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The identification of similarities in the material requirements for applications of interest and those of living organisms provides opportunities to use renewable natural resources to develop better materials and design better devices. In our work, we harness this strategy to build high-capacity silicon (Si) nanopowder—based lithium (Li)—ion batteries with improved performance characteristics. Si offers more than one order of magnitude higher capacity than graphite, but it exhibits dramatic volume changes during electrochemical alloying and de-alloying with Li, which typically leads to rapid anode degradation. We show that mixing Si nanopowder with alginate, a natural polysaccharide extracted from brown algae, yields a stable battery anode possessing reversible capacity eight times higher than that of the state-of-the-art graphitic anodes.

The polyimide cross-linked silica aerogels (PI -SiO 2 ) was constructed at the atomistic level. The specific volume-temperature curves of the materials at different crosslinking rate were simulated by molecular dynamics. The glass transition temperature of the material was obtained, which was consistent with the results obtained by free volume fraction and mean square displacement. The higher the crosslinking rate, the higher the glass transition temperature. At the same time, the free volume fractions of the material in the rubbery state, transition state and glassy state were analyzed. It was found that the free volume fractions of the material in the rubbery state and glassy state were mainly affected by the degree of crosslinking, while the free volume fraction of the material in the transition state was affected by the crosslinking bond. In this paper, the basic factors affecting the glass transition temperature are explained from the molecular level by studying the changes of the free volume fraction in the material. Combined with the analysis of self-diffusion coefficient, the influence of molecular chain motion on the properties of materials is revealed.

Nanoparticles assemble at the interface between two fluids into disordered, liquid-like arrays where the nanoparticles can diffuse laterally at the interface. Using nanoparticles dispersed in water and amine end-capped polymers in oil, nanoparticle surfactants are generated in situ at the interface overcoming the inherent weak forces governing the interfacial adsorption of nanoparticles. When the shape of the liquid domain is deformed by an external field, the surface area increases and more nanoparticles adsorb to the interface. Upon releasing the field, the interfacial area decreases, jamming the nanoparticle surfactants and arresting further shape change. The jammed nanoparticles remain disordered and liquid-like, enabling multiple, consecutive deformation and jamming events. Further stabilization is realized by replacing monofunctional ligands with difunctional versions that cross-link the assemblies. The ability to generate and stabilize liquids with a prescribed shape poses opportunities for reactive liquid systems, packaging, delivery, and storage.

Single-molecule fluorescence techniques 1 , 2 , 3 are key for a number of applications, including DNA sequencing 4 , 5 , molecular and cell biology 6 , 7 and early diagnosis 8 . Unfortunately, observation of single molecules by diffraction-limited optics is restricted to detection volumes in the femtolitre range and requires pico- or nanomolar concentrations, far below the micromolar range where most biological reactions occur 2 . This limitation can be overcome using plasmonic nanostructures, which enable the confinement of light down to nanoscale volumes 9 , 10 , 11 , 12 , 13 . Although these nanoantennas enhance fluorescence brightness 14 , 15 , 16 , 17 , 18 , 19 , 20 , large background signals 20 , 21 , 22 and/or unspecific binding to the metallic surface 23 , 24 , 25 have hampered the detection of individual fluorescent molecules in solution at high concentrations. Here we introduce a novel ‘antenna-in-box’ platform that is based on a gap-antenna inside a nanoaperture. This design combines fluorescent signal enhancement and background screening, offering high single-molecule sensitivity (fluorescence enhancement up to 1,100-fold and microsecond transit times) at micromolar sample concentrations and zeptolitre-range detection volumes. The antenna-in-box device can be optimized for single-molecule fluorescence studies at physiologically relevant concentrations, as we demonstrate using various biomolecules. A plasmonic nanoantenna enables a thousand fold-enhanced fluorescence brightness allowing single-molecule analysis to be carried out in a zeptolitre volume at physiological concentrations.

This paper addresses the modeling of the iron ore direct reduction process, a process likely to reduce CO2 emissions from the steel industry. The shaft furnace is divided into three sections (reduction, transition, and cooling), and the model is two-dimensional (cylindrical geometry for the upper sections and conical geometry for the lower one), to correctly describe the lateral gas feed and cooling gas outlet. This model relies on a detailed description of the main physical–chemical and thermal phenomena, using a multi-scale approach. The moving bed is assumed to be comprised of pellets of grains and crystallites. We also take into account eight heterogeneous and two homogeneous chemical reactions. The local mass, energy, and momentum balances are numerically solved, using the finite volume method. This model was successfully validated by simulating the shaft furnaces of two direct reduction plants of different capacities. The calculated results reveal the detailed interior behavior of the shaft furnace operation. Eight different zones can be distinguished, according to their predominant thermal and reaction characteristics. An important finding is the presence of a central zone of lesser temperature and conversion.

Purpose This paper aims to present a first step toward developing a comprehensive methodology for fully resolved numerical simulations of fusion deposition modeling (FDM). Design/methodology/approach A front-tracking/finite volume method previously developed for simulations of multiphase flows is extended to model the injection of hot polymer and its cooling down. Findings The accuracy and convergence properties of the new method are tested by grid refinement, and the method is shown to produce convergent solutions for the shape of the filament, the temperature distribution, contact area and reheat region when new filaments are deposited on top of previously laid down filaments. Research limitations/implications The present paper focuses on modeling the fluid flow and the cooling. The modeling of solidification, volume changes and residual stresses will be described in Part II. Practical implications The ability to carry out fully resolved numerical simulations of the fusion deposition process is expected to help explore new deposition strategies and provide the “ground truth” for the development of reduced-order models. Originality/value The present paper is the first fully resolved simulation of the deposition in fusion filament modeling.

Gd 2 O 3 -doped glasses in the B 2 O 3 –CaO–Na 2 O–SrO–P 2 O 5 system were synthesized via melt annealing route and characterized through physical properties. With the replacement of CaO by Gd 2 O 3 , the measured values of the density ( d s ), Gd 3+ ions concentration (N), packing density (P d ), oxygen packing density (OPD), Vickers’s hardness (H V ), and field strength (F) of the synthesized samples increased, whereas the molar volume ( V m ), free volume ( V f ), polaron radius ( r p ), average boron–boron distance ( d B–B ), and inter-nuclear distance ( r i ) decreased. The glassy nature of the synthesized samples is confirmed by the X-ray diffraction patterns. The change in the coordination number of boron and the different B–O vibrational bands with the incorporation of gadolinium ions in the investigated glass samples were examined by Raman and FTIR spectroscopy, which supported the presence of BO 3 , BO 4 , and GdO 4 groups.

The method of thermodynamic modeling was used to determine composition and thermophysical properties of a gas-plasma phase of a system of radioactive graphite - water vapor in the temperature range from 1000 to 3200 K. It has been established that in the temperature range from 1000 to 1100 K, the main components of the gas-plasma phase are H2, CO, H2O, CO2, CH4. In the temperature range from 1100 to 2200 K - H2, CO, H2O, CO2. At temperatures from 2200 to 2600 K those are H2, CO, H2O, CO2, H. In the temperature range from 2600 to 3000 K those are H2, CO, H2O, CO2, H, OH. In the temperature range from 3000 to 3200 K those are H2, CO, H2O, H, CO2, OH, O, O2. The thermophysical properties of the system under consideration have been calculated: specific volume, entropy, enthalpy, total internal energy, number of moles in the system.

The sorption properties of synthetic zeolites HF 512O and NaX were studied. In the course of the study, the volume method obtained the sorption capacities of zeolites for nitrogen and oxygen. The experimental setup for determining the sorption capacity by volumetric method consisted of two tanks. The first tank has a known volume, and the second tank is filled with the studied sorbent. Helium was used to determine the free volume of the second tank. The gas sorption capacity of which must be determined is fed to the first tank, the second tank is pumped out using a vacuum pump, after which the tanks are connected and the separation in the tanks is leveled. Thus, the sorption capacity of the sorbent can be calculated based on the pressure drop in the system. The selectivity of sorbents for the nitrogen - oxygen pair for pure gases was calculated.

In the paper, the pressure and temperature response of the containment with free volume 1400m3 and 2000 m3 is analyzed based on the mass and energy release for postulated loss of coolant accident (LOCA). And the relation between containment free volume and containment pressure also is analyzed. The results of calculation have certain guiding significance for the determination of the pressurized water reactor (PWR) volume.