Thin Layer Of Material Research Articles

The Use of Thin-Layer Insulation Material in Technical Installations in Building Reconstructions

This article is a part of a scientific work dealing with the research of thermal insulation properties of thin-layer insulation material made of hollow glass-ceramic microspheres in relation to technical equipment of buildings. Until now, there has been a lack of scientific studies describing the effectiveness of thermal insulation properties of thin-layer insulation materials on distribution systems or technical equipment. Thin-layer thermal insulation materials may have a great potential for use in building reconstructions and associated reconstruction of distribution systems, where there is often insufficient space for additional conventional thermal insulation and where energy savings of the whole system need to be addressed. For this reason, a series of laboratory measurements were made and in this particular case, the insulation material was applied in a 2 mm layer to the heat storage tank and the heat losses of two models of the heat storage tank (without insulation and with thin-layer insulation coating) were compared. In addition, for a more comprehensive view of the issue, the two models were compared in two situations that may occur in practice, which are the cases of free and forced convection.

Proximity-induced collective modes in an unconventional superconductor heterostructure

Unconventional superconductors have been long sought for their potential applications in quantum technologies and devices. A key challenge impeding this effort is the difficulty associated with probing and characterizing candidate materials and establishing their order parameter. Here we present a platform that allows one to spectroscopically probe unconventional superconductivity in thin-layer materials via the proximity effect. We show that inducing an $s$-wave gap in a sample with an intrinsic $d$-wave instability leads to the formation of bound states of quasiparticle pairs, which manifest as a collective mode in the $d$-wave channel. This finding provides a way to study the underlying pairing interactions vicariously through the collective mode spectrum of the system. Upon further cooling of the system we observe that this mode softens considerably and may even condense, signaling the onset of time-reversal symmetry-breaking superconductivity. Therefore, our proposal also allows for the creation and study of these elusive unconventional states.

Thermal design strategy for enhanced freshwater harvesting with interfacial evaporation

Solar driven interfacial evaporation is considered to be a low-carbon, environment-friendly technology for achieving efficient evaporation, but the solar still equipped with the interfacial evaporation structure is found to process low fresh water production rate and production efficiency. In this work, an optimization scheme for the interfacial evaporation structure of the solar still is proposed through the theoretical analysis of the heat and mass transfer process of the interfacial evaporation solar still. The theoretical results show that there are significant differences in the optimization design between the interfacial evaporation solar still and conventional solar stills. The fresh water production rate of interfacial evaporative solar still is less sensitive to the insulation performance of the solar still, while is greatly affected by the convective heat transfer process inside and outside the solar still. The solar still with interfacial evaporation structure can reduce the use of insulation materials to improve the illumination area and reduce the construction cost, without affecting the production efficiency of fresh water. Under the input energy intensity of 1 kW·m−2, when the convective heat transfer process inside the solar still is strengthened, the theoretical fresh water production rate of the interfacial evaporation solar still can be increased by 28 %, and the efficiency can reach 73 %. However, different from the optimization results of the traditional solar still, the enhancement of convective heat transfer process outside the glass cover will lead to the decline of the efficiency of the solar still. The experimental results show that in a monoclinic interfacial evaporation solar still with an evaporation surface area of 60 cm * 60 cm, a high system performance can be achieved by attaching a thin layer of insulation material to the inner wall and using a 2 W fan for forced convection of internal air. Under the outdoor environment with the maximum light intensity of 1 kW·m−2, the production efficiency of fresh water can be stabilized at 62.6 %. This work provides important guidelines for the design and optimization of solar still with interfacial evaporation structure.

Photoactive Cements: A Review.

This article presents a short overview of modified cements with photocatalytic activity. First, the types and three main methods of obtaining photoactive cements are presented. The most frequently used modification method is the incorporation of a photocatalyst into the total mass of the cement. The second group analyzed is cements obtained by applying a thin layer of photoactive materials, e.g., paints, enamels, or TiO2 suspensions, using various techniques. The third group is cement mortars with a thick layer of photoactive concrete on the top. In addition, methods for determining the photoactivity of cement composites, mechanical properties, and physicochemical parameters of such materials are briefly presented. Finally, examples of investments with the use of photoactive cements and development prospects are shown.

Axially symmetric continuum mechanical model for the oscillon

The oscillon is a highly localized dynamical phenomenon occurring in a thin horizontal layer of granular material, which rests on a rigid plate oscillating in the vertical direction. The geometry is axially symmetric and physically resembles a splash of liquid due to a falling drop, except that it continually perpetuates itself and does not generate a spreading wave, as is the case for a liquid splash. The oscillon moves from “peak” to “crater” and “crater” to “peak” such that the time from “peak” to “peak” or “crater” to “crater” is twice the period of the oscillating plate. The physics of granular phenomena is not properly understood, and there is no continuum mechanical theory of granular materials which is widely accepted as accurately describing their behaviour. Here for a free-flowing (cohesion-less) granular material, under axially symmetric conditions, we present a partial continuum mechanical analysis assuming the Coulomb–Mohr yield function and non-dilatant double-shearing theory. We examine small perturbations superimposed upon a purely vertical vibration, and make the assumption that throughout the motion, the lower surface of the layer remains in contact with the rigid metal plate. We show how the temporal dependence, which decouples from the spatial structure, is governed by Mathieu’s equation for the physically relevant case of the rigid plate oscillating sinusoidally, and therefore stability is determined by certain key parameters. We explore a variety of possible forms for spatial dependence. The present axially symmetric analysis complements that presented by the authors for plane strain conditions, and we find, quite remarkably, that apart from constants, both flows are governed by similar fourth-order systems of ordinary differential equations. This means that for both plane strain and axially symmetry, analogous pattern forming conditions can operate.

Tuning and switching effects of quasi-BIC states combining phase change materials with all-dielectric metasurfaces

Emission enhancement of quantum emitters is particularly relevant in the development of single-photon sources, which are key elements in quantum information and quantum communications. All-dielectric metasurfaces offer a route towards strong enhancement of local density of optical states via engineering of high quality factor optical modes. In particular, the recently proposed concept of quasi-bound states in the continuum (quasi-BIC) allows for precise control of such resonances in lattices with an asymmetric unit cell. Still, the spectral band of emission enhancement is usually fixed by the geometric parameters of the metasurface. Here, we propose to utilize phase change materials to tune the properties of light-emitting metasurfaces designed to support quasi-BIC states in the telecom wavelength range. In our design, a thin layer of a phase change material, which provides strong contrast of refractive index when switched from the amorphous to the crystalline state, is located on top of the resonators made of amorphous silicon (a-Si). Depending on the selected phase change material, we numerically demonstrate different functionalities of the metasurface, In particular, for low-loss Sb2Se3 we evidence spectral tuning effects, whereas for Ge2Sb2Te5, we report an “on”/“off” switching effect of the quasi-BIC resonance. Furthermore, we investigate the influence of the crystallization fraction and the asymmetry parameter of the metasurface on the results. This work provides concrete design blueprints for switchable metasurfaces, offering new opportunities for nanophotonics devices or integrated photonic circuits.

First principles calculations of charge shift photocurrent in vdWs slide double layered 2D h-BN and β-GeS homostructures

Shift photovoltaic current (SPC) in polar non-centrosymmetric materials has recently emerged as a promising candidate for the next generation photovoltaic devices in which Shockley-Queisser limits are fully overcome. Here, we apply first-principles calculations to predict colossal SPC in the slide bilayers of 2D h-BN and β-GeS vdW homostructures. The large SPC in slide bilayers h-BN and β-GeS reaches 49.3 μAV−2 and 130 μ μAV−2, respectively, in the ultra-violet (UV) region. Increasing the number of layers is further implemented to tune the band structure of the two homostructures. Consequently, giant SPC peaks about 3 times larger than those of the bilayers are predicted at photon energies of 7.40 eV and 5.95 eV in the 5-layers of h-BN and β-GeS, respectively. The two homostructures are thus promising building blocks for next-generation photovoltaic devices. These findings also suggest layering as a possible convenient approach to enhancing and also tuning the SPC output in thin layered materials.

Impact of Micro-Indentation on Hardness and Indentation Depth of Ni-Cr Super Alloys

ABSTRACT A material’s (metal, composite, polymer, etc.) behaviour is greatly influenced by the indentation hardness and elastic modulus during any operation (sliding, fretting, turning, etc.). To measure the micromechanical properties of surfaces, subsurfaces and coated thin layers of materials, depth-sensing measurement indentation techniques are most commonly used. The present study aims to develop a compressive model to investigate the influence of indentation parameters on the indentation hardness and indentation depth of Ni-Cr superalloy during indentation experiments. Experiments were conducted based on model L18 (21*32) full factorial design with a mixed orthogonal array using a microhardness tester. The experiments revealed that indentation hardness values show a normal indentation size effect with respect to indentation load. Indentation depth values increase with the increase in indentation load. Taguchi's approach and the regression analysis were used to model the indentation hardness and indentation depth with respect to indentation parameters. Analysis of variance was employed to check the effect of input parameters on performance outputs. The experimental and predicted values show a good degree of proximity. However, indentation load (79.22% and 52.34%) was found to be the most dominant parameter affecting indentation hardness and indentation depth, respectively, followed by dwell time.

Identification of a quasi-liquid phase at solid–liquid interface

An understanding of solid–liquid interfaces is of great importance for fundamental research as well as industrial applications. However, it has been very challenging to directly image solid–liquid interfaces with high resolution, thus their structure and properties are often unknown. Here, we report a quasi-liquid phase between metal (In, Sn) nanoparticle surfaces and an aqueous solution observed using liquid cell transmission electron microscopy. Our real-time high-resolution imaging reveals a thin layer of liquid-like materials at the interfaces with the frequent appearance of small In nanoclusters. Such a quasi-liquid phase serves as an intermediate for the mass transport from the metal nanoparticle to the liquid. Density functional theory-molecular dynamics simulations demonstrate that the positive charges of In ions greatly contribute to the stabilization of the quasi-liquid phase on the metal surface.

Electric field assisted dissolution of metal films on coated soda-lime glass

The process of glass poling and electric field assisted dissolution of metal films on coated glass substrates is investigated. The samples consist of soda lime glass substrates coated with thin dielectric layers of different materials (SiO2, Al2O3, TiO2) and an Ag film. The samples are subjected to the application of dc voltage at 200 °C. As a result, the metal film is dissolved and partially incorporated in the dielectric layer and glass substrate. It is shown that during the pre-heating process prior to the voltage application ions from the metal film and alkali ions from the glass substrate incorporate into the dielectric layer. The field-assisted dissolution, characterized by glass poling and drift of metal film ions into the dielectric layer and glass substrate, appears to strongly depend on the dielectric layer material and its ion incorporation during pre-heating. The process dynamics is corroborated by numerical simulations of ion drift and diffusion and compared to electrical current measurements. Overall, it turns out that the optical properties of the metal-doped dielectric layers can be varied in a complex manner by the described process, broadening the potential of glass poling and electric field assisted dissolution in photonics applications.

Simultaneous measurement of layer thicknesses in thin layered materials using the phase of ultrasonic reflection coefficient spectrum

The wide application of layered materials proposes more requests for their mechanical performance. The measurement of layer thicknesses is an important part of performance evaluation for the layered materials. Ultrasonic testing is an effective method for thickness measurement. However, in thin layered materials, the layer thicknesses are immeasurable due to the overlap of ultrasonic echoes from interlayer interfaces. This work presented an ultrasonic method for simultaneous measurement of layer thicknesses in thin layered materials using the phase of ultrasonic reflection coefficient spectrum (PRCS) at normal incidence, and the other method using the magnitude of ultrasonic reflection coefficient spectrum (MRCS) was also investigated for comparison. The inversion algorithm based on the particle swarm optimization (PSO) was used to avoid convergence to local minima. Both the sensitivities to the thickness parameters and effects of frequency bandwidth of the transducer were studied for PRCS and MRCS. The results indicate that PRCS is sensitive to the layer thicknesses and larger frequency bandwidth is favorable for convergence zones to be produced. Compared with MRCS, the narrower convergence zones can be obtained using PRCS. The experimental measurement results of the thin Al-Ti bi-layered material confirm that the measurement of layer thicknesses using PRCS is more accurate than MRCS. The relative errors of the Al layer and the Ti layer between the PSO estimated values and the real values are −3.77% and +1.91% using PRCS, respectively.

The performance of Perovskite solar cells with silicon carbide as an interfacial layer

The current work involved the numerical simulation of investigating the impact of conduction band offset (CBO) on the perovskite solar cell parameters. The solar cell structure under investigation comprises the (Spiro OMe TAD), (CH3NH3PbI3), and (SnO2) as HTL, the absorber layer, and ETL with electron affinities (χ) of (-2.45, -3.9, and -3.75) eV respectively. The conduction band alignment was controlled by inserting an interfacial layer between the absorber and ETL. The inserting layer is a thin layer of 3C-SiC material. Before utilizing the interfacial layer, a parametric study was attained, which included the doping variation and thickness variation of each layer. According to the findings, the device performs best at a thickness of 200 nm, 400 nm, 300 nm for HTL, perovskite absorber layer, and ETL respectively, with a doping concentration of 1019 cm-3, 1014 cm-3, and 1019 cm-3 for the same layers. These parameters provide a Jsc, Voc, FF, and PCE of 26.1 mA.cm-2, 1.11 V, 83.23%, and 24.19% respectively. Utilizing 3C-SiC as an interfacial layer with thickness 100 nm and doping 1018 cm-3 improved the performance of the device. According to the electron affinity for the proposed structure (the absorber layer and ETL) with the interfacial layer produce spike-spike band alignment. The results showed that the spike-spike band structure with (1= 0.07) eV for absorber layer with 3C-SiC and (2=0.08) eV for 3C-SiC interfacial layer and SnO2 as ETL, produces a good improvement in the cell performance with an increase in PCE (from 24.19 % to 28.36 %).

Implant Surfaces Containing Bioglasses and Ciprofloxacin as Platforms for Bone Repair and Improved Resistance to Microbial Colonization.

Coatings are an attractive and challenging selection for improving the bioperformance of metallic devices. Composite materials based on bioglass/antibiotic/polymer are herein proposed as multifunctional thin films for hard tissue implants. We deposited a thin layer of the polymeric material by matrix-assisted pulsed laser evaporation—MAPLE onto Ti substrates. A second layer consisting of bioglass + antibiotic was applied by MAPLE onto the initial thin film. The antimicrobial activity of MAPLE-deposited thin films was evaluated on Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa standard strains. The biocompatibility of obtained thin films was assessed on mouse osteoblast-like cells. The results of our study revealed that the laser-deposited coatings are biocompatible and resistant to microbial colonization and biofilm formation. Accordingly, they can be considered viable candidates for biomedical devices and contact surfaces that would otherwise be amenable to contact transmission.

Reconfigurable fiber-to-waveguide coupling module enabled by phase-change material incorporated switchable directional couplers

In silicon photonics, grating-assisted fiber-to-waveguide couplers provide out-of-plane coupling to facilitate wafer-level testing; however, their limited bandwidth and efficiency restrict their use in broadband applications. Alternatively, end-fire couplers overcome these constraints but require a dicing process prior usage, which makes them unsuitable for wafer-level testing. To address this trade-off, a reconfigurable fiber-to-waveguide coupling module is proposed and designed to allow for both grating-assisted and end-fire coupling in the same photonic circuit. The proposed module deploys a switchable directional coupler incorporating a thin layer of phase-change material, whose state is initially amorphous to render the coupler activated and hence facilitate grating-assisted coupling for wafer-level testing. The state can be altered into crystalline through a low-temperature annealing process to deactivate the directional coupler, thus facilitating broadband chip-level coupling through end-fire couplers. All the components encompassing conjoined switchable directional couplers as well as the grating and end-fire couplers were individually designed through rigorous simulations. They were subsequently assembled to establish the proposed reconfigurable coupling module, which was simulated and analyzed to validate the selective coupling operation. The proposed module gives rise to a low excess loss below 1.2 dB and a high extinction ratio over 13 dB throughout the C-band, when operating either under grating-assisted or end-fire input. The proposed reconfigurable coupling module is anticipated to be a practical solution for flexibly expediting the inspection of integrated photonic circuits on a wafer scale.

Pengaruh variasi konsentrasi terhadap sifat listrik lapisan tipis CoFe2O4

A thin layer is a very thin layer of material (organic, inorganic metal or a mixture of organic metals) which has the properties of a conductor, a semiconductor, a superconductor or an insulator. CoFe2O4 nanoparticles are very popular materials to be developed in the field of electricity and magnetism because they have cubic magnetocrystalline properties and high coercivity properties, as well as medium saturation magnetization. Sol-gel is one of the techniques in the manufacture of thin films that involves chemical processes in the form of hydrolysis and condensation reactions. Sol-gel dip coating is a technique for making a thin layer that has several advantages, namely a simple method, easy, few precursors so that it saves production costs and does not damage the environment. XRD test results of a 0.20 M CoFe2O4 thin layer found a peak in the 2Ө 18.1152 region with a diffraction pattern (111). The highest UV-Vis absorbance peak at a wavelength of 285 nm was 2.5423 A and the lowest bandgap value was 2.79 eV. The resistance value is 6.46 and the resistivity value is 0.00016225 m.

Theoretical Study on Polycarbonate-Based One-Dimensional Ternary Photonic Structures from Far-Ultraviolet to Near-Infrared Regions of Electromagnetic Spectrum

In the present research work, we have theoretically analyzed the photonic band-gap properties of one-dimensional photonic structures composed of polycarbonate and non-glass materials. These photonic structures, PC1, PC2, PC3 and PC4, are composed of alternating layers of polycarbonate/Al2O3, polycarbonate/MgF2, polycarbonate/BaF2 and polycarbonate/TiO2 materials, respectively. The period of each photonic structure is made up of a thin non-glass material layer sandwiched between two identical polycarbonate layers. The transfer matrix method has been used to investigate the transmission properties of PC1 to PC4. The comparison between the transmission spectra of PC1 to PC4 shows that the polycarbonate and TiO2-based photonic structure (PC4) possess three PBGs of zero transmission located at far-ultraviolet, visible and near-infrared regions of the electromagnetic spectrum at normal and oblique incidence (θ0 = 55°), both corresponding to TE wave only. The index of refraction of all five materials used in this study was obtained by applying the Sellmeier-type dispersion relationship to ensure accuracy in the results. The purpose of selecting polycarbonate along with Al2O3, TiO2, MgF2 or BaF2 as constituent materials of these photonic structures is due to the heat resistance properties of polycarbonate and the unique optical properties of oxide and fluoride materials with wide transparency from the ultraviolet to the near-infrared regions of the electromagnetic spectrum. The proposed work can be used to design some influential wavelength-selective reflectors composed of 1D PCs behind the active region of the solar cells for improving the photovoltaic performance of solar panels. This study can further be utilized for the fabrication of advanced solar cell designs consisting of 1D photonic mirror-based luminescence and reflection concentrators. The low temperature problem which arises in satellites may also be overcome with the help of smart windows based on the proposed multilayer structures.

Effectiveness of grouted layer in the mitigation of subway-induced vibrations

As a practical countermeasure against generally destructive subway-induced vibrations, the injection of a continuous thin layer of soft materials into the soil under adjacent receivers is investigated in this paper for the first time. To this aim, simulations were carried out using a finite/infinite element model of a railway track, tunnel, and surrounding soil. A straightforward analytical approach was implemented to model the dynamic excitation of the moving train. In addition, the effect of a soft V-shaped grouted layer on vibration mitigation on the ground was evaluated via a parametric analysis that determined the impacts of soil type, grout specifications, and train speed. The obtained results clearly indicated that a softer isolator (i.e., the grouted layer) in combination with a stiffer soil provides the best configuration for attenuating the subway-induced vibrations. Furthermore, the injection angle and train speed were shown to have minimal impacts on the isolator performance. Other contributions of the present paper include developing a simple equation to estimate the grouted layer effectiveness and describing how the isolator works in layered soils.

CHARACTERISTICS OF EDIBLE FILM (LAYER BY LAYER) FROM CARRAGEENAN-CHITOSAN WITH THE ADDITION OF BELIMBING WULUH LEAF EXTRACT AS ANTIOXIDANT SUBSTANCE

Packaging use from synthetic materials can have a negative impact for environment. One of the steps to reduce this impact with edible film packaging uses. Film can be defined as a thin layer of material, that usually composed by a polymer that allows for mechanical strengthening of a structured stand. The quality that continues to be improved from the edible film is antioxidant activity, namely by adding antioxidant substances such as flavonoids and phenols from starfruit leaf extract. As well as improving its mechanical quality by adding shrimp shell chitosan and using the layer by layer method. The purpose of this research is to find out characteristics of edible film from carrageenan-chitosan layer by layer and find the best results from the addition of different concentrations of chitosan and Belimbing Wuluh leaf extract. The variation that will be carried out is the addition of Belimbing Wuluh leaf extract by 0.2%, 0.4% and 0.6% and chitosan by 1.5%, 2% and 2.5%. The results showed that the best formula of edible film was made from 2.5% chitosan concentration and 0.6% Belimbing Wuluh leaf extract. The results of test are the thickness test is 0.21 mm, the tensile strength is 2.87 MPa, the elongation at break is 13.6673%, the water vapor permeability is 2.1682 g/m2h and the antioxidant value in terms of fruit weight loss is 4.01%.

Heterostructured alloys with enhanced strength-ductility synergy through laser-cladding

Heterostructuring has recently become a popular option to provide an excellent combination of strength and ductility in alloys. However, its production is a challenging multi-step process. In this study, we propose a simple process to develop heterostructured alloys by laser-cladding a thin layer of an identical material on the surface of the wrought material. The heterostructured laser-clad wrought samples exhibited enhanced strength and ductility compared to monolithic laser-clad and wrought 316L stainless steels. The enhanced twinning activity localized in the coating region generated high mechanical incompatibility. The hetero-deformation-induced strengthening of the heterostructured laser-clad samples resulted in an enhanced strength-ductility synergy. This approach is straightforward and viable for laser-clad available materials. This study presents a new direction for the use of laser-cladding to produce a heterostructurally-designed alloy with superior strength-ductility synergy.

Comparison of axon extension: PTFE versus PLA formed by a 3D printer

Three-dimensional (3D) printers mainly create 3D objects by stacking thin layers of material. The effect of the tools created using the fused deposition modeling (FDM) 3D printer on nerve cells remains unclear. In this study, the effects of polytetrafluoroethylene (PTFE) models and two different types of polylactic acid (PLA) models (white or natural), were created using the FDM 3D printer on axon extension were compared using the Campenot chamber. Neurons were isolated from the dorsal root ganglia and added to the central compartment of the Campenot chambers after isolation, processing, and culturing. On day 7, after the initiation of the culture, the difference of the axon extensions to the side compartments of each group was confirmed. We also compared the pH and the amount of leakage when each of these chambers was used. The PLA was associated with a shorter axon extension than the PTFE (white p = 0.0078, natural p = 0.00391). No difference in the pH was observed (p = 0.347), but there was a significant difference on multiple group comparison (p = 0.0231) in the amount of leakage of the medium. PTFE was found to be a more suitable material for culturing attachments.