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Volumen 8, Asunto 4 (2021)

Editorial

Intramolecular interactions in paracyclophanes

Birsa M L

Since its discovery in 1949 by Brown and Farthing, paracyclophane has been intensely studied by chemists. Consisting of two benzene rings bound together by two ethano bridges, the paracyclophane core can undergo chemical transformations specific to both aliphatic and aromatic compounds, resulting in a wide variety of functionalized paracyclophanes. Because of the rigid molecular framework provided by the paracyclophane moiety and its short interannular distance, functional groups in pseudo-geminally substituted paracyclophanes are often held in such a position as to allow highly specific reactions to take place between them. Both the parent hydrocarbon and its derivatives have been used in asymmetric catalysis, optoelectronics and polymer synthesis. Acetylene-substituted paracyclophanes are important because of the ability of the acetylene moiety to easily undergo coupling and addition reactions, leading to new derivatives that contain one or more units of the paracyclophane core. Orthogonal π-bridges have been introduced into paracyclophanes by the reaction of the pseudo-geminal bisacetylene with various monoacetylenes and nitriles. Mono, pseudo-gem and pseudo-para ethynylcyclophanes and bis(azides) have been employed as addition partners in CuAAC reactions to design and build complex extended molecular scaffolds. The reactivity of the resulting triazoles was investigated under photochemical conditions. A variety of newly substituted paracyclophanes were identified; deazotization of pseudo-gem and pseudo-para adducts provided indolophane derivatives. A photochemical rearrangement from a pseudo-para adduct to a pseudo-ortho product was identified.

Editorial

Hydraulics assumptions for the computation of electrical conductivity of flowing human blood

Katrin Ellermann

Nevertheless, some assumptions may cause invalid or inaccurate results. supported a worldwide sensitivity analysis, this work shows which fluid mechanical assumptions are incorrect and will be avoided. Moreover, positive effects supported accurate rheological modelling of the fluid properties are shown, and therefore the factors with a decisive influence on the computed conductivity change of flowing blood are illustrated.

Editorial

Nano biotechnology

Jae-Seong Lee

Nano biotechnology, bio nanotechnology, and Nano biology are terms that ask the intersection of nanotechnology and biology. As long as the topic is one that has only emerged very recently, bio nanotechnology and Nano biotechnology function blanket terms for various related technologies.

Editorial

Fundamentals of Fluid Mechanics

David A. Rubenstein

Fluid mechanics is that the study of fluids at rest and in motion. A fluid is defined as a cloth that continuously deforms under a continuing load. There are five relationships that are most useful in hydraulics problems: kinematic, stress, conservation, regulating, and constitutive. The analysis of hydraulics problems are often altered counting on the selection of the system of interest and therefore the volume of interest, which govern the simplification of vector quantities. By assuming that a fluid may be a continuum, we make the idea that there are not any in homogeneities within the fluid. Viscosity relates the shear rate to the shear stress. Definition of a fluid as Newtonian depends on whether the viscosity is constant at various shear rates. Newtonian fluids have constant viscosities, whereas non-Newtonian fluids have a nonconstant viscosity. for many bio fluid applications, we'll assume that the fluid is Newtonian.

Editorial

Fluid dynamic

Shaik. Akbar

In physics and engineering, fluid dynamics is a sub discipline of fluid mechanics that describes the flow of fluids—liquids and gases. It has several sub disciplines, including aerodynamics (the study of air and other gases in motion) and hydrodynamics (the study of liquids in motion). Fluid dynamics has a wide range of applications, including calculating forces and moments on aircraft, determining the mass flow rate of petroleum through pipelines, predicting weather patterns, understanding nebulae in interstellar space and modelling fission weapon detonation.

Fluid dynamics offers a systematic structure—which underlies these practical disciplines—that embraces empirical and semi-empirical laws derived from flow measurement and used to solve practical problems. The solution to a fluid dynamics problem typically involves the calculation of various properties of the fluid, such as flow velocity, pressure, density, and temperature, as functions of space and time. Before the twentieth century, hydrodynamics was synonymous with fluid dynamics. This is still reflected in names of some fluid dynamics topics, like magneto hydrodynamics and hydrodynamic stability, both of which can also be applied to gases.

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