Here, we report on the fabrication of light-switchable and light-responsive membranes based on graphene oxide (GO) modified with azobenzene compounds. Azobenzene and para-aminoazobenzene were grafted ...onto graphene oxide layers by covalent attachment/condensation reaction prior to the membranes’ assembly. The modification of GO was proven by the UV-vis, IR, Raman and photoelectron spectroscopy. The membrane’s light-responsive properties were investigated in relation to the permeation of permanent gases and water vapors under UV and IR irradiation. Light irradiation does not influence the permeance of permanent gases, while it strongly affected that of water vapors. Both switching and irradiation-induced water permeance variation is described, and they were attributed to over 20% of the initial permeance. According to in situ diffraction studies, the effect is ascribed to the change to the interlayer distance between the graphene oxide nanoflakes, which increases under UV irradiation to ~1.5 nm while it decreases under IR irradiation to ~0.9 nm at 100% RH. The last part occurs due to the isomerization of grafted azobenzene under UV irradiation, pushing apart the GO layers, as confirmed by semi-empirical modelling.
Wet assembly is the most common method of joining parts in the aircraft industry. In this case, a layer of liquid sealant is applied to the contact surface of one of the parts, after which the ...structure is bolted. Despite the practical importance of this issue, until now there has been no mathematical model or software tool that would allow simulating the wet assembly process. This study is devoted to modeling the wet assembly process of large-scale aircraft structures, taking into account the flow of sealant applied between the joined parts. The original mathematical model includes a full two-way interaction of deformable parts and a viscous liquid sealant. Such effects as contact interaction of parts, the presence of the free surface of sealant layer, the sealant curing, deformation and loosening of fasteners are taken into account. The developed mathematical model is applied to the simulation of the assembly process of wing to fuselage upper joint. A special full-scale model has been developed in order to reproduce the effects observed in practical assembly. The numerous numerical experiments demonstrate these effects and illustrate how different parameters of the process affect both intermediate and final results of the assembly. The performed investigation shows how mathematical modeling can contribute to the improvement of existing and development of new technologies on the assembly lines of aircraft manufacturing companies, where any experiments are extremely expensive or simply impossible.
The assessment of the radiolytic stability of media is an important task in the fields of nuclear power engineering and radiochemistry. Such studies must be carried out in special laboratory ...conditions with the use of sources of ionizing radiation, which may increase personal doses of the staff. In addition, difficulties arise in studying the products of irradiated media. While it is impossible to abandon experiments to obtain reliable results in this area, computational methods of quantum chemistry can reduce the number of experiments and help understand the mechanisms of the reactions that occur during radiolysis. Here we would like to present a software shell of the Qb@ll program performing time‐dependent density functional theory simulations of the radiolysis process.
This article presents a software shell for the Qb@ll program performing TDDFT simulation of a high‐energy particle behavior as well as the example of water radiolysis modeling. The discussed PyRad package acts both as input generator and output analysis tool for a TDDFT calculation.
Materials discovery is a grand challenge for modern materials science. In particular, inverse materials design is aimed at the accelerated search for materials with human-defined target properties. ...Unfortunately, this is associated with various obstacles, such as incremental improvements of known compounds, unreported properties of synthesized materials, and chemically plausible "missing compounds." A machine-learning-based approach using unified compositional-structural representations is proposed to overcome the issues mentioned above. The validity of the proposed method has been approved by searching for functional materials-some previously known phases were "re-discovered." In addition to well-known superhard compounds, unconventional structures that have never been considered in this context were also presented. Analysis of the generated populations provided insights into the underlying quantitative structure-property relationships. This data-driven approach can be successfully applied to discover materials with arbitrary functionalities given a reliable experimental/computational database for the target property.
New computational framework has extended an inverse materials design over all the possible stoichiometric compounds.
Adaptive immune responses to newly encountered pathogens depend on the mobilization of antigen-specific clonotypes from a vastly diverse pool of naive T cells. Using recent advances in immune ...repertoire sequencing technologies, models of the immune receptor rearrangement process, and a database of annotated T cell receptor (TCR) sequences with known specificities, we explored the baseline frequencies of T cells specific for defined human leukocyte antigen (HLA) class I-restricted epitopes in healthy individuals.
We used a database of TCR sequences with known antigen specificities and a probabilistic TCR rearrangement model to estimate the baseline frequencies of TCRs specific to distinct antigens epitopespecificT-cells. We verified our estimates using a publicly available collection of TCR repertoires from healthy individuals. We also interrogated a database of immunogenic and non-immunogenic peptides is used to link baseline T-cell frequencies with epitope immunogenicity.
Our findings revealed a high degree of variability in the prevalence of T cells specific for different antigens that could be explained by the physicochemical properties of the corresponding HLA class I-bound peptides. The occurrence of certain rearrangements was influenced by ancestry and HLA class I restriction, and umbilical cord blood samples contained higher frequencies of common pathogen-specific TCRs. We also identified a quantitative link between specific T cell frequencies and the immunogenicity of cognate epitopes presented by defined HLA class I molecules.
Our results suggest that the population frequencies of specific T cells are strikingly non-uniform across epitopes that are known to elicit immune responses. This inference leads to a new definition of epitope immunogenicity based on specific TCR frequencies, which can be estimated with a high degree of accuracy in silico, thereby providing a novel framework to integrate computational and experimental genomics with basic and translational research efforts in the field of T cell immunology.
An array of highly oriented anatase nanoparticles was successfully prepared from NH
TiOF
with the assistance of polyetheleneglycol-400 at 450 °C. The study showed the stability of obtained layered ...TiO
-anatase close to 1200 °C. This research confirmed for the first time that the transition of mesocrystalline anatase to the rutile phase occurs between 1000 °C and 1200 °C, which is more than 400 °C higher than the transition of bulk TiO
due to the used precursor. A small quantity of K-phase nanowhiskers, which issued after 800 °C in the composite based on TiO
, stimulated a fourfold increase in photocatalytic performance. This study offers a new approach to the construction and preparation of effective nanocrystalline photocatalyst.
We report a feasible and high-throughput method for high-quality W-doped VO2 nanostructured epitaxial films on r-sapphire substrate fabrication. Single-phase, smooth vanadium dioxide thin films with ...uniform distribution of tungsten (up to 2.3%) are formed using the solvothermal process from ethylene glycol/water V4+ and W6+ solutions. Compositional analysis by X-ray photoelectron and energy-dispersive X-ray spectroscopy (XPS and EDX, respectively); structural analysis (X-ray diffraction, Raman spectroscopy, selected area electron diffraction (SAED)); and detailed analysis of the surface morphology and substrate–film interface using scanning electron microscopy, atomic force microscopy, and high-resolution transmission electron microscopy (SEM, AFM, HRTEM, respectively) confirm the formation of nanoscale (50–60 nm) epitaxial W:VO2 (M1) on r-sapphire with epitaxial relationships (100)VO2∥(101̅2)Al2O3 and 010VO2∥011̅0Al2O3. The nanostructured films demonstrate excellent terahertz (THz) transmission properties: a phase transition temperature of 31 °C, a huge THz modulation depth of over 60%, and broad bandwidth (≥2 THz) operation. Hence, they can be efficiently used as active material for tunable THz manipulation devices.
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