</h3> Tracheal replacement based on a tissue engineered tracheal scaffold is an alternative for extensive benign or malignant tracheal disease. The mechanics of the scaffold depends on the decellularization protocol used. This study focuses on the mechanical properties of tracheal scaffolds obtained from the decellularization protocol used in our laboratory. <h3>Methods</h3> The protocol was approved by the Animal Ethics Committee (CEUA-FMUSP). Fresh tracheas (24) were obtained from adult Landrace pigs (100kg). Twelve were decellularized and 12 were tested <i>in natura</i>. Decellularization protocol included 10 cycles of detergent (DS 2%) followed by 3 washings with PBS for 10 min and agitation for 48h in an incubator (36°C). Decellularization of the scaffold was assessed by measuring residual DNA contents. The scaffolds were then submitted to freeze-drying, immersion in DNAse and Proteinase K for 12h each. The DNA extraction was done with the phenol-chloroform technique and quantified by absorbance in a spectrophotometer. Tracheal mechanical properties were assessed using a tensile test system (INSTROM Model 3365, Norwood, MA) in two axes according to the norm of the American Society for Testing and Material (ASTM D638-14). Data is represented as mean± STD. Comparison between data used Student t test and Mann-Whitney. Significance was assumed for p<0.05. <h3>Results</h3> There was no difference in the Young's (elastic) module in both axes between decellularized scaffolds and tracheas <i>in natura</i>. The maximum load increased in the longitudinal axis and decreased in the transverse axis of the decellularized scaffolds reflecting the changes in the extracellular matrix in the cartilage (transverse) and connective tissue (longitudinal) (table). <h3>Conclusion</h3> The mechanical properties of the scaffolds obtained after the decellularization protocol suggest that despite the changes in the extracellular matrix the decellularized scaffolds will be able to retain its physiological properties.

Functionalized carbon nanotube doped gel electrolytes with enhanced mechanical and electrical properties for battery applications

We report the functionalized carbon nanotubes (fCNTs) and graphene oxide (GO) doped polyvinyl alcohol (PVA) based gel electrolytes (GEs). The multiwalled carbon nanotubes (CNTs) were treated via microwave irradiation to alter the degree of carboxylation. The fCNT doped gel electrolyte (fCNTGE) showed significantly improved ionic conductivity, mechanical strength as well as electrochemical stability when compared to the pure GE and graphene oxide doped gel electrolyte (GOGE). The homogeneous distribution of ionic channels provided by fCNTs served as redox shuttle and facilitated the ion migration in the gel. The fCNTGE exhibited the best performance when the oxygen content was 12.8% by weight. The ionic conductivity was significantly improved by introducing fCNTs into the PVA gel and reached 6.9 × 10−2 S cm−1, revealing that the diffusion and transport of ions into electrolyte were much better than the GE and GOGE. A significant enhancement in the gel mechanical properties was observed as the Young's module (E = 2.3) and tensile strength (22.3 kPa) of fCNTGE was higher than that of GE and GOGE. Furthermore, the composite Zn–Ag2O batteries were made and tested using the fCNTGE, GE, and GOGE in the 3D-printed battery casings. The fCNTGE based batteries demonstrated good electrochemical stability with specific capacity reaching 204.3 mAh g−1 (C/20).

Three-point bending of beams with consideration of the shear effect

The subject of the paper pertains to simply supported beams with bisymmetrical cross sections under three-point bending with consideration of the shear effect. The deformation of a planar cross section of the beam is described taking into account the assumed nonlinear hypothesis-theory. Two differential equations of equilibrium are obtained based on the principle of stationary potential energy. This system is analytically solved and the shear coefficients and deflections of the beams are derived. Moreover, the Young's modules of the materials and deflections of the beams are experimentally determined on a test stand. The results of the studies are specified in tables and compared.

Static and Dynamic Stability Analysis of an Asymmetric Rotating Tapered Sandwich Beam Subjected to Pulsating Axial Load with Thermal Gradient

The static and dynamic stability of an asymmetric rotating tapered sandwich beam subjected to pulsating axial load in temperature environment is studied under two different boundary conditions. The non-dimensional equations of motion and the boundary conditions are derived by applying Hamilton's energy principle. A coupled Hill's equations with complex coefficients are derived from the non-dimensional equations of motion by the application of the generalized Galerkin method. By the application of the Saito-Otomi conditions, zones of instabilities are obtained and presented graphically. For the calculation of the Young's module for the elastic layers, the effect of temperature has been taken in to consideration by means of a uniform thermal gradient along the longitudinal axes for both the upper and lower elastic layers. The effects of the taper parameter, core loss factor, thermal gradient, rotational speed, hub radius, and core density parameter on the static buckling loads and the regions of instability are investigated.

Fracture systems and petrophysical properties of tight sandstone undergoing regional folding: A case study of the Cretaceous reservoirs in the Kuqa foreland thrust belt, Tarim Basin

Abstract The Kuqa foreland thrust belt of the Tarim Basin hosts a prolific hydrocarbon system. The main reservoirs are characterized by tight sandstone with low-porosity and ultra-low permeability, buried presently at more than 5000 m depth. Natural fracture systems have a significant impact on reservoir performance, and it may form paths for fluid flow in tight sandstone reservoirs, and therefore plays an essential role in controlling high production rates. With the aim of analyzing the distribution of favorable reservoir, we studied subsurface fracture patterns and petrophysical properties of the Bashijiqike Formation with data collected from Dabei structure and Keshen structure. We document the presence of four fracture systems whose distribution is related to far-field stress, thrusting and folding. In the Keshen anticlines, higher fracture intensities are observed in the limbs, with principal east-west (hinge-parallel fracture system) direction. The hinge-parallel fracture system includes a moderate-dipping fracture set and a vertical fracture set. Crosscutting relationships stress field inversion and fracture surface textures suggest that the moderate-dipping fracture set consists of shear fractures and can be explained by intra-layer shear caused by thrusting. The vertical fracture set may be formed due to the local outer arc extension during folding. The oblique fracture system shows scattering in strike, and is supposed to be related to a shear event of locally left-lateral strike-slip. Whereas, in the Dabei anticlines, the major system is hinge-perpendicular fracture system (NW-SE), showing a trending of increasing fracture intensity from limbs to hinge. The hinge-perpendicular fractures system in the Dabei anticlines consist of shear fractures and tension fractures. Stress inversion result shows it corresponds to northwest-southeast orientation compression stage. Besides, we analyzed petrophysical properties include porosity, permeability, Young's module, Poisson ratio and compressive strength of the Bashijiqike Formation concerning their structural position within folds. It indicates that the highest porosity and permeability are associated with dissolution and fracturing. The compressive strength of different structural positions also restrict the variations of mechanical properties of rocks. The best reservoir quality is suggested in the hinge zone and areas close to thrust. The findings have given maybe helpful for providing favorable reservoir targets for prospecting in the compressional basin.

Comparison of Strain Elastography, Shear Wave Elastography, and Conventional Ultrasound in Diagnosing Thyroid Nodules.

Objective:The purpose of this study is to compare the diagnostic performances of strain elastography (SE), shear wave elastography (SWE), and traditional ultrasound (US) features in diagnosing thyroid nodules.Subjects and Methods:This study included 185 adult patients with thyroid nodules who underwent conventional gray-scale US, SE, and SWE. SE was scored using a four-pattern elastographic scoring (ES) system. SWE values were presented as mean SWE values and standard derivation using Young's modules. The optimal cutoff values of the mean SWE values for predicting malignancy were determined using receiver operating characteristic (ROC) curve analysis. We used logistic regression models to test elastography as a novel significant predictor for the diagnosis of malignant nodules. The diagnostic performance of elastography parameters was compared with a traditional trained model.Results:Malignant thyroid nodules were stiffer for SE (ES patterns 1 and 2/3 and 4) and mean SWE values (4/17; 51.0 ± 24.4 kPa) than for benign nodules (114/50; 33.1 ± 25.2 kPa) (P < 0.01). In ROC curve analyses, a mean SWE value of 32 kPa was the optimal cutoff point, with diagnostic performance measures of 81% sensitivity, 65% specificity, a 23% positive predictive value (PPV), and 96% negative predictive value (NPV). In multivariate logistic regression, the mean SWE value (≥32 kPa) was an independent predictor for malignancy (odds ratio: 16.8; 95% confidence interval [CI]: 3.6–78.3). However, after the addition of SE and SWE to traditional US features, the C-statistic was not significantly increased compared to the traditional model (0.88, 95% CI: 0.81–0.94 vs. 0.91, 0.85–0.97, P = 0.4).Conclusion:In this study, we confirmed SWE as an independent predictor for malignant thyroid nodules. However, in comparing the new extended elastography model to our previous prediction model, the new extended model showed no significant difference in the diagnostic performance.

The dynamic elastic and mineralogical Brittleness of Woodford shale of the Anadarko Basin: Ultrasonic P-wave and S-wave velocities, XRD-Mineralogy and predictive models

The recent advances in drilling and hydraulic fracturing technology rendered the Woodford shale of the Anadarko basin a prolific resource play producing gas and liquid hydrocarbons. Among the challenges facing improved economics, there is variable production from one well to another as well as from a completion stage to another due to the variability in facture gradient or brittleness index (BI) and the kerogen content. This investigation relies on laboratory ultrasonic P-wave and S-wave velocity in Woodford core samples to estimate BI based on the estimated elastic moduli. We modified a literature mineralogical brittleness index equation in order to take into account additional iron-rich minerals like pyrite, hematite, and iron oxides that are present in the Woodford shales, and also investigated the impact of total organic content (TOC) on the mineralogical brittleness index. Furthermore, a number of new reliable equations based on different elastic properties have been introduced in this study for the evaluation of the elastic BI, which is of significant importance in designing hydraulic fracturing in shale and tight reservoirs. In another panel of our study, the sensitivities of both mineralogical makeup of Woodford shale and elastic properties calculated –including density, acoustic impedance, Poisson's ratio, Young's modules, Lame's parameters– to the elastic brittleness index are examined. It was indicated that they have a positive effect on the prediction and can be employed in the respective predictive methods for the estimation of elastic BI. However, the analysis demonstrated that TOC has no considerable effect on mineral BI, at least in Woodford sample studied. A comparison between these newly developed predictive equations and the most commonly used methods for the prediction of elastic brittleness index available in the literature demonstrates that the new equations have a better performance in terms of both accuracy and simplicity. On comparing the BI prediction equation, with highest prediction quality “Method 1”, that was developed based on ultrasonic elastic moduli with a corresponding equation based on sonic well-logs elastic moduli, Method1 was proven applicable to estimating BI based sonic frequency elastic moduli.

Fracture behavior of high-entropy alloy coating by in-situ TEM tensile testing

The fracture behavior of high-profile high-entropy alloy coating was characterized by in-situ TEM tensile testing. The samples for in-situ TEM tensile testing were obtained by FIB technology. The results show that irrelevant to phase constitution, the Young's module, fracture strength and ultimate elongation are measured as ∼107 GPa, ∼2.70 GPa and ∼2.6%, respectively. Transcrystalline fracture and cleavage fracture with the cleavage plane of {112} are observed evidentially and the evolution of the dislocation motion in the material could be directly connected with the fracture behavior from the recorded movies obtained by a Gatan CCD camera. The engineering stress-strain curve is nearly linearity, however, a slight deviation away from linearity could be noted in the end of engineering stress-strain curve, which is attributed that the extra elastic deformation results in part of continued deformation.

Dielectric relaxation of fulleroid materials filled PA 6 composites and the study of its mechanical and tribological performance

The effect of fulleroid materials (fullerene С60 and fullerene soot which is used for fullerenes production) on the mechanical and tribological properties of polymer nanocomposites based on polyamide 6 (PA6) was investigated. Composites were synthesized by direct mixing in an extruder. The use of the nanoparticles was an effective way to decrease the friction coefficient of the polymer composites because the fillers had the same size as the segments of the surrounding polymer chains. The steady state coefficients of friction with addition of fulleroid fillers were lower than that of unfilled PA6. The lowest coefficient of friction was observed for PA6 filled with 1 wt % fullerene soot. Dielectric spectroscopy was used to investigate the influence of nanoparticles on the relaxation processes in the polymer matrix. It is found that the segmental relaxation processes becomes faster with the addition of fullerene С60. In contrast, the secondary processes of PA6/fullerene C60 nanocomposites were observed to slow down with the addition of fullerene C60. This means that the local “molecular stiffness” is increased, and a phenomenological link between the secondary relaxation times and the mechanical properties explains the increase in the Young's modules of the nanocomposites upon the addition of С60. These observations suggest that nanoparticles can have a qualitatively different effect on the matrix polymer dynamics at different length scales, and caution must be taken in comparing the changes in the dynamics associated with different relaxation processes.