Photoelectrochemical water oxidation kinetics and antibacterial studies of one-dimensional SiC nanowires synthesized from industrial waste

Silicon wafers are significantly utilized in integrated circuits and memory devices for the fabrication of novel semiconductor devices. As a result, a substantial amount of silicon wastes are generated every year. But recycling process of pure silicon waste is expensive with an additional problem related to chemical waste generation. Thus, the possibility of inevitable silicon waste conversion into potential nanostructures is not only beneficial for the semiconductor industry but also resolves current e-waste pollution. Hence, we successfully achieved hexagonal silicon carbide (SiC) nanowires under a strategic combination of waste silicon wafers and graphite powder by robust high-energy ball milling and heat treatment approaches. Structural, morphological, chemical, and optical properties of SiC nanowires are systematically studied by XRD, SEM, TEM, XPS, and optical absorbance. This facile experimental technique recognized the value of SiC nanowire generation for exploring multifunctional photoelectrochemical (PEC) water splitting and antibacterial activity. Accordingly, SiC nanowires achieved a photocurrent density of about 0.21 mA cm⁻² vs. Ag/AgCl, which demonstrates enhanced light absorption capacity under reduced charge carrier recombination. Moreover, SiC nanowires prevailed decrement in the charge carrier resistance (27.53 Ω) under light state compared to the dark state (26.76 Ω). Specifically, potentiodynamic studies revealed superior exchange current density (− 3.17 mA cm⁻²), Tafel slope (80.1 mV dec⁻¹), and limiting diffusion current density (− 1.49 mA cm⁻²) under light state than the dark state. Also, these results are certainly applicable for superior antibacterial activity against E. coli and L. monocytogenes about 90% and 75% under visible light, respectively.

     

Characterisation of temperature-dependent phase transitions in 2,2-trimethylenedioxy- 4,4,6,6-tetrachlorocyclotriphosphazene, N3P3Cl4[O(CH2)3O]

Background  

The crystal structure of 2,2-trimethylenedioxy-4,4,6,6-tetrachlorocyclo triphosphazene has been determined at 120, 274 and 293 K. The result at 293 K confirms the room temperature Cmc2 ₁ structure, but at the lower temperatures the space group is Pna2 ₁. Nevertheless the basic structure remains the same, with only small displacements of the atoms, amounting to an average of 25 pm between 120 and 293 K.     

Vector least-squares solutions for coupled singular matrix equations

The weighted least-squares solutions of coupled singular matrix equations are too difficult to obtain by applying matrices decomposition. In this paper, a family of algorithms are applied to solve these problems based on the Kronecker structures. Subsequently, we construct a computationally efficient solutions of coupled restricted singular matrix equations. Furthermore, the need to compute the weighted Drazin and weighted Moore–Penrose inverses; and the use of Tian's work and Lev-Ari's results are due to appearance in the solutions of these problems. The several special cases of these problems are also considered which includes the well-known coupled Sylvester matrix equations. Finally, we recover the iterative methods to the weighted case in order to obtain the minimum D-norm G-vector least-squares solutions for the coupled Sylvester matrix equations and the results lead to the least-squares solutions and invertible solutions, as a special case.     

On the linear stability study of zonal incompressible flows on a sphere

The normal mode (linear) stability of zonal flows of a nondivergent fluid on a rotating sphere is considered. The spherical harmonics are used as the basic functions on the sphere. The stability matrix representing in this basis the vorticity equation operator linearized about a zonal flow is analyzed in detail using the recurrent formula derived for the nonlinear triad interaction coefficients. It is shown that the zonal flow having the form of a Legendre polynomial P_n(μ) of degree n is stable to infinitesimal perturbations of every invariant set I_m with |m| ≥ n. For each zonal number m, I_m is here the span of all the spherical harmonics $Y^{m}_{k}(x)$, whose degree k is greater than or equal to m. It is also shown that such small-scale perturbations are stable not only exponentially, but also algebraically. © 1998 John Wiley & Sons, Inc. Numer Methods Partial Differential Eq 14: 649–665, 1998     

Aminolysis of P-trichloro-N-dichlorophosphorylmonophosphazene and the crystal structure of 1-(dichlorophosphinyl)-2-chloro-2,2-bis(diisopropylamino)phosphazene

The reactions of Cl₃PN P(O)Cl₂ ( 1 ) with primary and secondary amines have been studied. The following monophosphazenes, (RRN)₃PN P(O)(NRR)₂, and bis(phosphinoyl)amines, [(RRN)₂P(O)]₂NH were isolated: NRR = NHCH₂Ph, Net₂, NH(CH₂)₂CH₃ groups for monophosphazenes, and Net₂, NH(CH₂)₂CH₃ for phosphinoyl amines. The unexpected geminal phosphazene, Cl(RRN)₂PN P(O)Cl₂, {RRN = N[CH(CH₃)₂]₂}, was also obtained in moderate yield. The spectral data (IR, ¹H, ¹³C, and ³¹P NMR, and MS) are presented. The structure of 1-(dichlorophosphinyl)-2-chloro-2,2-bis(diisopropylamino)phosphazene ( 5 ) was determined by X-ray crystallography. The basicities of these and related compounds in nonaqueous nitrobenzene solution were obtained by potentiometric titration.     

Conformational polymorphism in a chiral spiro-cis-ansa-bridged cyclo­triphosphazene derivative

The reaction of spermidine with 2,2,4,4-tetra­chloro-6,6-di­phenyl­cyclo­triphosphazene produces a mixture of products of which one of the fractions is a spiro-cis-ansa deriv­ative, namely 12-chloro-14,14-di­phenyl-2,6,11,13,15,16-hexa­aza-1,12-di­phosphatri­cyclo­[10.3.1.0^1,6]­hexadeca-12,14-diene, C₁₉H₂₆Cl­N₆P₃. Recrystallization of this fraction from different solvents results in the formation of two different crystalline forms. The rod morphology formed in di­chloro­methane–n-hexane (1:1) produces a triclinic structure with three mol­ecules in the asymmetric unit. These three mol­ecules adopt different conformations as a result of two NH groups flipping in an ansa-bridged ring system. The plate morphology crystals, grown in di­chloro­methane–n-hexane–ethyl acetate (1:1:1), produce a C-centred monoclinic structure that adopts a conformation that is essentially the same as one of the forms in the triclinic structure.     

RAFT‐mediated synthesis and temperature‐induced responsive properties of poly(2‐(2‐methoxyethoxy)ethyl methacrylate) brushes

Well‐defined, high‐density poly(2‐(2‐methoxyethoxy)ethyl methacrylate) [poly(MEO₂MA)] brushes were fabricated through a reliable strategy by the combination of self‐assembly of a monolayer of 3‐aminopropyltrimethoxy silane on silicon surface to immobilize 4‐cyano‐4‐(dodecylsulfanylthiocarbonyl)sulfanyl pentanoic acid chain transfer agent and reversible addition‐fragmentation chain transfer‐mediated polymerization of MEO₂MA. The whole fabrication process of the poly(MEO₂MA) brushes was followed by water contact angle, grazing angle‐Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and atomic force microscopy. Characterization of the poly(MEO₂MA) brushes, such as molecular weight and thickness determination, were measured by gel permeation chromatography and ellipsometry, and the grafting density was estimated. The temperature‐responsive property of the poly(MEO₂MA) brushes was further investigated and the result verified the brush‐to‐mushroom phase transition of the poly(MEO₂MA) chains from low to high temperature. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Crosslinking of recycled polyethylene by gamma and electron beam irradiation

Recycling of polymeric materials is usually accompanied by degradation and deleterious properties. Irradiation crosslinking of recycling low density polyethylene by electron beam and gamma rays could be the solution to improve their properties. This paper presents a comparison on the effects of gamma and electron irradiation on virgin and recycled polyethylene. Their mechanical, thermal and chemical properties were analyzed. VPE samples shown higher crosslinking percentages than RPE samples in all range of doses studied, unirradiated RPE samples had higher values on their tensile properties than VPE. Percentage crystallinity was similar in all range of doses studied.     

On pairwise Lindelöf bitopological spaces

In this paper, we shall continue the study of bitopological separation axioms begun by Kelly and obtained some results. Furthermore, we introduce two concepts of pairwise Lindelöf bitopological spaces and the properties for them are established. We also show that a pairwise Lindelöf space is not hereditary property.