1st Layer Research Articles

Behavior of Reinforced Gypseous Soil Embankment Model under Cyclic Loading

The construction of embankment for roadway interchange system at urban area is restricted due to the large geometry requirements, since the value of land required for such construction is high, and the area available is limited as compared to rural area. One of the optimum solutions to such problem is the earth reinforcement technique which requires a limited area for embankment construction. Gypseous soil from Al-Anbar governorate area was obtained and subjected to various physical and chemical analysis to determine it is properties. A laboratory model box of 50x50x25 cm was used as a representative embankment; soil has been compacted in five layers at maximum dry density (modified compaction) and an aluminum reinforcement strips were introduced between layers. The model was subjected to cyclic loading and the vertical and lateral deformations were detected at different stages of loading cycles using LVDT. The reinforced soil embankment under soaking condition exhibited vertical settlement at the top surface was (12.55 mm) while the lateral displacements at (1st, 3rd layer) were (2.18, 1.32) mm respectively at (47 load cycles).For reinforced gypseous soil, embankment without soaking cured for 24 hours, the Number of load cycles was found to be (165) loading cycles with vertical displacement (9.12 mm), that means an improvement of 59%. Accordingly, the lateral displacement in 1st and 3rd layers were (3.28, 2.59) mm respectively which observes improvement by (28% and 5%) respectively. The rates of improvement are taken with respect to the reinforced pure dry soil sample.

Development and Characterization of Multilayered Cu/HA/ZnS + PEEK Coating System by Hybrid Technology

In this study, multilayered Cu/HA/ZnS + PEEK coatings were fabricated using hybrid technology on Zr–2.5Nb alloy substrates. The use of electrophoretic deposition (EPD) and heat treatment allowed the 1st base composite ZnS + PEEK layer and the 2nd hydroxyapatite (HA) top layer to be obtained. The EPD kinetics of both layers was studied. Heating at a temperature of 450 °C and slow cooling resulted in densification and sulfonation of PEEK. It also led to an increase in the adhesion of HA particles on the surface of the PEEK + ZnS layer and to the settlement of HA particles deep into the 1st layer. The effect of substrate preparation on the adhesion strength of coatings was investigated. The ZnS + PEEK layer exhibited high adhesion to the chemically treated zirconium alloy. Furthermore, the first layer was characterized by a high scratch resistance. The selective distribution of Cu on the top of the coating was obtained by shadow-masked pulsed laser deposition (PLD). The multilayered coatings exhibited high roughness and mild hydrophobicity. This study showed the possibility of obtaining a multilayered coating system with a controlled distribution of bioactive components (HA) and antimicrobial components (Cu) on its surface using a hybrid method that combined EPD, heat treatment, and PLD.

Heat transfer and performance enhancement investigation of biomimetic honeycomb gas coolers in transcritical CO2 heat pumps

CO2 air source heat pump heating technology has characteristics of strong adaptability to outdoor temperature in cold areas and high outlet temperature, which is widely used in heating and domestic hot water supply. A gas cooler is one of the crucial components in CO2 heat pump systems, while its performance and different structural forms will directly affect the performance of the whole CO2 heat pump system. In order to improve its heat transfer efficiency, a biomimetic honeycomb gas cooler is proposed in this paper, the steady-state simulation model of the biomimetic honeycomb gas cooler is established, and the reliability of the model is verified by experimental data. In addition, the effect of structural parameters and operating parameters on the heat transfer performance is studied, also the heat transfer performance of the biomimetic honeycomb gas cooler is compared with that of the internal spiral tube gas cooler and triple tube-in-tube gas cooler. The results show that the performance of the biomimetic honeycomb gas cooler can be effectively improved by reducing the water flow rate. Under the same working condition, the performance evaluation criteria1 of the 1st, 2nd and 3rd layer biomimetic honeycomb gas cooler s are about 193.4%, 239.9% and 357.0% higher than that of the internal spiral tube gas cooler, and about 197.2%, 205.9% and 237.7% higher than that of triple tube-in-tube gas cooler. This research is helpful to provide the reference for the design and optimization of this type of gas cooler and is conducive to the popularization and application of CO2 air source heat pumps.

AHP를 활용한 공급사슬 중단 위험의 파급효과 발생 요인 분석

This study aims to analyze the main causes of ripple effect and their degree of risk propagation under supply chain disruption. To achieve the purpose of this study, we derived the priority of main causes for managing ripple effect focusing on domestic manufacturing companies and logistics & distribution companies using AHP method. The main results of this study are as follows. As a result of multiplying the weights of the 1st and 2nd layers, it was confirmed that the structural vulnerability factor of the supply chain had the highest weight value. In addition, the results of group comparison by the type of industry, business size, and manufacturing category are as follows. First, the uncertainty of suppliers and buyers was found to be important for logistics and distribution companies to manage the ripple effect. Second, while large enterprises evaluated the sub-factors of supply chain structural vulnerability as the most important, SMEs(Small and Medium-sized Enterprises) were identified to require more careful management of complexity and dependence on suppliers and buyers. Third, unlike consumer goods manufacturing, the three major factors of assembly and processing manufacturing are all related to supply chain structural vulnerability. This study provides academic implications by identifying the factors of the ripple effect and quantifying the degree of risk propagation. In addition, it is proposed to effectively manage the main causes of ripple effects according to industry type, business size, and characteristics of each company.

Assessment of the multilevel correlations of the pollution indicators and lithological vulnerabilities in a passive limestone mining and cement producing environment.

This study presents the assessment of the air, soil, and water quality within the residential communities around two passive limestone mining/cement factories. The associations between the pollutants were tested across the media, within each medium, between the layers, and between two groups of the communities. The mean values for the PM1.0, PM2.5, and PM10 were 65.8 µgm-3, 50.1, and 73.7, respectively, in the air; for the Mn, Fe, Cu, Zn, Cr, K-40, U-238, and Th-232 were 0.433g/kg, 8.950, 0.005, 0.054, 0.104, 161.57Bq. kg-1, 61.10, and 15.85, respectively, in the topsoil; 0.365g/kg, 8.259, 0.004, 0.029, 0.057, 71.84Bq. kg-1, 16.37, 4.66, respectively, in the subsoil; and for the Mn, Fe, and Zn were 0.190, 1.499, and 0.256mg/l, respectively, in the water. The PM10, Fe, and K-40 were the most abundant pollutants. The Co and Mn, Zn and Cu, Fe and Cu, the absorbed dose rate (ADR) and K-40, and ADR and U-238 correlated significantly. Though the Ibese group was more polluted than the Ewekoro group, the generally low levels of the pollutions were confirmatory of the earlier suspicions of the mining/production activities. The 2nd lithological layer at 0.5 to 1.9m depths or the 3rd lithological layer at 1.1 to 7.69m depths for the Ibese group and the 1st layer at the surface or the 2nd layer at 0.5m depth for the Ewekoro group are protective layers for the groundwater that must not be exploited, given the three classes of groundwater vulnerability indices observed in the area.

Preservatives penetration and retention in post-treated cross-laminated timber panels with different layup and thickness

Cross-laminated timber (CLT), a prefabricated multilayer engineered wood product, is a promising construction material for mid-and-high rise buildings due to its good mechanical properties, renewability, and low-carbon footprint. However, the vulnerability of CLT to biodeterioration limits its broad applications. Preservative treatment is an effective method of increasing the service life of structural wood products, while the treatment of CLT has not been widely studied. Herein, we fabricated 3- and 5-ply CLT panels and treated them with Cu-based preservatives. The effects of panel layup (lengthwise and crosswise) and thickness (3-and 5-layer) on the impregnation quality (i.e., Cu penetration and retention) are investigated using a color-based indicator approach and X-ray fluorescence spectroscopy . Generally, the Cu penetration ratio was mostly above 90%, especially for the top layers (1st layer in 3-ply and 1st and 2nd layers in 5-ply) of the treated CLT panels. Similarly, higher Cu retention values were observed in the 1st layer of the 3- and 5-layer CLT panels. Further, there was a similarity in the Cu penetration of the 2nd layer in 3- and 5-ply CLT, indicating the preservative diffusion across adjacent layers is negligible in the preservative treatment of lumber-based wood composites. Overall, copper-azole type C (CA-C) exhibited better treatability than micronized copper azole (MCA) for CLT panels, resulting in higher Cu penetration and retention across the panels. Also, we found the lengthwise orientation preferable in fabricating preservative-treated CLT, this is due to the complete panel protection of the 1st and 2nd layers at all panel locations. Thus, our results show the feasibility of successfully treating CLT, especially when CA-C preservative and lengthwise orientation are utilized in fabricating the panels.

The influence of aqueous butterfly pea (Clitoria ternatea) flower extract on active and intelligent properties of furcellaran Double-Layered films - in vitro and in vivo research

Innovative, intelligent and active double-layer films, based on furcellaran and with the addition of gelatin hydrolysates, have been obtained for the first time. An aqueous extract of clitoria flower in 3 concentrations was included in the 1st FUR layer. The films demonstrated strong antimicrobial effects, but did not exhibit fungicidal properties. The antioxidant properties of the films were within the range of 2.27–3.92 mM Trolox/mg (FRAP method) and 36.67–61.24 % (DPPH method). The films were used as active packaging materials in salmon fillets, which were stored for a period of 12 days in 4 °C. Analysis concerning microbiological properties of the stored fillets showed the possibility of extending their shelf-life by 6 days. Lipid oxidation, determined by TBARS has delayed. The obtained films are a promising material for the packaging industry. This is an important aspect within the context of global food waste and also the need to reduce synthetic materials.

Изменение ареала западной зелёной пеночки (Phylloscopus trochiloides viridanus Blyth, 1843) в Украине и на прилежащих территориях

The aim of the work is to analyze the distribution of the Greenish Warbler of the subspecies viridanus in Ukraine and to determine the status of the species in various regions of the country. We used the analysis of the 3 – layer GIS map of the distribution areas of the Greenish Warbler for the period 1936–2022 in the DIVA-GIS program: 1st layer – the first registrations of the species (1936–1974); 2 – bird sightings at the end of the migration period (1979–2022); 3 – registrations in the nesting period. 77 GIS coordinates were used to build maps: author’s data, collection’s data of the Zoological Museum of the NNPM NAS of Ukraine, reference’s data, photo’s databases. In 1936–1974, the Greenish Warbler showed 2 foci of flights: 1 – in the south (in the Crimea, Nikolaev and Odessa regions), 2 – in the northeast – in the Belgorod region. In the northeastern region, the territory of distribution of the Greenish Warbler has increased significantly by 2022, but not in the south. The analysis performed indicates that the southern border of the Greenish Warbler habitat has shifted even more to the south and passes through the northern and northeastern regions of Ukraine. There is a tendency for the species to move further through Central Ukraine to the south of the country. In the south, registrations of a species with an unclear status at the end of spring migration and the beginning of the nesting period are typical. In the northeast, the Greenish Warbler nests. For Chernihiv, Kyiv and Ternopil regions, we assume the possibility of nesting. The species was not recorded in the southeastern and southwestern regions of Ukraine. In the northeastern regions, the first appearance of birds actually coincided with the beginning of their nesting, but the species has remained rare for about 30 years, breeding sporadically. In the southern regions, birds appeared and then disappeared for a rather long period, and after a while they are recorded more often and over a larger area. In Ukraine, the Greenish Warbler inhabits urbanized biotopes and is noted in 3 natural-geographical zones: forest, forest-steppe and steppe. It is possible that the Greenish Warbler does not nest in the south of Ukraine due to significant differences in the habitat conditions of the steppe zone from the forests in which the species has evolved. We believe that the successful resettlement of the Greenish Warbler is associated with a complex of factors: another wave of increase in the number of birds, favorable for the species climatic changes in the territories adjacent to the southern border of the range, the synanthropizations of the Greenish Warbler, transformation of the steppe zone of Ukraine due to the creation of tree plantations on its territory.

A model for nano-scale spherical surface coverage and protein corona formation by amyloidogenic peptides

The conformation of three amyloidogenic peptides; amyloid beta 1−40 (Aβ1−40), alpha synuclein (α-syn), and beta2-microglobulin (β2m) are closely associated with the process of causing neurodegenerative diseases. Use of a peptide adsorbed gold nano-particle system allowed us to investigate the interactive segment of each peptide responsible for peptide-peptide networking, which is crucial to initiate the formation of an oligomer and leads to fibrillogenesis. The adsorption orientation of the amyloidogenic peptides on the nano-gold colloid spherical surface was explained by simulating how much area of the metal surface was covered by the peptides, i.e., coverage ratio, 2. The empirically extracted 2 was explained by the summation of the 1st layer and the 2nd layer with a spikingout orientation of the prolate. Of note, the involvement of the 2nd layer was peptide type dependent. The nanosize dependence of 2 was linearly correlated with available spacing between adjacent peptides, Sd, which were approximated as prolates, For Aβ1−40 and α-syn, the 2nd layer was more included as Sd increased. In contrast, β2m was found to gyrate over the gold surface as Sd increased, creating a partially positive (δ+) region and repelling the extra β2m from the surface. Thus, as Sd decreased, it prohibited the gyration of β > 2m resulting in less δ+ region, and more β2m monomers were adsorbed with δ+ segment as the 2nd layer than the case where β > 2m gyrates more under relatively larger Sd. Based on the trend found in an experimentally extracted 2 as a function of Sd, optimized charge distribution of Aβ1−40 and α-syn were concluded to be negative partial charge (δ−) region that was covered by the positive partial charge (δ+) region. However, β > 2m may have a relatively large and/or distributed δ+ region with a small portion of δ− at the one end of a prolate. The characterization made in this work confirmed current understandings on the formation of the protein corona over nano-particles

РАЗРАБОТКА НИЗКОРАНГОВЫХ ПРОСТРАНСТВЕННЫХ ВЕКТОРОВ ПРЕДВАРИТЕЛЬНОГО КОДИРОВАНИЯ ВО ВРЕМЕННОЙ ОБЛАСТИ

In this paper we consider the alternative way of development of spatial beamforming processing algorithm in time-domain under low-rank Massive-MIMO systems. It is well-known, that the telecommunication systems, which based on spatial multiplexing technology achieve following advantages: increase the spectral efficiency in many times due to spatial channel multiplexing gain, the beamforming technology implementation (effective energy distribution in the space). The organization of spatial filtering (the beamforming vector processing) – one of the most significant tools in MIMO-OFDM multiplexing. In this paper, we consider a new spatial filtering processing approach (precoding vectors calculation), which is a significant tool in large-scale antenna systems, due to the fact of smart processing of the radio narrow-beam implementation increases the efficiency of the communication system many times over. Nowadays, the spatial filter design algorithms with low computational complexity have attracted considerable attention from researchers seeking to improve existing MIMO-OFDM wireless communication systems. In the paper we developed basic algorithms for calculating precoding vectors in the frequency domain and proposed the time-domain precoder approach with aim to achieve the complexity reduction gain. The proposed method was tested on the geometric statistical simulation channel model QuAdRiGa according to the multipath channel scenario "3GPP-3D Uma-NLoS". We provide the assessment of whole presented methods and the evaluation range of discrepancies was revealed in the form of pictures of the correlation and integral metrics. The analysis of integral cumulative distribution function of simulation results shows the relation gap between accuracy of correlation metric and losses of beamforming processing recalculation approximately -0.5 dB for 1st layer. In conclusion of paper was revealed the fact that proposed SVD factorization for each impulse response did not take into account the beams and eigenvectors distribution over the whole frequency bandwidth

Classification Framework of the Bearing Faults of an Induction Motor Using Wavelet Scattering Transform-Based Features.

In the machine learning and data science pipelines, feature extraction is considered the most crucial component according to researchers, where generating a discriminative feature matrix is the utmost challenging task to achieve high classification accuracy. Generally, the classical feature extraction techniques are sensitive to the noisy component of the signal and need more time for training. To deal with these issues, a comparatively new feature extraction technique, referred to as a wavelet scattering transform (WST) is utilized, and incorporated with ML classifiers to design a framework for bearing fault classification in this paper. The WST is a knowledge-based technique, and the structure is similar to the convolution neural network. This technique provides low-variance features of real-valued signals, which are usually necessary for classification tasks. These signals are resistant to signal deformation and preserve information at high frequencies. The current signal data from a publicly available dataset for three different bearing conditions are considered. By combining the scattering path coefficients, the decomposition coefficients from the 0th and 1st layers are considered as features. The experimental results demonstrate that WST-based features, when used with ensemble ML algorithms, could achieve more than 99% classification accuracy. The performance of ANN models with these features is similar. This work exhibits that utilizing WST coefficients for the motor current signal as features can improve the bearing fault classification accuracy when compared to other feature extraction approaches such as empirical wavelet transform (EWT), information fusion (IF), and wavelet packet decomposition (WPD). Thus, our proposed approach can be considered as an effective classification method for the fault diagnosis of rotating machinery.

Analysis of Operational Characteristics of AlGaN/GaN High-Electron-Mobility Transistor with Various Slant-Gate-Based Structures: A Simulation Study.

This study investigates the operational characteristics of AlGaN/GaN high-electron-mobility transistors (HEMTs) by applying a slant-gate structure and drain-side extended field-plate (FP) for improved breakdown voltage. Prior to the analysis of slant-gate-based HEMT, simulation parameters were extracted from the measured data of fabricated basic T-gate HEMTs to secure the reliability of the results. We suggest three different types of slant-gate structures that connect the basic T-gate electrode boundary to the 1st and 2nd SiN passivation layers obliquely. To consider both the breakdown voltage and frequency characteristics, the DC and RF characteristics of various slant-gate structures including the self-heating effect were analyzed by TCAD simulation. We then applied a drain-side extended FP to further increase the breakdown voltage. The maximum breakdown voltage was achieved at the FP length of 0.4 μm. Finally, we conclude that the slant-gate structures can improve breakdown voltage by up to 66% without compromising the frequency characteristics of the HEMT. When the drain-side FP is applied to a slant-gate structure, the breakdown voltage is further improved by up to 108%, but the frequency characteristics deteriorate. Therefore, AlGaN/GaN HEMTs with an optimized slant-gate-based structure can ultimately be a promising candidate for high-power and high-frequency applications.

Continuous Capsule Network Method for Improving Electroencephalogram-Based Emotion Recognition

The convolution process in the Capsule Network method can result in a loss of spatial data from the Electroencephalogram signal, despite its ability to characterize spatial information from Electroencephalogram signals. Therefore, this study applied the Continuous Capsule Network method to overcome problems associated with emotion recognition based on Electroencephalogram signals using the optimal architecture of the (1) 1st, 2nd, 3rd, and 4th Continuous Convolution layers with values of 64, 128, 256, and 64, respectively, and (2) kernel sizes of 2×2×4, 2×2×64, and 2×2×128 for the 1st, 2nd, and 3rd Continuous Convolution layers, and 1×1×256 for the 4th. Several methods were also used to support the Continuous Capsule Network process, such as the Differential Entropy and 3D Cube methods for the feature extraction and representation processes. These methods were chosen based on their ability to characterize spatial and low-frequency information from Electroencephalogram signals. By testing the DEAP dataset, these proposed methods achieved accuracies of 91.35, 93.67, and 92.82% for the four categories of emotions, two categories of arousal, and valence, respectively. Furthermore, on the DREAMER dataset, these proposed methods achieved accuracies of 94.23, 96.66, and 96.05% for the four categories of emotions, the two categories of arousal, and valence, respectively. Finally, on the AMIGOS dataset, these proposed methods achieved accuracies of 96.20, 97.96, and 97.32% for the four categories of emotions, the two categories of arousal, and valence, respectively. Doi: 10.28991/ESJ-2023-07-01-09 Full Text: PDF

On the hydrophobic hydration, solvation and interface: A thought essay (I)

This essay covers aspects concerning with the hydrophobic hydration of apolar gas (H2, He, Ne, N2, O2, Ar, CH4, C2H6, C3H8, n-C4H10 and i-C4H10), solubilities in water and hexadecane, interfacial tensions of water/gases, hexadecane/gases and n-alkane (C7-C18)/N2 and O2 interface at 298 K. The main results are: (1) Two water layers of hydration should be taken into account. 1st layer closest to an apolar molecule is hot ice or ordered gas and independent to 2nd layer. Water dipoles orderly, dramatically and endlessly rotate and create a negative electric field, in turn electro-freeze 2nd layer. (2) Entropic change of H+ partition between 2nd layer and bulk water leads to the ionization of water. (3) Interfacial tension and internal pressure of 2nd layer caused by electric potential are −13.9 mJ/m2 and −54 MPa, respectively. (4) Thermodynamic process for solvation: (i) isothermally compressing gas to the solid state to take in all the kinetic energy of gas for creating a cavity with 4 free HBs; (ii) mixing the hydrates (solvated entities) with water (alkane) as mixing of ideal gas. (5) Gas collides with surface to create the crystalline foam consisting of 4 layers of hydrates or solvated entities. The solubilities of gases, the interfacial tension and internal pressure of water (alkane)/gas interface are calculated with quite appraisable results.

Double-Layered Films Based on Furcellaran, Chitosan, and Gelatin Hydrolysates Enriched with AgNPs in Yerba Mate Extract, Montmorillonite, and Curcumin with Rosemary Essential Oil.

Double-layered active films based on furcellaran (1st layer—FUR), chitosan, and gelatin hydrolysates (2nd layer—CHIT+HGEL) were successfully prepared. Bioactive ingredients were added to the 1st film layer: AgNPs, which were synthesized in situ with yerba mate extract; montmorillonite clay (MMT); and different loads of ethanolic curcumin (CUR) extract enriched with rosemary essential oil (REO). SEM images confirmed the presence of AgNPs with a size distribution of 94.96 ± 3.33 nm throughout the films, and AFM and SEM photos indicated that the higher substance concentrations had rougher and more porous film microstructures. However, the water vapor transmission rate was reduced only at the lowest load of this ingredient. Despite the tensile strength of the films having decreased, the incorporation of the compounds showed a tendency towards reducing the modulus of elasticity, resulting in a lower stiffness of the composites. The addition of CUR and AgNPs improved the UV light barrier properties of the materials. The presented films showed quick reactions to changes in the pH value (from orange to red along with an increase in pH from 2 to 10), which indicates their potential use as indicators for monitoring the freshness of food products. Composite No. 2 showed the highest antimicrobial potential, while none of the presented films showed an antifungal effect. Finally, the antioxidant activities of the films increased dramatically at higher AgNP and CUR loads, suggesting an outstanding potential for active food packaging applications.

Influence of storage conditions on functional properties of multilayer biopolymer films based on chitosan and furcellaran enriched with carp protein hydrolysate

In this paper, the impact of water activity regarding storage environment on mechanical and water properties is presented, as well as the structural and morphological features of triple-layered films. Furcellaran (FUR), chitosan (CHIT) and carp skin gelatin hydrolysates (HGEL) were used for the production of the film. The films were made using a casting method, in which three successive stages were applied. First stage: preparation (pouring onto the mould) of 1st layer – FUR + HGEL, second: 2nd layer preparation (pouring onto 1st layer) – FUR, and third: 3rd layer (pouring onto 1st layer) – CHIT + HGEL. The second and third steps began after gelation of the previously poured layer. The drying process of the film was carried out for 24 h under a fume hood at room temperature. The mechanical properties of control sample was: tensile strength The control sample has tensile strength 7.76 ± 0.35 MPa, elongation at break – 3.69 ± 0.33%, maximum breaking load – 15.86 ± 0.58 N. Water properties of control sample – water absorption a solubility were 25.80 ± 1.14% and 52.91 ± 1.31%, respectively. Reducing the water content in the film increased its tensile strength (from 7.76 ± 0.35 MPa for the control film to 14.36 ± 0.07 MPa) and elongation at break (from 3.69 ± 0.34% for the control film to 8.74 ± 0.69%). Reducing water content in the film also decreased its ability to absorb water, which is crucial in the case of biodegradable films due to their hydrophilic nature. The multimolecular sorption of the films was described using the BET model. Structural and morphological changes observed on the basis of surface and cross-section photographs of the films confirm the negative impact of high water activity on the film and its mechanical parameters.

FFF 3D Printing of Small Porous Structures from Polymer Compounds Using the Ultimaker 3

AbstractAdditive manufacturing offers a great potential for the production of objects with a tailor‐made inner structure especially in combination with material development in the field of polymer compounds. However, the design possibilities for the inner structure depend on printing resolution, accuracy, and reproducibility. The quality of small filigree objects printed by additive manufacturing processes for polymer materials like fused filament fabrication (FFF) depends on the polymer material itself as well as on the processing parameters in the additive manufacturing technology used. Here, the production of small porous structures by FFF with an Ultimaker 3 is analyzed using polylactic acid (PLA) as well as polymer compounds of PLA containing carbon nanotubes (CNTs) and polyvinyl alcohol (PVA) containing titanium dioxide (TiO2). The influences of the calibration of the building plate, the heights of the 1st, 2nd, and 3rd layers, and of particulate additives on the printing behavior of the polymer compound, and hence the resulting accuracy of the width of single printed lines, are studied. Additionally, the printing of lattice‐like scaffold structures using PLA/CNT forming the structure and PVA/TiO2 as soluble support structure is described.

Water-Graphene non-bonded interaction parameters: Development and influence on molecular dynamics simulations

Molecular dynamics simulations have been extensively used to study water-graphene systems, and the force field parameters are vital for the accuracy of simulation results. Herein, water-graphene non-bonded Lennard-Jones (LJ) parameters were developed according to the experimental water contact angle (θ), and were further validated by the quantum-chemistry calculated water-graphene interaction energy (Eint). The LJ parameters were developed based on various water models, and were employed to simulated a large diversity of water-graphene systems (e.g. water nanodroplet (or one water molecule) on graphene, water slab-graphene interface, graphene nanochannel connected to a water reservoir, water confined in graphene nanochannel, etc.), with thorough comparison against LJ parameters derived from Lorentz-Berthelot mixing rule. All these abundant data were studied in-depth to yield plenty of insights (some were rarely reported) that could be extended to other two-dimensional materials or systems, e.g. linear correlation of cos θ ∼ LJ parameter and the slope is also linear with the reciprocal of water’s surface tension, linear correlation of Eint ∼ density of the 1st water layer on graphene, correlation of Eint ∼ water molecules’ residue time on graphene, (roughly) linear correlation of water density inside graphene 2D nanochannel ∼ water’s diffusivity etc.

Corrosion resistance and biocompatibility of cold-sprayed titanium on 316L stainless steel

Porous coatings for biomaterials are provided to enhance biological response for bone fixation. Adhesion and cohesion strengths of the porous coatings can be improved by adjusting the porosity levels of the coating system. Different levels of the porous structure can possibly affect other properties such as corrosion resistance and biological properties. In this study, the corrosion resistance and biocompatibility of titanium (Ti) porous coating with high and low porosity gradients on grit-blasted and ground 316L stainless steel by cold spray were studied. The deposition of titanium (Ti) porous coating on all 316L stainless steel substrates was achieved by cold spray. The coatings comprised three layers, i.e. a low porosity layer (the 1st layer) at the interface coating/substrate, and higher porosity layers (the 2nd and 3rd layers) on top. The high and low porosity gradient samples had 8 % and 1 % porosity gradient, respectively. They related to the differing porosity between the 2nd and 3rd layers, deposited by the different process gas pressure used for the 2nd layer. Corrosion resistance was analyzed from the result of the potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) test. All EIS results presented capacitive behavior (high corrosion resistance) with phase angle close to −90°. High polarization resistance (R2) in the ground substrate indicated a highly stable passive film at the interface coating/substrate, which was higher than grit-blasted substrate. Surface preparation with grinding also exhibited a lower corrosion rate than grit blasting. However, the high and low porosity gradients hardly affected the EIS result and corrosion rate. Porous structures in all Ti coatings could promote bone cell ingrowth. The biological responses such as alkaline phosphatase (ALP) activity, and alizarin red S staining (ARS) concentration had high values in the ground substrate. The highest ALP and ARS could be found in the high porosity gradient on ground substrate after cell culture for 8 weeks.

Stochastic-Deterministic Assessment of Electric Field Radiated by Base Station Antenna above a Two-Layered Ground

The paper deals with stochastic-deterministic modelling of radiated electric field by base station antennas (BSAs) operating in GSM frequency range. Within the framework of deterministic analysis, the total electric field above a two-layered lossy ground is obtained by considering the incident and reflected ray in the far field zone. The influence of nonhomogeneous lower medium is taken into account via two approaches: Fresnel plane wave reflection coefficient (FRM) and simplified reflection coefficient stemming from Modified Image Theory (MIT). Antenna height, relative conductivity, and permittivity of each ground layer, as well as the thickness of the upper ground layer, are considered as input parameters with inherent uncertainty. To quantify the uncertainty of output electric field, deterministic models are treated as black boxes by two stochastic methods, Monte Carlo (MC) and Stochastic Collocation (SC), respectively. Stochastic mean and standard deviation of the output are computed, and sensitivity analysis is carried out in order to analyze the impact of input parameters’ variations on the resulting electric field variance. The presented results expose weakness and strength of the two stochastic methods, particularly identifying the cases when the preferred SC method fails to converge. Furthermore, sensitivity analysis reveals that despite the smallest variation around its respective average value, the antenna height has the highest impact on the output variance at observation points in the vicinity of the antenna. However, as the distance from the antenna increases, the 1st layer depth and its relative electric permittivity become the most significant parameters.