Effect Of Layer Number Research Articles

An analysis on the effect of layer number on the stability of thin DNA origami nanopores

PurposeThe present study aims to design and simulate various types of deoxyribonucleic acid (DNA) origami-based nanopores and explore their stability under different temperatures and constraints. To create DNA origami nanopores, both one-layer and two-layer structures can be utilized.Design/methodology/approachOne of the key applications of DNA origami structures involves the creation of nanopores, which have garnered significant interest for their diverse applications across multiple scientific disciplines. DNA origami nanopores can be studied individually and in combination with other structures. The structural stability of these nanopores across various temperature conditions is crucial for enabling the passage of diverse payloads.FindingsComparing these DNA origami structures can provide valuable insights into the performance of these nanopores under different conditions. The results indicate that two-layer nanopores exhibit better structural stability under various temperatures compared to one-layer nanopores. Additionally, small structural changes in two-layer nanopores enable them to maintain stability even at high temperatures.Originality/valueIn this paper, various DNA origami-based nanopores were designed and simulated, focusing specifically on one-layer and two-layer configurations. The two-layer nanopore consistently exhibited superior stability across both free and restrained scenarios, undergoing fewer structural changes compared to the one-layer nanopore. As temperatures increased, the two-layer nanopore remained less susceptible to deformation, maintaining closer to its original shape. Moreover, in the free scenario, the geometric shape of the two-layer nanopore demonstrated fewer variations than the one-layer nanopore.

Numerical and experimental behavior of fiber reinforced polymer type and layer number effect on the flexural properties of heat-treated black pine wood

Heat treatment is one of the environmentally friendly methods applied to improve the structural properties of wooden materials. While heat treatment improves some properties of wood material, it also negatively affects its mechanical properties depending on the heat treatment conditions applied. The decrease in mechanical properties due to heat treatment limits the use of wood material in various applications requiring mechanical strength. For this purpose, various fiber-reinforced polymers have been used in recent years. In this study, it was aimed to experimentally and numerically examine the flexural properties of unheat-treated and heat-treated black pine (Pinus nigra Arnold.) wood reinforced 1, 2 and 3 times with carbon, glass and aramid. Following the experimental flexural tests, the samples were modeled and analyzed in the finite element software program. The average flexural strength of the heat-treated sample is 11.72% lower, and the elasticity modulus is 1.23% lower than the unheat-treated sample.It has been determined that carbon-based polymer fabrics, among fiber-reinforced polymer fabrics, have the best reinforcement effect. The flexural strength of the UHT-C-3 sample is 6.1% and the elasticity modulus is 3.52% higher than the UHT-C-1 coded sample. Compared to the sample without reinforcement, flexural strength increased by 30% and elasticity modulus increased by 7%. It is seen that as the number of fiber reinforced polymer layers increases, the flexural properties also increase. When the experimental and numerical analysis results were examined, the flexural strength and modulus of elasticity values gave similar results at the R2: 0.88–0.99 level. In addition to technologies using kinds of reinforcement evaluated in conservation applications, it may be utilized for numerical analysis in the field of repairing or reinforcing different grades, patterns, and types of reinforcement in already-existing wooden structures.

Swelling characteristics of montmorillonite mineral particles in Gaomiaozi bentonite

Highly compacted bentonite is an ideal back-filling (buffer) material for the deep geological disposal of high-level radioactive waste. Montmorillonite is the main constituent mineral of it. The nanoscopic swelling characteristic of montmorillonite mineral particles greatly influences the macroscopic buffering performance of highly compacted bentonite blocks. Firstly, the montmorillonite suspension liquid was exfoliated by freeze-thaw cycles, the appropriate mineral particles were selected by atomic force microscope (AFM) for making colloidal probes. Then, the swelling pressure between mineral particles was measured by AFM, investigating the effects of interlayer distance, layer number, temperature, and interlayer cation type on the nanoscale swelling pressure. The experimental results showed that the swelling pressure of montmorillonite mineral particles peaks at about 0.7–0.8 nm interlayer distance. The swelling pressure of mineral particles with more layers is smaller. The higher the ambient temperature, the greater the swelling pressure. The swelling pressure of Ca-montmorillonite is significantly larger than that of Na-montmorillonite. The Laird model has a relatively good applicability with the interlayer distance of 0.6–1.2 nm; the DLVO theory has a good applicability with the interlayer distance greater than 1.5 nm. Finally, a predictive model was developed for the swelling pressure of nanoscopic mineral particles considering the effect of layer number. The research results provide data support and theoretical support for swelling pressure generation and cross-scale transmission mechanism of highly compacted bentonite hydration.

Effect of Layers Number on The Bending Properties of Chestnut Glulam Beams

In recent years, advances in adhesive and lamination technologies have offered significant opportunities in the production of high-quality and valuable products from low-quality and non-durable cheap wood raw materials. Lamination generally refers to a multilayer material production method. The main goal of this production process is to develop and improve many properties of the created composite product, such as durability and stability. Laminated timber, called glulam, is a layered composite material formed by preparing timber fibers parallel to each other and gluing them together with the help of glue. In this study, the bending properties of solid, 3-layer and 5-layer glulam beams produced from chestnut tree species were investigated experimentally and numerically. The modulus of elasticity (MOE) of 5-layer glulam beams is 13.39% higher than 3-layer beams and 48.31% higher than solid beams. The modulus of rupture (MOR) value of the 5-layer beam is 24.21% higher than the 3-layer beam and 65.28% higher than the solid beam. There is a maximum difference of 2% between the experimental and numerical analysis results. When the results are compared, it is seen that the results are close to each other.

The effect of graphene’s layer number on nanobubble distribution and evolution law

HOPG is commonly used to induce interface nanobubbles, but its layered feature influences nanobubble evolution characteristics that have not been reported yet. In this study, the difference in the distribution density of nanobubbles on the monolayer and multilayer morphology of HOPG surfaces was observed by atomic force under-liquid experiments. And a strong correlation was found between the growth evolution of nanobubbles and the number of layers during the 24 h in situ testing. A molecular dynamics study on the effect of layer number on the properties of nanobubbles was carried out, revealing the modulation of the local surface energy by changes in the number of layers on the HOPG surface. The mechanism of the influence of surface energy on the distribution and growth evolution of nanobubbles was established.

Study on unsteady evacuation characteristics of multi-layer insulation during launch/in orbit of the cryogenic propellant tanks

The MLI + foam is used for the thermal protection of the cryogenic propellant. However, the MLI generates unsteady evacuation when the cryogenic rocket is launched and traveled in space. The insulation performance of the MLI is determined by the evacuation level of the interstitial gas. Aiming at the unsteady evacuation of the MLI, the interlayer pressure node algorithm was developed. The transient evacuation characteristics of the interlayer pressure were predicted. The effect of layer number, slit rate, and layer density on evacuation was investigated. The evacuation and insulation performance of MLI were optimized. The results show that the innermost pressure of the 60 mm thickness (th60) MLI dropped to less than 0.5 Pa when the evacuation was conducted for more than 25 h. The pressure of the innermost layer and 10th layer is greater than 1 order of magnitude higher than that of the outermost layer. The evacuation rate of th20 is faster than that of th40 and th60. The innermost layer pressure value of the th20 is 0.168 Pa, which is 10.47 times higher than that of the outermost layer. The innermost layer pressure of the th20 is 48.3 % and 64.8 % lower than that of th40 and th60, respectively. The gas conduction decreased by 61.22 % when the opening pattern was optimized. These results can provide an important reference for the thermal protection design of cryogenic propellants.

Influence of layer number and sintering temperature on microstructural, tribological, and corrosion behavior of Al2O3–TiO2 multilayer coatings

The effects of layer number (2, 4, and 6-layer) and sintering temperature (800, 900, 1000, and 1100 °C) on the microstructure, wear, and corrosion properties of Al2O3–TiO2 multilayer coatings deposited on 316L stainless steel plates using the sol-gel dip coating technique were investigated. The wear characteristics were measured through ball-on-disc type dry sliding tests using an Al2O3 ball under a 1 N load, whereas the corrosion features were determined by potentiodynamic polarization tests conducted in a 3.5 wt% NaCl solution. Anatase, rutile, α-Al2O3, and γ-Al2O3 phases were obtained in the hybrid coatings, depending on the sintering temperatures. However, at 1100 °C, the coating did not adhere well to the substrate due to passive oxide film formation on the 316L plate, leading to spalling. Besides, the surface homogeneity deteriorated in the 6-layer coated sample due to higher organic removal and residual stresses. The corrosion rate decreased with the increasing number of layers, but the sensitivity to corrosion varied due to changes in surface properties. The 4-layer coated sample sintered at 1000 °C achieved the highest wear strength (improved by up to 71.1%) and corrosion resistance (increased by up to 90.4%) due to its decreased porosity and homogeneously distributed finer particles.

Preparation and sound absorption properties of multi-layer composites formed by waste polyphenylene sulfide filters

Composite materials with multi-layer structure were prepared by combining polyurethane film and waste polyphenylene sulfide filters by hot melting, which could be used as sound-absorbing materials to contribute to the noise control and reutilization of industrial waste. The structure, mechanical property, pore size distribution and stability of waste polyphenylene sulfide filters were investigated and could directly affect the quality of recycled products. The effects of layer numbers, layering sequence and polyurethane film thickness on sound absorption and insulation properties were also analyzed using an impedance tube absorption test system. The results showed that multi-layer materials had a better sound absorption effect than single-layer polyphenylene sulfide filters at low frequency. The sound absorption coefficients of the single-layer sample was only 0.081 at 1000 Hz, while the sound absorption coefficients of the five-layer sample could reach 0.26. The sound absorption properties of multi-layer materials were slightly affected by layering sequence, but polyurethane film thickness had a significant effect on sound absorption properties. The α of the SUS1 and USU1 samples were 0.151 and 0.170, while the α of the SUS3 and USU3 samples were only 0.076 and 0.056, respectively. Meanwhile, the sound insulation properties of multi-layer materials could be significantly influenced by the polyurethane film position. The sound transmission loss of the SUSUSU3 sample was just 32.83 dB, whereas that of the USUSU3 sample could reach 47.94 dB. Moreover, when polyurethane film was located on the sound facing side of multi-layer materials, the increase in polyurethane film thickness could cause the average sound reduction index of the USUSU sample to increase from 28.76 dB to 47.94 dB.

Strong and tough laminated ceramics prepared from ceramic foams

Here, we present a novel strategy to prepare laminated ceramics by combining the ceramic foams and hot-pressing sintering. Al2O3 and ZrO2 ceramic foams prepared by the particle-stabilized foaming method was cut into thin slices and then directly laminated and hot-pressing sintered. Al2O3/ZrO2 laminated ceramics with various structures were prepared. Compared with the slices prepared by conventional process, ceramic foams can easily regulate the thickness of laminate to resemble the nacre-like structure. In addition, the grain in the ceramic foams have lower activity and shrinkage rate, thereby weakening the residual tensile internal stress caused by grain coarsening and differences in coefficient of thermal expansion. The effects of layer number and thickness ratio on residual stress and the structure-activity relationship between mechanical properties and microstructure were investigated. The fracture toughness, flexural strength, and work of fracture of the optimal Al2O3/ZrO2 laminated ceramics are 8.2 ± 1.3 MPa·m1/2, 356 ± 59 MPa, and 216 J·m−2, respectively.

Effects of layer number and initial pressure on continuum-based buckling analysis of multi-walled carbon nanotubes accounting for van der Waals interaction

Effects of layer number and initial pressure on continuum-based buckling analysis of multi-walled carbon nanotubes accounting for van der Waals interaction

Energy dissipation of mechanical metamaterials composed of multilayer buckling elements

The effect of layer number, buckling sequence and drive velocity on energy dissipation per buckling event of mechanical metamaterials composed of representative volume element (RVE) is studied. Buckling behaviors of a single RVE encompassing buckling beams are investigated based on an approximate model. The metamaterials are modeled as a tandem model composed of identical RVEs. The buckling behavior can not induce energy dissipation if for the proposed structure. As or drive velocity increases, energy can be dissipated during elastic buckling. Besides, the dissipated energy per buckling event gradually decreases during one complete loading and unloading process.

Investigation into Layer Number Effect on Breakdown Strength of Multi-Layer Polymer Films.

The layer number effect on electric breakdown strength (EBD) of multi-layer polymer films is investigated using 10-μm polypropylene (PP) films under a dc condition. The layer number, n, of the films during the test is as large as 120. It is observed that the relation between EBD and n conforms to a minus power law, i.e., EBD(n) = E1′n−a, where the power exponent, a, is 0.27, E1′ is a constant. By reviewing the experimental data in references, it is found that the power law holds true for different types of polymers in different test conditions, but the value of a varies from 0.072 to 0.5. The variation of a is explained in perspective of the discontinuous structures within films and those between films. A small value of a means a good purity level of the film, which is due to the decrease of the size of the inter-layer defects. A large value of a means a poor purity level of the films, which is due to the increase of the amount of intra-layer defects. Both factors influence the value of a, leading to the variation of a.

Wear Resistance of Fe-Based Amorphous Powder Deposited Coatings in Air, Water, and SBF Solution: Effect of Layer Number

Amorphous alloys have high strength and high hardness, showing their potential applications as tribological materials. In order to improve the wear resistance of 316L stainless steel (SS), Fe-based amorphous powder was deposited on 316L SS by laser cladding. Since the microstructure of the laser clad coating was sensitive to the dilution between coating and substrate, multilayer Fe-based metallic coatings were fabricated layer by layer. When the laser cladding layer number increased, the microstructure evolved from a complete crystalline phase to a mixed structure with amorphous phase and dendrite. Meanwhile, the amorphous content increased and the average microhardness was enhanced. Accordingly, the wear resistance was improved generally under all the sliding conditions, including in air, distilled water, and simulated body fluid (SBF) solution. For the lubricant effect of liquid, the coefficients of friction in distilled water and SBF solution are relatively lower than that in air. Compared with 316L SS, the volume loss rate of nine-layer coating decreased by two orders of magnitude in air and about 5.5 times in SBF solution. Except for one-layer coating, the predominant wear mechanism of the laser clad coatings in air is abrasive wear accompanied by oxidative wear. The wear mechanism in SBF solution is dominated by abrasive wear and corrosive wear. The superior hardness and good corrosion resistance are responsible for the outstanding wear resistance improvement. Therefore, the laser clad coating with Fe-based amorphous alloy has a potential application in the surface strengthening of mechanical parts or metallic implants.

The effect of layer number on the gas permeation through nanopores within few-layer graphene

Few-layer graphene has been widely regarded as an efficient filter for gas separation, but the effect of the layer number on the gas permeation process is still unclear. To explore the layer number effect, we perform molecular dynamics simulations to investigate the gas permeation through a nanopore within the few-layer graphene. Our numerical simulations show that the permeation constant decreases with increasing layer number, which is analyzed based on the macroscopic Kennard empirical model. The macroscopic model is in good agreement with the numerical result in the limit of large layer number, but there are obvious deviations for the medium layer number. We generalize the macroscopic model by considering the nanoscale effect from the surface morphology of the nanoscale pore, which can well describe the layer number dependence for the gas permeation constant in the full range. These results provide valuable information for the application of few-layer graphene in the gas permeation field.

Effect of layer number on bending behavior of 3D spacer composite plates produced with different methods

Effect of layer number on bending behavior of 3D spacer composite plates produced with different methods

Fabrication and properties of symmetrical W/Si3N4/W functionally graded materials by spark plasma sintering

Si3N4 ceramics have shown promising application prospects as the sealing materials for liquid metal batteries (LMBs). However, the joining of Si3N4 to the metal shell of LMBs is rather difficult because of the non-wetting property and mismatch of their thermal expansion coefficients (CTEs). Herein, to solve the above issue, W/Si3N4 functionally graded materials (FGMs) were designed and fabricated via the spark plasma sintering (SPS) process. The effects of layer numbers and layer components on the phase composition, structure, and thermal stress of the FGMs were systematically investigated using both experimental and simulation methods. W/Si3N4 FGMs, with optimal layer numbers, were then utilized for fabricating symmetrical W/Si3N4/W FGMs. The thermal stress of the products can be effectively reduced by adjusting the MgO content of the central Si3N4 layer. As a result, the optimal product displayed good interface bonding between two adjacent layers and also exhibited high flexural strength (943.9 MPa) and electrical resistivity (2.0 × 1012 Ω cm). This route for the fabrication of symmetrical W/Si3N4/W FGMs exhibits the advantage of high efficiency, and the products with excellent properties can be used as sealing materials for LMBs.

Residual stress analysis and measurement in multi-layer bellows

Because large plastic deformation occurs in hydroforming bellows there is a residual stress distributing in the metal after forming, which is complex and not easy to be measured. The existence of residual stress might have an effect on the corrosive property and bulking performance of bellows. A finite element model was established to simulate the forming residual stress of the nickel alloy multi-layer bellow. The distribution of residual stress was calculated out and validated by cosα X-ray diffraction measurement. Thus the forming mechanics and the effects of layer number and forming pressure on the residual stress in the hydroforming bellow were both discussed in detail based on the established model. It was shown that the calculated residual stress had the same trend with the experimental results. The axial and circumferential residual stresses at the outer surface of the peak were both compressive. There existed the maximal Von Mises stress at the inner surface of the peak of the bellow. At this position the radial and axial residual stresses were both tensile. When applying multi-layer bellows and less forming pressure a lower forming residual stress could be obtained because of the narrow plastic strain region during forming.

Graphene-based Saturable Absorber for Pulsed Fiber Laser Generation

Recently, graphene has been considered as great candidate to be applied as the saturable absorber (SA) with its brilliant optical characteristics such as ultrafast recovery time and ultra-wideband absorption due to its zero bandgap energy and linear dispersion of Dirac electrons. This paper focuses on reviewing the generation of short pulses from passive mode-locked fiber lasers that employ graphene-based saturable absorber (GBSA). Various parameters that make it excellent for generation ultra-short pulsed including modulation depth, nonlinearity, saturation intensity, self-amplitude modulation, its crystal lattice structure, band gap energy distribution are discuss in details. Furthermore, comparison between single layers and multilayer GBSA is made to explain the effect of layers number on the behaviour of SA in ring cavity fiber lasers.

High Breakdown Strength and Energy Density in Multilayer-Structured Ferroelectric Composite.

All-organic dielectric composites are drawing increased attention owing to their high operating voltage, low loss, and superior processability. However, polymers usually possess a relatively lower dielectric constant than most the other dielectrics, which seriously suppresses the improvement of their energy density. In this work, multilayer-structured composites with excellent dielectric and energy storage properties are prepared by the stacking method, and the effect of layer numbers on the performance of the composites is studied. High-κ polymers such as poly(vinylidenefluoride) (PVDF) and poly(vinylidenefluoride-ter-trifluoroethylene-ter-chlorotrifluoroethylene) (P(VDF-TrFE-CTFE)) are used to prepare the composites with different layers. It is found that the dielectric constant is up to 14.45 at 1 kHz, which is increased with the volume fraction of the P(VDF-TrFE-CTFE) layer and layer number of the composites. Due to the increased dielectric constant, an ultrahigh discharge energy density of 18.12 J/cm3 is achieved at the electric field of 620 kV/mm. This study exhibits an effective routine to prepare flexible high-performance dielectric materials.

Effect of Fire on Carrying Capacity of Concrete Columns Confinement with Multi-Layers of CFRP

FRP reinforced polymers are widely accepted for use in civil engineering applications to strengthen constructions and application of confinement on the concrete columns, thereby increasing their ductility and increasing their carrying capacity as these materials are characterized by high tensile strength, high strength-to-weight ratio and high corrosion resistance of FRP composites, etc. In addition, the exposure of reinforced concrete structures to fire is one of the most dangers challenges that lead to great destruction and failure the structural in addition to loss of life. With the development of computer simulation theories to study the behavior of elements and structures under the influence of different loads (static, dynamic, thermal, etc.), it is possible to study the behavior of concrete columns under the influence of axial vertical and non-axial structural loads, and compare the results with previous research, thus saving time, effort and cost instead Of laboratory testing. Strengthening concrete columns with fiber-reinforced polymers (FRP) has been studied extensively, but the majority of published studies have focused on circular columns. Most concrete columns in the field have square or rectangular cross sections and resist eccentric loading as well. The objective of this study is to investigate the performance of square reinforced concrete (RC) columns, wrapped with carbon FRP subjected to fire so, in this paper, an analytical study was conducted using the ANSYS Workbench program, which follows the finite element method, to determine the effect of layers number of CFRP on carrying capacity of concrete columns and to know the effect of external standard fire on confined concrete columns with CFRP. The numerical results were compared with experimental results as far as possible, and revealed the accuracy of the analytical models, when compared to the experimental studies. The results shown that with increase the layer number of CFRP, the carrying capacity of concrete columns will increase, no benefit with increase the number of CFRP more than 4 layers where polymers materials are sensitive to fire so that it needs to insulation. Keywords: confinement, CFRP, External fire, ANSYS Workbench. DOI: 10.7176/CER/12-12-01 Publication date: December 31 st 2020