Low Si Concentration Research Articles

Effect of the addition of Ni and Cu on solidification microstructure evolution of Al-5Si-0.5Mg alloys

AbstractTo develop new high-performance hypoeutectic Al–Si–Mg alloys at elevated temperatures, it is often necessary to add alloying elements of Cu and Ni. The high-temperature strength of the most used Al–Si–Mg–Cu–Ni alloy depends on a load transfer from the α-Al matrix to the intermetallic compounds. However, there is still a lack of detailed investigation on the effects of the combined addition of Ni and Cu on the solidification microstructure evolution of Al–Si–Mg base alloys with a lower Si concentration. This investigation specifically addresses the effects of the addition of Cu or Cu and Ni on the solidification microstructure evolution of the Al–5Si–0.5Mg alloy. It was found that when Al–5Si–0.5Mg is alloyed with Cu or Cu and Ni, the solidus temperature decreases, while the freezing range of the Al–5Si–0.5Mg alloy increases. With the addition of Cu and even small amounts of Ni, the phases Al7Cu4Ni and Al5Cu2Mg8Si6 were predicted by TC simulations and also observed by SEM. With a higher Ni content, Al3Ni and Al3Ni2 also solidify. More importantly, the presence of Cu and Ni can partition into the α-AlSiFeMn phase and change the size and morphology of the α-AlSiFeMn phase. This investigation provides a helpful hint to the development of the high-performance Al–Si–Mg–Cu–Ni alloys with a simultaneous improvement of the thermal conductivity and mechanical properties.

Synthesis of Chabazite Zeolite via Faujasite Conversion Using 1‐(1‐Methylpropyl)‐4‐aza‐1‐azoniabicyclo[2.2.2]octane Hydroxide as Cost‐Effective Structure‐Directing Agent

Cu‐exchanged chabazite zeolite is the state‐of‐the‐art used on‐board catalyst for NOx selective reduction by ammonium (NH3‐SCR), and the zeolite is currently generated in the presence of N,N,N‐trimethyl‐1‐adamantylammonium hydroxide, serving as organic structure‐directing agent (OSDA). The expensiveness of this OSDA increases the catalyst production cost, while its low degradability brings about environmental concerns in post treatment of waste water. Here, a new type OSDA, 1‐(1‐methylpropyl)‐4‐aza‐1‐azoniabicyclo[2.2.2]octane hydroxide, is proposed to direct Faujasite‐to‐Chabazite inter‐zeolite conversion and generate chabazite with Si/Al ratio up to 7.2. The obtained zeolite possesses high hydrothermal stability for the high crystallinity, siliceous framework and low concentrations of Si(2Si, 2Al) sites. The Cu‐form catalyst exhibits better catalytic performance in standard NH3‐SCR process for the tiny crystallite size (35‐258 nm) and formation of highly dispersed copper sites. The synthesis offers a new type of OSDA to fabricate zeolites and expands the toolkit to regulate their physicochemical properties.

A Study of the Antioxidizing and Inhibiting Effects of the Alcoholic Extract of Sage Salvia Officinalis on Microorganisms

Objectives: A study of the antioxidizing and inhibiting effects of the sage salvia officinalis on microorganisms. Methods: Chemical constituents of sage leaves the percentage of the 98% ethanol extract of sage was 5.8% prepared in concentrations of 50, 100, 150 and 200 mg/ml, Antioxidizing and inhibiting effects on microorganisms, and sensory characteristics of the sage added biscuits. Results: Scanning electron microscope images, the structure of powder sage leaves which appear as long tubes and round crystals, Hight percent concentration of minerals carbon and oxygen while low concentrations of (Zn, Al, Na, Mg, Si, K, Co, Ca, and Ce) were also found. the percentage of the moisture, protein, fat and ash (11.09, 6.89, 13.14, 9.64) % respectively, the inhibition effect of sage leaves ethanol extract prepared in concentrations of 50, 100, 150 and 200 mg/ml on three bacteria and fungi species of disc method. maximum effect on all three bacteria species Escherichia coli, Staphylococcus aureus and Pseudomonas sp. was found with the concentration 50 and 100 mg/ml. compared with 150 and 200 mg/ml. It has been found that the 150 mg/ml concentration has the most inhibition effect on the three species of fungi studied Aspergillus niger, A. carbonarius, A. flavus. All extract concentration inhibited A. flavus, it was that the antioxidant activity, iron ion bonding, reducing power and the ability capture the hydrogen peroxide of sage ethanol extract increases with high concentrations. Peroxide values decreased with increased sage added biscuits percentage (0, 0.5, 0,75 and 1) w/w% in stored for periods. However, the sensory characteristics of the sage added biscuits samples were good and close to the standard biscuit control. Conclusions: Finally, we conclude that the sage plant has medicinal and nutritional benefits due to its antioxidant and antimicrobial activity.

Microsegregation Influence on Austenite Formation from Ferrite and Cementite in Fe–C–Mn–Si and Fe–C–Si Steels

The production reality of sheet steels from casting to the end product is such that in the cases of ultra- and advanced high-strength steels, we have to deal with the segregation of elements on macro- and microlevels. Both can have a significant impact on the microstructure formation and resulting properties. There are several production stages where it can influence the transformations, i.e., casting, hot rolling process and annealing after cold rolling. In the present work, we focus on the latter, and more specifically, the transformation from ferrite–cementite to austenite, especially the nucleation process, in cold-rolled material. We vary the levels of two substitutional elements, Mn and Si, and then look in detail at the microsegregation and nucleation processes. The classical nucleation theory is used, and both the chemical driving force and strain energy are calculated for various scenarios. In the case of a high Mn and high Si concentration, the nucleation can thus be explained. In the cases of high Mn and low Si concentrations as well as low Mn alloys, more research is needed on the nuclei shapes and strain energy.

High‐Temperature Oxidation Behavior of Cr‐Si Alloyed Press‐Hardened Steel in Comparison with 22MnB5 Steel

In the present study, a Cr–Si‐alloyed coating‐free press‐hardened steel (CF–PHS) is investigated and compared with the conventional 22MnB5 steel through a 60 min oxidation experiment at 1000–1200 °C. Compared to the 22MnB5 steel, the CF–PHS exhibits lower weight gain at 1000–1150 °C but a higher weight gain at 1200 °C. In the results, using scanning electron microscopy, energy‐dispersive spectroscopy, and X‐ray diffraction, it is revealed that the outer oxide layer of the CF–PHS consisted of Fe2O3 and Fe3O4, while its inner oxide layer is enriched with FeCr2O4 and Fe2SiO4—crucial for the oxidation resistance of the CF–PHS. The outer oxide layer of 22MnB5 comprises Fe2O3, Fe3O4, and FeO, while the inner layer contains low concentrations of Cr and Si. The mechanism of superior high‐temperature oxidation resistance of CF–PHS compared to 22MnB5 at 1000–1150 °C reveals that the existence of FeCr2O4 and Fe2SiO4 inhibits the diffusion of Fe2+ and O2−, effectively hindering the oxidation progress. Moreover, the oxidation resistance of the CF–PHS at 1200 °C deteriorates owing to the melting of Fe2SiO4 at 1200 °C, which significantly accelerates the diffusion of Fe2+ and O2−, thus exacerbating the oxidation of CF–PHS.

Impact of Deep Seawater on the Electrochemical Corrosion Performance of Hypoeutectic, Eutectic and Hypereutectic Al-Si Automotive Alloys

Corrosion of aluminum alloys is a significant concern for shipbuilders to ensure the longevity of ocean vessels and equipment. Hence, the study aims to evaluate the corrosion performance of Al-Si as automotive alloys with varying concentrations of Si in deep seawater using electrochemical impedance spectroscopy and potentiodynamic polarization techniques. The surface condition prior to corrosion, as well as after corrosion, is analyzed using optical and scanning electron microscopy. The entire test is performed at an ambient condition. The results demonstrate that the corrosion resistance improves in alloys with increasing amounts of Si near the eutectic level, after which the corrosion protection deteriorates. Higher Si concentrations show higher values for polarization resistance and open circuit potential. In contrast, corrosion current and corrosion rate values decrease with increasing Si concentration up to eutectic composition. Si assists the formation of SiO2 and MgO films through Mg2Si intermetallics along with the Al2O3 on the surfaces, which aids in corrosion resistance. Optical and scanning electron micrographs reveal the presence of films on the surfaces after corrosion, which exhibit pits and pinholes on the surfaces of the alloys with lower Si concentrations. Hypereutectic alloy is affected by corrosion of its pinhole-like defects. The corresponding EDS analysis also confirms the protective layer of different oxides on the surfaces.

Is there silicon in flowers and what does it tell us?

The emergence of flowers marked an important development in plant evolution. Flowers in many species evolved to attract animal pollinators to increase fertilisation chances. In leaves, silicon (Si) discourages herbivores, for example by wearing down mouthparts. Flowers are essentially modified leaves and hence may also have the capacity to accumulate Si. If Si in flowers discourages animal visitors as it does in leaves, Si accumulation may be disadvantageous for pollination. Whether flowers accumulate Si, and what the implications may be, was not known for many species. We analysed leaves and flowers of different taxa, separated into their different anatomical parts. Flowers mostly have low Si concentrations in all parts (mean ± SE of BSi in mg g-1 was 0.22 ± 0.04 in petals, 0.59 ± 0.24 in sepals, 0.14 ± 0.03 in stamens, 0.15 ± 0.04 in styles and stigmas and 0.37 ± 0.19 in ovaries for a subset of 56 species). In most cases, less Si was accumulated in flowers than in leaves (mean ± SE of BSi in mg g-1 was 1.51 ± 0.55 in whole flowers vs. 2.97 ± 0.57 in leaves in 104 species) though intriguing exceptions are found, with some species accumulating more Si in flowers than leaves. The large variation in concentration among flowers across the taxa examined, with a particularly high concentration in grass inflorescences, tantalisingly suggests differences in the use of Si for flowers across plant groups. We conclude that the study of the functions of Si for flowers warrants more attention, with pollination strategy a potential contributing factor.

Effects of silicon supplementation on growth and silicon accumulation in tall fescue (Festuca arundinacea) and bentgrass (Agrostis stolonifera)

Previous studies of the benefits of silicon (Si) supplementation in turfgrass have had inconsistent results. This study assessed the effect of Si supplementation on biomass production and Si accumulation of tall fescue (Festuca arundinacea) and bentgrass (Agrostis stolonifera). Plants were grown in buffered Hoagland’s media (pH 6) with four sodium silicate (Na2SiO4) treatments (0, 0.5, 1, 2, and 4 mM Si). The two species responded differently to Si supplementation in terms of biomass. For bentgrass, biomass was enhanced by Si supplementation, but only significantly (p < 0.05) at the highest concentration (4 mM Si). Lower Si concentrations (0.5, 1, and 2 mM Si) significantly increased biomass in tall fescue compared to control, but there was no increase in biomass at 4 mM Si. There was a positive linear relationship between Si concentrations in media and Si concentrations in tissue. At 4 mM Si, the Si concentrations in aboveground tissue of tall fescue and bentgrass averaged 24 and 30.5 g kg−1 dry mass, respectively. Elevated Si concentrations in growth media promoted formation of silica bodies. The highest Si rates (4 mM Si) resulted in the highest silica body areal coverage in leaves of both species. We observed two silica body morphologies (which we termed long and barbed). Our findings indicate that tall fescue is likely to benefit from Si supplementation when soil pore water dissolved Si is below 0.5 mM, but increases in soil pore water dissolved Si above 2 mM are unlikely to increase biomass. In contrast, benefits in bentgrass may only be realized if dissolved Si in pore water is increased to 4 mM.

Effect of Si on the hydrogen-based direct reduction of Fe2O3 studied by XPS of sputter-deposited thin-film model systems

Understanding the effect of gangue elements is of critical importance to optimize the efficiency of hydrogen-based direct reduction (HyDR) of iron ore, as one of the key steps towards climate-neutral steel production. Here, we demonstrate on the example of Si-doped Fe2O3, how thin films can be effectively utilized as a model system to facilitate systematic investigation of the solid-state reduction behavior. In-vacuo X-ray photoelectron spectroscopy (XPS) is used to probe the reduction kinetics by analyzing the chemical state of iron oxide thin films before and after annealing at 700 °C in an Ar+5%H2 atmosphere. It is demonstrated that even low Si concentrations of 3.7 at.% inhibit the HyDR of Fe2O3 by the formation of a SiOx-enriched reduction barrier in the surface-near region.

Coupling Molecular-Scale Spectroscopy with Stable Isotope Analyses to Investigate the Effect of Si on the Mechanisms of Zn-Al LDH Formation on Al Oxide.

While silicate has been known to affect metal sorption on mineral surfaces, the mechanisms remain poorly understood. We investigated the effects of silicate on Zn sorption onto Al oxide at pH 7.5 and elucidated the mechanisms using a combination of X-ray absorption fine structure (XAFS) spectroscopy, Zn stable isotope analysis, and scanning transmission electron microscopy (STEM). XAFS analysis revealed that Zn-Al layered double hydroxide (LDH) precipitates were formed in the absence of silicate or at low Si concentrations (≤0.4 mM), whereas the formation of Zn-Al LDH was inhibited at high silicate concentrations (≥0.64 mM) due to surface-induced Si oligomerization. Significant Zn isotope fractionation (Δ66Znsorbed-aqueous = 0.63 ± 0.03‰) was determined at silicate concentrations ≥0.64 mM, larger than that induced by sorption of Zn on Al oxide (0.47 ± 0.03‰) but closer to that caused by Zn bonding to the surface of Si oxides (0.60-0.94‰), suggesting a presence of Zn-Si bonding environment. STEM showed that the sorbed silicates had a close spatial coupling with γ-Al2O3, indicating that >Si-Zn inner-sphere complexes (">" denotes surface) likely bond to the γ-Al2O3 surface to form >Al-Si-Zn ternary inner-sphere complexes. This study not only demonstrates that dissolved silicate in the natural environment plays an important role in the fate and bioavailability of Zn but also highlights the potential of coupled spectroscopic and isotopic methods in probing complex environmental processes.

Structural investigation of ZrN+Si3N4 thin films co-deposited by magnetron sputtering

ABSTRACT Zirconium silicon nitride thin films with 1.6% Si addition were deposited via reactive magnetron sputtering and characterized by RBS, SEM-FEG, GAXRD, XPS and high temperature oxidation tests, aiming to investigate how silicon is structurally inserted in Zirconium nitride (ZrN) matrix. GAXRD results show a reduction in lattice parameter and grain size due to Si incorporation and XPS analyses demonstrate Si is present only in nitride form. Such observations proved the non-formation of substitutional or interstitial solid solution in ZrN, but the presence of Si3N4, even in low Si concentrations.

Dolomitization Mechanism in the Chorgali Formation (Eocene), Pakistan: Evidences from Field observations, Petrography, Mineralogical and SEM analysis

The subject of dolomite formation has always put researchers in the challenge. In this study, the origin of the dolomites of the Chorgali Formation near Chorgali Pass was explored through field observation, petrographic characteristics, mineralogical and geochemical analysis. Analytical analyses used in the present studies include XRD, SEM-EDS, and stable isotopes studies. The dolomites were categorized into three major genetic types based on their textural and structural features showing their distinct origins. These dolomites are named fine crystalline dolomite (Df), medium crystalline dolomite (Dm), and coarse crystalline dolomite (Dc). The analytical approaches linked with field observations and petrographic examinations identified that; the first type of dolomites (i.e., Df) is related to the early stage of diagenesis and contain the presence of mineral dolomite (40%), gypsum (27%), quartz (17%) and albite (16%) and are low stochiometric low ordered in character as recognized by XRD results. The SEM-EDS analysis identified low Mg, Ca, O, Na, Si, and Fe concentrations. Further, the stable isotopes (δ18O) values for Df (i.e., -5.95 to -396‰V-PDB) are less depleted. Moreover, Dm and Dc revealed 100% mineral dolomite and are stochiometric ordered dolomites. High concentrations of Mg, Ca and O are observed in Dm and Dc respectively. Stable isotopes (δ18O) result in exhibiting highly depleted values for Dm (-7.947‰V-PDB) and Dc (-9.227 to -8.302‰V-PDB) showing its formation with the elevated temperature at depth. In addition, δ13C values of Df, Dm, and Dc lie in the range of the original marine signature of Eocene times.

Synthesis of a novel MoSS+Mo5SiB2+Mo5Si3 based Mo–Si–B alloy and its enhanced fracture toughness

Mo–Si–B based alloys are promising ultrahigh-temperature structural materials for turbine blades. Different from traditional MoSS (Mo solid solution)+Mo5SiB2+Mo3Si based alloy, present paper focuses on a novel non-equilibrium MoSS + Mo5SiB2+Mo5Si3 based alloy, which shows more potential for excellent comprehensive performance. This alloy was synthesized by SPS (spark plasma sintering) technique using pure Mo and Mo5SiB2+Mo5Si3 powders as raw materials. SEM, EDS, XRD, EPMA, single-edge notched bending and nano-identation tests were used to reveal the formation mechanism of this alloy and evaluate its fracture toughness. The results showed that this MoSS + Mo5SiB2+Mo5Si3 based alloy was composed of MoSS, Mo5SiB2, Mo5Si3 and a little Mo3Si. Mo5SiB2+Mo3Si halos were found around the original Mo5SiB2+Mo5Si3 particles as a result of inter-diffusion between Mo and Mo5SiB2+Mo5Si3 during sintering processes. Compared with traditional cast or reaction sintered MoSS + Mo5SiB2+Mo3Si based alloy with the same composition, this MoSS + Mo5SiB2+Mo5Si3 based alloy showed superior fracture toughness benefiting from its higher MoSS content, larger coarseness of MoSS and lower Si concentration in MoSS.

The Theoretical Study of Unexpected Magnetism in 2D Si-Doped AlN

In this study, the structural and magnetic properties of Si-doped bulk and 2D AlN were systematically investigated by first-principles calculations. Si atoms prefer to substitute Al atoms in both bulk and 2D AlN under N-rich growth conditions. In bulk AlN, Si dopants exhibit a non-magnetic state, uniform distribution, and a strong anisotropic diffusion energy barrier. In contrast to that, Si dopants prefer to form a buckling structure and exhibit a magnetic moment of 1 μB in 2D AlN. At a low Si concentration, Si atoms tend to get together with antiferromagnetic coupling between each other. However, the magnetic coupling among Si atoms changes to ferromagnetic coupling as Si concentration increases, due to the enhanced exchange splitting and delocalized impurity states. At the extreme doping limit, monolayer SiN, along with its analogs GeN and SnN, is a ferromagnetic semiconductor with a large band gap and high Curie temperature. These results indicate that 2D AlN doped by group IV atoms has potential applications in spintronic devices.

A pericycle-localized silicon transporter for efficient xylem loading in rice.

Rice is able to accumulate high concentrations of silicon (Si) in the shoots, and this ability is required for the mitigation of abiotic and biotic stresses. Although transporters for Si uptake have been identified, a transporter for the xylem loading of Si has not been found. We functionally characterized a Si transporter, OsLsi3, in terms of tissue-specific localization, knockout line phenotype and mathematic simulation. OsLsi3 was shown to be an efflux Si transporter. OsLsi3 was mainly expressed in the mature root region, and its expression was downregulated by Si. Immunostaining with a specific antibody showed that OsLsi3 was localized to the pericycle in the roots, without polarity. However, when it was expressed under the control of the OsLsi2 promoter, OsLsi3 became polarly localized to the proximal side of both the exodermis and endodermis. Knockout of this gene resulted in decreased Si uptake and concentration in the xylem sap under low Si supply, but not under high Si supply. Mathematical modeling showed that localization of OsLsi3 to the pericycle accounts for c. 30% of the total Si loading to the xylem under low Si concentrations. In summary, OsLsi3 was involved in the xylem loading of Si in rice roots, which is required for the efficient root-to-shoot translocation of Si.

Si, P, S and Se surface additives as catalytic activity boosters for dehydrogenation of methylcyclohexane to toluene - A liquid organic hydrogen carrier system: Density functional theory insights

The controlled or optimized loading of sulfur (S) on a catalyst surface has been credited with boosting the catalytic activity of the catalyst. This is because the S binds strongly to the surface of the catalyst hence blocking other catalyst poisons such as CO and unwanted reaction intermediates from docking at the active sites. Using density functional theory calculations with van der Waals corrections, we investigated Si, P and Se surface additives as catalytic activity boosters, in addition to S. Different surface additive concentrations were considered (n = 0, 1, 2, 3, 4 — equivalent to 0, 0.2, 0.4, 0.6, 0.8 wt%). The calculated reaction energies for the full dehydrogenation of methylcyclohexane (MCH) to toluene revealed that at lower concentrations of Si, P, S and Se as surface additives, n = 1 (∼0.2 wt%) and n = 2 (∼0.4 wt%), all these surface additives reduced the overall MCH dehydrogenation reaction energy by about 40% on the Pt (111) surface. Increasing the additive concentration to n = 4 (∼0.8 wt%) yielded reaction energies of the same order of magnitude as obtained with a pristine Pt (111) surface. Our results revealed that Si, P and Se surface additives can also boost the catalytic activity of catalysts, in the same manner as S does.

Magnetic Phase Diagram of the MnxFe2-xP1-ySiy System.

The phase diagram of the magnetocaloric MnxFe2−xP1−ySiy quaternary compounds was established by characterising the structure, thermal and magnetic properties in a wide range of compositions (for a Mn fraction of 0.3 ≤ x < 2.0 and a Si fraction of 0.33 ≤ y ≤ 0.60). The highest ferromagnetic transition temperature (Mn0.3Fe1.7P0.6Si0.4, TC = 470 K) is found for low Mn and high Si contents, while the lowest is found for low Fe and Si contents (Mn1.7Fe0.3P0.6Si0.4, TC = 65 K) in the MnxFe2−xP1−ySiy phase diagram. The largest hysteresis (91 K) was observed for a metal ratio close to Fe:Mn = 1:1 (corresponding to x = 0.9, y = 0.33). Both Mn-rich with high Si and Fe-rich samples with low Si concentration were found to show low hysteresis (≤2 K). These compositions with a low hysteresis form promising candidate materials for thermomagnetic applications.

Exploiting eutectic formation and phase separation to produce plasmonic metamaterials

Novel Au mesostructures with a polyhedron shape, henceforth referred to as pyramids, are produced by annealing in vacuo an Au thin film on a Si(100) substrate. Gold diffusion and incorporation into pyramids is a function of the thickness of the Au film, the annealing temperature, and the vacuum pressure. The Au pyramids have unique surface morphologies due to the presence of channels and plateaus, where channels are cut into the surface of the pyramids and plateaus are the surfaces between adjacent channels. The bulk of the pyramids consists of Au with cavities that are devoid of Au or Si. Normalized energy dispersive spectroscopy of intact regions of the surface are 98.1 wt. % Au and 1.9 wt. % Si, while the bottom of the channels are 85.7 wt. % Au and 14.3 wt. % Si. Therefore, one step in the growth process is the formation of an Au–Si eutectic. The low concentration of Si in the solid regions of the pyramid and its high concentration in the walls of the cavities are indicative of phase separation of the Au–Si eutectic. The pyramids are oriented in the same direction relative to one another and are a consequence of eutectic formation-induced etching of the Si(100) surface. The scattering spectrum (non-specular reflectivity) of the Au pyramids consists of two very strong surface plasmon polariton states that correspond to excitation from the Au d-bands to the sp conduction bands. The surface morphology produces linearly polarized reflected light.

Novel strategies to grow natural fibers with improved thermal stability and fire resistance

This study aims to produce natural grown fungi fiber with improved thermal stability and fire resistance. A novel strategy was explored by supplying nutrition enriched with silicon source. The results showed that Si enrichment improved the thermal stability of fungi fiber, possibly due to the thermally stable Si being utilized for fungi cell wall construction. Meanwhile, while nutrition enriched with low Si concentration accelerated fungi fibers production, further increases in Si concentration inhibited the fungal growth. These were attributed to the effects of Si and pH and on fungal metabolism, which was verified by Fourier Transform Infrared (FTIR) and Scanning Electron Microscope/Energy Dispersion Spectroscopy (SEM/EDS) microstructural characterization. Based on experimental observations, the study further investigated two strategies to facilitate fungi to utilize more Si in the fiber construction to enhance its fire resistance, i.e., application of pH buffer and selection of a new fungi strain with higher Si tolerance (Fusarium oxysporum). Both strategies achieved favorable results. Performance wise, fibers produced by both fungi Pleurotus ostreatus and Fusarium oxysporum featured higher residual weights than synthetic PVA fiber (by 2122% and 2223% respectively by Thermogravimetric Analysis (TGA)). Furthermore, with Si source enrichment, the fire resistance of fungi fibers improved further. For example, adding 3% Si to the nutrition of Fusarium oxysporum increased the TGA residual weight of its fiber by 93.81% compared with fiber grown without Si enrichment. Besides, Si enrichment reduced the peak heat release rate and the total heat of combustion of the produced fungi fiber by 50% and 35.09% respectively as measured by Microscale Combustion Calorimetry (MCC) test; these are also significantly less than those of the PVA fibers commonly used for building constructions (87.26% and 72.59% respectively), indicating improved fire resistance.

Outstanding performance of Si-bilayer graphene using first-principle computation: Significant effects of Si atoms configuration

We theoretically investigate silicon doped bilayer graphene, Si-BLG, with different stoichiometry of Si-BLG structures. The dangling bonds of C-Si atoms are found at low concentration ratio of Si atoms inducing sp3-hybridization of buckled pattern in the structure. The Si-BLG with dangling bonds revel strong mechanical response at low strain of a uniaxial load, and the fracture strain is seen at low strain ratio. The sp3-hybridization forms a small bandgap which induces an intermediate thermal and optical response of the system. In contrast, at higher Si concentration ratio, the Young modulus and fracture strain are increased comparing to the low Si concentration ratio. This is due to presence of high number of C-Si bonds which have a high tolerant under uniaxial load. In addition, a relatively larger bandgap or an overlap between valence and conduction bands are found depending on the Si configurations. In the presence of gaped Si-BLG, the thermal and optical response are high. We thus obtain a high Seebeck coefficient and a figure of merit with low electronic thermal conductivity which are useful for thermoelectric nanodevices. Furthermore, an enhancement of optical response is obtained with a redshift in the visible range for the Si-BLG structures.