Materials Science Research Articles

Photocatalytic activity of TiO2:TiN nanocomposite films prepared by DC reactive sputtering technique for air purification

This study concerns the production of advanced materials and a novel technique for enhancing photocatalytic efficiency, focusing specifically on the purification of air contaminated with methane gas. Titanium dioxide:Titanium nitride (TiO2/TiN) nanocomposite films were prepared by dc reactive magnetron sputtering of highly-pure titanium sheet in presence of oxygen and nitrogen as reactive gases with optimized mixing ratios to produce the composite structures. The structural, morphological, and optical characteristics of the prepared nanocomposites were determined and analyzed. The primary goal of this study was to enhance the photocatalytic activity of such nanocomposites against methane gas pollution. It is observed that increasing the nitrogen content in the TiO2:TiN nanocomposite structure led to notable improvements in photocatalytic efficiency. Specifically, when these nanocomposites were subjected to a UV light, they exhibited enhanced photocatalytic activity in the removal of methane gas from the surrounding air, which demonstrates a direct correlation with increased nitrogen (N) content in the composite structure. These nanocomposites are reasonably promising in removing harmful gases and pollutants present in indoor and outdoor environments. This exploration not only sheds light on the remarkable potential of TiO2:TiN nanocomposites for air purification but also highlights the importance of innovative techniques, such as dc reactive magnetron sputtering in the field of materials science and engineering as well as in environmental remediation.

Phosphorus doped hydrogenated silicon oxycarbide: Film formation, properties and its application on silicon heterojunction solar cell

An ultrathin phosphorus doped hydrogenated microcrystalline silicon oxycarbide (n-μc-SiCO:H) layer deposited by plasma enhanced chemical vapor deposition (PECVD) method can be used as a window layer for silicon heterojunction solar cells. The optical and electrical properties of n-μc-SiCO:H films were controlled by PECVD deposition conditions. The interplay effects of H2, CO2 and PH3 to SiH4 gas ratio on the chemical composition, material structure and properties of n-μc-SiCO:H film were systematically determined. O, H, C and P atoms were observed to incorporate into the silicon network of n-μc-SiCO:H layer, while most of the atoms bond directly to Si atoms. Incorporation of oxygen and carbon atoms into n-μc-SiCO:H film, confirmed by XPS as formation of Si-O and Si-C bonds, enlarged the optical absorption band gap (Eg) value. Both film crystallinity and phosphorus concentration in n-μc-SiCO:H layer were observed to be controlled by the H2, CO2 and PH3 to SiH4 gas ratio. The electric performance of HJT solar cell was depended on the optical and electrical properties of n-μc-SiCO:H layer. An average efficiency (across ∼ 120 cells) of 26.32 % was achieved in cells with optimized deposition parameters for the n-μc-SiCO:H layer. The reaction gas ratio was also the dominant factor in determining the number and size of nanoscale Si crystallites embedded in the n-μc-SiCO:H layer. The conductivity of n-μc-SiCO:H layer was determined by the activated phosphorus concentration but independent of the total phosphorus concentration. It was also found that large concentrations of small Si crystallites of size less than 3 nm improved film conductivity.

Valorization of lignin-rich solid residues from different eucalyptus wood conversion processes as oil structurants via electrospinning

The growing demand for sustainable materials has been driving research towards the use of biopolymers from natural resources. This study explores the valorization of lignin-rich solid residues derived from different eucalyptus wood conversion processes, specifically autohydrolysis (AHL), steam-explosion (SEL), and kraft pulping (EKL), via electrospinning. The potential of these electrospun nanostructures as eco-friendly oil structurant is investigated for lubricant applications. Solutions of AHL, SEL, and EKL fractions in a 3:1 v/v trifluoroacetic acid (TFA)/N,N-dimethylformamide (DMF) binary solvent were prepared at concentrations of 0.015, 0.03, and 0.05 g/mL. AHL and SEL samples exhibited superior spinnability due to higher carbohydrate content and molecular weight and lower ash content. Increasing the solution concentration to 0.05 g/mL resulted in the consecution of larger average fiber diameters (up to 0.44 and 0.39 μm, for AHL and SEL, respectively) and reduced bead formation. Stable oleo-dispersions were achieved solely with electrospun homogeneous nanofiber mats, while nanostructures predominantly composed of electrosprayed particles, like those obtained with EKL produced physically unstable dispersions from which the oil readily separates. The rheological response and microstructure of oleo-dispersions were significantly affected by both the conversion process of eucalyptus wood and the spinning solution concentration. The rheological properties of the oleo-dispersions can be tailored by modifying the spinning solution concentration, with G′ values ranging from 5·102 to 5·104 Pa and consistency and flow indices roughly ranging from 90 to 990 Pa sn and from 0.06 to 0.19, respectively, depending on the nature of the lignin-rich fraction and the type of electrospun nanostructure employed. These results highlight the potential of electrospun nanostructures obtained from lignin-rich solid residues in advanced materials applications, promoting the valorization of waste streams derived from different biorefinery processes, as well as the development of novel environmentally friendly lubricants.

Constitutive modeling and extended performance evaluation of concrete reinforced with non-hybrid waste tire steel fibers

This paper investigates the extended performance and constitutive modeling of waste tire steel fiber reinforced concrete (WFRC), making notable contributions to civil engineering materials. The study assesses constitutive modeling, reinforcement indices, and the long-term performance of concrete reinforced with varying percentages of waste tire steel fiber (WSF) ranging from 0.30 % to 1.75 %. A modified analytical model for predicting compressive stress-strain curves of WFRC is introduced and compared with previous analytical models for fiber-reinforced concrete. Additionally, a novel waste tire steel fiber reinforcing index, based on WSF properties, is proposed. Empirical relationships between strength properties and reinforcement indices are established. Experimental strength properties at the standard age, as well as water absorption, carbonation depth, and split-tensile strength of specimens aged beyond the standard age at 600 days and fiber-matrix interaction obtained by SEM analysis, are reported. Prediction models are proposed for estimating the mechanical properties of WFRC at the standard age, with results compared against existing codes. The proposed modified analytical model for the uniaxial compressive stress-strain curve demonstrates better coherence with experimental curves than existing models. Furthermore, empirical equations developed in terms of the waste tire steel fiber reinforcing index demonstrate satisfactory alignment between predicted and experimental strength properties. Significant improvements are observed in specimens aged 600 days, indicating the promising role of WSF in enhancing the long-term performance and serviceability of structures. Further studies are recommended to explore the performance of WFRC in aggressive environmental conditions.

Making sense of making: bringing a design and making project to school

ABSTRACT This study focuses on a design and making project carried out in a Finnish school and situated within the schedules of a multidisciplinary learning module and English as a foreign language. A group of technology students led the project as part of their university studies. Design and making are a recent development at school that allows the ideals of maker culture and school to converge. In this study, we analyse the sense making that emerged from this convergence during the project. The school participants were ninth graders, approx. 15 years old, working in teams. During the project, the teams ideated, planned, and produced artefacts envisioned to promote entrepreneurial goals for their professional future. The primary research materials include video recordings gathered from students’ work in the classroom and the digital fabrication lab (Fab Lab) as well as group interviews. Field notes provided additional support for the analysis. The research advanced through the cycles of engaging, navigating and changing the nexus of practice. Nexus analysis shed light on how participants’ pasts, interactions and discourses in place were shaping design and making at school. The study provides implications for guiding the design and making projects at school and inquiry-driven collaboration more generally.

Rational Design of Cyclopentadiene-Based Super- and Hyperacids Based on Aromaticity.

The design and synthesis of neutral organic superacids have been of interest recently due to their vast applications in chemistry and material sciences, for example, olefinic polymerization, isolation of highly reactive short-lived cations, etc. Cyclopentadiene behaves as a mild organic acid, producing a stable conjugate base by gaining aromaticity and conjugation after deprotonation. To stabilize conjugate bases of organic acids to show superacidities and hyperacidities, we considered aromatic phenyl substituents with cyclopentadiene (mono-, di-, and triphenyl-substituted cyclopentadiene and their cyano derivatives). The MP2, DFT (B3LYP, M06-2X), and CBS-QB3 methods were used to calculate the gas-phase proton affinities of the parent cyclopentadiene, and the DFT methods were chosen for the substituted cyclopentadiene as they yield an experimental proton affinity of cyclopentadiene of 253.66 kcal/mol (Expt. 253.6 ± 1.3 kcal/mol). The stable trisubstituted cyclopentadiene derivative shows gas-phase enthalpies of deprotonation (ΔHacid) of 245 and 239 kcal/mol with DFT B3LYP and M06-2X methods, respectively, with values in the range of hyperacidity. Some of the tautomers of cyclopentadiene derivatives show hyperacidity, with proton affinity values of 205-240 kcal/mol. Triphenyl-substituted cyclopentadiene behaves as a moderate acid but transforms into a superacid after replacing the phenyl group with nitrobenzene, which is a stronger acid than H2SO4 (ΔHacid = 298 kcal/mol). The nucleus-independent chemical shift (NICS) shows the extent of conjugation in the derivatives of cyclopentadienyl anions after deprotonation, which affects the stabilities of conjugate bases, i.e., the acidities of the protonated species. The calculated harmonic oscillator model of aromaticity and NICS indices reveal that the stability of conjugate bases as well as their acidities increase with increasing aromaticity of cyclopentadiene rings after deprotonation in all molecules.

Nanostructure silver absorbance with polarized light spectroscopy (PLS) and mobile imaging

This study presents a novel interdisciplinary approach for characterizing the optical properties of nanostructured silver films, combining methodologies from polarized light spectroscopy (PLS) and mobile app-based spectroscopic image detection. Silver nanofilms were deposited using electron beam evaporation (EBE) and subsequently analyzed for their absorbance across the visible light spectrum through PLS spectroscopy. The innovative aspect of this study lies in the validation of PLS spectral data using a mobile application developed with MIT App Inventor, which analyzes the intensity of light beams captured in images taken by a smartphone. The findings indicate that the silver nanofilm exhibits peak absorbance at approximately 400 nm within the violet region, corroborated by the mobile app’s data, which shows the lowest light intensity. However, discrepancies were observed from 500 to 600 nm, likely due to ambient light interferences and inherent optical phenomena such as diffraction, reflection, and refraction. Despite these deviations, the app’s readings closely align with the PLS data, supporting the film’s selective absorption properties. This study demonstrates the potential of this multidisciplinary technique in nanomaterial research, highlighting the application of nanotechnology in material science and the transformative potential of integrating software engineering for in-depth material characterization. These findings open avenues for advancements in both academic and practical applications.

Driving Deployment of Bioengineered Products-An Arduous, Sometimes Tedious, Challenging, Rewarding, Most Exciting Journey That Has to Be Made!

More than three decades ago, we embarked on a number of bioengineering explorations using the most advanced materials and fabrication methods. In every area we ventured into, it was our intention to ensure fundamental discoveries were deployed into the clinic to benefit patients. When we embarked on this journey, we did so without a road map, not even a compass, and so the path was arduous, sometimes tedious. Now, we can see the doorway to deployment on the near horizon. We now appreciate that overcoming the challenges has made this a rewarding and exciting journey. However, maybe we could have been here a lot sooner, and so maybe the lessons we have learned could benefit others and accelerate progress in clinical translation. Through a number of case studies, including neural regeneration, cartilage regeneration, skin regeneration, the 3D printing of capsules for islet cell transplantation, and the bioengineered cornea, here, we retrace our steps. We will summarise the journey to date, point out the obstacles encountered, and celebrate the translational impact. Then, we will provide a framework for project design with the clinical deployment of bioengineered products as the goal.

Smart Spare Parts (SSP) in the Context of Industry 4.0: A Systematic Review.

The implementation of Industry 4.0 has integrated manufacturing, electronics, and engineering materials, leading to the creation of smart parts (SPs) that provide information on production system conditions. However, SP development faces challenges due to limitations in manufacturing processes and integrating electronic components. This systematic review synthesizes scientific articles on SP fabrication using additive manufacturing (AM), identifying the advantages and disadvantages of AM techniques in SP production and distinguishing between SPs and smart spare parts (SSPs). The methodology involves establishing a reference framework, formulating SP-related questions, and applying inclusion criteria and keywords, initially resulting in 1603 articles. After applying exclusion criteria, 70 articles remained. The results show that while SP development is advancing, widespread application of AM-manufactured SP is recent. SPs can anticipate production system failures, minimize design artifacts, and reduce manufacturing costs. Furthermore, the review highlights that SSPs, a subcategory of SPs, primarily differs by replacing conventional critical parts in the industry, offering enhanced functionality and reliability in industrial applications. The study concludes that continued research and development in this field is essential for further advancements and broader adoption of these technologies.

Development of Advanced Solid-State Thermochromic Materials for Responsive Smart Window Applications.

This study introduces the synthesis and detailed characterization of a novel thermochromic material capable of reversible alterations in its thermotropic transmittance. Through an emulsion polymerization process, this newly developed material is composed of 75-85% octadecyl acrylate and 0-7% allyl methacrylate, demonstrating a pronounced discoloration effect across a narrow yet critical temperature range of 24.5-39 °C. The synthesized powder underwent a battery of tests, including differential scanning calorimetry and thermogravimetric analysis, as well as scanning electron microscopy. These comprehensive evaluations confirmed the material's exceptional thermal stability, uniform particle size distribution, and strong anchoring properties. Building upon these findings, we advanced the development of thermochromic polyvinyl butyral films and laminated glass products. By utilizing a coextrusion technique, we integrated these films into laminated glass, setting a new benchmark against existing glass technologies. Remarkably, the incorporation of thermochromic PVB films into laminated glass led to a significant reduction in solar irradiance of 20-30%, outperforming traditional double silver low-emissivity glass. This achievement demonstrates the exceptional shading and thermal insulation properties of the material. The research presented herein not only pioneers a valuable methodology for the engineering of smart materials with tunable thermotropic transmittance but also holds the key to unlocking enhanced energy efficiency across a spectrum of applications. The potential impact of this innovation on the realm of sustainable building materials is profound, promising significant strides toward energy conservation and environmental stewardship.

Emulsion electrospun epigallocatechin gallate-loaded silk fibroin/polycaprolactone nanofibrous membranes for enhancing guided bone regeneration

Guided bone regeneration (GBR) membranes play an important role in oral bone regeneration. However, enhancing their bone regeneration potential and antibacterial properties is crucial. Herein, silk fibroin (SF)/polycaprolactone (PCL) core-shell nanofibers loaded with epigallocatechin gallate (EGCG) were prepared using emulsion electrospinning. The nanofibrous membranes were characterized via scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, water contact angle (CA) measurement, mechanical properties testing, drug release kinetics, and 1,1-diphenyl-2-picryl-hydrazyl radical (DPPH) free radical scavenging assay. Mouse pre-osteoblast MC3T3-E1 cells were used to assess the biological characteristics, cytocompatibility, and osteogenic differentiation potential of the nanofibrous membrane. Additionally, the antibacterial properties againstStaphylococcus aureus (S. aureus)andEscherichia coli (E. coli)were evaluated. The nanofibers prepared by emulsion electrospinning exhibited a stable core-shell structure with a smooth and continuous surface. The tensile strength of the SF/PCL membrane loaded with EGCG was 3.88 ± 0.15 Mpa, the water CA was 50°, and the DPPH clearance rate at 24 h was 81.73% ± 0.07%. The EGCG release rate of membranes prepared by emulsion electrospinning was reduced by 12% within 72 h compared to that of membranes prepared via traditional electrospinning.In vitroexperiments indicate that the core-shell membranes loaded with EGCG demonstrated good cell compatibility and promoted adhesion, proliferation, and osteogenic differentiation of MC3T3-E1 cells. Furthermore, the EGCG-loaded membranes exhibited inhibitory effects onE. coliandS. aureus. These findings indicate that core-shell nanofibrous membranes encapsulated with EGCG prepared using emulsion electrospinning possess good antioxidant, osteogenic, and antibacterial properties, making them potential candidates for research in GBR materials.

Molecular Dynamics Simulation Study of Aluminum-Copper Alloys' Anisotropy under Different Loading Conditions and Different Crystal Orientations.

The commonly used aluminum-copper alloys in industry are mainly rolled plates and extruded or drawn bars. The aluminum-copper alloys' anisotropy generated in the manufacturing process is unfavorable for subsequent applications. Its underlying mechanism shall be interpreted from a microscopic perspective. This paper conducted the loading simulation on Al-4%Cu alloy crystals at the microscopic scale with molecular dynamics technology. Uniaxial tension and compression loading were carried out along three orientations: X-<1¯12>, Y-<11¯1>, and Z-<110>. It analyzes the micro-mechanisms that affect the performance changes of aluminum-copper alloys through the combination of stress-strain curves and different organizational analysis approaches. As shown by the results, the elastic modulus and yield strength are the highest under tension along the <11¯1> direction. Such is the case for the reasons below: The close-packed plane of atoms ensures large atomic binding forces. In addition, the Stair-rod dislocation forms a Lomer-Cottrell dislocation lock, which has a strengthening effect on the material. The elastic modulus and yield strength are the smallest under tension along the <110> direction, and the periodic arrangement of HCP atom stacking faults serves as the main deformation mechanism. This is because the atomic arrangement on the <110> plane is relatively loose, which tends to cause atomic misalignment. When compressed in different directions, the plastic deformation mechanism is mainly dominated by dislocations and stacking faults. When compressed along the <110> direction, it has a relatively high dislocation density and the maximum yield strength. That should be attributed to the facts below. As the atomic arrangement of the <110> plane itself was not dense originally, compression loading would cause an increasingly tighter arrangement. In such a case, the stress could only be released through dislocations. This research aims to provide a reference for optimizing the processing technology and preparation methods of aluminum-copper alloy materials.

Utilizing ubiquitous learning to foster sustainable development in rural areas: Insights from 6G technology

Rural education frequently grapples with demanding situations such as isolation, confined assets, and a virtual divide. The emergence of the sixth generation (6G) era, characterized by its speedy connectivity, minimal latency, and robust reliability, stands out as a beacon of desire, promising to revolutionize these educational landscapes by adopting ubiquitous Learning (U-Learning) environments. This research delves into the transformative skills of the 6G generation in rural schooling through U-Learning. It highlights 6G's position in ensuring identical entry to advanced instructional materials, fostering immersive and tailored learning stories, and permitting immediate interplay within virtual school rooms. Employing a combined-methods framework, this look intertwines an in-depth literature assessment with empirical inquiries, such as case studies, surveys, and dialogues with critical rural schooling stakeholders. It scrutinizes the prevailing situations of pastoral training, 6G's technological advancements, and the conditions for deploying green U-Learning ecosystems. The findings indicated significant improvements in educational resource access, student engagement, and learning outcomes due to implementing 6G technology. The key benefits observed were high-speed connectivity, reduced latency, and enhanced reliability, facilitating more interactive and immersive learning experiences. 6G emerges as a pivotal pressure in reshaping rural education, addressing essential problems of accessibility, pupil engagement, and academic excellence. Achieving this vision needs concerted efforts in infrastructure improvement, instructional programming tailored to 6G, and collaborative endeavors amongst all stakeholders. Future research should focus on developing specific 6G deployment strategies and educational programs tailored to the unique needs of rural populations.

Scalable In-situ Microfibrillar dielectric films: Achieving exceptional energy density and efficiency

It is a formidable challenge to develop a feasible strategy for the scalable fabrication of all-organic dielectrics with simultaneous improvements in both discharged energy density (Ud) and efficiency (η). Herein, an innovative technology of “melting extrusion-hot stretching-quenching” was put forward for the large-scale preparation of all-organic polymer dielectric films, where polymethyl methacrylate (PMMA) was miscible with polyvinylidene fluoride (PVDF) to form single dispersed phase in the polypropylene (PP) matrix and in-situ transformed into microfibrils with the aid of elongational flow field. Thereby, a simultaneous enhancement in the dielectric constant and breakdown strength was achieved and the as-prepared PP-based all-polymer dielectric film exhibited an unprecedented ultrahigh Ud of 9.6 J cm−3 and an exceptional η of 90.9 %. Experimental verification and computational simulation confirmed that the formation of highly oriented PMMA/PVDF microfibrils and well-aligned interfaces are constructive to enhancing breakdown strength by suppressing electric field distortion. The highly oriented dipoles in PVDF and PMMA, coupled with the eliminated ferroelectric behavior of PVDF, synergistically contributed to the heightened Ud and η. The approach presented in this work opens up a promising avenue for the large-scale production of all-organic capacitor films with enhanced Ud and η, heralding a new era of advanced dielectric materials.

Spectroscopic and solution properties characterization of quaternary ammonium ion containing polycations complexed with fluorescent rhodamine sulfonic acid dyes

Based on the growing range of applications for polycations in research and commercial materials, a continuing need exists to advance the fundamental knowledge and understanding of this class of materials. Spectroscopic and solution properties characterizations of noncovalently labeled, fluorescent Alexa Fluor® dye complexes of two commercial polycations, poly(2-(trimethylamino) ethyl methacrylate) monocation and poly[bis[2-chloroethyl] ether-alt-1,3-bis[3-(dimethylamino) propyl] urea] dication are reported to help address this need. A variety of fluorescence spectroscopic methods are used with a special emphasis on fluorescence correlation spectroscopy (FCS) which is applied to characterize the Stokes radius (RS) and equilibrium dissociation constants (Kd) of dye-polycation complexes at nanomolar dye concentrations. Resulting RS values indicate dye binding to individual polycation chains. Measured Kd values in the sub-micromolar range are consistent with strong dye binding. Increasing solution ionic strength with sodium chloride addition inhibits dye binding and decreases the RS of dye-polycation complexes due to size collapse of polycation chains. The complexes differ in their solution stability to ionic strength changes suggesting that both electrostatic and hydrophobic binding interactions influence dye binding. This study establishes the viability of noncovalent dye-polycation complexation in concert with FCS characterization as a general approach for investigating the properties of quaternary ammonium ion containing polycations in aqueous solution.

Diffusion enhancement by spontaneous formation of Frenkel defects in NaCl-type high-entropy materials

High-entropy materials (HEMs) are attracting attention due to their exceptional properties, such as enhanced mechanical toughness, irradiation resistance, ionic conductivity, and thermoelectric performance. Although diffusion is an important phenomenon as it is closely related to these physical properties of materials, there is a lack of understanding of the mechanisms of diffusion due to the complexity of the atomic interactions in HEMs. Here, we investigates diffusion mechanisms in PbTe-based HEMs AgInSnPbBiTe5, focusing on the role of indium (In). Molecular dynamics simulations reveal that In+ spontaneously forms Frenkel defect and enhancing diffusion not only of In+ but also other cations. Furthermore, as a result of enhanced diffusion, short-range order is formed by structural relaxation. This insight not only enhances comprehension of HEMs diffusion mechanisms but also develops HEMs with properties such as self-healing from damage and high ion permeability, advancing the field of material science.

AMGPT: A large language model for contextual querying in additive manufacturing

Generalized large language models (LLMs) such as GPT-4 may not provide specific answers to queries formulated by materials science researchers. These models may produce a high-level outline but lack the capacity to return detailed instructions on manufacturing and material properties of novel alloys. We introduce “AMGPT”, a specialized LLM text generator designed for metal AM queries. The goal of AMGPT is to assist researchers and users in navigating a curated corpus of literature. Instead of training from scratch, we employ a pre-trained Llama2-7B model from Hugging Face in a Retrieval-Augmented Generation (RAG) setup, utilizing it to dynamically incorporate information from ∼50 AM papers and textbooks in PDF format. Mathpix is used to convert these PDF documents into TeX format, facilitating their integration into the RAG pipeline managed by LlamaIndex. A query retrieval function has also been added, enabling the system to fetch relevant literature from Elsevier journals based on the context of the query. Expert evaluations of this project highlight that specific embeddings from the RAG setup accelerate response times and maintain coherence in the generated text.

Chiral liquid crystal dimers with smectic phases for stabilization of anticlinic state in surface-stabilised geometry

The growing demand for enhanced optical quality and faster electro-optical response in liquid crystal (LC) photonic devices has expanded the search for advanced materials capable of improving the properties of LCs beyond conventional ones. Among these compounds are LC dimers with ferroelectric and antiferroelectric properties which can be incorporated into LC mixtures to enhance performance. However, existing dimers often feature high melting temperatures, enthalpies, and other physicochemical characteristics that render them unsuitable as dopants in antiferroelectric liquid crystal (AFLC) mixtures targeted to modern photonic devices. Here, we show the design and physicochemical properties of novel dimers which are characterized by low melting points, high tilt angles and spontaneous polarizations, temperature-stable helical structures, and reasonably broad temperature ranges of ferroelectric or antiferroelectric phases. These features have facilitated the effective use of one dimer as a dopant in AFLCs. This eliminates the primary drawback of the electro-optical effect based on the surface-stabilised geometry of AFLCs by strongly promoting the anticlinic state in this effect. Importantly, for the first time, the above can be achieved without affecting any other physicochemical or optical properties of AFLCs. Thus, the obtained results represent a pivotal link between the longstanding concept of developing AFLCs that meet the stringent requirements for electro-optical effects based on surface-stabilised geometry and the realization of novel photonic devices demonstrating all the benefits of this effect.

Mechanical and hydraulic characteristics of unvegetated or vegetated loess soils amended with xanthan gum

With the development of western and central China, the increasing construction of transportation infrastructures (e.g., roads, railways, etc.) has been producing a large number of man-made slopes in loess regions. Biopolymer as an eco-friendly stabilizing material, has a great potential to amend soils for the purpose of ground improvement and slope stabilization, with its application in vegetated soils particularly at the initial growing stage to support vegetation growth as well as offer reinforcement to unprotected soils being reported recently. In the current study, the contribution of xanthan gum (XG) to both mechanical and hydraulic behaviors of the unvegetated and vegetated loess soils subjected to climatic wetting–drying cycles under the impacts of degree of compaction and biopolymer content are explored, whilst the effectiveness of the two XG-based soil reinforcing methods (with and without vegetation) are compared. Results indicate that XG treatment improved the water-retention capacity of loess soils to an extent that even the degradation of water retention upon initial wetting–drying cycles could be mitigated particularly at higher degrees of compaction. The strengthened shear resistance of loess soils was observed, mainly attributed to the increased soil cohesion, whilst the friction angle remained almost constant. The unvegetated loess soils basically had an increased cohesion proportional to the XG content up to 1.00% of the dry soil mass, whilst the vegetated soils had the highest soil cohesion at a fixed XG content of 0.50% which corresponded to the mostly promoted vegetation growth. Although a dense soil structure inhibited the seed germination and growth of sprouts and roots, it contributed to the overall shear strength of the vegetated soils similar to its effect on the unvegetated soils. XG amendment outperformed planting vegetation at enhancing soil shear strength at a degree of compaction of 95% (comparable to those adopted for design of highway subgrade), whilst providing XG in combination with vegetation was able to result in a more sizable strength increment over the summation of gains in strength by utilizing XG and vegetation separately, suggesting the considerable potential of XG in assisting vegetated soils for ecological slope stabilization. The results obtained from the current research support the broader usage of biopolymers (either used alone or in combination with vegetation) as reliable geotechnical engineering materials in practical implementations.

Evaporation of a water droplet on composite materials Cu-SiC, Cu/G and alloy AlMg3: Modeling the wettability of a metal-matrix composite with MDS

Composite materials are widely used in technology. The choice of exact composite material depends on its purpose, functional properties, stability of parameters over time, and specific conditions of use. In this work, the wettability of various materials was studied. The materials used were processed in two ways: polishing and laser texturing with and without craters. The surface wettability using molecular dynamics methods was modeled when changing the concentration of the reinforcing component in the composite. The crystalline grain orientation and surface roughness of the Cu-SiC composite after texturing is different from Cu, which is important to consider when modeling the wettability. The sensitivity of the wettability of various materials to the surface temperature (Δθ0/ΔTw) was studied experimentally. The maximum sensitivity of the contact angle to temperature was found for the superhydrophobic surface. The minimum sensitivity was observed for polished AlMg3 surface. Power-law dependences of the evaporation rate of water droplet on the contact angle were obtained for various materials in the temperature range of 25–90 °С. As the droplet diameter increases, the influence of the wetting diameter on the evaporation rate decreases, while that of convection increases. The data obtained can be useful for the development of composite materials technologies and optimization of their functional properties.