Facile synthesis of Schiff and Mannich bases of isatin derivatives

We report herein on the synthesis of some isatin Schiff’s bases (1–11), which were prepared from the reaction of isatin and some aromatic amines. These in turn were converted to the corresponding Mannich bases (12-23) by reaction with a number of secondary amines and formaldehyde, taking advantage of the active –NH group in the isatin. The structures of these compounds were elucidated using standard spectroscopic and analytical methods

Comparative performance of complex-valued B-spline and polynomial models applied to iterative frequency-domain decision feedback equalization of Hammerstein channels

Complex-valued (CV) B-spline neural network approach offers a highly effective means for identifying and inverting practical Hammerstein systems. Compared with its conventional CV polynomial-based counterpart, a CV B-spline neural network has superior performance in identifying and inverting CV Hammerstein systems, while imposing a similar complexity. This paper reviews the optimality of the CV B-spline neural network approach. Advantages of B-spline neural network approach as compared with the polynomial based modeling approach are extensively discussed, and the effectiveness of the CV neural network-based approach is demonstrated in a real-world application. More specifically, we evaluate the comparative performance of the CV B-spline and polynomial-based approaches for the nonlinear iterative frequency-domain decision feedback equalization (NIFDDFE) of single-carrier Hammerstein channels. Our results confirm the superior performance of the CV B-spline-based NIFDDFE over its CV polynomial-based counterpart

Higher‐Order Topological Band Structures

The interplay of topology and symmetry in a material's band structure may result in various patterns of topological states of different dimensionality on the boundary of a crystal. The protection of these “higher‐order” boundary states comes from topology, with constraints imposed by symmetry. Herein, the bulk–boundary correspondence of topological crystalline band structures, which relates the topology of the bulk band structure to the pattern of the boundary states, is reviewed. Furthermore, recent advances in the K‐theoretic classification of topological crystalline band structures are discussed

Influence of Operational Parameters on Photocatalytic Degradation of Linuron in Aqueous TiO2 Pillared Montmorillonite Suspension

TiO2 pillared clay was prepared by intercalation of titan polyoxocation into interlamelar space of an Algerian montmorillonite and used for the photocatalytic degradation of the linuron herbicide as a target pollutant in aqueous solution. The TiO2 pillared montmorillonite (Mont-TiO2) was characterized by X-ray photoelectron spectroscopy (XPS), X-Ray diffraction (XRD), X-Ray fluorescence (XRF), scanning electronic microscopy (SEM), thermogravimetry and differential thermal analysis (TG-DTA), Fourier transformed infra-red (FT-IR), specific area and porosity determinations. This physicochemical characterization pointed to successful TiO2 pillaring of the clay. The prepared material has porous structure and exhibit a good thermal stability as indicated by its surface area after calcination by microwave. The effects of operating parameters such as catalyst loading, initial pH of the solution and the pollutant concentration on the photocatalytic efficiency and COD removal  were evaluated. Under initial pH of the solution around seven, pollutant concentration of 10 mg/L and 2.5 g/L of catalyst at room temperature, the degradation efficiency and COD removal of linuron was best then the other operating conditions. It was observed that operational parameters play a major role in the photocatalytic degradation process. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Experimental Investigation on Spray Characteristics of Waste Cooking Oil Biodiesel/Diesel Blends at Different Injection Parameters

Biodiesel is a promising alternative solution for the energy crisis, as it is renewable, biodegradable, non - toxic and it has a fully competitive edge with petrol diesel in most technical aspects. Because of the increasing global request for diesel fuel consumption, consumption of non-renewable fossil fuels, exhaust emissions, all these led to search about alternative fuels. Biodiesel is one of the potential alternatives for depleting fossil fuels. Biodiesel fuel is an eco-friendly and renewable source of energy. Biodiesel fuel is an eco-friendly and renewable source of energy. Biodiesel is one of the best solutions and alternatives available to all countries of the world. Inedible plants and vegetable oils such as Jatropha oil, Karanji Pongamia oil, Neem oil, Jojoba oil, Cottonseed oil, Linseed oil, Mahua oil, Deccan hemp oil, Kusum oil, Orange oil, and Rubber seed oil were used as biodiesel in diesel engine. Biodiesel is produced by chemical methods from vegetable oils, but the use of vegetable oils is a high cost.Scientists searched for other sources and at the same time has a low cost. They found that waste cooking oil is the ideal solution to that problem. Four methods to minimize the high viscosity of vegetable oils to enable their use in common diesel engines without operational problems such as engine charges have been investigated: blending with petro diesel, pyrolysis, microemulsification (solvent blending), and transesterification. Transesterification is by far the most common method. Only the transesterification reaction leads to the products commonly known as biodiesel, i.e., alkyl esters of oils and fats. Biodiesel was produced from waste Cooking-oil by transesterification process have been applied for most countries to improve and raise the national energy return. Blends of WCOB and diesel were used instead of pure diesel fuel in diesel engine. However, the spray characteristic of the injected fuel depends on different parameters such as fuel injection pressure, the temperature of the injected fuel, ambient pressure, fuel viscosity, and fuel density.In internal combustion engines, such as the diesel engine used to conduct the experiment, a 20 mm window and a transparent glass box are used to facilitate the visualization of spray characteristics. The spray characteristics of the diesel/ waste cooking oil biodiesel blends fuel were studied experimentally at different injection pressure and temperature. Spray characteristics of biodiesel WCOB / diesel under various injection pressures of 150 to 300 bar and injection temperature of 25 to 275 ºC have been measured and illustrated by sparing the fuel blends in a surrounding area using a high-speed Digital camera. In this work, the biodiesel/diesel blend of B40D60 has been tested. The experimental data shows the WCOB biodiesel of B40D60 gives longer spray tip penetration and spray angle are smaller than those of diesel fuels at different pressure and temperature

An Investigation Into The Relationship Between The Implementation of Lean Manufacturing and Energy Efficiency in Industrial Organizations

Abstract: There is a general acceptance in literature that implementing lean manufacturing is concerning the effective utilization of available resources. Thus, it is argued that lean implementation may enhance, among others, energy efficiency. In accordance