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In this article, we have developed the mixed virtual element formulation for the nonlocal parabolic problem. A priori error estimates for the semi‐discrete and the fully‐discrete schemes are derived and analyzed. The spatial discretization is based on the mixed virtual element framework, and the backward Euler method is used for the time discretization. Using Brouwer's fixed point argument, we have proved the existence and uniqueness of a fully‐discrete scheme. A set of representative numerical examples investigates such theoretical results. [ABSTRACT FROM AUTHOR]

Role of Silica nanoparticles as feasible advantageous material has already been recognized due to its good thermal, low density, mechanical stability, and chemical inertia whereas industrial by product; fly ash has been also modified with different approaches for better environmental solution in recent times. In this present exertion, initially about ∼20 nm of silica nanoparticles was synthesized and characterized by XRD, Zeta size analyzer, TEM, and Fourier Transformed Infrared spectra (FTIR) spectroscopy. Furthermore, the synthesized silica NPs was impregnated in fly ash to synthesize the Faujasite materials at 50°C while various characterizations techniques (XRD, FTIR, SEM equipped with EDS) explore the developed Faujasite material are in nanodimensioned (∼200 nm) cubical shaped. The heavy metal (Lead, Chromium, and Cobalt) adsorption and degradation of dyes (Methylene blue and Methyl red) were investigated by varying different parameters (i.e., pH, temperature, Contact time, amount of Faujasite, initial concentrations of solutions). Minimum amount (1 g) of Faujasite is adequate to adsorb the heavy metal at pH 5.0 in contact time 120 min at >35°C temperature and only 20 mg of Faujasite is considered as the optimizing value for photocatalytic activity at the similar condition. Such observations suggest budgetary and ecofriendly aspects to exploit the vast resources of fly ash along with silica NPs for wastewater treatment. © 2018 American Institute of Chemical Engineers Environ Prog, 38: S15–S23, 2019 [ABSTRACT FROM AUTHOR]

In this article, we discuss and analyze new conforming virtual element methods (VEMs) for the approximation of semilinear parabolic problems on convex polygonal meshes in two spatial dimension. The spatial discretization is based on polynomial and suitable nonpolynomial functions, and a Euler backward scheme is employed for time discretization. The discrete formulation of both the proposed schemes—semidiscrete and fully discrete (with time discretization) is discussed in detail, and the unique solvability of the resulted schemes is discussed. A priori error estimates for the proposed schemes (semidiscrete and fully discrete) in H1‐ and L2‐norms are derived under the assumption that the source term f is Lipschitz continuous. Some numerical experiments are conducted to illustrate the performance of the proposed scheme and to confirm the theoretical convergence rates. [ABSTRACT FROM AUTHOR]

Geopolymer concrete is an inorganic polymer composite which has the potential to build an eco‐friendly and sustainable construction by replacing the existing conventional concrete. Herein, cement is totally replaced by mineral admixtures rich in aluminosilicates such as fly ash and is formed by the alkali activation using alkaline activator solutions, such as sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). Fly ash, a waste material from industry, can be incorporated in the manufacture of geopolymer concrete. The replacement of cement by fly ash in geopolymer concrete reduces the huge energy consumption and restricts carbon dioxide emission to the atmosphere during its production. In this paper, experimental investigations have been carried out involving the variation of total aggregate content (viz., 74, 76, 78, 80, and 82%), NaOH concentration (8, 10, 12, and 14 M), and curing temperature (60, 70, 80, 90, and 100°C) on the strength of geopolymer concrete by keeping a constant alkaline liquid to fly ash ratio of 0.45 and a 24‐hour rest period. It is concluded that 76% of total aggregate content is suitable for producing geopolymer concrete without hindering the workability. Further, strength of geopolymer concrete has been found to be increased at 90°C having 12 M NaOH concentration. [ABSTRACT FROM AUTHOR]