Microscopic Structure Properties Research Articles

Dense and continuous networks of aerial hyphae improve flexibility and shape retention of mycelium composite in the wet state

The mycelium composites composed of fungal mycelium and plant substrate are a practical alternative to petroleum plastic-based foam materials. However, the effects of the physiological traits of fungus on the composites’ microscopic structure and mechanical properties remain poorly understood. Here, we compared two basidiomycetes with distinct mycelium morphology and white-decay modes. Cross-sectional observation revealed that the mycelium composites possess a core/shell structure with the shell formed of dense aerial mycelium and the core of plant particles and spongy aerial mycelium. Dense and continuous mycelium networks provided by Trametes hirsuta strengthen the mechanical properties of the composite compared to the coarse mycelium networks of Pleurotus ostreatus. In particular, the firm mycelial shell skeleton confers high flexibility and shape-retention to the composite in the wet state. This unique characteristic of the mycelium composite indicates its potentials in new industrial applications.

Recycling of municipal solid waste incineration fly ash in foam ceramic materials for exterior building walls

In this study, municipal solid waste incineration fly ash (MSWI FA) and waste glass were used as the main raw materials to prepare foam ceramics, which have good application prospects as exterior building insulation materials. The effects of different ratios of MSWI FA to waste glass and firing temperature on the physical properties, microscopic structure, and heavy metal leaching properties of foam ceramics were studied. The results showed that when the MSWI FA content was 30 wt%, the apparent porosity of the samples fired at 1090 °C was 70.3%, the compressive strength was 7.94 MPa, the bulk density was 0.79 g/cm3, and the thermal conductivity at room temperature was 0.071 W/(m·K). The mean pore size of the samples was 31.77 μm. In addition, the results of heavy metal leaching showed that the foam ceramics were compliant with industry standards. Therefore, the preparation of foam ceramics from MSWI FA and waste glass is a promising method to realise efficient recycling as well as reduce product costs.

Colloidal structure and proton conductivity of the gel within the electrosensory organs of cartilaginous fishes

SummaryCartilaginous fishes possess gel-filled tubular sensory organs called Ampullae of Lorenzini (AoL) that are used to detect electric fields. Although recent studies have identified various components of AoL gel, it has remained unclear how the molecules are structurally arranged and how their structure influences the function of the organs. Here we describe the structure of AoL gel by microscopy and small-angle X-ray scattering and infer that the material is colloidal in nature. To assess the relative function of the gel's protein constituents, we compared the microscopic structure, X-ray scattering, and proton conductivity properties of the gel before and after enzymatic digestion with a protease. We discovered that while proteins were largely responsible for conferring the viscous nature of the gel, their removal did not diminish proton conductivity. The findings lay the groundwork for more detailed studies into the specific interactions of molecules inside AoL gel at the nanoscale.

Functionalized Attapulgite for the Adsorption of Methylene Blue: Synthesis, Characterization, and Adsorption Mechanism.

Attapulgite (denoted as APT, also called palygorskite) has been regarded as the green material in the “21st century world” and has attracted widespread attention due to its advantages of low cost, natural abundance, nontoxic nature, and environmental friendliness. However, the limited adsorption sites and surface charges of natural APT greatly hinder its application as an adsorbent in industrial fields. In this work, natural APT was modified with sodium humate (SA) via a facile one-step hydrothermal process to improve its adsorption capacity and systematically studied its ability to remove methylene blue (MB) from aqueous solutions. The effect of hydrothermal modification in the presence of SA on the microscopic structure, morphology, and physicochemical properties of APT was studied by field-emission scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffraction, and Brunauer–Emmett–Teller analyses. The adsorption properties of the modified APT toward MB were evaluated systematically. The results demonstrated that the modified APT has a high adsorption capacity of 227.27 mg/g and also shows a high removal rate up to 99.7% toward MB in a dye solution with an initial concentration of 150 mg/L, which was a 64.7% increase as compared to that of raw APT. The adsorption kinetics could be fitted to the pseudo-second-order model, while the adsorption isotherm could be well-described with the Langmuir model. It was concluded that electrostatic attraction, hydrogen-bonding interaction, and chemical association are the main driving force during the adsorption process.

Pore structure and heterogeneity of shale gas reservoirs and its effect on gas storage capacity in the Qiongzhusi Formation

Fine characterization of pore systems and heterogeneity of shale reservoirs are significant contents of shale gas reservoir physical property research. The research on micro-control factors of low productivity in the Qiongzhusi Formation (Fm.) is still controversial. The lower Cambrian Qiongzhusi Fm. in the Qujing, Yunnan was taken as the object to investigate the influence of mineral compositions on the physical properties of the reservoir and the heterogeneity of shale, using the algorithm to improve the characterization ability of Atomic Force Microscopy (AFM). The results showed that: (1) The pores are mainly wedge-shaped pores and V-shaped pores. The pore diameter of the main pore segment ranges from 5 to 10 nm. Mesopores are mainly developed in the Qiongzhusi Fm. shale in Well QD1, with the average pore diameter of 6.08 nm. (2) Microscopic pore structure and shale surface properties show strong heterogeneity, which complicates the micro-migration of shale gas and increases the difficulty of identifying high-quality reservoirs. (3) The increase of clay mineral content intensifies the compaction and then destroys the pores. Conversely, brittle minerals can protect pores. The support and protection of brittle minerals to pores space depend on their content, mechanical properties and diagenesis. (4) Compression damage to pores, large microscopic roughness and surface fluctuations and strong pore structure heterogeneity are the reasons for the poor gas storage capacity of the Qiongzhusi Fm., which will lead to poor productivity in the Qiongzhusi Fm.

Interaction between gliadin/glutenin and starch granules in dough during mixing

In order to explore the interaction between gliadin/glutenin (gli/glu) and starch granules, rheological, microscopic and molecular structural properties of gluten-starch dough with varied gli/glu ratios during mixing was investigated. The effect of gli/glu ratio on dough elasticity (G′) and strength (extension resistance) depended on the mixing state. The increase in gliadin ratio could weaken the dough strength at optimum-mixing stage while enhance it at under and over-mixing stages. At optimum stage, increasing gliadin could embed in and reduce the intermolecular attraction of glutenins, leading to lower stability (higher z values) of dough. At under and over-mixing stages, increasing gliadin could promote the formation of a temporary gli/glu-starch physical network structure, leading to higher stability (lower z values). Polymerization or depolymerization of glutenin macropolymer (GMP) depended on both the gli/glu ratio and mixing time, which could be correlated to the changes in rheological behaviors. The cohesiveness of glutenin caused large clumps in dough with high glutenin content, while the increase in gliadin ratio was favor for the dispersion of glutenin, promoting the formation of gluten network. Covalent and hydrogen bonds were the main interactions for high glutenin content dough, while hydrophobic and hydrogen interaction became predominate with increasing gliadin ratio.

Study on the Effect of High-Temperature Heat Treatment on the Microscopic Pore Structure and Mechanical Properties of Tight Sandstone

The investigation of changes in physical properties, mechanical properties, and microscopic pore structure characteristics of tight sandstone after high-temperature heat treatment provides a theoretical basis for plugging removal and stimulation techniques, such as high energy gas fracturing and explosive fracturing. In this study, core samples, taken from tight sandstone reservoirs of the Yanchang Formation in the Ordos Basin, were first heated to different temperatures (25-800°C) and then cooled separately by two distinct cooling methods—synthetic formation water cooling and natural cooling. The variations of wave velocity, permeability, tensile strength, uniaxial compressive strength, and microscopic pore structure of the core samples were analyzed. Experimental results demonstrate that, with the rise of heat treatment temperature, the wave velocity and tensile strength of tight sandstone decrease nonlinearly, yet its permeability increases nonlinearly. The tight sandstone’s peak strength and elastic modulus exhibit a trend of the first climbing and then declining sharply with increasing temperature. After being treated by heat at different temperatures, the number of small pores varies little, but the number of large pores increases obviously. Compared to natural cooling, the values of physical and mechanical properties of core samples treated by synthetic formation water cooling are apparently smaller, whereas the size and number of pores are greater. It can be explained that water cooling brings about a dramatic reduction of tight sandstone’s surface temperature, generating additional thermal stress and intensifying internal damage to the core. For different cooling methods, the higher the core temperature before cooling, the greater the thermal stress and the degree of damage caused during the cooling process. By taking into consideration of changes in physical properties, mechanical properties, and microscopic pore structure characteristics, the threshold temperature of tight sandstone is estimated in the range of 400-600°C.

Preparation of carbon/silica composite aerogel and application of fire insulation

In order to improve the disadvantages of aerogel brittleness and easy structural destruction during drying, carbon/silica dual network aerogel composites were constructed by copolymerizing carboxylated carbon nanotubes and tetraethyl orthosilicate decomposition products on chitosan templates. The composites were characterized by microscopic morphology and structural properties. The results show that the bulk carbon/silica aerogel composites can be prepared by freeze-drying through the reinforcement of chitosan templates and carbon nanotubes. The N2 adsorption and desorption curves of the composites show a type IV curve. The thermal conductivity of the material is only 0.0375 W/(m*K) at higher temperatures, which does not change much compared to that at room temperature (0.0312 W/(m*K)).

Comparison and analysis of one- and two-step activation for preparation of activated carbon from furfural residues

Activated carbon (AC) was prepared from furfural residue (FR) in a horizontal tube reactor under a carbon dioxide atmosphere comparing one- and two-step activation methods. Considerable differences were observed between ACs produced from these two methods in microscopic morphology, structural properties, organic structure, and crystallinity. It showed that the AC obtained by one-step activation (800 oC, 20 min, K2CO3: FR = 0.5:1) exhibited microporous and alkaline surface characteristics, and achieved the highest iodine value of 1305.7 mg/g and BET surface area 2083.6 m2/g. While, for the two-step method, the iodine value was 1004.9 mg/g and the BET surface area was only 726.3 m2/g. Furthermore, one-step activation obtained a higher yield of high-quality AC in a shorter activation time than the two-step method. The adsorption data fitted well with the Redlich-Peterson isotherm model and reached the highest value of 1761.1 mg/g, while the adsorption kinetics agreed well with the pseudo-second-order model.

Biodiesel production from alternative raw materials using a heterogeneous low ordered biosilicified enzyme as biocatalyst

BackgroundCumulative reported evidence has indicated that renewable feedstocks are a promising alternative source to fossil platforms for the production of fuels and chemicals. In that regard, the development of new, highly active, selective, and easy to recover and reuse catalysts for biomass conversions is urgently needed. The combination of enzymatic and inorganic heterogeneous catalysis generates an unprecedented platform that combines the advantages of both, the catalytic efficiency and selectivity of enzymes with the ordered structure, high porosity, mechanical, thermal and chemical resistance of mesoporous materials to obtain enzymatic heterogeneous catalysts. Enzymatic mineralization with an organic silicon precursor (biosilicification) is a promising and emerging approach for the generation of solid hybrid biocatalysts with exceptional stability under severe use conditions. Herein, we assessed the putative advantages of the biosilicification technology for developing an improved efficient and stable biocatalyst for sustainable biofuel production.ResultsA series of solid enzymatic catalysts denominated LOBE (low ordered biosilicified enzyme) were synthesized from Pseudomonas fluorescens lipase and tetraethyl orthosilicate. The microscopic structure and physicochemical properties characterization revealed that the enzyme formed aggregates that were contained in the heart of silicon-covered micelles, providing active sites with the ability to process different raw materials (commercial sunflower and soybean oils, Jatropha excisa oil, waste frying oil, acid oil from soybean soapstock, and pork fat) to produce first- and second-generation biodiesel. Ester content ranged from 81 to 93% wt depending on the raw material used for biodiesel synthesis.ConclusionsA heterogeneous enzymatic biocatalyst, LOBE4, for efficient biodiesel production was successfully developed in a single-step synthesis reaction using biosilicification technology. LOBE4 showed to be highly efficient in converting refined, non-edible and residual oils (with high water and free fatty acid contents) and ethanol into biodiesel. Thus, LOBE4 emerges as a promising tool to produce second-generation biofuels, with significant implications for establishing a circular economy and reducing the carbon footprint.

Introduction of 5,6-dihydro-4H-cyclopenta[b]thiophene core unit into phenyl-tolane: Expanding the mesophase range and increasing the birefringence and dielectric anisotropy of liquid crystal

ABSTRACT Six novel phenyl-tolane type liquid crystals based on 5,6-dihydro-4 H-cyclopenta[b]thiophene core were designed and synthesised by Sonogashira coupling reactions in high yields. Two reference compounds were then used to clarify the effects of this new core on the mesomorphic behaviours and physical properties of phenyl-tolane type mesogens and found that these new core-based mesogens possessed wider mesophase ranges. Both the birefringence (Δn) and dielectric anisotropy (Δε) values were increased after the employment of this new core, offering an alternative option for the design and synthesis of high-performance phenyl-tolanes. The geometry, ultraviolet absorption, polarisability (α) and dipole moment (μ) of two representative compounds and their references were calculated by density functional theory to correlate the structure–property relationship of the new mesogens. The calculated energy minimum structures of the new mesogens showed well linearity and the molecular length/width ratio was increased, which would benefit the formation of the nematic phase. The orders of the calculated polarisability (α) and dipole moment (μ) of two representative compounds and their references were in accordance with the sequences of the measured birefringence (Δn) and dielectric anisotropy (Δε) values, respectively, which might shed light on the correlation between microscopic molecular structure and macroscopic physical properties.

Spatially Resolved Optical Characterization of Functional Materials Using Coherence Scanning Interferometry

Herein, some of the work in adapting white light interference microscopy to perform local spectroscopy for measuring the optical properties of microscopic structures is reviewed. Theoretical and experimental results are shown in which Fourier transform processing of the polychromatic fringe signal combined with careful calibration of the optical system is used to make measurements of local reflectance spectra. This approach captures the spectral information within the entire field of view in a single scan, allowing rapid spectral mapping of spatially extended surfaces. Results are shown of local reflectance spectra measured on different materials and buried under transparent layers with a lateral spot size of between 0.5 μm and several micrometer over a field of view up to 650 × 650 μm. The technique is extended to the measurement of local refractive index and thickness of transparent layers as well as to the size determination of small spherical beads buried in transparent and scattering layers with a priori information. The significance of the work is the potential for local materials characterization in complex, hybrid, and functional materials and even disease detection through the study of living cells.

Construction of rGO@Ti/SnO2–Sb composite electrode for electrochemical degradation of fluoroquinolone antibiotic

Efficient and stable [email protected]/SnO2–Sb composite electrodes were prepared by the sol-gel method. The microscopic morphology, crystal structure, and electrochemical properties of the [email protected]/SnO2-Sb composite electrodes were characterized by a range of characterization techniques. The electrocatalytic oxidation activity of the electrodes was evaluated by the degradation efficiency of the fluoroquinolone antibiotic norfloxacin (NOR). Simultaneously, the effects of different experimental conditions on the degradation efficiency of NOR were also investigated, such as calcination temperatures, brushing times, initial pH, initial electrolyte concentration, etc. The enhanced electrocatalytic oxidation activity can be attributed to the excellent electron transfer efficiency, higher electrode specific surface area, and stronger adhesion of the electrode coating to the substrate. Additionally, the possible NOR degradation pathway was deduced through the main intermediates, and the mechanism of NOR degradation was discussed based on experimental and characterization results. This work provides a simple and effective method to prepare highly active composite electrodes for electrocatalytic oxidation to remove organic pollutants from water.

Effect of Extrusion Temperature and Thermal Treatment on Microstructure and Mechanical Properties of Ti-1300 Alloy Tube

Effects of extrusion temperature and heat treatment process on the microstructure and mechanical properties of Ti-1300 titanium alloy tube billets were studied by tensile testing and microstructure observation, and the relationship among the thermal processing technique and microscopic structure and mechanical properties of the billets were also investigated. The results showed that the transverse structure of Ti-1300 alloy after extrusion in the a+b two-phase region was uniform and fine. And the longitudinal structure could be seen that the extrusion processing streamline was broken uniformly. Ti-1300 alloy extruded at a+b two-phase has a good match of the strength and ductility, and the ductility of two-phase extrusion is obviously better than that of β single-phase extrusion, especially for the reduction of area.

How do the doping concentrations of N and B in graphene modify the water adsorption?

Understanding the interaction of water and graphene is crucial for various applications such as water purification, desalination, and electrocatalysis. Experimental and theoretical studies have already investigated water adsorption on N- and B-doped graphene. However, there are no reports available that elucidate the influences of the N and B doping content in graphene on the microscopic geometrical structure and the electronic properties of the adsorbed water. Thus, this work is devoted to solving this problem using self-consistent van der Waals density functional theory calculations. The N and B doping contents of 0.0, 3.1, 6.3, and 9.4% were considered. The results showed that the binding energy of water increases almost linearly as a function of doping content at all concentrations for N-doped graphene but below 6.3% for B-doped graphene. In the linear range, the binding energy increases by approximately 30 meV for each increment of the doping ratio. Analyses of the geometric and electronic structures explained the enhancement of the water–graphene interaction with the variation in doping percentage.

Colloidal Structure and Proton Conductivity of the Gel within the Electrosensory Organs of Cartilaginous Fishes

Cartilaginous fishes possess gel-filled tubular sensory organs called Ampullae of Lorenzini (AoL) that are used to detect electric fields. Although recent studies have identified various components of AoL gel, it has remained unclear how the molecules are structurally arranged and how their structure influences the function of the organs. Here we present the first structural description of AoL gel using microscopy and small angle x-ray scattering, revealing that the material is colloidal in nature. To assess the relative function of the gel’s protein constituents, we compared the microscopic structure, x-ray scattering, and proton conductivity properties of the gel before and after digestion with proteolytic enzymes. We discovered that while proteins were largely responsible for conferring the stiffness of the gel, their removal did not diminish proton conductivity. The findings described here lay the groundwork for more detailed studies into the specific interactions of molecules inside AoL gel at the nanoscale.

Coal Structure and Its Implications for Coalbed Methane Exploitation: A Review

Coal structure refers to the internal structural characteristics of coals including the degree of macroscopic and microscopic deformation, pore structure, and mechanical properties after various ge...

Assessment of Mixing Properties of Liquid Cu-Sb Alloy at Different Temperatures

The addition of copper (Cu) can decrease the toxicity of the most usable element antimony (Sb). Concentration-dependent thermodynamic, microscopic structural and transport properties of Cu-Sb melt at different temperatures were examined using the quasi-lattice theory of mixing. Moelwyn-Hughes’s approach was implemented for the computation of viscosity. Liquid Cu-Sb shows the segregating nature in the Sb rich region and the ordering nature in the Cu rich region at the temperature range of 1190-1490 K. The viscosity of the respective alloy decreases with an increase in temperature.

Curvature effects on electric-double-layer capacitance

Understanding the microscopic structure and thermodynamic properties of electrode/electrolyte interfaces is central to the rational design of electric-double-layer capacitors (EDLCs). Whereas practical applications often entail electrodes with complicated pore structures, theoretical studies are mostly restricted to EDLCs of simple geometry such as planar or slit pores ignoring the curvature effects of the electrode surface. Significant gaps exist regarding the EDLC performance and the interfacial structure. Herein the classical density functional theory (CDFT) is used to study the capacitance and interfacial behavior of spherical electric double layers within a coarse-grained model. The capacitive performance is associated with electrode curvature, surface potential, and electrolyte concentration and can be correlated with a regression-tree (RT) model. The combination of CDFT with machine-learning methods provides a promising quantitative framework useful for the computational screening of porous electrodes and novel electrolytes.

Effect of B, Al, Ga doping on the electronic structure and optical property of 4H-SiC system by the first principles calculation

In this paper, the microscopic electronic structure and related optical properties of the 4H-SiC (111) surface doped with B, Al, Ga elements are explored by first principles calculation methods. Compared with Al- and Ga-doped systems, the formation energy of B-doped system is found to be very small, showing excellent stability. The bandgaps of doped system decrease obviously, and an indirect bandgap is observed in all the systems. Charge density difference maps show that the covalency is increased after B doping and the iconicity is increased after Al and Ga doping. Moreover, due to the sharp increase in static dielectric constant and dielectric loss, the B-doped system can be used as the candidate for absorbing materials. In addition, the increase in the peak value of the absorption and reflectivity makes the doped systems more promising in the development of solar cells.