Properties Of Different Layers Research Articles

Elastic behaviour of bamboo at nano- and microscale

This paper presents an anatomy-based numerical multiscale approach for modelling the mechanical behaviour of Moso bamboo, addressing limitations in previous research where the intricate microstructure was often simplified. The mechanical response of bamboo culms is predicted at the nano and microscale considering the orthotropic behaviour of cellulose microfibrils in different layers of tissues, deviating from conventional isotropic assumptions. Through nano and microscale finite element models, the impact of chemical composition and microfibril angle on elastic properties of different layers of the fibre and parenchyma cells are explored at two different levels of moisture content. At low moisture content, fibres within vascular bundles exhibit significantly higher longitudinal and transverse elastic moduli compared to parenchyma cells. When the moisture content is high, the properties of the fibre and parenchyma cells are less different. Anisotropic behaviour at the nanoscale contributes to a more accurate prediction of the mechanical properties of bamboo culms at the microscale, particularly in the transverse direction in moist conditions. This study lays the groundwork for forthcoming research in modelling the mechanical behaviour of bamboo culm at meso and macroscales.

Comprehensive analysis of spatial heterogeneity reveals the important role of the upper-layer fermented grains in the fermentation and flavor formation of Qingxiangxing baijiu

Different spatial positions lead to inconsistent fermentation effects and flavors, however, the spatial heterogeneity of Qingxiangxing (QXX) Baijiu remains unknown. We investigated the microbes, flavors, and physicochemical properties of different layers in fermented grains of QXX Baijiu using Illumina HiSeq sequencing, two-dimensional gas chromatography–mass spectrometry (GC × GC–MS) and ultra-high performance liquid chromatography-mass (UHPLC-MS). A total of 79 volatiles, 1596 metabolites, 50 bacterial genera, and 52 fungal genera were identified. The contents distribution followed the order: upper layer > bottom layer > middle layer. Organic acids and derivatives were the main differential metabolites across the three layers. Starch, pH, and reducing sugar levels increased from the upper to bottom layer. Saccharomyces and Lactobacillus were dominant microbes. Pediococcus, the biomarker of upper layer, showed positive correlations with formic acid, ethyl lactate, acetic acid, ethyl linoleate, and ethyl oleate. These findings deepen our understanding of the fermentation and flavor formation mechanisms of QXX Baijiu.

Improvement of wear and hot melt loss resistance of metal carbide layers on H13 steel

Abstract In this paper, H13 steel was pre-carburized. Then niobizing and vanadizing layers were prepared by pack cementation method. The high temperature friction and wear properties and hot melt loss properties of different layers and substrates were studied by microhardness tester, metallographic microscope, scanning electron microscope, energy dispersive spectrometer, high temperature friction and wear tester, optical profilometer and Raman spectrometer. The results show that the thickness of the vanadizing layer is 12.7 μm, and the microhardness of the niobizing layer and the vanadizing layer is close, which is about 5 times that of the matrix. The lowest wear rate at 500 °C of the vanadizing layer is 1.03 , which is about 1/6 of the matrix. The vanadizing layer and niobiumizing layer can effectively reduce the friction coefficient, greatly improve the surface hardness and wear resistance of H13 steel, and prolong its service life. The comprehensive performance of vanadizing layer is the best. The vanadizing and niobiumizing treatment can significantly improve hot melt loss resistance of H13 steel and it can be used to prolong the serving life of hot die casting mold for Al.

Investigation of the Relationship Between the Structural Properties and Air, Water Drop and Particle Permeability of Different Masks Available in the Market

This study was performed on the masks which started to have vital importance after the Covid-19 which were first seen in China at the end of 2019 and spread all over the world in a short time and became a global epidemic. By examining the structural and morphological properties (number of layers, fabric properties used in different layers, average fiber diameter, fiber distribution, average porosity diameter, etc.) of different masks procured from local producers, air permeability, water drop and particle permeability were investigated. Structural and morphological properties of different layers of masks were observed through SEM analysis. The air permeability analysis of the masks was performed at 100 pascals pressure, in an area of 5 cm2 in 4 repetitions using Textest-Fx 3300 Air Permeability Device. The water drop permeability analysis was carried out with 0.3 µM NaCl solution under standard atmospheric conditions in a non-pressurized environment. A crocmeter was used for particle permeability analysis. And it was tested whether the fine particulate dust passed to the back of the mask. It has been determined that the air permeability, water drop and particle permeability behavior of the masks with different structural and morphological properties are very different.

Transient simulations and theoretical modeling of near-junction heat conduction in GaN-on-diamond HEMT

Under high-power working conditions, accurate predictions of the maximum temperature and thermal resistance distribution in devices during transient states are essential for monitoring the health status of the devices. In this work, the heat conduction characteristics of GaN-on-diamond high electron mobility transistors (HEMTs) near the junction region under transient conditions with thermal impedance are systematically investigated with the aid of finite element simulations and thermal impedance analyses. The effects of pulse characteristics, thermal properties of different layers on the maximum temperature and thermal resistance of the device are discussed specifically. The results show that pulse characteristics have a significant effect on the maximum temperature of the device. The shorter the pulse switching time is, the higher the maximum temperature will be. Regarding the effects of the thickness of the GaN layer, the maximum temperature initially decreases and then increases, with the lowest maximum temperature observed at 1.7 μm. As the TBR increases uniformly from 10 to 40 m2K/GW, the temperature increases by approximately 4 % per 10 m2K/GW. The analyses on the thermal resistance show that the GaN layer occupies the largest proportion of thermal resistance, while the diamond substrate occupies the smallest. The optimal substrate thickness is obtained by analyzing the thermal penetration depth in the substrate for working conditions with various pulse widths. For diamond substrate, the optimal thickness at a pulse width of 5 μs is about 25 μm, and increases as the increase in pulse width. At the end, a modified Cauer RC model is proposed for predicting the transient maximum temperature based on heat spreading analysis. The difference between the maximum temperatures predicted by the model and the finite element simulations is within 8 %.

Noninvasive identification of directionally-dependent elastic properties of soft tissues using full-field optical data

This paper introduces an innovative approach for elastic property characterization of soft tissues, having directional-dependent material behavior, via their vibration response measurement and interpretation. The full-field time-dependent surface displacements as a result of externally excited soft tissues are collected through digital image correlation (DIC). A developed analytical model, capturing the low-amplitude vibration behavior of anisotropic layered human skin with the incorporation of the influence of subcutaneous elasticity and inertia, is employed to accurately predict its resonant frequencies and pertaining displacement field images. An efficient solution approach for the model is implemented into an inverse algorithm to rapidly characterize the anisotropic elastic properties based on importing the vibration characteristics. To show the merit of the approach, a 3-D finite element (FE) simulation model was used to generate full-field data, detected and matched with a set of specific vibration modes via modal assurance criterion (MAC). The validity of the model implemented into the inverse characterization algorithm is demonstrated through a comparison of predicted vibration frequencies and mode-shapes simulated via the 3-D FE model for different cases with anisotropic elastic properties in different layers of the skin. It is shown that modes are influenced differently when anisotropic properties are introduced to the model. Thus, the established inverse characterization algorithm is capable of rapidly predicting the elastic material properties of anisotropic soft sheets with adequate accuracy.

Modeling of a Hexagonal Microstrip Patch Antenna for Breast Cancer Detection

Abstract Breast cancer is a global problem, and it is inevitable to detect cancerous cells at early stages. In recent years, microwave imaging (MWI) technology has been widely applied in biomedical applications for its non-ionizing radiation. Therefore, in this paper, a low profile hexagonal microstrip patch antenna has been proposed for the technology to detect breast cancer. This antenna has wide operating bandwidth of 13.5 GHz (6.6 GHz ¬to 20.1 GHz), and the return loss is as low as -50.83 dB at 8 GHz. To evaluate the antenna performances, the proposed antenna has been simulated in two different simulation software like HFSS and CST MWS. The antenna has achieved a maximum gain of 8.82 dBi with a quasi-omnidirectional radiation pattern. A three-layered human body mimicking breast phantom with different dielectric properties has been designed with and without tumor mimicking tissue. The difference between the dielectric properties of the tumor and the dielectric properties of different layers of breast phantom in the presence of external radiation field can inform the existence of tumor inside the breast phantom. An array of eight elements of proposed antenna is distributed around the breast phantom to detect the tumor with a minimum radius of 2 mm. Because of the low profile and compact in size (7.9 mm×11.4 mm), the proposed antenna is suitable for multi-static MWI technology for breast cancer detection at early stage.

A Design and Optimization Method of Performing Layer Combinations in Separate-Layer CO2 Flooding to Improve Oil Recovery

Separate-layer CO2 flooding has increasingly been used to improve the overall development of multi-layer heterogeneous reservoirs. Due to their field technical limitations, layer combinations have to be carried out to reduce the number of layer-groups required for the separate injection of CO2. Currently there are few studies of the method of designing layer combinations. In field practice, the layer combinations are often made based on the permeability ratio of the layers to be developed, but it is not possible to accurately obtain the optimal scheme in many cases. Therefore, in this paper, a new design and optimization method based on the weighted standard deviation of permeability is proposed, which comprehensively considers the effects of multiple geological and fluid properties in different layers. The new method is applied to study the layer combination schemes in separate-layer CO2 flooding in H block, Daqingzijing Oilfield, Jilin, China. The prioritization of all of the schemes is obtained via the method, and a related numerical model is also established to perform verification and quantitative analysis. The results show that designing layer combinations using the new proposed method can achieve better development effect than using the conventional permeability ratio based method. It can achieve a more uniform interlayer CO2 displacement with an obvious improvement in the CO2 swept volume in low permeability layers and a higher overall oil recovery. According to the numerical simulation results, using the optimal layer combination scheme designed via the new proposed method, the ten-year swept volume of CO2 in the low permeability layer can be increased by 16.2%, and the ten-year overall oil recovery efficiency can be increased by 3.3%, with both measures showing a remarkable improvement. The work can provide a significant reference point for the field design of layer combinations in separate-layer CO2 flooding.

MULTILAYER DENTAL CERAMICS BLANKS BASED ON ZIRCONIUM DIOXIDE. Literature review.

An overview of multilayer dental ceramics based on zirconium dioxide is presented. Classifications of dental ceramics based on zirconium dioxide and types of multilayer billets made of zirconium dioxide are considered. Examples of companies producing multilayer zirconium dioxide are given, strength and aesthetic properties in different layers of multilayer blanks are described. It is indicated that the introduction of coloring additives does not affect the mechanical strength of multilayer zirconium dioxide. An increase in the content of yttrium oxide in the composition of multilayer zirconium dioxide leads to an increase in transparency, but at the same time the mechanical strength decreases. Multilayer ceramics of a higher degree of transparency have worse physical and mechanical properties than less transparent materials. Sandblasting reduces the mechanical strength of multilayer zirconium dioxide. If the layers of multilayer zirconium dioxide differ in color, but have the same structure, then the strength indicators of each layer of the multilayer billet are at the same level, however, if the layers of multilayer zirconium dioxide differ in structure, then their strength within one billet will be different. The advantages and disadvantages of multilayer dental ceramic blanks based on zirconium dioxide are given. Attention is paid to the prospects of using multilayer dental ceramics based on zirconium dioxide in Russia.

Utilization of deep learning and semantic analysis for opinion mining in information extraction: a review

In concern of the increasing availability and popularity of the opinion information sources at a different platform like individual blogs, online feedback, and social network are proliferating and gaining new opportunities and challenges that can be actively exploited using information technology to seek and comprehend people's opinions. In today's field people or entrepreneurs before taking any decision they must be considering the opinion of peoples or information networks. Most of them express the view or opinion through social media platform like Tweeter, Facebook, or blogs on the internet. Therefore, it is essential to analyze to automatically analyze the immense amount of social data available on the internet. Deep learning (DL) has appeared as an influential machine learning (ML) method that studies the properties of different layers or data and provides more advanced predictive results. The study of DL, along with success in many other practical fields, has been widely used in opinion and emotion analysis in recent years. This review explores new challenges in brainstorming and facilitates DL study and the use of semantic analysis. The analysis focuses mainly on methods that try to solve new challenges identified by empathy programs, compared to those already in place. It also conducts extensive research on its current uses in emotion analysis.

Development of a sustainable and antibacterial food packaging material based in a biopolymeric multilayer system composed by polylactic acid, chitosan, cellulose nanocrystals and ethyl lauroyl arginate

Biodegradable packaging materials with antimicrobial properties are main key for developing sustainable active packages able to protect different foodstuff. Thus, the aim of this research was developing a biopolymeric and antibacterial packaging material with a trilayer structure through the combination of extrusion, electrospinning and coating techniques. This trilayer system was composed by a support extruded layer of polylactic acid (PLA), an intermediate PLA electrospun layer loaded with ethyl lauroyl arginate (LAE) and cellulose nanocrystals (CNC), and a third inner chitosan coating. Morphological, wettability, antibacterial and disintegrability properties of this material were evaluated. The morphological surface analysis evidenced the heterogeneity of the chitosan coating over the electrospun PLA layer, and this effect affected negatively the evaluation of wettability of this trilayer material. Antibacterial assays evidenced a fast and strong bactericidal effect against Gram(+) and (−) bacteria that maintained this activity for 15 days. Finally, the biodegradable properties of different layers favored the disintegration of developed trilayer material at 21 days under composting conditions.

Comparative study of elastic properties of marl and limestone layers in the Eagle Ford formation

Eagle Ford Formation has significant heterogeneity due to the existence of marl and interbedded limestone layers. The objective of this paper is to study the elastic properties of different layers in the Eagle Ford Formation. To achieve the goal, the relationships between compressional and shear velocities in marl and limestone layers were investigated in two representative Eagle Ford wells. These empirical equations can be used to estimate the shear velocity in Eagle Ford wells without sufficient well log data. Moreover, correlations between elastic properties and GR were obtained. Among all layers in the Eagle Ford Formation, marl layers of the lower Eagle Ford have the lowest averaged values of compressional velocity, shear velocity and dynamic Young’s modulus, while the limestone layers of the upper Eagle Ford have the highest averaged values of these three elastic parameters. In addition, the effect of elastic properties of shale layers on the aspect ratio of unconfined and confined fractures were evaluated. The influence of Young’s modulus contrast of shale layers on the aspect ratio of confined fractures was remarkable.

Two-dimensional heterostructures formed by graphenelike ZnO and MgO monolayers for optoelectronic applications

Two-dimensional heterostructures are an emerging class of materials for novel applications because of extensive engineering potential by tailoring intriguing properties of different layers as well as the ones arising from their interface. A systematic investigation of mechanical, electronic, and optical properties of possible heterostructures formed by bilayer structures graphenelike ZnO and MgO monolayers is presented. Different functionality of each layer makes these heterostructures very appealing for device applications. ZnO layer is convenient for electron transport in these structures, while MgO layer improves electron collection. At the outset, all of the four possible stacking configurations across the heterostructure are mechanically stable. In addition, stability analysis using phonon dispersion reveals that the AB stacking formed by placing the Mg atom on top of the O atom of the ZnO layer is also dynamically stable at zero temperature. Henceforth, we have investigated the optical properties of these stable heterostructures by applying many-body perturbation theory within the framework of GW approximation and solving the Bethe-Salpeter equation. It is demonstrated that strong excitonic effects reduce the optical band gap to the visible light spectrum range. These results show that this new two-dimensional form of ZnO/MgO heterostructures open an avenue for novel optoelectronic device applications.

Analytical study on the upheaval thermal buckling of sandwich pipes

Sandwich pipe is one of the most promising subsea pipelines for oil and gas transportation in deep waters due to its high-strength performance and thermal insulation. The gradient of the temperature distribution through the cross-section of sandwich pipes may be significant due to good thermal insulation of the core layer, so it is necessary to consider the temperature distribution in the upheaval thermal buckling analysis. In this study, analytical solutions are derived for the temperature distribution through the cross-section of a sandwich pipe by using the heat conduction equation, and they agree well with the results in the literature. Taking the temperature distribution into account, a mathematical model is proposed to simulate the upheaval buckling of sandwich pipes based on the von-Kármán type of geometrical nonlinearity and the Euler-Bernoulli beam theory. The coupled transverse and axial deflections of sandwich pipes are considered. The buckled section and the slip section are connected by the continuous boundary conditions. The force and moment resultants in the inner pipe, the core layer and the outer pipe are solved separately. Different material properties of different layers can be considered in this mathematical model. Semi-analytical solutions are derived and verified. The typical buckling process is analysed, and the forces, moments and stresses in different layers of sandwich pipes are discussed. Finally, several simplified models for the temperature distributions are proposed. The results show that the temperature distributions in the inner and outer pipes can be assumed to be constant and equal to the temperatures of the internal and external fluids, respectively.

Boosting the Power Conversion efficiency of CsPb0.75Sn0.25IBr2 Alloy-based Perovskite Solar Cell with Charge Transport Layer Mg:SnO2: A Theoretical Study

The perovskite-based photovoltaic cells are the best way to convert photon radiation into electrical energy. The fundamental focus of this work is to stimulate and boost the power conversion efficiency (PCE) of an alloy-based CsPb0.75Sn0.25IBr2 perovskite solar cell. The simulation was run on SCAPS-1D cell simulator software (ver. 3.3.09). In this current work, a perovskite CsPb0.75Sn0.25IBr2 with the suitable composition of ions coupled with Tin-based electron transport layers (ETLs)-SnO2 and Mg:SnO2. The thickness and defect density of absorber layer-CsPb0.75Sn0.25IBr2 has been optimized. The impact of the thickness variation of ETL-SnO2 and Mg:SnO2 on device performances was also studied. The effect of working temperature, rate of charge carrier generation, and recombination on photovoltaic outputs like open-circuit voltage (Voc), short-circuit current (Jsc), fill factor (FF), and PCE has been studied and analyzed. The simulated cell achieved an efficiency of 13.82% under optimum conditions. The optimized efficiency was comparatively higher than the experimental efficiency of 11.85%. This study demonstrates the role of optimization of various properties of different layers of solar cells.

Boosting the Power Conversion efficiency of CsPb0.75Sn0.25IBr2 Alloy-based Perovskite Solar Cell with Charge Transport Layer Mg:SnO2: A Theoretical Study

The perovskite-based photovoltaic cells are the best way to convert photon radiation into electrical energy. The fundamental focus of this work is to stimulate and boost the power conversion efficiency (PCE) of an alloy-based CsPb0.75Sn0.25IBr2 perovskite solar cell. The simulation was run on SCAPS-1D cell simulator software (ver. 3.3.09). In this current work, a perovskite CsPb0.75Sn0.25IBr2 with the suitable composition of ions coupled with Tin-based electron transport layers (ETLs)-SnO2 and Mg:SnO2. The thickness and defect density of absorber layer-CsPb0.75Sn0.25IBr2 has been optimized. The impact of the thickness variation of ETL-SnO2 and Mg:SnO2 on device performances was also studied. The effect of working temperature, rate of charge carrier generation, and recombination on photovoltaic outputs like open-circuit voltage (Voc), short-circuit current (Jsc), fill factor (FF), and PCE has been studied and analyzed. The simulated cell achieved an efficiency of 13.82% under optimum conditions. The optimized efficiency was comparatively higher than the experimental efficiency of 11.85%. This study demonstrates the role of optimization of various properties of different layers of solar cells.

Tissue-mimicking phantom materials with tunable optical properties suitable for assessment of diffuse reflectance spectroscopy during electrosurgery.

Emerging intraoperative tumor margin assessment techniques require the development of more complex and reliable organ phantoms to assess the performance of the technique before its translation into the clinic. In this work, electrically conductive tissue-mimicking materials (TMMs) based on fat, water and agar/gelatin were produced with tunable optical properties. The composition of the phantoms allowed for the assessment of tumor margins using diffuse reflectance spectroscopy, as the fat/water ratio served as a discriminating factor between the healthy and malignant tissue. Moreover, the possibility of using polyvinyl alcohol (PVA) or transglutaminase in combination with fat, water and gelatin for developing TMMs was studied. The diffuse spectral response of the developed phantom materials had a good match with the spectral response of porcine muscle and adipose tissue, as well as in vitro human breast tissue. Using the developed recipe, anatomically relevant heterogeneous breast phantoms representing the optical properties of different layers of the human breast were fabricated using 3D-printed molds. These TMMs can be used for further development of phantoms applicable for simulating the realistic breast conserving surgery workflow in order to evaluate the intraoperative optical-based tumor margin assessment techniques during electrosurgery.

Impact of different layers within a blank on mechanical properties of multi-layered zirconia ceramics before and after thermal aging

ObjectivesTo compare the mechanical properties of different layers of multi-layered zirconia materials. Methods720 cylindric test plates were fabricated from four defined layers of three multi-layered zirconia ceramics (IPS e.max ZirCAD Prime, Optimill Multilayer 3D; Ceramill zolid fx multilayer) and divided into two equal groups. One group underwent thermal cycling (5–55 °C, 10 000 cycles; “TC”) and one did not (“no TC”), before density, flexural strength, Weibull modulus, and Vickers hardness were evaluated. EDX analysis was conducted using an additional cylinder of each material. Data were analyzed using Kruskal–Wallis and Mann–Whitney U tests. Statistical analysis was performed with Bonferroni correction (α < 0.001). ResultsAfter aging, ZirCAD layer 4 showed the overall highest density (6.04 ± 0.02 g/cm3), which was significantly higher than density of layer 4 of Optimill (6.02 ± 0.06 g/cm3) and Ceramill (5.80 ± 1.08 g/cm3) (both p < 0.001). Flexural strength of ZirCAD and Optimill increased consecutively after thermal aging. ZirCAD layer 4 had the overall highest flexural strength before and after artificial aging. After thermal cycling, the Weibull modulus ranged between 4.32 (ZirCAD layer 1) and 13.58 (Ceramill layer 4). ZirCAD had the overall highest Vickers hardness: in layer 1 (1579.18 ± 47.14 HV) before aging, and in layer 2 (1607.1 ± 149.71 HV) after aging. Flexural strength and Vickers hardness differed significantly between the four ZirCAD layers (p < 0.001). Thermal ageing had no significant impact on mechanical properties (p > 0.001). SignificanceMechanical properties were affected by plate position within the blank. When nesting a restoration within a multi-layered zirconia blank, the mechanical properties required should be considered.

Viscoelastic dynamic response of asphalt pavement with imperfect interface bonding base on transfer matrix

AbstractThe interface bonding condition between asphalt pavement layers is always imperfect because of the differing material properties of different layers and the limitation of construction techniques. Therefore, designing asphalt pavement by considering the interface to be completely continuous is not precise. The viscoelastic character of the asphalt layer contributes significantly to the performance of asphalt pavement. To explore the influence of the imperfect interface on the viscoelastic dynamic response of asphalt pavement, the Hankel–Laplace transformation was applied to convert the partial differential equations to ordinary differential equations and a transfer matrix was introduced to describe the behavior of the imperfect interface. Based on the boundary condition and integral inverse transformation technique, an analytical solution for the displacement, stress, and strain of the pavement can be obtained. By considering the variation in the interface condition and the viscoelastic characteristics of the asphalt layer, the dynamic response of the pavement was calculated based on a practical example. The results show that the interface condition between the asphalt layer and the base course has a marked influence on the viscoelastic dynamic response of the pavement and that enhancing the strength of this interface can reduce the deflection of the pavement. The series elastic component in the modified Burgers model is another significant factor that affects the calculation results of the pavement dynamic response.

Measuring the Damping Performance of Gradient-Structured Bamboo Using the Resonance Method

Bamboo has natural damping properties, but, due to the obvious gradient differences in bamboo walls, the damping properties of different layers may vary. Using bamboo slivers as the research object, this study investigated the underlying mechanism of the effect of microstructural and chemical components on the damping properties (η, damping ratio) of bamboo using the resonance and nonresonance methods. The damping ratio decreased on L3 (inner layer), L2 (middle layer), and L1 (outer layer) due to lower microfibril angles, increased crystallinity of cellulose, and decreased hemicellulose content. All of these limited the motion of the bamboo’s molecular chains. The damping ratio successively increased in the oven-dried, air-dried, and water saturated states because water acted as a plasticizer. The damping ratio of L1, in the oven-dried state, was slightly higher than that of the air-dried state because L1 had the lowest water content. This allowed less water to escape during drying, which intensified the molecular distortion. The initial tan δ (tangent of the loss angle) decreased successively on the L3, L2, and L1 layers of the bamboo, and the tan δ of L3 was lower than that of L2 due to changes in the temperature sensitivity of hemicellulose.