Thickness Of Compact Layer Research Articles

Hierarchical Porous Electrode Impedance Model Based on Diffusion Dynamics and the Electrode Morphology and Prediction of Electric Double-Layer Structures

The capacitance performance of a hierarchical porous carbon (HPC) electrode mainly depends on the dipole storage capacity and the rate of electric double-layer (EDL) reorganization. However, it is difficult to directly measure the effect of microscopic changes of pores and electrolytic characteristics on the internal ionic mechanism of the EDL. Therefore, a model is proposed to easily and accurately describe both the diffusion and EDL dynamics of the HPC electrode. In general, diffusion in the mesoporous channel can be characterized in the middle-frequency region (5–500 Hz) and in the micropore in the low-frequency region (0.05–5 Hz). What is more, we have proven that the diffusion layer thickness is inversely proportional to the electrolytic concentration and positively proportional to the mesoporous size, microporous depth, and surface roughness. In particular, the thicker diffusion layer makes it easier for ions diffusing into micropores and a better EDL recombination in mesoporous channels. However, the thinner diffusion layer means a better EDL recombination in micropores. The low-frequency region (0.01–0.05 Hz) characterized the compact layer dynamics, which shows the constant phase element behavior obviously. Moreover, the compact layer thickness is inversely proportional to the surface heterogeneity, thus determining the dipole storage capacity. The model offers a general framework for impedance analysis and EDL prediction of HPC.

Anguimorpha as a model group for studying the comparative heart morphology among Lepidosauria: Evolutionary window on the ventricular septation.

The group Anguimorpha represents one of the most unified squamate clades in terms of body plan, ecomorphology, ecophysiology and evolution. On the other hand, the anguimorphs vary between different habitats and ecological niches. Therefore, we focused on the group Anguimorpha to test a possible correlation between heart morphology and ecological niche with respect to phylogenetic position in Squamata with Sphenodon, Salvator, and Pogona as the outgroups. The chosen lepidosaurian species were investigated by microCT. Generally, all lepidosaurs had two well-developed atria with complete interatrial septum and one ventricle divided by ventricular septa to three different areas. The ventricles of all lepidosaurians had a compact layer and abundant trabeculae. The compact layer and trabeculae were developed in accordance with particular ecological niche of the species, the trabeculae in nocturnal animals with low metabolism, such as Sphenodon, Heloderma or Lanthanotus were more massive. On the other hand athletic animals, such as varanids or Salvator, had ventricle compartmentalization divided by three incomplete septa. A difference between varanids and Salvator was found in compact layer thickness: thicker in monitor lizards and possibly linked to their mammalian-like high blood pressure, and the level of ventricular septation. In summary: heart morphology varied among clades in connection with the ecological niche of particular species and it reflects the phylogenetic position in model clade Anguimorpha. In the absence of fossil evidence, this is the closest approach how to understand heart evolution and septation in clade with different cardiac compartmentalization levels.

Evaluation of the Flexural Rigidity of Underground Tanks Manufactured by Rotomolding

This study focuses on the flexural properties of the layered wall structures of plastic tanks produced by rotational molding technology. The aim was to assess the possibility of replacing the homogeneous walls of rotationally cast large-volume underground tanks with structural walls for stability and warpage prevention. The possibilities of material saving by combining lightweight and non-lightweight tank wall layers were investigated. By applying the engineering theory of bending inhomogeneous layered walls, the flexural rigidity values of the walls of the tanks of different structures were determined. The values of the flexural rigidity of the tank wall samples produced by rotomolding technology were determined experimentally. Moreover, a comparison of the calculated and experimentally determined flexural rigidity values of the layered walls and optimization of these structures was carried out. In the case under study, it was theoretically and experimentally confirmed that the optimum ratio of compact layer thickness versus total wall thickness is given by the resulting value: t1OPT = 0.189 h.

Modeling Subsurface Drainage in Compacted Cultivated Histosols

Reclaiming histosols in Montéregie region, Québec, Canada, increases peat decomposition and compaction rate and decreases the effectiveness of subsurface drainage. The objective of this paper was to use HYDRUS-2D to model the behavior of subsurface drainage systems, in order to evaluate the compaction effect on drain depth and spacing, and to determine the compact layer thickness and saturated hydraulic conductivities (Ksat) resulting in an improvement of subsurface drainage]. The drainage model was calibrated [Nash-Sutcliffe efficiency coefficient (NSE) = 0.958, percent bias (PBIAS) = −0.57%] using Ksat, meteorological data, and matric potential (h) data measured on the project site from June 10 to July 19, 2017. The calibrated and validated model was used to analyze the variation of h values (Δh in cm d−1) as a function of drain spacing (2–7 m) and drain depth (1 and 1.2 m) and to identify the response surface of Δh to various compact layer thickness and Ksat combinations. The results showed that Δh was on average 58% greater below the compact layer than above it and that reducing drain spacing or increasing drain depth does not improve the drainage rate. The analysis of the compact layer thickness and Ksat effect on Δh showed that for a Δh of 40 cm d−1, Ksat actual values in the two uppermost layers should be multiplied by 50 for compact layer thickness varying from 12 to 35 cm. Water percolation in the soil is reduced by the compact layer. Soil management methods for improving Ksat should therefore be better than deepening the drains or and reducing the spacing.

Enhancing the electron transfer process of TiO2-based DSSC using DC magnetron sputtered ZnO as an efficient alternative for blocking layer

Abstract Developing dye sensitized solar cell (DSSC) technology by exploiting different alternative semiconductors has attracted research attentions. Among all types of semiconductors, ZnO nanostructures due to their unique electrical properties and the facile preparation of various morphologies, have considered as the promising materials for application in DSSCs. In the present study, DC magnetron sputtering method was utilized to prepare a ZnO thin film as an efficient alternative for TiCl4 pre-treatment to suppress the charge recombination process occurring at a conventional TiO2-based DSSC. Different thicknesses of ZnO seed layers on fluorine tin oxide conductive glass substrates (FTO) were prepared via various sputtering deposition times. Field emission-scanning electron microscopy (FE-SEM) and x-ray diffraction (XRD) analyses were utilized to study the surface uniformity and crystallinity of the ZnO nanostructures. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques were employed to investigate the photoanode interface properties via determination of the electron lifetime and density of electron in conduction band. The results demonstrated that the thickness of ZnO compact layer which either acts as electron trapping states or blocking layer has the important role in cell performance. Finally, by the optimum thickness of ZnO thin film, the highest efficiency was achieved at 5.1%.

Die Soldering Behavior of H13 and Cr-Mo-V Tool Steel on Die Casting Process on Nitriding-Shot Pinning Die Surface Treatment

Die soldering is a sticking phenomenon between molten aluminum with the surface of steel die in the die casting process, which results in damage to the cast products and l the steel die. In this research, two die materials, H13 and Cr-Mo-V steels were used. Those dies were then treated by two process variables, shot pinning and nitriding-shot pinning. To simulate the die casting process, the samples were dipped into molten Aluminum-Si alloy, ADC12 at 680oC for 30, 300, and 1800 seconds. Characterizations were focused on the surface of the steel, which includes microstructure observation by a microscope, microhardness profile, compound identification, and weight loss measurements. It was found that H13 steel and Cr-Mo-V steel treated by nitriding–shot pinning have higher hardness up to 100% and thinner intermetallic layer. On H13 steel, the compact layer thickness decreased from 19 μm to 17 μm and from 96 μm to 80 μm for the broken layer. Similar trends occurred for Cr-Mo-V steel, where the thickness of the compact layer and broken layer decreased from 38 μm to 19 μm and 119 μm to 45 μm respectively. These results indicate that H13 and Cr-Mo-V steels that were treated by nitriding–shot pinning have a better resistance to die soldering.

Polypropylene/Chemical Blowing Agent Foams: Effect of the Injection Speed and Core Back Distance on Microstructure and Mechanical Properties

In recent years, many parts of the automotive industry, previously made of metal, has been passed to polymers due to their light weight, ie lower carbon emission and fuel consumption advantage. The aim of this work was to investigate the microstructure and mechanical properties of chemical foaming agent added polypropylene foam samples produced by injection molding. In particular, the effects of injection speed and core back distance on the evolution of cell diameter, compact outer layer thickness, cell density and mechanical properties were examined. In the first step the effect of various injection speeds (110; 125; 140 mm/s) was investigated. Then, various core back positions (0; 0.7 and 1.5 mm) were analyzed at a constant injection speed (110 mm/s). The results showed an increase of the cell diameter, the compact outer layer thickness and the elastic modulus as the injection speed increases. In addition, an important effect of the core back distance was observed with the presence of a critical core back distance. Below this critical value, the cell diameter and the elastic modulus drop due to a notable decrease of the skin layer thickness. Above this critical value, the cells started to collapse and lose their circularity.

Methods of the analytical construction of diagrams of the vibratory drum vertical movements into the soil for the compacted soil strength assessment

The soil compaction process by a vibratory drum is performed during a slow horizontal progressive movement and high-frequency vertical movements of the vibratory drum by a vibration exciter. Let’s consider the process of a single vertical movement of the vibratory drum into the soil on a horizontal compacted surface. As a result of the vibratory drum progressive movement vertical movements take place on new horizontal areas of compacted soil. The problem of the vibratory drum cylindrical surface vertical indentation into the soil is first presented in a differential form. The stress distribution law as per the soil depth is set taking into consideration the compacted soil layer thickness h 0 and general soil deformation modulus E 0. The relative vertical deformation of elementary soil columns according to Hooke’s law is determined as the ratio of the vertical movement of the vibratory drum elements to the thickness of the layer to be compacted. The analytical integration of equations connecting the vertical load on the vibratory drum with elementary forces of the soil reactions on the vibratory drum bearing surface has been performed. The state of soil strength under the vibratory drum is determined as the initial state σ0 and additional state Δσ, caused by an increase of the soil strength due to the compaction σ=σ0 + εE 0, caused by relative deformation. The problem of the determination of the vibratory drum vertical movement by vertical forces has been solved. Obtained analytical dependences and method allow to construct the dependence diagrams of the vibratory drum movement into the soil on different types of soils. The problem of the vibratory drum vertical movement into the soil has been analytically solved on the basis of the deformation of vertical soil columns in the form of Hooke’s law using the general soil deformation modulus E 0. The vertical interaction of the vibratory drum with the soil has been formulated as the equilibrium problem of the vertical reaction forces along the contact arc. Finite integrals have been obtained connecting the vertical load on the vibratory drum with the parameters of the soil and vibratory drum. The calculation method of the dependence diagrams of loads on the vibratory drum and vertical movements (settlement) of the vibratory drum into the soil has been developed.

Functional Blocking Layer of Twisted Tungsten Oxide Nanorod Grown by Electrochemical Anodization for Photoelectrochemical Water Splitting

Using electrochemical anodization of tungsten foil in a fluorinated-based electrolyte, the twisted WO3 nanorods (T-WO3 NRs) were grown, and the film properties were controlled by post-annealing conditions. The anodized WO3 material was composed of two distinct layers; the T-WO3 NRs which functions as an active layer for the PEC reaction and another compact WO3 (C-WO3) barrier which acts as a blocking layer for the charge transport. From more resistance of thicker C-WO3 layer, to minimize the formation of the C-WO3 layer under constant applied voltage, we performed rapid-thermal annealing under air ambient as a post-thermal treatment. As the post-annealing time increased, the thickness of T-WO3 NRs layer remained at approximately 680 nm, but the C-WO3 thickness gradually increased from about 91 nm at 1 min to 633 nm at 120 min. Unexpectedly, the anodic WO3 film having a compact layer thickness of about 475 nm exhibited the highest PEC performance, corresponding to a photocurrent density of 0.75 mA cm−2 at 1.23 V vs reversible hydrogen electrode, subsequently followed by anodic WO3 films with less thick compact layers. This suggests that the C-WO3 layer promotes the charge separation/transfer events by formation of cascading band alignments between the T-WO3 NR and C-WO3 layers.

Study on Laser-Induced Oxidation of Ti6Al4V Alloy Under Two Different Reactive Atmospheres

Abstract The oxidation behavior of Ti6Al4V titanium alloy under laser irradiation in atmospheric and oxygen-assisted conditions was studied. A nanosecond-pulsed Yb: glass fiber laser was used. The thickness of oxide layer, microstructure, and phase composition of the material after laser irradiation were investigated. The characterization of the surface and subsurface microstructure, as well as the cross-sectional morphology were performed using scanning electron microscopy (SEM). The phase identification was performed using X-ray diffraction (XRD). The combined effects of accumulated laser fluence and reactive atmosphere on the oxidation behavior of Ti6Al4V were also studied in detail. With an increase in accumulated laser fluence, a porous and easily removable oxide layer gradually formed on the surface, whereas a compact oxide layer was also formed. At high accumulated laser fluence, the thickness of the porous oxide layer increased dramatically, while the change of thickness of compact oxide layer was not obvious. The reactive atmosphere also had a significant influence on the microstructure of the surface and subsurface layers. SEM and XRD results revealed existence of strong oxidation reactions that underwent in the condition of assisted oxygen delivery at a fixed accumulated laser fluence. The oxide layer was composed mainly of anatase and rutile titanium oxides.

Water and salt exchange flux and mechanism in a dry saline soil amended with buried straw of varying thicknesses

Salt stress severely constrains crop productivity in arid lands of the world. Burying straw at the 40 cm soil depth plus plastic film mulching could mitigate root zone salinity, but little is known about how the thickness of buried straw affects soil water and salt transport. Therefore, a three-year field experiment was conducted from 2010 to 2013 to address this issue, with treatments including: compacted straw thickness of 3 cm (T3), 5 cm (T5), or 7 cm (T7) (corresponding to straw application at rates of 6, 12 and 18 t ha−1, respectively). In addition, a supplementary experiment, which included treatments of no buried straw layer (CK) and 5 cm of compacted straw layer thickness (t5) in the same micro-plot experiment, was carried out from 2014 to 2016 to identify soil pore structure and hydraulic parameters after three years of deep straw burial. Results showed that the initial soil water content increased with increasing thickness but significantly (P < 0.05) decreased in later periods. Soil salinity consistently decreased with increasing straw thickness, and T7 was most effective for improving salt leaching. However, the water and salt regulation under T5 gradually decreased mainly due to the change in saturated water conductivity and porosity among layers. After irrigation, the flux of salt leaching (FL) increased with straw thickness, and the FL under T7 significantly exceeded that under T3 by 105, 89 and 33% and that under T5 by 84, 66 and 33% in 2011, 2012 and 2013, respectively. The salt flux during evaporation under T7 was much higher (P < 0.05) than that under T3 and T5 by 92 and 10% in 2012 and 38, 44% in 2013. At harvest, salt storage within the soil consistently ranked as T3 > T5 > T7. Although T7 had the most pronounced effect on salt mitigation, it was difficult to implement under normal field conditions. Thus, for relatively good water infiltration, salt leaching and inhibition of salt return, straw buried to a thickness of 5 cm is recommended.

Oblique Electrostatic Inkjet-Deposited TiO2 Electron Transport Layers for Efficient Planar Perovskite Solar Cells

In this study, a new, simple, and novel oblique electrostatic inkjet (OEI) technique is developed to deposit a titanium oxide (TiO2) compact layer (CL) on fluorine-doped tin oxide (FTO) substrate without the need for a vacuum environment for the first time. The TiO2 is used as electron transport layers (ETL) in planar perovskite solar cells (PSCs). This bottom-up OEI technique enables the control of the surface morphology and thickness of the TiO2 CL by simply manipulating the coating time. The OEI-fabricated TiO2 is characterized tested and the results are compared with that of TiO2 CLs produced by spin-coating and spray pyrolysis. The OEI-deposited TiO2 CL exhibits satisfactory surface coverage and smooth morphology, conducive for the ETLs in PSCs. The power-conversion efficiencies of PSCs with OEI-deposited TiO2 CL as the ETL were as high as 13.19%. Therefore, the present study provides an important advance in the effort to develop simple, low-cost, and easily scaled-up techniques. OEI may be a new candidate for depositing TiO2 CL ETLs for highly efficient planar PSCs, thus potentially contributing to future mass production.

Interfacial Engineering for High-Efficiency Nanorod Array-Structured Perovskite Solar Cells.

TiO2 nanorod (NR) array for perovskite solar cells (PSCs) has attained great importance due to its superb power conversion efficiency (PCE) compared to that of the traditional mesoporous TiO2 film. A TiO2 compact layer for the growth of TiO2 NR array via spin-coating cannot meet the requirements for efficient NR-based PSCs. Herein, we have developed and demonstrated the insertion of a bifunctional extrathin TiO2 interlayer (5 nm) by atomic layer deposition (ALD) at the interface of the fluorine-doped tin oxide (FTO)/TiO2 compact layer to achieve alleviated electron exchange and a reduced energetic barrier. Thus, an accelerated extraction of electrons from TiO2 NR arrays via the compact layer and their transfer to the FTO substrate can improve the PSC efficiency. The thickness of the spin-coated TiO2 compact layer on the ALD-deposited TiO2 layer is spontaneously optimized. Finally, an outstanding efficiency of 20.28% has been achieved from a champion PSC with negligible hysteresis and high reliability. To the best of our knowledge, this is the first study demonstrating the superiority of TiO2-NR-based PSCs withstanding the dry heat and thermal cycling tests. The results are of great importance for the preparation of efficient and durable PSCs for real-world applications.

Thickness and Ratio of Noncompacted and Compacted Layers of the Left Ventricular Myocardium Evaluated in 56 Normal Fetuses by Two-Dimensional Echocardiography.

The thickness and ratio of noncompacted and compacted layers of the left ventricular (LV) myocardium in the normal fetus were investigated by fetal echocardiography. We aimed to investigate the compaction process of the LV myocardium during the normal gestation period and provide reference for echocardiographic diagnosis of a fetus with ventricular myocardium noncompaction. A total of 56 pregnant women in the gestational period of 23–30 weeks were included. Complete fetal echocardiography was performed with system ultrasonographic examination to exclude congenital heart malformation or extracardiac malformation. All 56 fetuses showed normal development. In the short-axis view of the fetal heart, the LV wall was divided into an upper and lower section at the level of the papillary muscle. Each section was then further divided into four segments, namely, anterior, posterior, lateral, and inferior wall. Thus, the LV wall was divided into eight segments. The thickness of the ventricular noncompacted and compacted layers and the ratio of the ventricular noncompacted to compacted layers of these segments at end-systole were measured and calculated. In echocardiography, the fetal LV myocardium is a two-layered structure: the endocardial noncompact myocardium (NC) with higher echo and the epicardium compact myocardium (C) with lower echo. The noncompacted layer is thinner than the compacted layer in the anterior wall, but thicker than the compacted layers in the posterior, lateral, and inferior wall. With respect to the upper and lower sections of the LV myocardium, the noncompacted layer in each segment of the upper section is thinner than that in each segment of the lower section, whereas the compacted layer of the upper section is thicker than that of the lower section. This study suggests that the densification of the fetal LV myocardium occurs gradually from base to apex and from the anterior to lateral, posterior, and inferior walls. This finding aids in further understanding the process of myocardial densification and provides a diagnostic reference for noncompaction of noncompaction cardiomyopathy (NCCM).

Impact of soil compaction on water content in sandy loam soil under sunflower

Abstract Soil compaction causes important physical modifications at the subsurface soil, especially from 10 to 30 cm depths. Compaction leads to a decrease in infiltration rates, in saturated hydraulic conductivity, and in porosity, as well as causes an increase in soil bulk density. However, compaction is considered to be a frequent negative consequence of applied agricultural management practices in Slovakia. Detailed determination of soil compaction and the investigation of a compaction impact on water content, water penetration depth and potential change in water storage in sandy loam soil under sunflower (Helianthus annuus L.) was carried out at 3 plots (K1, K2 and K3) within an experimental site (field) K near Kalinkovo village (southwest Slovakia). Plot K1 was situated on the edge of the field, where heavy agricultural equipment was turning. Plot K2 represented the ridge (the crop row), and plot K3 the furrow (the inter–row area of the field). Soil penetration resistance and bulk density of undisturbed soil samples was determined together with the infiltration experiments taken at all defined plots. The vertical bulk density distribution was similar to the vertical soil penetration resistance distribution, i.e., the highest values of bulk density and soil penetration resistance were estimated at the plot K1 in 15–20 cm depths, and the lowest values at the plot K2. Application of 50 mm of water resulted in the penetration depth of 30 cm only at all 3 plots. Soil water storage measured at the plot K2 (in the ridge) was higher than the soil water storage measured at the plot K3 (in the furrow), and 4.2 times higher than the soil water storage measured at the most compacted plot K1 on the edge of the field. Results of the experiments indicate the sequence in the thickness of compacted soil layers at studied plots in order (from the least to highest compacted ones): K2–K3–K1.

Influence of Li+ on the Compact and Porous Anodizing of Ti: Achieving Porous Anodizing Conditions Just By the Addition of Li+ Ion

The incorporation of foreign atoms in trace amounts modifies electronic properties and spectral response by the so-called band gap engineering 1. Among different dopants, the incorporation of Li+ cations into TiO2 is important for expanding the oxide’s technological applications. Li+ and H+ doping of TiO2 was carried out using electrochemical processes or salt impregnation, which improved solar to electricity efficiency of Dye Sensitized Solar cells and Perovskite solar cells (where a TiO2 layer is used as electronic transporting layer), as well as photocatalytic performance 2-3. Thermochemical treatments, N and V doping by standard ion implantation or Ag doping by metal plasma ion implantation was also reported 4-6. We recently reported 7 that Li+ is incorporated in the bulk of compact TiO2 layers during the anodization of Ti in lithium perchlorate (LiClO4), moving in the opposite direction expected for a cation under the applied electric field. Using Elastic Recoil Detection Analysis (ERDA) we observed that Li+ is accumulated in the form of more or less flat concentration profile along the thickness of compact layer (Fig. 1). Moreover, cell voltage profiles are strongly affected when Li+ is added to the electrolyte independent of anion of the salt. When the Li+ concentration is increased from 0.1 M to 0.5 M by addition of perchlorate or nitrate, the cell voltage transient changes from a curve typical for a compact anodizing with sparking to that of porous anodizing (Fig. 2). This transient change and the fact that the potential plateau during anodizing decreases as [Li+] is increased indicates that Li+ incorporation into the oxide greatly increases ionic conductivity and Ti oxide dissolution. Preliminary results show that a thick irregular tubular oxide structure is formed. The direct incorporation of Li+ into tubular TiO2 during its formation opens new possibilities for techniques of tubular oxide preparation. A mechanism for Li incorporation against the electric field is presented, as well as for the enhanced oxide dissolution. 1. Y.-C. Nah, I. Paramasivam and P. Schmuki, ChemPhysChem, 2010, 11, 2698–2713. 2. B. H. Meekins and P. V. Kamat, ACS Nano, 2009, 3, 3437–3446. 3. L. Tsui, M. Saito, T. Homma and G. Zangari, J Mater Chem A, 2015, 3, 360–367. 4. F. Giordano, A. Abate, J. P. Correa Baena, M. Saliba, T. Matsui, S. H. Im, S. M. Zakeeruddin, M. K. Nazeeruddin, A. Hagfeldt and M. Graetzel, Nat. Commun., 2016, 7, 10379. 5. N. A. Kyeremateng, N. Plylahan, A. C. S. dos Santos, L. V. Taveira, L. F. P. Dick and T. Djenizian, Chem Commun, 2013, 49, 4205–4207. 6. Y.-Y. Chang, Y.-N. Shieh and H.-Y. Kao, Thin Solid Films, 2011, 519, 6935–6939. 7. J. A. Penafiel-Castro, B. Hahn, R. L. Maltez, G. Knornschild, P. Allongue, and L. F. P. Dick, Chemical Communications , 2018, 54, 3251-3254. Figure 1

Rockfill dam compaction quality evaluation based on cloud-fuzzy model

The quality of compaction is key to the safety of dam construction and operation. However, because of incomplete information about the construction process and the unknown relationship between compaction quality and the factors that influence it, traditional evaluation methods such as neural networks and multivariate linear regression models fail to take uncertainty fully into account. This paper proposes a cloud-fuzzy method for assessing compaction quality by considering randomness, fuzziness, and incomplete information. The compaction parameters and material source parameters are the key parameters in the assessment of compaction quality. A five-layer neural-network model of compaction quality assessment is established that considers compacted dry density and its classification membership and probability as the criteria, and the rolling speed, rolling passes, and compacted layer thickness as alternatives. Because of uncertainties in the criteria and alternatives, the cloud-fuzzy method, in which a fuzzy neural network is extended with a cloud model to handle uncertain and fuzzy problems more effectively, is introduced to determine the compaction quality. A case study is presented to evaluate the compaction quality of a hydropower project in China. The results indicate that the cloud-fuzzy model is feasible in relation to precision and makes up for the sole focus on precision by traditional methods. The proposed method provides a triple index for understanding compaction quality, which facilitates assessment of the compaction quality of an entire dam surface.

Microstructural characterization of a V2C and V8C7 ceramic-reinforced Fe substrate surface compound layer by EBSD and TEM

Microstructural characterization of a vanadium carbide (V2C and V8C7) surface compound layer was performed by electron backscatter diffraction (EBSD), scanning electron microscopy and transmission electron microscopy. The phase composition and phase distribution of the compound layer and the morphologies, grain sizes and crystallographic orientations of the vanadium carbides were investigated through elemental distribution and crystallographic analyses. The results indicated that the compound layer was composed of four distinct zones consisting of a compact and uniform V2C layer (thickness of 3.2 μm) over the topmost surface followed by a nonuniform V + V2C (2.4 μm) zone, a V8C7 layer (10.7 μm) and a relatively deep V2C + V8C7+α-Fe + Fe3C zone (23.2 μm). The V2C layer was found in the V-rich region, and the EBSD results revealed that this phase grew mainly along the {0001} and {11–20} orientations. However, the V8C7 phase appeared to be nearly random, which indicates that the growth of this phase had no specific orientation. The V2C and V8C7 phases exhibited low-angle grain boundaries, and their misorientation angle distributions were mainly concentrated within the range of 0–5°. Furthermore, nanoindentation tests demonstrated that the hardnesses of the V2C and V8C7 layers were 22.16 ± 0.52 and 32.42 ± 0.61 GPa, respectively. Examination of the vanadium carbide powders obtained by chemical extraction indicated that the V2C grains with a hexagonal structure exhibited equiaxial and short rod-like morphologies, and the V8C7 particles with a cubic structure possessed short rod-like and spherical morphologies.

Нормирование основных транспортно-эксплуатационных качеств зимних лесовозных автомобильных дорог

The main material for the construction of the coatings of the winter forest roads is snow. The creation of this snow and ice durable material of the structural layers of pavement associated with a number of features. The main parameter that will define the structural strength of the pavement to be the hardness of the snow. In the operation of the winter timber-carrying roads this option almost never defined. We have conducted studies on the formation of a layer of compacted coating on the roadway depending on the amount of precipitation. The evaluation of the degree of influence of the density of falling snow on the magnitude of the compacted layer. When studying the degree of influence of precipitation was analyzed climatic conditions that operated hauling winter roads. It has been shown that the density of snow in the compacted layer affects the intensity of movement of trains, composition of traffic flow, the humidity of the snow and air and snow temperature. The density of the layer of the same influences and the evaporation of snow. Based on the experimental data were obtained the coefficients of evaporation of snow for the entire winter for the conditions of the Ural region. Based on these data, the calculated values of the possible maximum thickness of compacted layer at various speeds of movement of logging trucks and the different density of freshly fallen snow. The dependencies of the density layer of snow monthly. Found that to find the value of the thickness of the compacted layer to the end of the winter period, it is necessary to take into account the wear and evaporation of snow in the next months. This was carried out to estimate the depth gauge on a Packed snow surface. The recommended values for the maximum depth gauge on the surface for various road-climatic sub-zones. Set values of a compacted snow layer on the roadway by the end of the winter period for winter timber transportation trunk roads for winter logging winter logging mustache and branches.

Impact of Film Thickness of Ultrathin Dip-Coated Compact TiO2 Layers on the Performance of Mesoscopic Perovskite Solar Cells.

Uniform and pinhole-free electron-selective TiO2 layers are of utmost importance for efficient perovskite solar cells. Here we used a scalable and low-cost dip-coating method to prepare uniform and ultrathin (5-50 nm) compact TiO2 films on fluorine-doped tin oxide (FTO) glass substrates. The thickness of the film was tuned by changing the TiCl4 precursor concentration. The formed TiO2 follows the texture of the underlying FTO substrates, but at higher TiCl4 concentrations, the surface roughness is substantially decreased. This change occurs at a film thickness close to 20-30 nm. A similar TiCl4 concentration is needed to produce crystalline TiO2 films. Furthermore, below this film thickness, the underlying FTO might be exposed resulting in pinholes in the compact TiO2 layer. When integrated into mesoscopic perovskite solar cells there appears to be a similar critical compact TiO2 layer thickness above which the devices perform more optimally. The power conversion efficiency was improved by more than 50% (from 5.5% to ∼8.6%) when inserting a compact TiO2 layer. Devices without or with very thin compact TiO2 layers display J-V curves with an "s-shaped" feature in the negative voltage range, which could be attributed to immobilized negative ions at the electron-extracting interface. A strong correlation between the magnitude of the s-shaped feature and the exposed FTO seen in the X-ray photoelectron spectroscopy measurements indicates that the s-shape is related to pinholes in the compact TiO2 layer when it is too thin.